SOHC.co.uk Forums > CB500/550

sluggish 550

(1/9) > >>

mickwinf:
hi guys,today i had a play with the k3, took the carbs off to clean out again and fit the new carb to airbox rubbers which arrived from America last week.Once they were refitted i set them with vaccum gauges,timing and valve settings etc and also fitted another twistgrip as the old one was sticking.Now for a quick roadtest before dinner.It started up first kick and sounded great, but when out on the road it seems a bit flat about 5000 rpm it dosn`t seem to want to go above that.Any ideas from you experts out there?? thanks,Mick

totty:
You might want to take a look at this thread with similar symptoms http://www.sohc.co.uk/index.php?topic=2647.0

z1100r:
 Obviously somethings very wrong...5,000 revs, blimey my mates got a 13,000 mile from new K3 that he dug out with the intention of a similar rebuild to my 500 - I think he reckons I'm going to be keen to help. We had a quick spin round the block on it. I hit 9.500 revs easy and it pulled from nothing in 5th all the way. I was very surprised how good it was. Its a very tidy bike anyway, but the stock exhausts are a bit pitted and with alot of use I can see them falling apart...a shame.  Lovely bike to ride though.

 Not sure what your problem is...What happens at 5,000 exactly.....what do the plugs look like. Is the advance and retard mechanism OK, are you absolutely sure you got the valve timing right. Is the throttle fully opening, is the choke closing. Are point and condensors OK, does it rev high and freely on the stand. It really is imposible to pinpoint something definate...if I heard and rode it I'd know pretty much instantly....its one of those sort of problems that require you go over everything again...have you got  a strobe..?? have you got good fuel supply...??

mickwinf:
thanks for ideas, i have checked valve timing and clearances,static timing spot on,will check with strobe for advance/retard.Carbs have been cleaned thorougly several times with carb cleaner and compressed air, but i have not checked float hight.I do have a in line filter, will try without to see if that makes a difference, i do have a motad fitted.At low speed it seems to be ok but dosn't want to rev above about 5000 rpm, the exhaust sounds flat, as if it was on 3 cyls, but no misfire, seems to rev ok on the stand.Compressions were ok when checked before( see my other threads)I remember my old 500/4 reving right through the red line and out the other side once when i tried to outrun a gold wing!!

totty:
Does it also come to life above 6,000 if you down change to get it there?
Does the effect get less severe if you give it a longer run out?

I richened the needles 1 notch which made a significant improvement but haven't gotten around to adjusting the jetting further. In my case the flat spot is present regardless of throttle position.

Navigation

[0] Message Index

[#] Next page