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SECTION H:

CLUTCH/TRANSMISSION/DRIVETRAIN:

--Transmission and Middle Gear


TRANSMISSION:

Hopefully, you're reading this section of the catalog just out of intellectual (or morbid) curiosity, and not because you have a transmission problem.....which in fact, is pretty rare with these XJ series engines (except, perhaps, on the XJ1100 models). The trannies are pretty bulletproof, and many "shifting" problems or issues are really caused by worn or improperly adjusted clutch system components, shifter mechanism issues, or shifter drum (the infamous disintegrating primary chain guide problem).

However.........that's not to say that they are infallible, especially on very high-mileage or improperly operated or maintained bikes. Indeed, bikes that jump out of gear, or that won't stay in gear or even go into gear, may be suffering from worn gear "dogs" or "slots" which, taken together, are what act to synchronize and "lock" two gears together while in operation, and thus can cause all sorts of problems when worn.......due to rapid shifting, forceful shifting, or extreme high-torque shifting events.


If you've determined that your transmission problems are caused by gear or fork issues, and feel up to the task, then we can still provide you with some of these GEARS, SHIFT FORKS, and HARDWARE that you'll need. Be aware that while you can replace some of these items with the engine still in the bike, it's a tricky proposition, at best. You really should resign yourself to the fact that the engine needs to come out, the crankcase halves need to be split, and as long as you're doing that level of surgery, you might as well do a partial or full engine rebuild at the same time.............


To add a little more confusion to the whole mix, when you have these types of problems, although they typically manifest themselves on 1st gear (won't go into it) or 2nd gear (won't go in, stay in, or jumps out of), it's not always a problem with the actual "1st Gear" or "2nd Gear" set. Because of the way that these transmissions operate, it may be that the problem is actually caused by the 4th GEAR itself, since the "slots" are on the 1st Wheel Gear and the "dogs" are on the 4th Pinion Gear.......and the interaction of those two gears is what actually puts the transmission in "1st gear".


Confused yet? We certainly hope so, it means you're paying attention! For further information, we suggest you read this extremely well-written article.....although written by and for XS1100 owners, the exact same principles and circumstance apply to all of the XJ-series transmissions:

http://www.xs11.com/xs11-info/tech-tips/repairs/33/107-transmission-overview.html

Further comprehension can be achieved by reviewing this pictorial guide about how XJ transmissions operate:

http://www.xs11.com/xs11-info/tech-...11-transmission-pictures-and-explanation.html


These two fantastic videos show how power gets from your crankshaft, thru the clutch and transmission, and onto to the rear wheel. Although the animations show a chain-driven bike transmission (much like an XJ550 or any of the XJ600 models), the same concepts apply to shaft-driven bikes. Understanding how these seemingly “voodoo” parts operate and interact with each other can help make troubleshooting and repair much simpler.

I’d suggest watching both of them, in the following order (although it may seem “backwards”) to get the best understanding:


How the shifter mechanism and transmission works (and transmits power to the rear wheel):




How the clutch works (and transmits power to the transmission)….shown on 1100 engines; again, just like all of the others work:




And here’s an few un-animated versions, to show you “the real thing”:





Okay, so if your transmission is suffering from any of these problems, then typically this is what the underlying problems are:

FIRST GEAR PROBLEMS:

* bike didn't seem to want to slide into first gear:

The dogs on the 4th pinion gear and slots on the 1st wheel gear can get worn quite significantly (as well as the number 3 shift fork) when wear occurs to these parts, and the previous owner(s) have been holding their foot down on the shift lever during acceleration to keep the bike in first gear. The gears get worn, and the rider compensates by holding the bike in gear by applying pressure to the shifter pedal, which then damages the shift fork itself.

The wear on these items appear to occur most during shifts from neutral to first at a standing position, and during direct 2nd-to-1st gear shifts during deceleration when the shift occurs at too fast of a speed.

Note that these gears are located on the "output shaft" or "countershaft" as it is sometimes referred to.

Solution: replace the worn 1st wheel gear, the worn 4th pinion gear, the shifter fork, or any combination of the three.


SECOND GEAR PROBLEMS:

* the infamous "jumping out of 2nd gear" problem is due to a poor contact area between the dogs on 5th wheel gear, and slots on 2nd pinion gear, both located on the main (or input) shaft (the main or input shaft is the shaft that the entire clutch assembly is bolted to).

Solution: replace the worn 2nd pinion gear or the worn 5th wheel gear, or both.


Of course, some of these issues may be due to something as simple as broken shifter mechanism SPRINGS (see the INTERNAL SHIFTER MECHANISM PARTS:section further above for details) or the dreaded "disintegrating primary chain guide" issue, and it's always best to determine whether a simple problem exists first, before digging into the bowels of the engine case..........


