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How hard should a 4 mill run?


crustydemon

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It revs clean, no sputter or popping or anything, just low reving. I wouldnt even say it pulls hard till mid but not too bad,its hard to say because I have to shift so soon to keep it in what power it has. Its like its falling flat right before where I think it should be getting on the pipe and taking off. I would guess its my jetting but I have made so many changes to this bike all at once I dont know. Ive read that someone had problems with there pickup being too far away from the flywheel but I dont see how thats even adjustable. :unsure:

whats the gearing and rear tire size?maybe it feels slower cause your gearing is off?
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It revs clean, no sputter or popping or anything, just low reving. I wouldnt even say it pulls hard till mid but not too bad,its hard to say because I have to shift so soon to keep it in what power it has. Its like its falling flat right before where I think it should be getting on the pipe and taking off. I would guess its my jetting but I have made so many changes to this bike all at once I dont know. Ive read that someone had problems with there pickup being too far away from the flywheel but I dont see how thats even adjustable. :unsure:

 

 

Oh yea its adjustable and if its not right it will not run for shit.If its real bad the power will be completely gone bike will not rev at all if its a little closer but still not right it will rev but act like its on limiter at high rpms. The pickup will slide if you loosen the screws up. If something has happened to it you may have to bend it to get it back right. I assure you you can jet and rejet till the cows come home but if that pickup aint right it wont run right for shit.

Edited by RILS
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I dont think that jetting is lean at all,how does the chop look.With those durations that pipe is within its limits.I just jetted a 4mil with 196 deg w/34pjs at 162 50.I could have dropped mor but most people dont jet daily like myself so I left it richside/safeside.What makes you think its lean if thers no popping or spitting,if its lean the plug will be almost white still after running it

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I dont think that jetting is lean at all,how does the chop look.With those durations that pipe is within its limits.I just jetted a 4mil with 196 deg w/34pjs at 162 50.I could have dropped mor but most people dont jet daily like myself so I left it richside/safeside.What makes you think its lean if thers no popping or spitting,if its lean the plug will be almost white still after running it

 

 

I agree with it sounding rich. I run a 4mill cub 34pjs 50pilot cel needle 155mains at 900ft.What needle and pilot are you running?

Edited by RILS
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Did you use a spacer between the cylinder or do you use stroker domes?

Was your porting done prior to the stroke because if so you may need to lower your exhaust port and actually get the port work re-done completely; if the piston falls below the exhaust port on its downward stroke the stream will hit the cylinder below the port dead on and cause a lot of turbulence and will kill your top end.

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Just checked the pickup gap and I have .035. That might be it. Gearing is 14-41 on little 18 inch rears. There was no need to do a plug chop because with the 160's the plugs were as white as can be, just glad there was none of that pretty melted aluminum on them.I did think I would be rich though. Needle is CGL which I put on the bottom clip and I think that is the same as the CEL on the middle clip but have been wrong before.If it warms up today Im going to take it out and try it with the tighter pickup gap.

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The whole "cant keep the front down thing" is a very broad statement imo. Has to do A LOT with traction. Your squish seems fine. That's how mine is. The person who ported your engine should be able to help you with that and getting the bike running imo.

 

Anyways, here's what it looks/sounds like with a slipping clutch.

 

here's some playing around.

 

Here's some drag racing with no traction.

 

If the pickup gap is too big, the bike will cut out in the higher revs onces it warms up. At least that's what it did to me one time.

 

Did you to a leakdown test?

Edited by RagunCajun
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Did you use a spacer between the cylinder or do you use stroker domes?

Was your porting done prior to the stroke because if so you may need to lower your exhaust port and actually get the port work re-done completely; if the piston falls below the exhaust port on its downward stroke the stream will hit the cylinder below the port dead on and cause a lot of turbulence and will kill your top end.

 

No, Im not using any spacers anywhere,stroker domes. The porting was done for the stroke and at BDC the exhaust and all transfers are perfectly inline with the edge of the pistons, No edge at all.

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Just checked the pickup gap and I have .035. That might be it. Gearing is 14-41 on little 18 inch rears. There was no need to do a plug chop because with the 160's the plugs were as white as can be, just glad there was none of that pretty melted aluminum on them.I did think I would be rich though. Needle is CGL which I put on the bottom clip and I think that is the same as the CEL on the middle clip but have been wrong before.If it warms up today Im going to take it out and try it with the tighter pickup gap.

 

 

I thought that was it ur pickup gap is way too much needs to be .015-.020. Fix that and u should be getting somewhere then u can start on your jetting.

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The whole "cant keep the front down thing" is a very broad statement imo. Has to do A LOT with traction. Your squish seems fine. That's how mine is. The person who ported your engine should be able to help you with that and getting the bike running imo.

 

Anyways, here's what it looks/sounds like with a slipping clutch.

 

here's some playing around.

 

Here's some drag racing with no traction.

 

If the pickup gap is too big, the bike will cut out in the higher revs onces it warms up. At least that's what it did to me one time.

 

Did you to a leakdown test?

 

I know about the traction ,thats not my problem right now. Those are good vids and I'll see about the clutch after I get it running right.I did a leakdown test for about a half hour and it didnt leak at all.Thanks.

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I guess I'll just put the 165's back in and work from there. There's no way that can be lean. I dont even have pods on it yet,I had to rig up one of those toomey 2 into 1's so I had it filtered so if anything it should be restricting airflow or so I would think.

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Do you think its possible that I need to run high test. The regular pump gas has gotten real bad around here,low octane like 91 tops cause they try to push that corn gas shit off on everyone by staying one point higher and 10 cents a gallon cheaper.I have access to plenty of race gas but didnt think it was going to be necessary.

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