Swap the spark plugs and leads from cylinder 2 and 3. Give it a good run and then repeat your spark plug check. See if the problem stays with the cylinder (carb / fuelling issue) or moves with the spark plugs/leads
It's a fuelling issue, too late now to go into detail will tomorrow.
Quote from: Bretty on 17 May 2017, 11:15:10 pmSwap the spark plugs and leads from cylinder 2 and 3. Give it a good run and then repeat your spark plug check. See if the problem stays with the cylinder (carb / fuelling issue) or moves with the spark plugs/leadsAfter replacing the spark plugs, plug no. 2 was black after 2 km's already.I haven't changed the leads so far...
Quote from: Gnasher on 17 May 2017, 11:17:49 pmIt's a fuelling issue, too late now to go into detail will tomorrow.I agree, looking forward to hear more about it What to look for/replace/...?
Quote from: jan.van.gent on 18 May 2017, 08:01:26 amQuote from: Gnasher on 17 May 2017, 11:17:49 pmIt's a fuelling issue, too late now to go into detail will tomorrow.I agree, looking forward to hear more about it What to look for/replace/...?Ok, based on your post I’m assuming a few things here so this may not be correct: -1.The cylinder giving trouble has the carb you rebuilt, or did you rebuild them all?2.Plus you state everything runs fine at high rpm/big throttle positions, if it was the HT circuit it would usually be the opposite.The part of the rev range you’re having issues with is just past pilot circuit, this now points to several possible problems: -1.Pilot/Main jet damage/blockage2.Needle height setting3.Enricher circuit jammed/blocked.Your leaking crab would have had nothing to do with shot rubbers, but rather worn metering valve/jet, stuck/damaged or wrongly set float height. When you “rebuilt” the carb what did you do?Your black plug is over fuelling, i.e. too richer mixture which can be any or all of the above. If you rebuilt all the carbs and it’s not the one that was leaking, it’s still very possible you didn’t assemble one of them correctly, there's crap in the pilot circuit or you missed something like jammed enricher plunger. Personally based on what you’ve said and what I know at present I’d go for No 3 first check the plunger is not stuck out, then No 1 as being your problem, it could be something else. Tell me more if there is any more?
Quote from: jan.van.gent on 18 May 2017, 08:00:57 amQuote from: Bretty on 17 May 2017, 11:15:10 pmSwap the spark plugs and leads from cylinder 2 and 3. Give it a good run and then repeat your spark plug check. See if the problem stays with the cylinder (carb / fuelling issue) or moves with the spark plugs/leadsAfter replacing the spark plugs, plug no. 2 was black after 2 km's already.I haven't changed the leads so far...(Ignore me if you already know this but...) Spark plugs 2and3 spark at the same time, but as one is on exhaust stroke and the other is on the compression stroke only one fires. So if you swap the leads over between cylinders 2and3 you can eliminate the problem being with the coil or plug cap. This is a very simple thing to do and worth eliminating before going to the trouble of removing and stripping the carbs again.An intermittent spark could cause that spark plug to foul like that, and electrical faults can change with rev range as the mixture resistance changes. I'm not saying it IS the problem, just an easy check that is worth doing, before the ball ache that is removing and stripping the carbs again.
Looking at Bretty's and Gnasher last posts I am really glad I joined FOC-U, there is so much useful information, knowledge and experience in this forum, and I store it all away for future reference, hoping of course that I never need it.It might sound silly but when I read stuff like those posts I copy and paste the information into a word document and save it into a 'Fazer Tips' folder on my computer.Keep the useful info flowing guys.
Would a blockage not rather cause a fuel shortage instead of to much fuel?
What do you mean by enricher circuit? Is this linked to the choke? Or? What to look for in the manual (http://foc-u.co.uk/index.php?action=downloads;sa=downfile&id=8) ?
Quote from: jan.van.gent on 18 May 2017, 10:27:10 amWould a blockage not rather cause a fuel shortage instead of to much fuel?No not if it's air.Quote from: jan.van.gent on 18 May 2017, 10:27:10 amWhat do you mean by enricher circuit? Is this linked to the choke? Or? What to look for in the manual (http://foc-u.co.uk/index.php?action=downloads;sa=downfile&id=8) ?The bike doesn't have a choke in the real sense, when you pull the choke lever out, look closely at what happens, it pulls out 4 plungers, they can stick open even when you push the lever back in. This cuts off air at low RPM through the pilot circuit, thus enriching the mixture, so when you rev the bike when it's warm with a stuck open plunger it's over fuelling.