And here’s some good videos showing the proper method of installing ball bearings into engine cases and onto shafts:



and





XJ550 and FJ600 engines:

- the following "pinion" gears and hardware components are located on the main axle shaft (or "input shaft"):

HCP7326 OEM input/main axle shaft 2nd PINION GEAR, for all XJ550, 1984-85 FJ600, 1986-88 FZ600, 1986-90 YX600 Radian, and 1982-83 XS400 RJ/RK engines.
$ 129.95

HCP7325 OEM input/main axle shaft 6th PINION GEAR, for all XJ550, 1984-85 FJ600, 1986-88 FZ600, 1986-90 YX600 Radian engines.
$ 189.95


HCP7327 OEM input/main axle shaft BEARING, right end, use on all XJ550 and 1984-85 FJ600 engines.
$ 64.95

HCP7330 OEM input/main axle shaft BEARING, left end, use on all XJ550 and 1984-85 FJ600 engines.
$ 42.95


HCP7322 OEM input/main axle shaft SPACER WASHER, fitted between the 3rd and 4th/5th pinion gears on all XJ550 and 1984-85 FJ600 engines.
$ 4.95


HCP7323 OEM input/main axle shaft CIRCLIP, fitted between the 3rd and 4th/5th pinion gears on all XJ550 and 1984-85 FJ600 engines.
$ 7.95

HCP7328 OEM input/main axle shaft HALF-CIRCLE CLIP, fitted outside of the bearing at the right end of the shaft on all XJ550 and 1984-85 FJ600 engines.
$ 9.95

HCP7331 OEM input/main axle shaft CIRCLIP, fitted at the left end of the shaft on all XJ550 and 1984-85 FJ600 engines.
$ 5.95


HCP7332 OEM input/main axle shaft OIL NOZZLE, fitted at the left end of the input shaft on all XJ550 and 1984-85 FJ600 engines.
$ 8.95


- the following "wheel" gears and hardware components are located on the output drive axle shaft (or "output shaft"):

HCP7344 OEM output shaft 1st WHEEL GEAR, for all XJ550, 1984-85 FJ600, 1986-88 FZ600, 1986-90 YX600 Radian, and 1982-83 XS400 RJ/RK engines.
$ 239.95

HCP7335 OEM output shaft 2nd WHEEL GEAR, for all XJ550, 1984-85 FJ600, 1986-90 YX600 Radian, and 1982-83 XS400 RJ/RK engines.
$ 149.95

HCP7339 OEM output shaft 3rd WHEEL GEAR, for all XJ550, 1984-85 FJ600, 1986-88 FZ600, 1986-90 YX600 Radian, and 1982-83 XS400 RJ/RK engines.
$ 149.95

HCP7340 OEM output shaft 4th WHEEL GEAR, for all XJ550, 1984-85 FJ600, 1986-88 FZ600, 1986-90 YX600 Radian, and 1982-83 XS400 J/RJ/RK engines.
$ 149.95

HCP7343 OEM output shaft 5th WHEEL GEAR, for all XJ550 and 1982-83 XS400 J/RJ/RK engines.
$ 229.95

HCP7338 OEM output shaft 6th WHEEL GEAR, for all XJ550, 1984-85 FJ600, 1986-88 FZ600, and 1986-90 YX600 Radian engines.
$ 149.95




HCP7330 OEM output shaft BEARING, right end, use on all XJ550 and 1984-85 FJ600 engines.
$ 42.95

HCP7780 OEM output shaft BEARING, left end, use on all XJ550 and 1984-85 FJ600 engines.
$ 47.95


HCP7322 OEM output shaft SPACER WASHER, fitted between the 4th and 5th wheel gears on all XJ550 and 1984-85 FJ600 engines.
$ 4.95

HCP7336 OEM output shaft SPACER WASHER, fitted to the left of the 2nd wheel gear on all XJ550 and 1984-85 FJ600 engines.
$ 6.95

HCP7345 OEM output shaft SPACER WASHER, fitted to the right of the 1st wheel gear on all XJ550 and 1984-85 FJ600 engines.
$ 6.95


HCP7323 OEM output shaft CIRCLIP, fitted between the 4th and 5th wheel gears on all XJ550 and 1984-85 FJ600 engines.
$ 7.95

HCP7328 OEM output shaft HALF-CIRCLE CLIP, fitted between the oil seal and the bearing on the left end of the shaft on all XJ550 and 1984-85 FJ600 engines.
$ 9.95

HCP7331 OEM output shaft CIRCLIP, fitted at the right end of the shaft on all XJ550 and 1984-85 FJ600 engines.
$ 5.95


HCP7332 OEM output shaft OIL NOZZLE, fitted at the right end of the output shaft on all XJ550 and 1984-85 FJ600 engines.
$ 8.95



XJ550 shifter forks:

HCP8493 OEM shifter fork slider bar retaining bracket COUNTERSUNK SCREW, use 1 per engine, torx-drive, fits all XJ550 engines, each:
$ 2.95

HCP22177 Aftermarket shifter fork slider bar retaining bracket COUNTERSUNK SCREW, use 1 per engine, torx-drive, fits all XJ550 engines, each:
$ 2.95

The above screw is the shift fork guide rod retainer bracket screw. There is also another "screw" (actually a threaded stud) which has a central nut, and one side of the stud is threaded, while the other side has a smooth shank:

