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Hi everyone, i hoping someone may be able to shed some light on this.
I have a problem with my recently rebuild engine. It’s all back in the frame but no connected up yet or any oil in it. The problem is with the kickstart (I think) - basically if you try to turn the engine over with the kickstart it feels terrible with a huge amount of compression, so much so that you would never have enough ‘swing’ for it to fire, however with the plugs out it turns over fine. The engine has been rebored to take NLM 375cc pistons, at this point I do have to admit that I’ve never owned a new bike nor ever in 20+ years had a freshly rebuilt one, but something just doesn’t feel right to me. I’ve checked the valve timing, and that seems ok, valve clearances are ok, I’ve reinstalled the kickstart mechanism as per Paul’s video. But the problem persists. This is going to be difficult for someone to answer without having the bike but should a rebuilt engine be this tricky to kick over with that much compression? Maybe I should also mention that I can rotate the engine by hand with the flywheel no problem (even with the plugs in).
Does anyone have any ideas, suggestion? If I was closer to NLM (ie not in Spain) I would take it too them for them to look at, but obviously that’s not an option……at the moment!
Thanks, Tony

if you can turn the engine over by hand using the flywheel , the kick start mechanisim must be jamming check you have it fiited correctly it takes a few goes to perfect.

What happens if you loosen the left hand case bolts slightly? It sounds like the kickstart is binding doesn't it.But i cannot envisage how.

Thinking laterally, I had to relieve at least one of the oil-pump mounting screws (I forget how many now) to clear the Primary-gears on one of my engines. Could it be something like that, and removing the plugs just reduces compression/resistance enough to turn it over?

My Sport can be very difficult to kick over sometimes when hot and the compression is perfect.

New engines can be quite tight and if you can't feel any problems when kicking with the plugs out, you should be OK.

Morning Everyone,

Well i have reset the kickstart mech, swapped it for a spare one i have and the 'problem' is still there. But with out the plugs in it turns over smoothly with no issues. So i think that i may be worrying over nothing and will take Paul's advice, working on the theory that as its a fresh rebore and complete bottom end rebuild the engine will be a little tight and compression should be perfect. Its also probably highlights the fact my old sport engine was a little worn!

Many thanks for all the advice, i will start connecting it all up and report back. Thanks, Tony