jetting?

[05blasterkid]

I just got my blaster bored and am hopefully going to get the jug today but idk. But anyway I was running lean before and I have a 310 main jet with my mods and I'm just wondering what I should start with and go down from? Also, just curious if you bore ur fourwheeler will that effect the jetting? It doesn't much matter cuz mine was lean anyway

 

[yb200]

i ran a 340 main with my toomey and open air box with oil injection blocked off

 

[05blasterkid]

Ok my lid is off too and my oil injection will be blocked off soon

 

[yb200]

mine ran a tad rich with the 340 but thats the way i wanted it, went 6 years on a topend that way

 

[royalt67]

I'm surprised you were running lean with a 310. Are you sure that was the problem? Either way, eliminating the injection will change your mixture so you might want to check your plug before jetting.

 

[05blasterkid]

Dam well I might just start with a 340 and see where that takes me. Also how am I suppose to run my fourwheeler if its running lean and I have to break it in to do plug chops, won't that just blow it again cuz I'm running lean? Or can I just throw a 340 or something else higher than a 310 so I can break it in then do the chops?

 

[05blasterkid]

Well I don't know myself that I was running lean but whn my blaster quit the pipe was red hot and everyone I talked to told me that was because it was running lean ( too much air and not enough gas) except for one guy who told me he thought the oil injection quit

 

[royalt67]

You should leak test it first, always with a new motor. Chances are if you were running lean, that was the culprit.

But yeah, you can always go down.

 

[royalt67]

Hot pipe is a good indicator of running lean.

 

[05blasterkid]

How can I be leaking I just put all new gaskets in the top end and nothing else has ever been touched

 

[royalt67]

A leakdown tester tests the entire motor, seals, gaskets, everything that has to hold pressure or vacuum while running. I built two motors this spring. Both were just top ends. Both had bad crank seals, one much worse than the other, and both leaked at brand new reed gaskets. Do it. It is good insurance and the only way to be sure your motor will be RIGHT.

 

[05blasterkid]

Ok I will but can u answer my question that I posted about the plug chops on the first page

 

[yb200]

1. could of been the oil injection deff remove it and mix 4oz of oil to a gal of premium gas

2. contact holeshotman on here for a leakdown tester i think he charges like 30 bucks

3. once all the above is done get a 340 main and do your break in/plug chop

 

[royalt67]

Dam well I might just start with a 340 and see where that takes me. Also how am I suppose to run my fourwheeler if its running lean and I have to break it in to do plug chops, won't that just blow it again cuz I'm running lean? Or can I just throw a 340 or something else higher than a 310 so I can break it in then do the chops?

I thought I did. Sure, run something higher than a 310 for break-in if you want, then do plug chops. I'm just betting you will find an airleak, like bad crank seals, that was the real cause of your lean condition. If you do find something that doesn't hold air, especially if it is something you haven't worked on, then I wouldn't bother rejetting until after break-in. Most people seem to think the 310 is on the large side, but a 340 is good insurance I guess.

To be honest, I lost a topend last year with a Toomey and a 310. I put on a PWK28 after that and never looked back, but this is the same motor that ended up having really bad crank seals. Bad crank seals = lean.

 

[05blasterkid]

Is 4oz of oil to a gallon of gas the same as 32:1?

 

[royalt67]

Exactly...................

 

[2strokemania]

yea i been having the same problem wit mine i have to toomey set up 340 main but cant figure out whats wrong pipe runs hotter than it did and boggs when pullin the clutch in....but heres my problem the temp outside has been over 100 degrees the last couple days and falls comin up cooler weather what should i do?

 

[royalt67]

100+ temps don't cool as well, but cooler weather requires fatter jetting usually. Same recommendation really. Do a leakdown test to insure engine sealing and then rejet as necessary.

The first time I read about leakdown testing I thought, "Oh, that's interesting, I should do that someday." Now I know it is a basic and required procedure if you are running 2-stroke engines, especially engines like ours that aren't getting any newer!

 

[05blasterkid]

so just clarifying before I get into it, 4oz of oil to a gallon of gas is exactly the same as a 32:1 mixing ratio?

 

[Awk08]

yes on the mixture,
and the breakin should not involve the main jet, only up to 1/2 throttle revs, not 3/4 to wot, < which is where the main kicks in, and one run on a lean main should not fry it, there is always extra oil laying in the cases to cover that if needed,
btw, the 340 should be close, possibly lower, plug chop it after proper breakin
5 heat cycles, lightly revving it till completely warmed up, no more than 1/2 throttle, then complete cooldown, repeat