HCP5068 OEM shifter fork slider bar STOPPER STUD ("SCREW"), use 1 per engine on all XJ550 engines, each:
$ 14.95

HCP506 OEM shifter fork slider bar stopper stud LOCKWASHER, use 1 per engine, phillips-drive, fits all XJ550 engines, each:
$ 4.95




XJ650, XJ700, XJ750, and XJ900RK engines:

- the following "pinion" gears and hardware components are located on the main axle shaft (or "input shaft"):

HCP7774 OEM input/main axle shaft 4th PINION GEAR, for all XJ650, XJ700, XJ750, all XJ900RK, RL, N/FN, and F engines.
$ 129.95

HCP7776 OEM input/main axle shaft 5th PINION GEAR, for all XJ650, XJ700, XJ750, all XJ900RK, RL, N/FN, and F engines.
$ 149.95


HCP7778 OEM input/main axle shaft BEARING, left end, use on all XJ650, XJ700, XJ750, and all XJ900RK, RL, and N/FN engines.
$ 39.95

HCP19257 Aftermarket input/main axle shaft BEARING, left end, use on all XJ650, XJ700, XJ750, and all XJ900RK, RL, and N/FN engines.
$ 24.95


HCP13940 OEM input/main axle shaft BEARING, left end, used in XJ900F engines.
$ 29.95

HCP19280 Aftermarket input/main axle shaft BEARING, left end, used in XJ900F engines.
$ 19.95


HCP7780 OEM input/main axle shaft BEARING, right end, use on all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F engines.
$ 47.95


HCP7322 OEM input/main axle shaft SPACER WASHER, fitted between the 2nd/3rd pinion gears and the 4th pinion gear on all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F engines.
$ 4.95

HCP7345 OEM input/main axle shaft SPACER WASHER, fitted to the left end of the shaft, just inside the support bearing, on all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F engines.
$ 6.95


HCP7323 OEM input/main axle shaft CIRCLIP, fitted between the 2nd/3rd and 4th pinion gears on all XJ650, XJ700, XJ750, all XJ900RK, RL, N/FN, and F engines.
$ 7.95

HCP7328 OEM input/main axle shaft HALF-CIRCLE CLIP, fitted on the right end of the shaft on all XJ650, XJ700, XJ750, and XJ900RK engines. NOTE: all XJ650 (except Turbo) engines is shown as using only 1 of these clips, but we believe that is wrong, and just like all of the engines in these models, they should use 2 of these clips. All XJ650 Turbo, XJ700, XJ750, all XJ900RK, RL, N/FN, and F engines are specified to use 2 of these clips. Each:
$ 9.95

HCP7777 OEM input/main axle shaft CIRCLIP, fitted on the left end of the shaft, just inside the support bearing, on all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F engines.
$ 2.95


- the following "wheel" gears and hardware components are located on the output drive axle shaft (or "counter-shaft"):

HCP7790 OEM output/counter-shaft 1st WHEEL GEAR, for all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F engines.
$ 109.95

HCP7804 OEM output/counter-shaft 2nd WHEEL GEAR, for all XJ650 and air-cooled XJ750 engines. NOTE: only fits 1981-later 650 engines with engine case number higher than 114697, or 650 Midnight Maxim models with engine case number higher than 002134.
$ 199.95

HCP7803 OEM output/counter-shaft 2nd WHEEL GEAR, for all XJ700, water-cooled XJ750-X, and all XJ900RK, RL, N/FN, and F engines. This gear will fit in place if HCP7804 above and is of a higher strength material.
$ 109.95

HCP7806 OEM output/counter-shaft 3rd WHEEL GEAR, for all 1980 and early 1981 XJ650 engines. NOTE: only fits 1981-later 650 engines with engine case number lower than 114697, or 650 Midnight Maxim models with engine case number lower than 002134.
$ 169.95

HCP7807 OEM output/counter-shaft 3rd WHEEL GEAR, for all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F engines. NOTE: only fits 1981-later 650 engines with engine case number higher than 114697, or 650 Midnight Maxim models with engine case number higher than 002134.
$ 79.95

HCP7789 OEM output/counter-shaft 4th WHEEL GEAR, for all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F engines.
$ 149.95

HCP7809 OEM output/counter-shaft 5th WHEEL GEAR, for all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F engines. NOTE: only fits 1981-later 650 engines with engine case number higher than 114697, or 650 Midnight Maxim models with engine case number higher than 002134.
$ 199.95


HCP7814 OEM output/counter-shaft BEARING, left end, use on all XJ650 (except Turbo) and all XJ750 air-cooled engines.
$ 89.95


HCP7815 OEM output/counter-shaft BEARING, left end, use on all XJ650 Turbo, all XJ700, all water-cooled XJ750-X, and all XJ900RK, RL, N/FN, and F engines.
$ 29.95

HCP19259 Aftermarket output/counter-shaft BEARING, left end, use on all XJ650 Turbo, all XJ700, all water-cooled XJ750-X, and all XJ900RK, RL, N/FN, and F engines.
$ 24.95



HCP7813 OEM output/counter-shaft BEARING, right end, use on all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F engines.
$ 42.95

