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sluggish 550

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K2-K6:
That comment you made when you said "I thought I'd cracked it" what made you think the revs were better?

I ask because of this scenario:- if you start the motor, warm up and go on a ride at normal use then, IF the fuel supply is restricted it's possible that you've depleted the volume of petrol in the float chambers by doing this so that when you wind it up you get no revs increasing as fuel demand can't be met.

Soooo if you for example stop at roadside and turn it off, wait say 10mins (for the float chambers to fill)then restart and straight away nail it in first in theory while the carbs are full, then if it will get past 5000ish this would confirm supply problem and not timing of cam / ignition if that makes sense. If that's the case you need to strip and examine the whole supply pipes unions junctions etc to find it.

If you can't supply fuel at high enough rate then the simptoms can mimic very low float levels as the chambers will not be maintained at the expected level anyway.

It goes without saying that if you're not cnfident of cam timing you should verfy this as a priority.

mickwinf:
i have checked fuel supply and is all clear,i thought it was fuel partly because it sometimes runs better than others.very fed up now will try again in a day or two thanks for all the advice guys,if anyone wants to discuss i can be contacted on 07870112945,cheers all, Mick

SteveD CB500K0:

--- Quote from: mickwinf on May 25, 2011, 08:28:28 PM --- one cyl is down to 50 psi another is only 100 ish.

--- End quote ---

Are you sure? Can't have been finger trouble with the compression tester can it?

50 psi is on the lower side of bad.

Try again. Kill switch off, throttle wide open.

If low, pour a little oil into the plug hole and try again. A different (higher) reading indicates broken or stuck rings.

K2-K6:
Aah, bit of a bummer! If it's cam timing I wonder what could be leading you the wrong way.

I think I was writing my last post as you were, so some of it's a bit out of sequence.

You should be able to measure an increase in valve clearance if you set them when they were all straight a bent one should now show a big gap to the tappet.

I'm sure you'll get there and eventually be able to get it going well.

z1100r:

--- Quote from: mickwinf on May 25, 2011, 08:28:28 PM ---bad news, i tried another set of carbs but their condition is unknown although it did seem to rev better in first gear but ran badly so not conclusive.I thought i would recheck compressions and one cyl is down to 50 psi another is only 100 ish. Bugger

--- End quote ---

Well the thing is ....there is never just one valve down....if you clattered one you just have to have clattered the others. We have been talking fine tuning to resolve your problem, but you just have to have a more serious problem than that. I know how serious it can be... I've been there with a German guy and a 400 four in teh IOM. He was just trying to start his bike on the Kickstart and bent four valves seriously badly when his cam chain snapped whilst he was kicking it over. I put his four valves in a lathe borrowed in the IOM by the quay and straightened them for him just to get him home. He wrote mke a letter a year later thanking me and to say the bike was still going on the same valves.

The guy that built your engine originally needs shooting.

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