problem starter

[Andy C]

Hi people thanks for letting me join.
I have a question for you all I have just bought a 2000 400cc Bergman, the issue is it won't crank over properly with the spark plug in, take the spark plug out and it flies over.
New starter fitted new battery, valves adjusted and timed all the earths checked still won't turn past full compression.
Has anybody any ideas as I am at a loss, tomorrow I am going to connect my car battery up and see what happens.
many thanks in advance Andy C

[Normsthename]

I seem to remember that the early Burgmans sometimes had problems with the de-compressor not working correctly???
Might be worth a further investigation.

Andy

[roadster]

Just to expand on that good suggestion. Most 4-stroke scooters have/had a centrifugal mechanism which kept the exhaust valve open at cranking speed. generally this is located on the timing chain end of the camshaft and it can seize up or self destruct in some way. I don't know anything specifically about this early Burgman so if someone has more details no doubt they will chime in.

PS:

Just seen this on C90 club forum

Can some one answer Andy C please. 400 Burger no turn over:
They have a Decompressor on the cam and the drive pin may have broken off.
Ta Lyn.

[Andy C]

Thank you for your replies, I was lay in bed last night thinking about my other single pot bike I have owned my Honda RS 250 had an automatic decompressor and my BSA B31 and M20 were manually operated.
I shall investigate this decompressor on the cam and let you know

[Andy C]

Hi an update on the on the centrifugal camshaft and starting problem, the problem is there is no mechanism at all I have now bought another one.
Thank you that is that problem solved.
My next question is the cam chain guide on a 400cc 2000 Bergman, the Haynes manual says clip one end into the crank case and the other end has a bolt through it my guide is free at the casing and and bolted at the top that to me does not seem right to me as most cam chain guides are fixed at both ends, I can see a slot in the casing below where the tensioner goes but if I get in the slot it is about 1 inch short of getting the bolt in.
does any body have experience with the 1999/2000 400cc Bergman engine.
many thanks

Andy C

[wizzid99x]

Since you've already replaced the starter, battery, and checked the valves, a couple of things to check next might be the compression itself. It could be too high, which might make it harder for the starter to crank. You could also try turning the engine over by hand with the spark plug out and see if it moves smoothly.