HCP19258 Aftermarket output/counter-shaft BEARING, right end, use on all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F engines.
$ 29.95


HCP7812 OEM output/counter-shaft SPACER WASHER, fitted between the 1st wheel and 4th wheel gears on all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F engines.
$ 2.95

HCP7322 OEM output/counter-shaft SPACER WASHER, fitted between the 2nd wheel gear and the 5th wheel gear on all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F engines.
$ 4.95

HCP7782 OEM output/counter-shaft SPACER WASHER, fitted between the 3rd wheel and 4th wheel gears on all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F engines.
$ 4.95


HCP7323 OEM output/counter-shaft CIRCLIP, fitted between the 2nd and 5th wheel gears on all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F engines.
$ 7.95

HCP7781 OEM output/counter-shaft CIRCLIP, fitted between the 3rd and 4th wheel gears on all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F engines.
$ 3.95



HCP8480 OEM main gear shaft bearing retainer housing RETAINING BOLT, use 3 per housing. For all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F models. Each:
$ 2.25

HCP2424 Aftermarket main gear shaft bearing retainer housing RETAINING BOLT, use 3 per housing. Black oxide coated alloy steel socket head, allen-drive. For all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F models. Each:
$ 1.95

HCP80 Aftermarket main gear shaft bearing retainer housing RETAINING BOLT, use 3 per housing. Black oxide coated alloy steel socket head, allen-drive. Features a small nylon thread patch, making this a self-locking bolt. For all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F models. Each:
$ 1.95

HCP2423 Aftermarket main gear shaft bearing retainer housing RETAINING BOLT, use 3 per housing. Bright 18-8 stainless steel socket head, allen-drive. For all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F models. Each:
$ 1.95


HCP10467 OEM main gear shaft bearing retainer housing O-RING, use 1 per housing. For all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F models. Each:
$ 3.95

HCP22166 Aftermarket main gear shaft bearing retainer housing O-RING, use 1 per housing. For all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F models. Each:
$ 1.95



XJ650, XJ700, XJ750, and XJ900RK shifter forks:

HCP5055 OEM shifter forks SHAFT. For use on all XJ650, XJ700, XJ750, and XJ900RK models.
$ 29.95

HCP5056 OEM shifter forks shaft retaining CIRCLIP, for use on all XJ650, XJ700, XJ750, and XJ900RK models.
$ 2.50


HCP5052 OEM #1 SHIFTER FORK, for use on all XJ650, XJ700, XJ750, and XJ900RK models.
$ 59.95

HCP5053 OEM #2 SHIFTER FORK, for use on all XJ650, XJ700, XJ750, and XJ900RK models.
$ 49.95

HCP5054 OEM #3 SHIFTER FORK, for use on all XJ650, XJ700, XJ750, and XJ900RK models.
$ 59.95



XJ1100 and XS1100 engines:

- the following "pinion" gears and hardware components are located on the main axle shaft (or "input shaft"):

HCP7829 OEM input/main axle shaft BEARING, right end, use on all XJ1100 and XS1100 engines.
$ discontinued

HCP12778 OEM output/counter-shaft BEARING, left end, use on all XJ1100 and XS1100 engines.
$ discontinued


HCP7824 OEM input/main axle shaft 2nd/3rd PINION GEAR SET, for all XS1100 and XJ1100 engines.
$ 399.95

HCP7821 OEM input/main axle shaft 4th PINION GEAR SET, for all XS1100 and XJ1100 engines.
$ 219.95

HCP7827 OEM input/main axle shaft 5th PINION GEAR, for all XS1100 and XJ1100 engines.
$ 199.95



HCP7832 OEM input/main axle shaft SPACER WASHER, fitted at the far left end of the main axle shaft on all XS1100 and XJ1100 engines.
$ 6.95

HCP7822 OEM input/main axle shaft SPACER WASHER, fitted between the 2nd/3rd and the 4th pinion gears on all XS1100 and XJ1100 engines.
$ 29.95

HCP5060A OEM input/main axle shaft SPACER WASHER, fitted between the 2nd/3rd and the 5th pinion gears on all XS1100 and XJ1100 engines.
$ 4.95

HCP7828 OEM input/main axle shaft SPACER WASHER, fitted to the left of the 5th pinion gear on all XS1100 and XJ1100 engines.
$ 4.95



HCP7781 OEM input/main axle shaft CIRCLIP, fitted between the 2nd/3rd and 4th pinion gears on all XS1100 and XJ1100 engines.
$ 4.95

HCP7826 OEM input/main axle shaft CIRCLIP, fitted between the 2nd/3rd and 5th pinion gears on all XS1100 and XJ1100 engines.
$ 2.95

HCP7830 OEM input/main axle shaft CIRCLIP, fitted at the far right end of the main axle shaft on all XS1100 and XJ1100 engines.
$ 7.95

HCP7777 OEM input/main axle shaft CIRCLIP, fitted on the left end of the shaft, just inside the support bearing, on all XS1100 and XJ1100 engines.
$ 2.95



- the following "wheel" gears and hardware components are located on the output drive axle shaft (or "counter-shaft"):

