How Hot Should My Rear End Get?

[Toolmaker Tim]

Just got my 850 FD transplant done. Cobbled together what I could to give the bike a test run. RPM's dropped by 600 to 3400 RPM@60 MPH. That I expected. However when I got home I checked the FD housing and it was borderline hot. I could lay my hand on it with some discomfort, but I didn't get burned. I never checked my stock drive to be able to have a comparison. Needless to say I am somewhat concerned. I pumped in 30 strokes of grease, checked the middle drive, put in 10 oz. of 80/90 lube in the new pumpkin, torqued everything to specs, and I did check the pinion gear preload before assembly. Splines and wheel drive splines were lightly greased before assembly. Maybe I don't have a problem and I am just paranoid. What have those who have already done the transplant found?

[xschop]

FD difference

All 3 of the 750FD swaps that I did ran a little cooler than the stock XS11 FD.....Thinking back on it I could have used an laser temp sensor to tell the diff..... I used 80-90 transaxle oil

[Toolmaker Tim]

Thanks chop, I just don't want to cook anything. The main problem here is I have no point of reference, and it wasn't something that I thought of beforehand. If I had I could have measured the temp from the old drive. I've had to cobble everything together after the knock over. I screwed things up by not getting the parts from the right person in the first place (apologies to andreas), but that was my being impatient. So I went ahead and did the FD transplant.

[skids]

Re: FD difference

Hey Chop, are we supposed to use the xs11's dip stick to measure the oil level in the 750 rear end??? That is what I have done so far, but I wonder if it is correct.

Originally posted by xschop
All 3 of the 750FD swaps that I did ran a little cooler than the stock XS11 FD.....Thinking back on it I could have used an laser temp sensor to tell the diff..... I used 80-90 transaxle oil

[Toolmaker Tim]

Hey skids, thats a real good question. I just went into robot mode in my eagerness to get back on my bike and poured in 10 oz. dino elixer. On the same note, would synthetic lower the temp? I seem to have read somewhere in here that synthetic also ups the MPG. Kind of pricey tho.

[Paintman]

Gear oil

I run Synthetic in my Middle and Final drive dropped temp by almost 18 degrees from dino stuff.


John

[xschop]

Yo skids

good question. If someone has a 750/850 dipstick to compare?....The second biggest part of the mod I discovered was to make sure the 750 "spooge holes" were closed solid with the RTV and large washer since the XS11 shaft doesn't have the Large o-ring seal to lock the gear oil in the FD.....Kind of important ya know.....chop

[skids]

Yeah, the RTV and washer did the trick to keep it sealed.

[red bandit]

I put in 10oz. of gear oil and used the 11 dip stick. My FD gets luck warm.

[Toolmaker Tim]

Synthetic

Hey Paintman,
What were the temps you got when you did the changr in oil type? That would make it easy to compare the temp. that my FD has right now.
Chop, I plugged the holes with a piece of oversize ejector pin (.159) and put #2 gasket maker on each end along with a washer. The pins were a tap fit and I staked the ends of the holes slightly. They aren't going anywhere.
Right now I am pleased with the Mod., but I don't want to cook a bearing.
Tim

[planedick]

Gear oil

The heat probably isn't caused by bearings, but the gears themselves. These type of gears slide together while running and require a special oil refered to as Hypoid gear oil. Some here scoff the idea of special oil, but it is important and heavy wear on the gears and heat is caused by the wrong oil.

[TopCatGr58]

Limited research info?

Hey Folks,

Just did a check of the Yamaha Fiche, and regrettably they only list part #'s for the ENTIRE FD assembly for each bike, not just the CASING #, and of course the #'s are different due to the different ratio gears used within each one!!!

I would think that Yamaha would NOT have gone thru the trouble to engineer different shaped/sized FD casings for the different bike when they could use essentially the same casing and just different internal parts with different gear ratios for the different applications....750, 850, 1100, which looks like what they did!?

I did find the Service Data for the 750, and it states that 300cc of hypoid oil is needed for the FD, which is the same as the 1100, so I would think that the 1100 dipstick level would be applicable!!

T.C.

[xschop]

hmmm

300/29.6=10.13......10 ounces of hypoid oil for the 750/850 FD then would be poifect, coitainly....hey Moe, hey Larry

[red bandit]

How Hot Should My Rear End Get?

.
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pretty dang hot if I'm around.
Hey... that was askin for it.

[Dsxs11]

My 1100 dipstick and my 750 are the same looks to be the same part number now for either one. The final the middle on both bikes appear to use the same stick.