do i have the right jetting??

0

03BlasterJohn

New Member
Apr 27, 2012
22
0
0
South Florida
What main jetting do I need if I have the following upgrades: Fmf gold series fatty with powercore 2 silencer, uni airfilter (w/stock box) and a small overbore (0.050mm:-/)??

Thanks for your input

Btw I have a #260 in now.
 
a 260 should be very close. Most are in the 250-270 range, as SI said above if air box lid is removed it may need a larger jet only one way to know for sure! PLUG CHOP!
 
03BlasterJohn said:
What main jetting do I need if I have the following upgrades: Fmf gold series fatty with powercore 2 silencer, uni airfilter (w/stock box) and a small overbore (0.050mm:-/)??

Thanks for your input

Btw I have a #260 in now.
Click to expand...

If you Do Not Own One, You Should , Talk to Slickerthanyou about his Leak Down Tester , The First Tool You Should use on your Blaster before Every Ride !
 
03BlasterJohn said:
Ok, but I need to know if I have the right size jetting, not if I have any gasket leaks.
Click to expand...

How long did your leak down tester hold pressure for?

Slick posted 2 words. Plug chop

We can only give ballpark jetting advice, the final choice is made by you, depending on your elevation, temperature, and oil ratio.
 
No leakdown test, motor was just rebuilt with 0.050 overbore. Trust me, no leaks. I can buy the tester and test but I am sure no leaks.

Im in South Florida, below sea level lol.

I appreciate any advice trust me. I just want to know if I have the right jetting with the mods I have. For some reason the previous owner had a #220 Main in there with these current mods and the bike was running kinda rough, so I took the carb out and changed to a #260 main. Bike is running a lot better. I just want to know if this #Main jet is ok.

I'm currently not premixing cause when I bought the bike a coupl months ago it still has the resevoir on it. Just ordered the block off kit from Vito's.
 
03BlasterJohn said:
No leakdown test, motor was just rebuilt with 0.050 overbore. Trust me, no leaks. I can buy the tester and test but I am sure no leaks.

Im in South Florida, below sea level lol.

I appreciate any advice trust me. I just want to know if I have the right jetting with the mods I have. For some reason the previous owner had a #220 Main in there with these current mods and the bike was running kinda rough, so I took the carb out and changed to a #260 main. Bike is running a lot better. I just want to know if this #Main jet is ok.

I'm currently not premixing cause when I bought the bike a coupl months ago it still has the resevoir on it. Just ordered the block off kit from Vito's.
Click to expand...

i really recomend a leaktest but whatever its your blaster, and i would start at a 270 and plug chop and go down from there.
 
03BlasterJohn said:
with the leakdown tester, what PSI should it be at? What will I need to look for?
Click to expand...

make sure the piston is at BDC and then pressurise the head to 7 psi and if it hold 7psi for 15 min or longer your good. dont forget to block the exhaust port and get soapy water and squirt it on the gaskets and reeds, and the case halfs if it starts losing pressure.
 
03BlasterJohn said:
No leakdown test, motor was just rebuilt with 0.050 overbore. Trust me, no leaks. I can buy the tester and test but I am sure no leaks.

.
Click to expand...

Brother when it comes to trust, never trust that a fresh rebuild is leak free.

I have been building 2 strokes for over fifty years, and still get air leaks.

Do yourself a favor and leak test, before you try to jet and ride.

If you have started it, have you done heat cycles, to condition the gaskets, and then re tightened the head and jug bolts?
 
89blaster89 said:
make sure the piston is at BDC and then pressurise the head to 7 psi and if it hold 7psi for 15 min or longer your good. dont forget to block the exhaust port and get soapy water and squirt it on the gaskets and reeds, and the case halfs if it starts losing pressure.
Click to expand...

I didn't know this was going to turn into a leakdown thread. But this sounds like a lot of work just to find out if I have the proper jetting.

What is a plug chop and how is this used to determine proper jetting?
 
Blaaster said:
Brother when it comes to trust, never trust that a fresh rebuild is leak free.

I have been building 2 strokes for over fifty years, and still get air leaks.

Do yourself a favor and leak test, before you try to jet and ride.

If you have started it, have you done heat cycles, to condition the gaskets, and then re tightened the head and jug bolts?
Click to expand...


Heat cycles have been done by my mechanic and he also retightened after break-in.

I will purchase a leak down tester this week and let you guys know the results.
 
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