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How hard should a 4 mill run?


crustydemon

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Try checking your stator with a multimeter, the instructions are in the FAQ's. I am running 140 mains @ 5000 feet, and it feels incredible, temps are as low as 50 degrees. I think you need more octane, I am running about 175 psi, and run straight av gas. make sure your spark plug gas is about .025, and try some new plugs. I came from stock stroke non ported too where I am now, and the difference is day and night.

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Ok, I didnt get as far as I had hoped today but I did drain the fuel and now I have a 50/50 mix of 92 and 110 and 32:1 techniplate. I Put the 160 mains back in but have not tried it out yet. I did warm it up and then tried to rev it out(It still didnt rev right), I just happened to have the seat off and noticed a popping coming from the carbs. Could this possibly be my reeds not sealing against the cages?I ported my cages quite thin but the petals did have a area to sit on when I installed them.

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maybe thats detonation ?? maybe you should run straight AV gas or race gas ..im lucky i pretty much live next to a small airport where i can buy like 102 octane

 

 

The popping is not detonation. Ive got a card for the airport pumps to get avgas 24hrs a day if I wanted but we have race gas on hand 110 and 114. I just didnt want to have to rely on it if I wanted to go on a trip somewhere that I couldnt get it.

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Unless I'm mistaken, the higher octane gas like the 110 and so on won't really make it run any better or have more hp. It just protects against detonation at a higher level which is usually required on a built motor, but mostly depending on the compression ratio. That being said, you should be running 110 or so to keep from frying your motor. But I don't think that's the root of your problems. It could very easily just be the reeds, dirty carbs, poor spark, etc. It's probably something simple bud, it's just a matter of narrowing it down.

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Gearing is 14-41 on little 18 inch rears.

 

I think this is a huge part of your problem..You are wayy under geared for the power that thing is putting out.On 18 inch tires you should be running a 16-41..I would go 15-41 on 20's

 

Your engine should make enough torque to pull those gears and then some.I run a knarly pipe on my 4mill and Im running 15-41 with 22's!

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I think this is a huge part of your problem..You are wayy under geared for the power that thing is putting out.On 18 inch tires you should be running a 16-41..I would go 15-41 on 20's

 

Your engine should make enough torque to pull those gears and then some.I run a knarly pipe on my 4mill and Im running 15-41 with 22's!

 

 

That very well could be, I have a set of 20in. razar's I could try. Anyway I changed the reed cages and petals and got rid of the spacers and I think that made a huge difference. Havent had time to jet today but hopefully get back to it Sunday.

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I was gonna say if you ported your stock cages you should look into getting some one piece reeds...... tdr makes a set....

 

what I mean by that is there is not a slit in the middle of the peddle where it sits on the cage.....

 

Yeah, Ive seen them but dont know what I want yet. I just thought I was doing something good by porting them but it was just a waste of time. I just wanted to save a couple hundred bucks but I guess I'll eventually end up getting some vforce or pyramids. Ive had this problem before but not quite so bad, I must overtighten the screws and it lifts the petals but I am always afraid of having a screw come out. I couldnt get the petals that I took out of it today to seal against a different set of cages either so now I got the low tension petals in instead of the stiffer ones but It is running better and havent noticed any popping through the carbs yet.

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