Wont exceed 4,500 rpm then stalls and wont restart - on route to MOT

[notobikeparkingtax]

I set the tappets when I first bought it 350 miles ago, could they cause these symptoms?

Sure could. If they're too tight then at higher revs either the inlet or exhaust valves might not be closing completely - causing lack of compression.

Worth checking, supposing there was a spot of carbon on one of the valve seats last time you checked them, giving a false reading ? How long will it take, 30 minutes ? How long have you spent on it already ?

And yes, valve clearances close with wear, and camshafts do flex.

[rigwit]

clean float chamber out sounds like a dropplet of water  which will be picked up and resonate at a certan flow /revs also clean out your inline fuel filter as if any water droplets in with petrol you could go 1 to 1,000 miles b4 it happens again  one of those annoying probs that come and go ...........

[totty]

I hope to get some time to work on it this week end. I'm going to work in order of easyness - check fuel filter and drain carb bowls, check tappets, relay coil feed, adjust needles and re sync. Hopefully one of those steps will sort it out.

[K2-K6]

Hi Anoyone checked the air filter? just run it with it out for a test to see effect (had a filter do this on another Honda and I could not beleive the effect was so defined, took me ages to sort). Not sure of the intake on the 550 but friend had 400/4 and put overtrousers over air box intake under seat and caused similar probs once. It'll be interesting to find out what it is, shame we can't get you more help.

Have you done a plug inspection on all cylinders when it's running hot to give you an idea of mixture?

What is the psi reading for compressions on each cylinder?

If you start it from cold, run for 30secs, switch off and touch the header pipes to see if all are similar temp tells you if they are all firing straightaway.

Check through the fuel tap to make sure there is no blockage in any passageway

BTW fuel always comes from the bottom of the tank when on reserve!! I've always run everything I've owned bike/car to as near empty as I can (what's the point having range if you don't use it) and never ever used additional filters. My theory is you might as well run anything that could be a problem out so it will never accumilate things you don't want in there. On that note, if you don't use it down to the bottom do you have a tank cleaning schedule? to get out the mythical junk.

[totty]

Hi,

I tried without the airfilter and checked the plug colours, the airfilter made little if any differance and the plugs looked good but that was some time ago and I've replaced the ignition system since. Also tried pulling the choke on when it bogged, but the choke doesn't stay on when the revs are up and in that rev range power delivary is a too bit unpredictable and rough for 1 handed riding.

I don't recall the compression readings and i can't find my notes but they were all within 5%.

I've twice found that number 4 didn't heat up imediately, but I then made a point of checking on most startups and it hasn't done it since.

The fuel flow seemed good when I let it flow into a can.

I don't normaly aim to drain a tank or have a cleaning schedule, but I have drained and rinsed out this tank.

[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.

[totty]

This is kind of on hold as I've discovered the front brake needs servicing (other thread).

I've dropped the needle clips to the centre notch but haven't had an opportunity to test it out. (needles were moved before checking cam timing as I could only find 2 elastic bands and needed 4 to hold the rockers)

[Yoshi823]

As far as refitting the cam cover is concerned, just back off all the tappet adjusters completely, and this will give you sufficient clearance. Get it wrong & you could end up bending a valve...i've seen it done.

I had a thought over the weekend about the situation that you have on your engine. Does the automatic advance & retard mechanism work? You may well need to remove the points in order to get a firm enough grip on the points cam. If the cam was seized in the fully advanced position, it would make it difficult to start & to not rev properly. If it is seized, make a mark on both the cam & the A/R units back plate, as it's easy to get the cam 180 degrees out. Check the springs have sufficient strength in them to return the weights back to the rest position...if they've been stuck in the advanced position, it may well have stretched the springs.

[totty]

I've removed the advance/retard unit as part of the fitting of a Boyer ignition kit.

Cheers

Allan

[K2-K6]

I'll bet you'll be glad when you get it fixed.

When it stops is it really roasting hot or more normal range? as dropping the neadles will make it hotter ordinarily.

[totty]

temp seems normal to me, but i've only got a monkey bike to compare it to. I'm never sure of the needle terminology, I've lowered the clip to the mid notch thereby raising it one notch making it richer.
I can't wait to get it sorted!