[308] Not running like it used to

[delcowizzid]

it will most likely still run advance weights and springs does the shaft turn when you grab the rotor and try turning it maybe the advance has rusted or is not moving freely maybe some lube required

 

[crazybiker]

It's definitely advancing. We're getting advance on it, we know that.

Plus, wouldn't a vacuum advance problem just make you lose a little power? Not 1500RPM?

 

[delcowizzid]

when the throttle is wide open it shouldnt effect it unless you are out flowing the carb and causing vacum at high revs that would effect it then if the vacuam advance wasnt working .but ide say you can rule the vacuam advance out really.it might of been running a lot of base timing and now its so low it cant rev out try advancing it more and see just listen out for pinging.if the dizzy was ever regraphed to suit the cam it will need to run more base timing thats pretty much how the regraph works you put stiffer springs in and advance the base advance the stiffer springs stop it over advancing giving you the same max advance even though you have more base advance.

 

[crazybiker]

Well, dad and I have ended up putting it down to a problem with a valve.

Not sure specifically, but we've got suspicions of a weak valve spring on cylinder 3.

It's the only side that breaks down in high RPMs.
It has started to make an awful sound, not loud, but not normal.
Cylinder 3's plug isn't burning right. There's carbon build up.

Dad's decided that he's gonna get a new motor anyway, so now we're in the hunt for a reputable performance motor builder in sydney.