Magnum tuning

You got any expreience with puch perfromance tuning? I have a magnum MKII (oil injected) with 14mm bing, 14mm intake and a biturbo pipe. I bought it with the mods. I think I have it jetted proper cause it runs good wide open (34mph). Can't get it to idle and it 4 strokes or bogs depending on needle position. Carb has new bowl gasket and I am running the stock air filter. Is it time to check the timing or is this still a fuel/air thing or......? Thanks in advance.

MikeS

Re: Magnum tuning

sounds like air leak

Re: Magnum tuning

check for air leaks, then down jet one size.

bing tuning tip, keep the needle as 2nd position from the top till you figure out the right jet.

grab one of those foam bing filters from treats 15 bucks?

~SABAT!

Re: Magnum tuning

foam bing and check for air leaks. I'll give it a try, thanks.

Re: Magnum tuning

does the connection between the air filter and carb count? It seems kind of loose on mine. I will check the manifold to cylinder and carb. thanks

Re: Magnum tuning

i always tune my bing with no air filter.

figure out the proper jet without a airfilter because you can just put your hand over the carb to figure out if your too lean.

then i go with a high-flow filter.

uni-pods work great, and those foam guys i mentioned before.

you can spray water/gas/starter fluid (waste) over the gaskets to find a leak, also they can show up at higher rpms (high case compression situations)

~SABAT!

Re: Magnum tuning

I got it sealed up tight with some gasket cement. I sealed manifold to case and manifold to carb. It definately runs different. Guess when you fix a leak then you have to retune? My top end got worse, but it idles now.

Thanks

Re: Magnum tuning

Weather changes to much you have to retune. Joys of a carb. Air leaks and dirty cabs are most of the problems people have with these old mopeds. Do some plug chops to see whats goin on with the top end. Install a new plug fire it up and run it at top end for alittle bit then kill with the switch and pull the plug. If its black your to rich on the top end white and your lean. Adjust from there. Rinse and repeat till you get it to where your happy with it. I tend to keep mine a tad rich. Seize it once and you figure out why I run alittle rich.

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