killer454

Member
Jan 3, 2011
47
0
right now the needle is on the 4th slot from the top im going to put it on the second from the top and lean it out,and install the new seals and get back to you guys after i do these fixes.

thankyou for the help and please dont giveup on me im fixing anything you guys think it might be.i dont care about the cost if you guys have an idea of whats wrong with it let me know and i will look at it and then purchase it if you guys feel that could be the problem.

i will get back to you on here after i put the new seals in and start over on the jetting from scratch to see how its running.

thankyou from killer454
 

Uchytil

LIFETIME SPONSOR
Jun 29, 2003
814
9
Advise? If you replace the main seals (on the crank), and have a correctly installed PV, and all the other crankcase sealing points, ie. reed block, jug, PV, etc. are new and tight, you could do a crankcase pressure test which is hard to get exact without the proper sealing tools. I use a machined piece that fits into the carb. boot that has a port & needle valve to allow air in (or vacuum) from a hand pump. I use about 2-3 psig and allow it to set a few minutes to watch for drop. Newer bikes (meaning ones with multiple sealing areas) can give false readings at the PV seal which (in my testing) has never been very good for sealing. I'd say if the seals are all new go back to stock jetting and start over. I still think the steel liner and domed piston are mods that may have affected the mill. Good luck.
 

killer454

Member
Jan 3, 2011
47
0
ok i will do what you said,and get back to you after new seals and rejet from stock settings.

thanyou for the help

what do you mean by affected the mil?
 

Uchytil

LIFETIME SPONSOR
Jun 29, 2003
814
9
Sorry, mill = engine, same thing, different name. All I mean is that any mods done to an engine can affect your ability to dial-in the engine. Not that it can't be done, just that it may be outside normal parameters. Hey, you can always send the engine to eric Gorr for a 144 upgrade ;)
 

killer454

Member
Jan 3, 2011
47
0
i had a guy from a shop tell me that its my gas.

i have a dome piston in it and he said to run 105 octain gas with a very good oil for mix.

we have 89 octain fuel in this bike now

could this be the problem?
 

whenfoxforks-ruled

Old MX Racer
~SPONSOR~
Oct 19, 2006
8,129
2
Merrillville,Indiana
It is not the best thing, running regular gas? If it was bad, it would be detonating. Run premium, 91~93, what ever is the highest should be fine. If it is detonating, the spark plug is coming unscrewed, you hear a knock? I would be guessing the compression would be well over 200 psi? Then it MAY need 100 octane.
 

Uchytil

LIFETIME SPONSOR
Jun 29, 2003
814
9
I was thinking the same thing as FF. If you now have a high compression engine you may have to run a higher octane fuel. Problem is you still don't have an accurate compression test, never mentioned if the head or deck height was altered, and etc, etc. Fun, fun - right? I guess if you replace the seals and check everyting over try it on premium, and if no joy try a higher octane.
 
Nov 8, 2010
142
0
man domed piston would be massive comp not 155 any other mods? head decked to? is the ring all good? dont go below 95 is my rule its 98 or if i can get it 100 pretty sure my manual says use over 95 anyway lol
 

killer454

Member
Jan 3, 2011
47
0
no other mods that i know of bought the bike used needing a top end rebuild.

when we got the cylinder and new piston i noticed it was domed and new ring and rist pin bearing,but did not think the gas could be the problem.

the bike does not seem to be making a nocking noise that i can tell,i have two blasturds and it sounds like them to me.plug really rich
i did not have nothing done to the head but dont no about anybody before me.

only thing i have done to the bike is basically have a LA sleeve installed with new piston (domed),boysen power reeds,it has a pro-circuit header and stock cylincer.

im thinking gas my be my problem,im going to put the new seals in and try a 100 octain and see.
what ratio would you mix 100 octain at?
 

killer454

Member
Jan 3, 2011
47
0
ok were ganna put seals in and and get 100 octain in it and mix 32:1 and rejet

hopefully it fixes the off idle bog.

thanks guys for all your help! :cool:
 

killer454

Member
Jan 3, 2011
47
0
we finally got it fixed lol it was the cheap 89 octain gas we had in it lol we put 110 racing gas in it and jetted and runs like a striped ass ape :nener:

thanks guys for all your advice. im really glad to have my bike running. :cool:
 

killer454

Member
Jan 3, 2011
47
0
my nephew posted the post above guys thought i would give more info in detail incase sombodys having the same problem.
we bought the 110 octain fuel and mixed 32-1 and started with a 420 main 32.5 pilot,needle on the first slot(lean).

the bike ran better than it has since we started,he took the bike for a run and then back.it still had a very slight bog off idle but was not as bad as before.we pulled the plug and it was not wet.it was actually cardboard brown so the main is right on.

while the bike was idleing i noticed it would race up,so i thought this was lean pilot so we put a 37.5 pilot.man this thing did not bog at all after going up to a 37.5 pilot.

thinking we are going to try the 40 next and maybe raise the needle to the second notch from top.and start over to see what we come up with in the end.

the whole problem with this bike was the low octain fuel we had in it.
thanks for the help and hope this helps others
 
Last edited:

whenfoxforks-ruled

Old MX Racer
~SPONSOR~
Oct 19, 2006
8,129
2
Merrillville,Indiana
Was it the fuel or the jetting? Personally, 89 is too low, and 110 is too much. You did not try premium/93, pretty much what all modern mx bikes run on? Good gas and good race fuel are that far apart now a days, But the bog was not the defining moment for 110. I run race gas for the smell, or for detonation. Not because of jetting issues. There is a lot of race fuel out there that will burn up a 2 stroke quicker than I can type.
 

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