HCP7848 OEM output/drive axle shaft BEARING, right end, use on all XJ1100 engines.
$ 44.95

HCP12778 OEM output/drive axle shaft BEARING, left end, use on all XJ1100 and XS1100 engines.
$ 59.95


HCP7834 OEM output/drive axle shaft 1st WHEEL GEAR, for all XS1100 and XJ1100 engines.
$ discontinued

HCP7840 OEM output/drive axle shaft 2nd WHEEL GEAR, for all XS1100 and XJ1100 engines.
$ discontinued

HCP7838 OEM output/drive axle shaft 4th WHEEL GEAR, for all XS1100 and XJ1100 engines.
$ discontinued

HCP7841 OEM output/drive axle shaft 5th WHEEL GEAR, for all XS1100 and XJ1100 engines.
$ discontinued


HCP7836 OEM output/drive axle shaft SPACER WASHER, fitted between the 1st and the 4th wheel gears on all XS1100 and XJ1100 engines.
$ 7.95

HCP7853 OEM output/drive axle shaft SPACER WASHER, fitted at the far right end of the output shaft on all 19801-81 XS1100 Specials and XJ1100 engines.
$ 6.95


HCP7837 OEM output/drive axle shaft CIRCLIP, fitted between the 1st and the 4th wheel gears, and between the 3rd and 4th wheel gears on all XS1100 and XJ1100 engines.
$ 4.95

HCP7846 OEM output/drive axle shaft CIRCLIP, fitted to the right of the middle drive gear on all XS1100 and XJ1100 engines.
$ 2.95



NOTE: in some situations, you can use the following technique to remove larger oil seals that would otherwise require case-splitting to remove. All large oil seals have a metal inner structure that you can (very carefully!) drill into and then pry out:

http://www.xjbikes.com/forums/threads/replacing-the-output-shaft-seal.110522

HCP7844 OEM output/drive axle shaft OIL SEAL, fitted at the far left side of the output shaft on all XJ1100 and XS1100 engines.
$ 34.95

HCP20945 Aftermarket output/drive axle shaft OIL SEAL, fitted at the far left side of the output shaft on all XJ1100 and XS1100 engines.
$ 29.95



XJ1100 shifter forks:

HCP5168 OEM #1 SHIFTER FORK, for use on all XS1100 and XJ1100 models.
$ discontinued

HCP5170 OEM #3 SHIFTER FORK, for use on all XS1100 and XJ1100 models.
$ discontinued




MIDDLE DRIVE GEAR and DRIVEN GEAR:

First of all, let's clear up a bit of terminology: what Yamaha refers to as the "middle gear" is actually inside the engine case (at the very rear of the engine case) on all XJ650- XJ900 engines, and in a separate housing on XJ1100 engines. It's in the "middle" of the entire power-transmission path (which loosely can be described as the "forward" component being the engine and clutch/transmission components, the "middle" being these "middle gear" components, and the "rear" is the driveshaft and final drive components at the rear wheel.

Luckily, the MIDDLE GEAR COMPONENTS are practically bullet-proof, and rarely need any attention nor suffer significant enough wear to cause any problems. Usually, they outlast the bike itself.

Of course, there are exceptions to every rule, so here is a list of parts that are available, should the need ever arise.

And here’s some good videos showing the proper method of installing ball bearings into engine cases and onto shafts:

https://www.youtube.com/watch?v=5dThHN7Rj6c

and

https://www.youtube.com/watch?v=wXZ-agyDsXY


Transmission Middle DRIVE GEAR Components:


HCP7810 OEM transmission middle DRIVE GEAR, for all XJ650 (except Turbo), all XJ700, and all 1982 XJ750 Maxim and all 1983 XJ750 Midnight Maxim engines.
$ 49.95

HCP7811 OEM middle gear assembly DRIVE GEAR, for all XJ650 Turbo, all XJ750 Seca, 1983 XJ750 Maxim, all XJ900RK, RL, N/FN, and F engines.
$ 199.95



Transmission Middle DRIVEN Gear Components:

HCP7818 OEM middle gear assembly DRIVE GEAR, for all XJ900RK, RL, N/FN, and F engines.
$ 189.95


HCP7788 OEM middle driven gear BEARING, right side of the middle driven gear, use on all XJ650, XJ700, XJ750, all XJ900RK, RL, N/FN, and F engines.
$ 59.95

HCP7783 OEM middle driven gear BEARING, left side of the middle driven gear, use on all XJ650, XJ700, XJ750, all XJ900RK, RL, N/FN, and F engines.
$ 54.95

HCP7849 OEM middle driven gear BEARING, use 1 on each side of the middle driven gear on all XJ1100 and XS1100 engines.
$ 79.95


HCP7854 OEM middle driven gear SPACER WASHER, fitted just to the left of the middle driven gear on all XJ1100 engines.
$ 4.95


HCP7786 OEM middle driven gear CIRCLIP, fitted to the right end of the middle drive gear on all XJ650, XJ700, XJ750, all XJ900RK, RL, N/FN, and F engines.
$ 3.95

