750 Final Drive enigma

[Brian_D]

Venture final drive

check the Yamaha Final (shaft) Drives thread for the details on the Yamaha final drives....but yes, the early ventures have the same ratio as the XS11...both are lower than the 33/9 ratio of the V-Max and the FJR1300

[xschop]

lost in translation?

maybe the english speaking Techs named it a "Shim". I have heard my Grandfather call what I call washers, Shims before....JAT.... I tore open an xs11 FD and from the design of it the pinion helicals could only move back and forth by the large square SHIMS between pinion housing and FD housing.....My coworker is japanese and if someone could produce the orig. Jap manual, We could retranslate....

[dntemp_ca]

Have any of those converting to the 750/850 FD noticed any middle gear whine at highway speeds? I have a 78 Standard w original FD and I get a significant (annoying) amount of gear whine that builds and is loudest at about 3500 rpm. It disappears at around 3700rpm. I'm wondering if this noise is typical since FD conversions cruise around that engine speed.

[trbig]

Nope... no noises. It sounds like there may be issues there. Have you checked/ changed the gear oil?

Tod

[MAXIMAN]

Originally posted by dntemp_ca
Have any of those converting to the 750/850 FD noticed any middle gear whine at highway speeds? I have a 78 Standard w original FD and I get a significant (annoying) amount of gear whine that builds and is loudest at about 3500 rpm. It disappears at around 3700rpm. I'm wondering if this noise is typical since FD conversions cruise around that engine speed.

Ah yes...and isn't music to my ears?

Actually every Eleven I've ever had (four now) and all the ones I've ridden have a certain amount f gear whine. It is most evident in the 3500 to 4500 range. The bike sound like it's singing! That is one of the things I have always loved about the XS and XJ shaft driven bikes; the proverbial gear whine.

Having said that...how loud is it? You should be ableto speak over it in a normal voice. If you think it's to loud ...have you drained the oil to see what it looks like. Does the middle drive housing seem to be getting warmer than normal. Usually the middle gear gets pretty hot due to the proximity of the engine anyway.

[ExcessiveBiker]

750 FD shims

Max,
It seems we have a semantics problem, a misunderstanding of washer and shim. I assume we are all on the same page about this.
I also have quite a whine from my driveline, plus a rapping sound from 3k up. It almost sounds like an exhaust leak. Stumped.
Anyway, I love that "extra" gear now, so much more pleasant to ride. If I really need to piss off the cops, there is always 3rd and 4th gear on call.

4100 at 70 all day long---sweet
Excessive biker

[MAXIMAN]

Re: 750 FD shims

Originally posted by ExcessiveBiker
Max,
It seems we have a semantics problem, a misunderstanding of washer and shim. I assume we are all on the same page about this.
I also have quite a whine from my driveline, plus a rapping sound from 3k up. It almost sounds like an exhaust leak. Stumped.
Anyway, I love that "extra" gear now, so much more pleasant to ride. If I really need to piss off the cops, there is always 3rd and 4th gear on call.

4100 at 70 all day long---sweet

Excessive biker

Actually the part I'm refering to is a shim. They are called bearing spacers but they come in a variety of thicknesses according to the Yamaha parts diagrams. I still haven't figured out why Yamaha used these on the 750 pinion assembly but not on the 850.


Until this "mod" is proven beyond any doubt to be "failsfe" I'd reccomend keeping a close eye on the differential oil...as in drain it and look at it. If it's ok you can always put it back in.

[xschop]

what's tha hoopla

Seriously, all the FD's (750,850,1100) have the expansion spacer to keep the pinion from tightening to much on the bearings inside the pinion housing. Correct me if I'm wrong. I believe the xs11 engineers realized that the pinion nut "shims" were overkill and just put a washer there to seal up the newly designed xs1100 pinion O-RING to keep in the gear oil in the housing (the 750 FD oil passed through and lubed the Drive Shaft Splines)......to make a long story short, when this swap is performed, JUST DON'T REMOVE THE PINION HOUSING, AND TORQUE THE PINION NUT TO SPEC AFTER YOU PUT ON THE FAT WASHER TO COVER THE OIL PASSAGE HOLES....

