One side only fires at high revs

[chrispunk]

Hey guys, I've finally got my 250se running, it's got a 400 top end on and mikuni vm32 carbs. It runs well if a bit rich on the right cylinder but the left only fires at high revs. The carbs are pretty new and have only been round the block a few times I've broken them down and given them a spray through with carb cleaner incase but it hasn't made any difference.

I'm going to switch the carbs to opposite sides this afternoon to try and rule out a carb issue.

What else is useful info...

It's points
I think the left spark is weaker than the right
It's got new coils and condenser
Spent a bit of timing and it seems good to the eye. I should really give it a check with the strobe.


Any ideas would be helpful

 

[xschris]

Hook the bike's intake manifolds up to a manometer and sync the carbs. This will make each carb pull at the same amount.

 

[drewpy]

def need to strobe it too and if you have points, use a dwell meter first.

 

[chrispunk]

A dwell meter? I'll look in to that.

I went to strobe it earlier and discovered there are flanes shooting out of the card on the running side. I checked the valve clearances and they're all within spec. I don't think the timing can be that far out.

Cheers for the info guys

 

[TimBuz]

Im having a pretty similar experience with my VM30's. My builds going pretty slow atm, but i am getting flames out the exhaust if i jump on the throttlel, mind you i still need to rtv silicone around my boots and get some stronger clamps for the carbs as they are definitely leaking at the boots. also my mufflers are off so its def leaning out.

give us some more info about your setup. ie.

Post up your jetting specs
Exhaust setup,
air filter situation,
sync the carbs using the paddle pop stick method
make sure there are no air leaks because i know the vm's are a little smaller spigot diameter than the stock carbs.

 

[chrispunk]

So I got the strobe on it and despite being seemingly spot on to the marks both sides where way off on the strobe. It now runs great on the left, not so good on the right but I need to balance the carbs still so hopefully that will clear that up.

Next it's my charging issues, I round a thing dressy posted about bench testing a reg/rec so I'll hopefully do that tomorrow.

Also what's the smallest battery I can still run a button start with?

Thanks