Smoking '65 250

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65bayracer
Cucciolo - the Lil Pup
Posts: 4
Joined: Wed Oct 08, 2008 9:32 am

Smoking '65 250

Post by 65bayracer »

Hey guys,

Recently picked up a '65 250 Scrambler in a deal, sight unseen. It hadn't been started in probably 9 months or so when I got it, tank was drained, etc. I put in some gas, checked the oil, and fired her up after about 5 mins, which was great. However - it was smoking like a 5 alarm fire, horrible throttle response, and kept dying.

I was getting a bunch of work done to it to get it streetable again, so had my shop adjust the timing, do a full compression and leakdown, tune the carb, etc. and they now have it running well...but it still smokes like all hell! The compression was very good and leakdown showed no problems...what is up with all this smoke? It's black smoke coming out of the pipe, no longer the carb. Should i just run it around for a while and see if it clears up? Where do I start? Would have thought the compression and leakdown would tell me if I have an issue or not...

Cheers,
AK
Andy Whitaker
Cucciolo - the Lil Pup
Posts: 8
Joined: Thu Nov 15, 2007 3:44 pm
Location: Berkshire, UK

Post by Andy Whitaker »

Could it be excessive valve guide wear? Don't know if this model has guide seals but could these be shot.....
Lumpy
SD900 Darmah
Posts: 329
Joined: Sun Mar 25, 2007 5:49 am

sticky rings

Post by Lumpy »

I have seen rings get stuck in the piston grooves after long periods laid up. I have an old XR500 Honda dirt bike for bush bashing which I don`t ride a lot and it smokes like Thomas the tank after long periods of inactivity. It then clears up after a good thrashing. I tried squirting some of that Valve saver you put in your fuel (lead replacement) down the spark plug hole when I`d park her up and this seemed to help. Don`t know how that would show with a compression test, but I guess if only the oil ring was stuck it might not show with a leak down test. Oil burning is usually a definate blue smoke and smells of burnt oil. As previously mentioned crook guide seals can smoke like crazy if they are not sealing. The guide seal on my GTS860 came off on the front pot and she smoked like Fidel Castro. Hope this helps.
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