new build

[blastblast2]

I just built the top on my blaster and it has a higher compression piston and a fmf slip on.it was bored. 80 and I'm still running the air box lid I just want to know if I should run a bigger jet and move the clip on the needle for more fuel so I don't go lean I would rather have to change the plug a lot than have to rebuild my top again.I have a 240 and 250 main already I just don't know what I need to do

 

[Blaaster]

If you have fitted a FMF header pipe they recommend a #260 main jet with the airbox lid on.

If you premix at 32:1 try a #270.

Use the stock pilot of 32.5.

Leave the needle on the middle clip and plug chop to confirm the jetting.

Leak down test it before starting it.

Do heat cycles and break in proceedure and it will last.

You should not have to change the b8es plug with correct jetting, other than regular maintenance.

I run 25:1 and jet on the rich side and never foul plugs.

 

[blastblast2]

I don't have the full pipe just the silencer the bigger part of the pipe is the stock one

 

[blasterBruce]

Well then you do not need to change your jetting then

 

[blastblast2]

The piston is like a vitos with the exhaust side of the top slanted so the extra compression and the way the piston is made should not need jetting? What's good news I didn't want to take the Carb back off lol

 

[Blaaster]

Have you leak tested it?

 

[blastblast2]

No I don't have the tester for it

 

[blastblast2]

It seems to run fine an all I just don't want to go lean

 

[Triplecrown421]

The piston is like a vitos with the exhaust side of the top slantedl

the top of the piston is slanted?

 

[Blaaster]

No I don't have the tester for it

The most important tool in the box is a leak tester.

A leak test should be done after every rebuild or modification done to the intake side of a 2 stroke.

It is also a great idea to do a test at least twice a season.

It seems to run fine an all I just don't want to go lean

If no leak test was done there is no guarentee that it is air tight.

 

[best]

the top of the piston is slanted?

Yeah, it is a trick often done rather than grind the exhaust port higher,
just put a bit of a chamfer on the exhaust edge of the piston.
We'll do it to that old test mule of yours before we wear it out to see what even more exhaust duration will do.