HCP7787 OEM middle driven gear HALF-CIRCLE CLIP, fitted to the right end of the middle drive gear on all XJ650, XJ700, XJ750, all XJ900RK, RL, N/FN, and F engines. Use 1 per engine.
$ 10.95

HCP7784 OEM middle driven gear HALF-CIRCLE CLIP, fitted to the left end of the middle drive gear on all XJ650, XJ700, XJ750, all XJ900RK, RL, N/FN, and F engines, and XJ1100 engines. NOTE: use 1 of these clips on all of the above engines, and a total of three (3) of these half-circle clips on the XJ1100 models. Each:
$ 10.95



Middle Gear Input Gear Shaft:

The input shaft unit on the Middle Gear Assembly consists of a special spring-loaded damper unit and a heavy-duty shaft bearing.


HCP12851 OEM middle gear input shaft BEARING, fits all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F models.
$ 69.95


HCP12852 OEM middle gear input shaft SPECIAL NUT, fits all XJ650 and 181-83 XJ750 engines.
$ 14.95


HCP12853 OEM middle gear input shaft DRIVE CAM, fits all XJ650 (except Turbo) and 1981-83 XJ750 engines.
$ 64.95

HCP12869 OEM middle gear input shaft DRIVE CAM, fits all XJ700, XJ750-X, and all XJ900RK, RL, N/FN, and F engines.
$ 54.95

HCP12870 OEM middle gear input shaft DRIVEN CAM, fits all XJ700, XJ750-X, and all XJ900RK, RL, N/FN, and F engines.
$ 59.95

HCP12871 OEM middle gear input shaft SPRING, fits all XJ700, XJ750-X, and all XJ900RK, RL, N/FN, and F engines.
$ 14.95

HCP12856 OEM middle gear input shaft SPRING HOLDER, fits all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F engines.
$ 23.95

HCP12857 OEM middle gear input shaft THRUST WASHER, use 2 per shaft on all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F engines. Each:
$ 3.95



HCP28405 OEM middle gear input shaft THRUST SHIM .15mm thick, use on all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F engines, as well as the following non-XJ models: . 1982-83 XZ550 K/RK/RJ Vision, 1987-88, 1990, and 1993 and 1995-00 XV535 Virago, and 1998-16 XVS650 V-Star models. Each:
$ 14.95

HCP12858 OEM middle gear input shaft THRUST SHIM .20mm thick, use on all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F engines, as well as the following non-XJ models: . 1982-83 XZ550 K/RK/RJ Vision, 1987-88, 1990, and 1993 and 1995-00 XV535 Virago, and 1998-16 XVS650 V-Star models. Each:
$ 7.95

HCP12859 OEM middle gear input shaft THRUST SHIM .30mm thick, use on all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F engines, as well as the following non-XJ models: . 1982-83 XZ550 K/RK/RJ Vision, 1987-88, 1990, and 1993 and 1995-00 XV535 Virago, and 1998-16 XVS650 V-Star models. Each:
$ 14.95

HCP12860 OEM middle gear input shaft THRUST SHIM, .40mm thick, use on all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F engines, as well as the following non-XJ models: . 1982-83 XZ550 K/RK/RJ Vision, 1987-88, 1990, and 1993 and 1995-00 XV535 Virago, and 1998-16 XVS650 V-Star models. Each:
$ 14.95

HCP28406 OEM middle gear input shaft THRUST SHIM, .50mm thick, use on all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F engines, as well as the following non-XJ models: . 1982-83 XZ550 K/RK/RJ Vision, 1987-88, 1990, and 1993 and 1995-00 XV535 Virago, and 1998-16 XVS650 V-Star models. Each:
$ 14.95



HCP20944 Aftermarket middle driven sleeve gear output shaft OIL SEAL, fits onto the output shaft where it exits the crankcase housing behind the bearing plate “half-moon” retainers. For all 1980-81 XJ650 Maxim and Midnight Maxim engines, 1982 XJ650RJ Seca, XJ650 Euro 4K0 models, and 1981-82 XJ750 Seca engines.
$ 22.95


HCP10469 OEM middle gear input shaft bearing RETAINER PLATE, half-moon shaped plate used on the upper crankcase section. Fits all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, F, and S/SH models.
$ 19.95

HCP10472 OEM middle gear input shaft bearing RETAINER PLATE, half-moon shaped plate used on the lower crankcase section. Fits all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, F, and S/SH models.
$ 7.95


HCP10470 OEM middle gear input shaft bearing retainer plates TORX SCREW, use 2 with each of the half-moon shaped plate retainer plates. Fits all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, F, and S/SH models. Each:
$ 3.95

HCP22176 Aftermarket middle gear input shaft bearing retainer plates TORX SCREW, use 2 with each of the half-moon shaped plate retainer plates. Fits all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, F, and S/SH models. Each:
$ 2.50


HCP12868 OEM middle gear input shaft gear-to-shaft retainer TABBED LOCK WASHER, use 1 on all XJ700, XJ750, and all XJ900RK, RL, N/FN, and F models. Each
$ 1.95



