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Exhaust smoke musings

Posted: Fri Apr 24, 2020 7:32 pm
Author: warren3200gt
Scenario, grey blue smoke on over run last summer so over winter did a leisurely head off valve seal replacement with new viton seals. Exhaust port # 2 very coked and oiley. Re assembled recently and fired her up. Unsurprisingly, now grey blue smoke on throttle acceleration as hot exhaust fumes burn off residue oil in the port and exhaust down pipe. Whipped off #2 down pipe and gave the port a good wipe around with carb cleaner soaked rag. Now smokes much less on throttle acceleration so I am thinking the smoke is definately residue burn off. Question is, would you think the residue would burn off in minutes at idle or it will take a good post covid blast. Have had it ticking over for about 10 minutes so far. Just after some reassurance something more sinister is not occurring as I would prefer to fix whilst under lockdown if it is.
Have good plug colour, burn colour and compression on all four.
Whats your thoughts gents.

Re: Exhaust smoke musings

Posted: Fri Apr 24, 2020 7:54 pm
Author: compo z1r
While u we’re doing that id have honed and refresh rings :D

Re: Exhaust smoke musings

Posted: Fri Apr 24, 2020 7:54 pm
Author: zed1015
Probably a fair bit of oil in the pipe needs burning off especially if the oil has been running down the guide whilst being stood.
I suggest a run out asap as part of your essential maintenance schedule.

Re: Exhaust smoke musings

Posted: Fri Apr 24, 2020 8:06 pm
Author: warren3200gt
compo z1r wrote:While u we’re doing that id have honed and refresh rings :D

I honed it and put new rings it about 2k miles / 4 years ago. Im blaming the crappy seals in the gasket set but in reality it may have been me knicking the seal lip on the valve collet recess when I originally built it. :oops:

Re: Exhaust smoke musings

Posted: Fri Apr 24, 2020 8:08 pm
Author: warren3200gt
zed1015 wrote:Probably a fair bit of oil in the pipe needs burning off especially if the oil has been running down the guide whilst being stood.
I suggest a run out asap as part of your essential maintenance schedule.

Sounds like a plan once covid resolves itself.

Re: Exhaust smoke musings

Posted: Fri Apr 24, 2020 8:23 pm
Author: DavidZ1R
Do you leave the bike on the side stand when not using it? I notice when my z1r is left for a time of the side stand, when it starts it smokes a bit, if it's on the main stand it does not, it has had the head rebuilt with new nos seals,I firmly believe , when left on the side stand the oil migrates to cylinder 1 and 2 some seeps down the seal, if it is submerged in oil then : :?: some is bound to rundown, I also note that plugs 1 and 2 do get black.

Re: Exhaust smoke musings

Posted: Fri Apr 24, 2020 8:27 pm
Author: warren3200gt
Hi David, no mate its the period custom 650 and when not in use is on a paddock stand.

Re: Exhaust smoke musings

Posted: Fri Apr 24, 2020 9:55 pm
Author: DavidZ1R
warren3200gt wrote:Hi David, no mate its the period custom 650 and when not in use is on a paddock stand.


Hi Warren, back t'drawing board.

Re: Exhaust smoke musings

Posted: Sat Apr 25, 2020 6:56 am
Author: kev edwards
Give it a hard run down to Tesco in Strood Warren for some essential shopping that should burn it out of the exhaust's.

Re: Exhaust smoke musings

Posted: Sat Apr 25, 2020 7:36 am
Author: warren3200gt
I was thinking maybe a 300 mile each way trip for that essential genuine conish pasty is in order. :lol: :lol: