Engine makes power, but having trouble transfering to the rear wheel

[HooliganCycles]

I have a 77 with stock motor and carbs (rejetted according to 5twins suggestions) k&n cone filters, pamco ignition... The bikes runs great for the most part in town and on the freeway but when on the rode the throttle response seems slow, if i twist the throttle the engine revs up immediately but takes a minute to transfer that to the rear wheel. Im assuming this is not normal for these bikes (atleast i hope not) has anyone experienced this?

 

[5twins]

Sounds like your clutch is slipping. Usual fix is to replace the springs. If that doesn't help (but it usually does), you may need to take further steps like replacing the friction plates. When doing the springs, check the friction plate thickness. 3mm is the new spec, 2.7mm the wear limit.

 

[HooliganCycles]

It has new springs and friction plates (aftermarket), thats not to say the new ones werent crap to begin with though

 

[5twins]

Well, I would check the adjustment at the worm gear to make sure it's not too tight and maybe try a different brand of oil. What oil are you using now?

 

[HooliganCycles]

I think it has torco or something like that in it now which i wasnt crazy about using to begin with but i was in a pinch and it was all i could get my hands on.... What kind of oil would you suggest?

 

[burns]

I think it has torco or something like that in it now which i wasnt crazy about using to begin with but i was in a pinch and it was all i could get my hands on.... What kind of oil would you suggest?

That has got to be the most controversial question you could ask. So many people are romanitily attached to the oil of their choice. The formulas of car oils have changed in a way that is not good for the tappets and cams of older machines like the XS.

But, I'll cut to the chase : my choice is Shell Rotella

 

[Moody]

make sure your check your clutch adjustment pushrod in the left side cover! anytime new plates are installed you must readjust the pushrod and then adjust the cable up at the lever.....

as far as oil goes I am yet to be convinced that oil will make clutches slip, i build and drag race modern sportbikes and they use a wet clutch just like a xs, my 08 suzuki hayabusa runs low 8's in the 1/4 mile at a speed of 165+ mph and i run only mobile 1 full synthetic car engine oil. the only think i could see oil effecting the xs clutch is the fact they are cork frictions where my busa i run kevlar frictions....

 

[HooliganCycles]

I have readjusted the clutch a few times hoping that would fix it, without luck, so i will do an oil change and hope for the best. Thanks for the suggestions

 

[Moody]

you adjusted at the engine case first right? i also reuse a lot of steels if they are not warped but they can get glazed...so take 200 grit sand paper and rough them up again to take the glaze off and clean the crap out of them then reinstall.

 

[HooliganCycles]

Yes i adjusted it at the worm gear first then at the cable (which is also new) i did reuse the steel plates but checked all of them and none were warped, the alignment hole is correct.... All the symptoms point to clutch slipping but i cant think of anything i might has missed, i guess my final option is open it back up, remeasure all the plates, i will scuff the steels slightly just incase and change the oil, i will probably try shell rotella non synthetic, is that a diesel engine oil? Or motorcycle specific?

 

[burns]

Yes i adjusted it at the worm gear first then at the cable (which is also new) i did reuse the steel plates but checked all of them and none were warped, the alignment hole is correct.... All the symptoms point to clutch slipping but i cant think of anything i might has missed, i guess my final option is open it back up, remeasure all the plates, i will scuff the steels slightly just incase and change the oil, i will probably try shell rotella non synthetic, is that a diesel engine oil? Or motorcycle specific?

Rotella is not motorcycle specific. It is for diesel and gasolene applications. It has phorosphorous levels that are higher than most motorcycle specific oils. That additive is needed to protect the old style tappetts and cams, and has been reduced in car oils because catalytic converters don't get along with it. Now that diesils are getting cats that oil will go the same route soon. But right now it has the additives old motors need and it is cheap enough to encourage frequent changes. I read quite a bit on this topic a while back and am inclined to agree that oil is not a factor with wet-clutch slippage. Mobil Oil published a fairly lengthy rebuttal of that claim that I found convincing.

In the comparrison test results published by one mineral based motorcycle oil maker synthetic oils were conspicuous by their absense. The synthetics are better lubricants than the mineral based oils and don't break down, but of course anything will get contaminated and the oil filtration on the XS is minimal. If I was drag racing I'd use synthetic for sure.

Bottom line: I think the best bang for the buck for a street biker is to us Rotella and change frequently.

But there are sure to be others with deeply held non-concurring opinions.


And oil choice is unlikely to solve your issue.