Symptom: Rear tire spins in neutral

[enrgizerbunny]

Situation: My bike was in the shop recently. I had a new chain/sprockets installed, the carbs synced and tuned.

I got my bike back, replaced the shift shaft seal that had been leaking oil for some time now and I replaced all my fuel lines and the inline fuel filter that was on there. It ran perfectly smooth after I got it back, but since I replaced the seal I've had it die on me coming to a stop. I'll pull in the clutch, the rpms just drop off and it dies. I've also had idle issues, especially when cold. I'll start it up and it will run fine choked for a bit, then the rpms will drop off and then it will die. If I put it on the center stand, it will spin the rear wheel and idle alright (in neutral, wheel speed is same regardless of RPM). Eventually the rear tire stops spinning and it idles normally. The rear wheel will spin when I put it in gear without releasing the clutch, and it will change speed with the RPMs. I'm befuddled by the spinning in neutral though.

Any ideas? I feel like this could be an oil problem. Oil change was 2k miles ago, I've topped up with some castrol GTX 10w-30 because I had it, I put Valvoline conventional ATV 10w-40 in it when I changed. My wal-mart doesn't sell valvoline motorcycle oil and the ATV oil is $5/qt at tractor supply. It's designed for wet clutches, too.

I'll have to make a video on Friday of it doing this.

[lucas]

My guess at this is that you just need to adjust your idle and that there is no problem with your bike.

When you run your bike in neutral on the center stand if the back wheel rotates that means there is enough friction between the input shaft and counter shaft to overcome the friction in the chain and rear wheel bearings.  If the transmission was slightly engaged it would make a clattering noise.

The rear wheel will stop rotating (when the engine oil is hot?) and my guess is that you could apply the brakes and stop it, heck rotate it backwards.  So this is not related to the engine dying.

[enrgizerbunny]

My guess at this is that you just need to adjust your idle and that there is no problem with your bike.

When you run your bike in neutral on the center stand if the back wheel rotates that means there is enough friction between the input shaft and counter shaft to overcome the friction in the chain and rear wheel bearings.  If the transmission was slightly engaged it would make a clattering noise.

The rear wheel will stop rotating (when the engine oil is hot?) and my guess is that you could apply the brakes and stop it, heck rotate it backwards.  So this is not related to the engine dying.

It idles fine when (it gets warm enough?) the wheel stops spinning. If I let the wheel spin on the centerstand it will idle easier than if I put it on the side stand. Eventually it warms up and idles at 1200 or so. I've adjusted the idle up slightly already.

When I choke it and start up cold, it starts up and revs to about 3-4k, after a little bit <1minute the rpms drop off, it starts to idle around 1k and then it dies. After that, it won't stay running (even fully choked) unless I am actively giving it throttle.

My jets are 40/125 I believe and the mechanic said I'm at about 4 turns out. From everything I've read here it should be closer to 3 turns, but I attributed it to cold weather/needing more fuel.

[Big Rich]

Rear wheel spinning in neutral? Not a problem at all mechanically. I've seen plenty of bikes that were in top shape doing the same thing. As long as you can hit the back brake and the engine doesn't stall, you're good.

[enrgizerbunny]

Okay, how long does it normally take to warm up then? My bike doesn't run right for about the first 20 minutes, sometimes longer- mainly it won't idle very well. Once it's warm it idles at 1300-1400 rpm.

[Big Rich]

Stock jetting? There are a couple factors that go into it, but 20 minutes isn't unheard of.

I can say this though: when I leave work in the morning (about 45° sometimes) I'll apply full choke to start the bike and then half choke as soon as it's running. It'll sit there for a minute or two while I get everything else ready. Once the bike is in gear I turn the choke off completely. For the first 5 minutes of riding it will hesitate slightly if I get on the throttle - but it runs fine after that. I should mention too: my GS450 has first generation GS500 carbs on it, and they are jetted for a K&N filter and Supertrapp exhaust.

[BockinBboy]

Ditch the inline fuel filter - typically cause more problems than they are worth.  You have a screen inside the gas tank that should take care of anything that would potentially cause problems in the carbs.  Only case its worth a filter is if your gas tank is in bad shape (really rusty) - but you'll be replacing filters often if that's the case. 

If you feel you need one, make sure it is suitable for gravity fed fuel systems - a paper filter of most any type won't work, they inhibit fuel flow.

- Bboy

[enrgizerbunny]

Ditch the inline fuel filter - typically cause more problems than they are worth.  You have a screen inside the gas tank that should take care of anything that would potentially cause problems in the carbs.  Only case its worth a filter is if your gas tank is in bad shape (really rusty) - but you'll be replacing filters often if that's the case. 

If you feel you need one, make sure it is suitable for gravity fed fuel systems - a paper filter of most any type won't work, they inhibit fuel flow.

- Bboy

I put it right below where the fuel line goes into the carbs, makes that 90 turn real easy. I've got a little rust in my tank, but nothing serious. I replaced a paper filter that was installed. If it's relevant, I also converted the petcock to non-vacuum operated because I had vacuum issues, so I just took the vacuum out of the equation.


Looks like this:

[BockinBboy]

If you use one, the type in the pic is the better option over paper type.



- Bboy