Topic: Heavy Smoking?

[Loudpipe]

My 750 has started acting wierd.  It's seemed to get progressively worse, but recently I'll go to start the bike up, cold or hot, doesn't really matter very often, and it'll fire up like normal, everything looks good, but then I take off on it, and by the first stoplight I get to, smoke is POURING out of the exhaust.  This lasts for maybe 5 or 10 minutes, and then it will be smoke-free as long as I don't shut the thing off and restart it.  It does fine if I shut it off for just a few seconds and then restart it...it will not start smoking again then, but if I leave it off for over maybe 2 minutes, it'll start right back again as soon as it's running.  I think it's oil smoke...I honestly can't tell if it's got a blue tint or not, and I know what oil smoke looks like very well, having worked as a mechanic and owning a Triumph TR6. It looks gray/white more than blue, but with this amount of smoke I can't imagine it being condensation.  You'd ALMOST think I'd seafoamed the thing. Any ideas as to what this is?  Oh, bike is a '78 F, 18k miles, all original.  I bought it last year and I have been very easy on it, and it has been adult owned in the past, but I don't know much more than that.

[mlinder]

Bad valve seat... oil dumps down to combustion chamber, you ride it, it smokes, it burns off, no more smoking until you let it sit and more oil can pool in the combustion chamber...

My guess.

[hymodyne]

I've been posting about the same type of smoke issues--also only after I've stopped or am accelerating from a dead stop. Took a 30 mile ride from salisbury MD to Ocean city this morning, bike ran great at 65mph the full trip, no smoke, nothing but steady runnning. as soon as I stop at a light, or accelerate from a stop, I give off a good amount of smoke and then, as I get back up to speed, it goes completeley away. re-seating these or buying new valves and having head work done will have to wait until winter... maybe by then I'll break down and get HD head studs, and that megacycle mild cam...

hym

[mark]

Sounds like valve guide/seal issues to me.

My 2 cents. carry on.


Cheers.

[kaysystems]

Sounds like valve guide/seal issues to me.

My 2 cents. carry on.

Agreed.

But heavy duty studs can make it worse!! They are thicker in diameter and slow the oil draining from the head (especially when cold). I ran out of oil pressure a week ago. Never had this before HD studs. I'm going back to Honda ones.

David

[TwoTired]

Sounds like valve guide/seal issues to me.

My 2 cents. carry on.


Cheers.

+2 (or 3)

The 77-78 Model F heads are notorious for worn valve guides, taking the valve guide seals with them.  Just a guess, about 20K miles on the engine?

Description:
At rest, oil leaks past the seals on to the backs of the valves.  It takes a while to burn off, blow off, the oil when next started.

Cheers,

[Loudpipe]

The 77-78 Model F heads are notorious for worn valve guides, taking the valve guide seals with them.  Just a guess, about 20K miles on the engine?

Yeah, just turned 18k the other day.  Bought it with 14k and it wasn't nearly so bad.  How much is a F2 top end rebuild? I assume I could trust this to a local machine shop who has done good work for me in the past with my TR6? Also, who supplies the necessary parts and a manual for doing all this work?  I'll do it my garage over the winter if I can locate everything before hand.

[TwoTired]

I don't know personally.  There was a recent post about this you could search for.  Or, send a PM to Mrieck.

Cheers,

[Wheelhorse77]

I've got a 77 with the same problem. Start it up, in about 30 seconds oil starts choo chooing out of the exhaust and then five minutes later... all is good.

guides an seals... I will pull the mill this winter and go through it.

Use Honda OEM seals and most seem to prefer Kibble white guides.

Mrieck is a great source for heads.

APE and Dynoman have parts for the F models.

http://www.aperaceparts.com/

http://www.dynoman.net/