SOHC.co.uk Forums > CB500/550
Wont exceed 4,500 rpm then stalls and wont restart - on route to MOT
Yoshi823:
There are two air jet inlets at the intake part of each carb. From what I remember the left one is for the primary jets & the right one is for the main jets. When you last had the carbs off to clean did you spray carb cleaner in via these air jets to see that the fluid comes out of the relevant orifice?
http://www.google.co.uk/imgres?imgurl=http://www.dansmc.com/carbs/japanese_carbs/suzy_re5_carb.jpg&imgrefurl=http://www.dansmc.com/carbs/japanese_carbs/carb_pics.htm&usg=__vYxHYn_Xyr7XOV7XJmyNl65HUHU=&h=555&w=750&sz=55&hl=en&start=20&um=1&itbs=1&tbnid=junylZL4_PQTcM:&tbnh=104&tbnw=141&prev=/images%3Fq%3Dmotorcycle%2Bcarburetor%26um%3D1%26hl%3Den%26client%3Dfirefox-a%26hs%3D0Q4%26sa%3DX%26rls%3Dorg.mozilla:en-GB:official%26channel%3Ds%26ndsp%3D20%26tbs%3Disch:1
http://www.google.co.uk/search?hl=en&client=firefox-a&hs=7ij&rls=org.mozilla%3Aen-GB%3Aofficial&channel=s&q=carburetor&aq=1&aqi=g10&aql=&oq=+carbu&gs_rfai=
totty:
Yes I sprayed carb cleaner into the air jets. I don't recall which air jet came out of the main jet/ emulsion tube area and which came out of the pilot, but the passages were clear on all carbs.
K2-K6:
Hi
Was it going when you got it / have you seen it run correctly?
If not it might be wise to check cam timing, think you can remove cam cover in frame on this one.
To check fuel flow fully you need to remove a float bowl (go for furthest from supply pipe) and turn tap on, it should flow reasonably fast into this say an egg cup ish in 5secs (is an egg cup an official scale in bike mechanics!!).
Looks like you've checked carbs quite well and if two sets of ignition give the same results that seems to get them off the hook.
Seems like you've got a few of us scratching our heads on this one so hopefully somone can come up with a reason for it.
totty:
You could be onto something there, no I have never seen it run correctly. It ran when I bought it but it was very flat and took ages for the revs to build, correcting the ignition timing made it more responsive and that's when I discovered the current issue. I'll check the manual for cam timing instructions.
K2-K6:
I've seen quite a few things run with "curious" cam timing both car and bike and it can be used as a method of changing power curve particularly on twin cam in which it alters the valve overlap period but you'd really have to have good reason and knowledge to vary from stock.
It'll be interesting to see if yours is correct or not, but if not i'd guess at cam timed early as being slightly late I would have thought it would give a bit of a screamer with poor starting.
If you don't find anything we'll have to think harder!
Cheers.
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version