Middle Gear Output Gear Shaft:

HCP12862 OEM middle gear output shaft BEARING, use on all XJ650, XJ700, and all XJ900RK, RL, N/FN, and F models. NOTE: this is the bearing on the front (or forward) end of the output shaft. The rear output shaft bearing is part of the output housing and is not available as a separate component.
$ 24.95

HCP19278 Aftermarket middle gear output shaft BEARING, use on all XJ650, XJ700, and all XJ900RK, RL, N/FN, and F models. NOTE: this is the bearing on the front (or forward) end of the output shaft. The rear output shaft bearing is part of the output housing and is not available as a separate component.
$ 17.95


HCP10466 OEM main gear shaft BEARING HOUSING, use on all XJ650 Turbo, all XJ700 and XJ750-X models, and all XJ900RK, RL, N/FN, and F models. NOTE: this is the housing (cover) directly behind the shifter drum segment inside the shifter cover.
$ 42.95


HCP12861 OEM middle gear output shaft forward bearing retaining HALF-CIRCLE CLIP, use on all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F models.
$ 3.25



Note that the following pinion shims are “half-circle”; thus 2 shims of each size (thickness) are required to be fitted to make one “shim” spacing on the shaft/gear. Shim sizes can be calculated through a procedure outlined in the factory service manual, and the stock shim sizes (for your particular engine) are scrawled into the upper crankcase (along with the crank main journal sizes) as can be seen here, in the sectioned titled “Crankcase Main Bearing Sizes”:

http://www.xj4ever.com/catalog/frame-engine-id.pdf

HCP28409 OEM middle gear output shaft PINION GEAR SHIM .10mm thick, use on all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F engines, as well as the following non-XJ models: . 1982-83 XZ550 K/RK/RJ Vision, 1987-88, 1990, and 1993 and 1995-00 XV535 Virago, and 1998-16 XVS650 V-Star models. Each:
$ 21.95

HCP13745 OEM middle gear output shaft PINION GEAR SHIM .15mm thick, use on all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F engines, as well as the following non-XJ models: . 1982-83 XZ550 K/RK/RJ Vision, 1987-88, 1990, and 1993 and 1995-00 XV535 Virago, and 1998-16 XVS650 V-Star models. Each:
$ 15.95

HCP13747 OEM middle gear output shaft PINION GEAR SHIM .20mm thick, use on all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F engines, as well as the following non-XJ models: . 1982-83 XZ550 K/RK/RJ Vision, 1987-88, 1990, and 1993 and 1995-00 XV535 Virago, and 1998-16 XVS650 V-Star models. Each:
$ 15.95

HCP13748 OEM middle gear output shaft PINION GEAR SHIM .30mm thick, use on all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F engines, as well as the following non-XJ models: . 1982-83 XZ550 K/RK/RJ Vision, 1987-88, 1990, and 1993 and 1995-00 XV535 Virago, and 1998-16 XVS650 V-Star models. Each:
$ 15.95

HCP13749 OEM middle gear output shaft PINION GEAR SHIM .40mm thick, use on all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F engines, as well as the following non-XJ models: . 1982-83 XZ550 K/RK/RJ Vision, 1987-88, 1990, and 1993 and 1995-00 XV535 Virago, and 1998-16 XVS650 V-Star models. Each:
$ 14.95

HCP13750 OEM middle gear output shaft PINION GEAR SHIM .50mm thick, use on all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F engines, as well as the following non-XJ models: . 1982-83 XZ550 K/RK/RJ Vision, 1987-88, 1990, and 1993 and 1995-00 XV535 Virago, and 1998-16 XVS650 V-Star models. Each:
$ 15.95



Middle Gear Output Shaft Housing (except XJ1100):

The output shaft housing is the large aluminum housing bolted to the back of the engine case. It contains the housing, the output shaft rear bearing, and the shaft damper. It is sealed to the engine case via a large rubber o-ring and an oil seal.

HCP12863 OEM middle gear output shaft HOUSING, fits all XJ650 and 1981-83 XJ750 engines.
$ 119.95

HCP12867 OEM middle gear output shaft HOUSING, fits all XJ700, XJ750-X, and all XJ900RK, RL, N/FN, and F models.
$ 104.95

HCP12864 OEM middle gear output shaft housing BOLT, fits all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F engines. Use 4 per housing. Each:
$ 1.50


HCP7260 OEM middle gear output housing O-RING, fits on the inside of the output shaft housing. For all XJ650, XJ700, XJ750, all XJ900RK, RL, N/FN, and F engines, and XJ1100 and XS1100 models.
$ 9.95

HCP21656 Aftermarket middle gear output housing O-RING, fits on the inside of the output shaft housing. For all XJ650, XJ700, XJ750, all XJ900RK, RL, N/FN, and F engines, and XJ1100 and XS1100 models.
$ 6.95


NOTE: in some situations, you can use the following technique to remove larger oil seals that would otherwise require case-splitting to remove. All large oil seals have a metal inner structure that you can (very carefully!) drill into and then pry out:

http://www.xjbikes.com/forums/threads/replacing-the-output-shaft-seal.110522

HCP6080 OEM middle gear output housing OIL SEAL, fits on the output shaft where it exits the crankcase housing. For all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F engines.
$ 16.95

