Jump to content
Sign in to follow this  

xr grief

Recommended Posts

my old thumper, is quit odd. Sometimes when it has been sitting for a while in the cold, when i start it up it smokes a crap load for about fifteen minutes, i mean real bad. but then it clears up and runs smokeless. Other times ill start it up after a couple weeks and it wont smoke at all. What could this be? also on first start up the oil pump? i think makes a loud rattle but that also stops when its warm. the bike is still as powerfull as the day i got it though- xr 500

Share this post


Link to post
Share on other sites
my old thumper, is quit odd. Sometimes when it has been sitting for a while in the cold, when i start it up it smokes a crap load for about fifteen minutes, i mean real bad. but then it clears up and runs smokeless. Other times ill start it up after a couple weeks and it wont smoke at all. What could this be? also on first start up the oil pump? i think makes a loud rattle but that also stops when its warm. the bike is still as powerfull as the day i got it though- xr 500

I dont like the sound of the oil pump, me thinks its time to dive into the engine and have a looksy and fix it before it fails and seizes the engine, whilst in there maybe a piston and rings along with valve stem seals to stop the smoking.

Share this post


Link to post
Share on other sites
But wouldnt it be smoking all the time if it where the rings/piston

Most likely, yes. Smoke on startup that goes away is usually caused by worn valve seals. Also, are you sure the rattle is from the oil pump? Many attribute cold "oil pump noise" to the bypass valve, but I personally don't see how any of the parts could make a noticeable racket.

Is this an RFVC XR500, or an earlier wet sump model?

Share this post


Link to post
Share on other sites

1983 rfcv xr 500 yes sirr. Is replacing these seals hard. I want to keep this bike as it is an extremely good shape not a pinhead of rust on the thing

Share this post


Link to post
Share on other sites

Not that hard. Head needs to come of,,Valves out etc. I've found with the smoking that it's never a guarantee that it's only valve seals. I thought the same with my 86 after it had been smoking like that. Turned out the Bore was scoured,, piston and rings gone..Replaced ,rebored..good as gold now but still a bit rattley..

Share this post


Link to post
Share on other sites

Yeah, the head needs to come off and the valves out. the seals can be changed while the head is bolted down if some special techniques are used, but in my opinion, it's easier to just pull the head.

FYI, I made a valve spring compressor out of a piece of square steel tube with some holes in it and a big(six inch?) c-clamp. Didn't cost me anything and I can still use the c-clamp for other things. I can snap a photo if you like.

Share this post


Link to post
Share on other sites

say i wanted> a new cam chain, new valves, new seals, and new guides. What would that run me for parts. my dads a mechanic so well figure it out

Share this post


Link to post
Share on other sites

These motors will leak the oil out of the tank into the lower end when they sit long periods of time. Head pressure in the tank pushes oil through the oil pump while sitting and fills the engine. Till you run the engine long enough to pump the excess back into the tank they can smoke. Check the oil level before you start it. If the level in the tank goes up after running a while that's most likely the problem. If it smokes alot you probably need rings at least and possibly to replace the oil pump.

Share this post


Link to post
Share on other sites

That is also a common reason for people overfilling these bikes with oil which is another possible reason for smoking. The engine needs to be run for at least several minutes before checking the oil level. I prefer to run it long enough for the frame reservoir to get warm.

Share this post


Link to post
Share on other sites

aha i did over fill it a bit i suspected, but i can never seem to get an accurate read on oil level. sometimes it will be more than half on the stick, somtimes a quarter above low. and i pinpointed the rattaling sound to the clutch. possibly cold plates sticking? it goes away when warm. all i know is this pig needs an oil change. How would i correct the oil seeping problem from the resivoir?

Share this post


Link to post
Share on other sites

The rattling is more likely notches worn in the clutch basket fingers. The leakdown can't be cured apparently. I've seen very low mileage bikes do it. If you want to try either blueprint your oil pump to make sure all clearances are dead on or buy a new pump and still check said clearances. The leakage is entirely through the pump while it sits. The only thing that can "fix" it is tighter clearances. When checking oil level cold just make sure it's on the stick even if low. Then start up and warm the motor. Recheck oil level. Don't add oil past the low level on a cold motor.

Share this post


Link to post
Share on other sites
How would i correct the oil seeping problem from the resivoir?

You don't. Just check the oil as was mentioned.

Share this post


Link to post
Share on other sites

i just wanted to say that i changed my valve stem seals without removing the head. and just compressed the valve springs with an adjustable wrench and pulled the keepers out with a magnet.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×
×
  • Create New...