CB350 K0 smoking on left cylinder only

shoom

New Member
Hey all

I have just got my carbies sorted and most other things. I changed the oil to some silkolene MA2 10w/40. The smoking wasn't happening before with the old oil thats been in the sump for an eternity. Fired it up last weekend and i'm getting big smoke coming out of that cylinder, right is fine. I did put some valvesaver stuff in, maybe a little too much into the few litres I bought, but the right hand side doesn't do it! I really hope I don't need a new hone and ring.. A headgasket I can deal with. As I'm in Australia and we're lucky to see less than 2 degrees celcius maybe a month a year and for the rest its in the 20s to high 40s, I think I should go to 20w/40 . I really hope that cylinder ain't cactus. I have had enough dramas with this bike, and it wasn almost gonna just need a new chain and fuel tank cleaned out and resealed and it was a running proposition. Damn.. it alos smokes outta the header seal, so I will need a new one of those, hopefully not too much for the local dealer. I will compression test it on the weekend, but I'm not too confident. Its the 250 not thr 350 so parts as that much more harder to find. I will try the thicker oil too and hope for the best. anyway got any ideas? could timing be making this happen? or an overfill of oil? oh well, I've come this far and I've got a decent cam chain breaking kit so if its a cylinder gasket it needs, its one it shall get. but having it happen just on the one cylinder makes me suspect rings. o well, wish me luck! Tom.
 
Could very well be a valve stem seal. The detergency of the new oil could have cleaned out gunk that was sealing things up. Probably not a ring issue.

Try Mobil 1 20W-50 V-Twin oil. It has seal conditioners that might correct the problem after a little while.
 
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