78 XS11E final drive question

[sweet78xs]

I am getting tires put on my E and I am looking at all the maintenance to be done whilst the wheels are off. I removed the final drive to grease the splines on both the housing and the drive shaft and noticed that the input coupler turns really stiff. It spins, but not like I "think" it should. Is that supposed to be that way and "loosens" up with warming up or do I have a bad bearing or something. I'd like to know if I have a problem whilst I have the final drive and rear end off.

I checked milage on 2 tanks last week and got 34 and 33.5 mpg, the second being lower due to twisting harder to keep up with my buddy's R6. I hear of people getting 40+ and would like to see if I can achive that, and if there is a bind someplace in the rear, that can help raise milage. If it is normal, tell me so.

Also, is there anything else I should look for while everything is apart?

All your input would be greatly appreciated. I am a proud new owner of 3 weeks now. I really am impressed with this bike and would like to keep it in tip top operating condition.


_Carey

[trbig]

I was spinning the middle drive on the engine I was putting in and thinking the same thing. A bit stiff... not notchy or anything, just not free-spinning like I would have thought. I have a couple others around, and they were the same way. SO... either there's 4 bad middle drives between us... or it's normal.



Tod

[sweet78xs]

I was thinking that if the drive spun more freely, it would raise the milage a lot, going by how "stiff" mine is.

[jjwaller]

Tight is subjective.
Do you have to use tools to turn it?
It won't spin, of course, but it should
turn "freely" without binding.
Does it feel like it is grinding or binding?
Should be able to turn it with 2 fingers inside splines.
Have you changed the gear oil in the FD?
Might have crap in there. See what the oil looks when it comes out.

[trbig]

Yeah, but you have to add in the 90 degree bend the torque is having to do to get there. You're going to lose some.

These machines aren't the best if you're looking for a gas mileage mobile. The mileage you reported is just about the average. I have gotten 40 a couple times, but it was a lot of downhill and wind at my back, but that isn't going to be the norm for these. Some get less, a few get more, but yours is in the middle.

If you swapped to a chain drive, it would get better.... but then you'd have a chain driven bike?? lol. The drive shaft will take more H/P to operate, but to have a smooth shaft drive... it's more than worth it to me.
You can spend a ton of money on one of these and still not get the H/P a crotch rocket 600cc gets now days. BUT... it still does pretty good against any V-twin out there.

You could find someone that does dynos on motorcycles, and they would get your bike to the best tuned for what you have. But the 2 more miles a gallon may take a long time to make up for the cost of that.


Tod

[sweet78xs]

I grab the outside of the coupler with 3 fingers and it spins without tools. I will check the oil tomorrow to see the condition. On the back of the housing, there is a cast flat with a plug of sorts in it. Do I pop that out with a flat screwdriver or what? Also, do I use 80/90 gear oil back there?

Would it be better to clean and inspect the unit by removing all the nuts that hold the cover on the wheel side of the housing to the main housing?

[trbig]

Use synthetic oils in the gear boxes (Middle and final drives) but NOT in the engine oil. It makes the clutches slip. 80/90 is fine. It does mention Hypoid oil... whatever that is? lol.


Tod

[sweet78xs]

Hell no I don't want a chain drive. The shaft drive is the main thing that attracted me to this bike. My wifes' opinion was also a deciding factor as she will be riding to work on it with me. It's a sexy bike.

[bikerphil]

FD

Don't take those nuts off on the wheel side, no reason to go in there. Drain the oil from the bottom plug, when refilling use 10 oz. (300 cc) 80w90 (synthetic if you like). Pop that little black plug out & remove filler plug with a 6mm allen wrench. If the plug is stuck, penetrating oil and a few taps on the plug with a hammer should free it. These FD units are pretty much bullet proof.

[sweet78xs]

should I try flushing it, or just drain it really good and refill.

[sweet78xs]

phil, I see you have the 750 fd mod, are you happy with that?

[trbig]

Just drain, fill, and go!

[sweet78xs]

Thanks Guys...

Carey

[bikerphil]

FD mod

Hey sweet78xs, yeah man, real happy. Loses a little launching power, but cruises like a bat out of h*ll. 3500 RPM = 70 MPH.