[Rubin]

Gear Lash Adjustment

Maximan, the gear lash adjustment you mentioned earlier has me thinking. My final drive no longer moves with the rest of the engine, and my gears all work well - no problems getting through the gears. When I release the clutch in gear however, I get no movement. Could my gear lash be so far out of adjustment that it no longer is seated properly and so cannot drive the rear wheel? I am ordering a middle drive gear as soon as I can get a M.O. out to Andreas just in case, but any thoughts on this?

[MAXIMAN]

Re: what's tha hoopla

Originally posted by xschop
...JUST DON'T REMOVE THE PINION HOUSING, AND TORQUE THE PINION NUT TO SPEC AFTER YOU PUT ON THE FAT WASHER TO COVER THE OIL PASSAGE HOLES....

Watchout now Robert! Just because I didn't know what I was doing the first time is no reason to YELL AT ME!




Seriously the pinion housing lieterally fell out on the first one I did when I turn the unit upside down to get the pinion retainer nut out of the coupler. The set screw that keeps the pinion assembly in the FD housing was missing and so the entire pinion assemblage fell out.

Rubin - in a word...NO. Sounds like something sheered...maybe a shaft or the shaft yoke. What about the clutch.

[xschop]

not yelling

just reiterating what you posted before on not taking out that housing. the pinion housings are also more than likely diff. between the models because the pinion splines are also different, that's why you can't just put the xs11 coupler on the 750/850 pinion.....

[Rubin]

I finally had the time to tear into my drive shaft/final drive for the replacement. I pulled off the final drive to find nice shiny splines - the only problem there was no grease and it was shiny due to the polishing it was receiving. So I need to replace the drive shaft as well. I am picking up a slide hammer to pull it out, and when the shaft arrives from ebay, I will pop it in. (Any tips here would be appreciated!!) I had also ordered a new middle gear, but I will not put it in yet and keep it as a spare.

I had asked my mechanic to grease the splines on the drive shaft when I put new tires on, but apparently this was not done. I think I will be bringing my wheels in, off the bike, and grease them myself from now on. Thanks for the manuals, they came in handy so far.

[John]

You don't need any type of puller to get the driveshaft out. A pair of #10 WR Vise Grips will work. Just clamp onto the exposed gear of the shaft and give it a good pull, and it will/should pull right out. If not, a couple of whacks with a hammer on the Vise Grips will do the job. I've done three swaps, and each time i didn't need any special puller.

[MAXIMAN]

One thing I've picked up on that everyone should be aware of. I did not realize this when I wrote up the procedure.

The torque on the pinion retainer nut IS CRITICAL. As is the preload.

I suggest following the manual. After installing the larger washer to seal the spooge holes on the drive coupling be sure and torque the pinion nut to the specified torque...75-105 ft-lbs or there about. Then double check the bearing preload with the appropriate inch-pound torque wrench. On a type it is about 10 inch pounds. On a type two (read 850) it is 3.4 to 4.3 inch-lbs. If the bearing preload is not within the specified range damage could result as I found out on mine.

After the 3000 miles trip to west Texas I pulled the drive for inspection. There were some small metal shaving on the magnetic drain plug and the pinon assembly was very loose. MY BAD!!!

I chucked that drive and installed another. This time around I torqued everything back to spec and the bearing preload was fine.

HOWEVER... should you button everyhing up to spec and the beaing preload is not close to the specified torque in the manual...you should replace the expansion spacer (a crush washer) that is between the pinion gear and the retainer nut. These are only $10 and will assure ou the right tolerances are maintained.

So far I know of no one that has had this problem and simply re-torquing everything back to spec should work fine without having to replace the expansion spacer. At least it worked for me on the second drive.

[xschop]

torque

Good find. I just torqued the nut back down using "fudge" judgement to where the coupler turned with just as much drag before the 750 FD mod....when it stops raining AGAIN, I will pull the 750 FD off and check it again with PICS too! I am almost at 5,000 miles on it....chop