I'm stuck, we've been right through the electrics & wasted a bit of cash thinking it was an electrical fault. She won't rev up past about 3 - 4k revs & I originally thought it was carbies. So now I'm sure it is but I've been right through them 3 times & everything looks perfect. So after looking at the schematics on CMSNL I can see a part that looks like a diaphram & spring under a side plate thats linked to the slides & mine doesn't have them. The parts listed as No.11 aren't listed & wonder if they weren't ever produced or something. I'm hoping someone out there has a similar model & knows if there's a diaphram supposed to be there, it might be the answer to my problems.
No it's electronic, CDI. Replaced the CDI & checked all the resistances in the magneto wireings & coil, all within spec.
I had a problem with my ST1100 when I first got it in that it would not rev past 3500. Turned out to be the PO had fitted a foam outer ring to the paper air filter and the poor thing couldn't breathe. New filter and all fine. How is your filter? Tried it without the filter? The small diaphragm may be a fuel shut off valve for US models. Have found a few things like that on cmsnl.
All this testing is with out any airbox at the moment. The filter was non existent when we got it, literally spent the last 6 years in a shed on a farm. The rats hadn't got to it luckily. You are right about the diaphram, it's an air cut off valve used on the 400's. Ive been reading of similar problems on the 400's but one was fixed with a new CDI, his was hard to start & got worse with heat, mine starts astonishingly well & idles like a dream, she revs up to 3k perfectly then dies anything over. I can get a rev response when the choke is pulled out which is why I believe it's carby related. I'll check the valve clearances but don't expect to find anything there, the compression test showed all good. Whats the chance of getting another faulty CDI ? The best test now would be with another set of carbies, but thats going to have to be the last straw.