HCP20943 Aftermarket middle gear output housing OIL SEAL, fits on the output shaft where it exits the crankcase housing. For all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F engines.
$ 11.95



HCP10471 OEM middle gear cavity-to-shifter case cavity rubber GROMMET, fits into the recess on the crankcase on the southwest corner of the middle gear cavity (northeast corner of the shifter cover cavity) in the crankcase. For all XJ650, all XJ700 engines, all XJ750 engines, and all XJ900RK, RL, N/FN, F, and S/SH engines.
$ discontinued

HCP21657 Aftermarket middle gear cavity-to-shifter case cavity rubber GROMMET, fits into the recess on the crankcase on the southwest corner of the middle gear cavity (northeast corner of the shifter cover cavity) in the crankcase. For all XJ650, all XJ700 engines, all XJ750 engines, and all XJ900RK, RL, N/FN, F, and S/SH engines.
$ 19.95



Middle Gear Housing (XJ1100 and XS1100):

XJ1100 and XS1100 models were unique in that the middle gear components were housing separate from the crankcase, inside their own little gear case. Listed below are the most common items that may need replacement.

HCP7248 OEM middle gear input shaft BEARING, right end, used on all XJ1100 and XS1100 engines.
$ 34.95

HCP12290 OEM middle gear input shaft BEARING, left end, used on all XJ1100 and XS1100 engines.
$ 109.95


HCP7261 OEM middle gear output shaft BEARING, forward end, used on all XJ1100 and XS1100 engines.
$ 39.95

HCP7262 OEM middle gear output shaft BEARING, rear end, used on all XJ1100 and XS1100 engines.
$ 44.95


HCP7272 OEM middle gear housing-to-crankcase GASKET for all XJ1100 and XS1100 models.
$ 29.95

HCP22412 Aftermarket middle gear housing-to-crankcase GASKET for all XJ1100 and XS1100 models.
$ 19.95


HCP7257 OEM middle gear housing outer cap GASKET for all XJ1100 and XS1100 models.
$ discontinued

HCP22411 Aftermarket middle gear housing outer cap GASKET for all XJ1100 and XS1100 models.
$ 21.95


HCP7245 OEM middle gear housing input shaft housing O-RING, fits where the input shaft cover joins the main case. For all XJ1100 and XS1100 models.
$ 7.95

HCP22007 Aftermarket middle gear housing input shaft housing O-RING, fits where the input shaft cover joins the main case. For all XJ1100 and XS1100 models.
$ 4.95


HCP967 OEM middle gear housing-to-crankcase locating DOWEL PIN, use 1 per engine on all XJ1100 and XS1100 models. Each:
$ 4.95


HCP7260 OEM middle gear output housing O-RING, fits on the inside of the output shaft housing. For all XJ650, XJ700, XJ750, all XJ900RK, RL, N/FN, and F engines, and XJ1100 and XS1100 models.
$ 9.95

HCP21656 Aftermarket middle gear output housing O-RING, fits on the inside of the output shaft housing. For all XJ650, XJ700, XJ750, all XJ900RK, RL, N/FN, and F engines, and XJ1100 and XS1100 models.
$ 6.95


NOTE: in some situations, you can use the following technique to remove larger oil seals that would otherwise require case-splitting to remove. All large oil seals have a metal inner structure that you can (very carefully!) drill into and then pry out:

http://www.xjbikes.com/forums/threads/replacing-the-output-shaft-seal.110522

HCP6081 OEM middle gear output housing OIL SEAL, fits on the output shaft where it exits the crankcase housing. For all XJ1100 and XS1100 models.
$ 14.95



Middle Gear Output Flange, Seals, and Hardware:

Although the "middle gear" components are actually part of and located within the engine case, since they are the "beginning" of the power transmission path to the driveshaft, we have also included these parts here. Even though the output flange rarely gets damaged, the seals can leak and should be replaced if such a situation develops, and these items can be replaced without splitting the engine cases apart.


HCP6082 OEM middle gear output shaft to u-joint FLANGE, the cast "X" flange that the U-Joint bolts to. Fits all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F models.
$ 49.95


HCP6083 OEM middle gear output shaft flange O-RING, fits under the flange nut and washer. Fits all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F engines.
$ 5.95

HCP20655 Aftermarket middle gear output shaft flange O-RING, fits under the flange nut and washer. Fits all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F engines.
$ 3.95


HCP6084 OEM middle gear output shaft flange PLATE WASHER. Fits all XJ650, XJ700, XJ750, all XJ900RK, RL, N/FN, and F engines, and XJ1100 and XS1100 models.
$ 5.95

HCP6085 OEM middle gear output shaft flange NUT, retains the flange to the middle gear output shaft. Fits all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F engines.
$ 12.95

HCP2239 OEM middle gear output shaft flange NUT, retains the flange to the middle gear output shaft. Fits all XJ1100 and XS1100 models.
$ 7.95
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