Hey all,
I've got this '89 VTR 250 Honda that will smoke about 50% of the times I start it up. One time it'll run fine with no smoke...the next time it'll smoke like crazy. It's oil smoke, gray-blue, I'm pretty sure. When it starts and doesn't smoke, it seems fine. When it starts and does smoke...it never seems to clear up during that running.
This has only been while sitting still or riding up and down my street (2nd gear tops).
I wouldn't think piston rings would seal intermittently (I'd think it would ALWAYS smoke if it was rings). I don't know anything about these little v-twin engines (or almost any other bike engine) to know if this is something I can fix, or if I should just give up on the project. It was a free bike...
Any advice on potential causes or what to look for to narrow down the problem would be appreciated.
Thanks,
Clem
Have you ridden it more than around the block, or has up and down the street been it? Also, any correlation between how bad it smokes and things like how long it sat before last running, how long it ran before you shut it down, etc.? Any trend will make it a lot easier to do the internet-guess.
Bryce
Have you done a compression test?
Nashco wrote:
Have you ridden it more than around the block, or has up and down the street been it? Also, any correlation between how bad it smokes and things like how long it sat before last running, how long it ran before you shut it down, etc.? Any trend will make it a lot easier to do the internet-guess.
Bryce
Only up/down the street thus far. I haven't been able to make a correlation yet like you stated...so I'll try that next.
I can't ride it far because, aside from being completely illegal (no lights, no title, no bodywork, no insurance...the list goes on), it doesn't have a rectifier/regulator. Something I'm putting of purchasing used off ebay until I can figure out if the engine's worthy.
I haven't done a compression test yet. it runs pretty strong at times. I guess a compression test can lend more insight too. Not sure I want to spring for a compression tester...I'll have to see if someone has one I can borrow.
Thanks,
Clem
If it sat for a long time, there could have been condensation in the cylinder. That will leave little rust pits (BTDT) and make it smoke. Another possiblity is stuck rings. Dump some Marvel Mystery oil, PB Blaster, or similar in the cylinder, spin it over slow with the plug out, let it sit a week or so. Then spin it fast with the plug out (to blow out the excess) and start. Hopefully that'll free stuck rings.
I might give that a try. I'm still guessing that anything with crankcase leakage past the rings would most likely be constand and not intermittent in nature like what I'm seeing.
I'll probably go for MMO (even though I have PB Blaster on-hand and love the stuff) because I assume the MMO can stay in the oil for a little while and the PB Blater would thin it out pretty bad. By a little while...I mean long enough to run it a bit before changing the oil...another thing I'm avoiding until I know the engine is worth the effort ;).
Clem
