Jetting vito's 240 bbk

[BlasterFreak860]

Hey guys, Im new to the forum and need some help jetting my blaster. I have a 01 blaster with a fresh vitos big bore kit that i just installed about 2 weeks ago. It has the air box lid removed, D&G header pipe, and lrd silencer. Right now i have a 330 main jet, the clip is in the middle postion, and i believe the pilot jet is a 32.5? whatever comes with the vitos..and the air/fuel screw is out 1 1/4 turns..Im running br9es plugs and premix my own 32:1 gas. Ever since i took the airbox lid off it started to run sh*tty and i havent put it back on yet..With the way the jets are now and clip is set up, when i have punch the gas, its like its starving for fuel then gets up and goes, then i get down the road a little bit and then the quad will die on me. And once i turn the petcock to reserve it starts up. And its running a little hot, and sometimes it smokes and sometimes it doesnt..thanks for the help!

 

[Blaaster]

Leak down test, NOW, b8es plug, plug chop!

But I fear it may be too late!

 

[BlasterFreak860]

Alright thanks! Vitos says run br9es plugs, does it really matter that much or no? Isnt one just gunna run cooler? and plug chop is WOT in 5th or 6th gear then kill motor and pull in clutch till stop then pull plug and check it?

 

[Blaaster]

Leak test it first!

Plug chop.

Warm up motor to operating temp.

Fit new B8ES plug, ride through the gears and hold WOT in 5th or 6th gear for 10 seconds, or as long as you can safely.

Switch off the motor and pull in the clutch, roll to a stop.

Take the plug out and replace the old one for the ride home.

Carefully cut the threaded end off the plug to expose the insulator.

There should be a smoke ring of a cardboard or biscuit colour around the insulator.

If it is non existant or a very light colour, you are lean and require a larger main jet.

If it is a lot darker you are rich and may go down a size in main.

I prefer to run a little on the darker side, I may loose a little power but it is worth it for the peace of mind that I won't need a rebuild so soon.

http://www.blasterforum.com/engine-13/plug-chop-how-vid-48226/

Heres one posted by Awk a while ago, this is a good to go plug.

This one is a little rich, but I would run it, I like to be on the safe side.

 

[BlasterFreak860]

Alright thanks for the help buddy!

 

[BlasterFreak860]

Alright well i did my version of a leak down test lol..at work we have a machine called the smoke pro for cars we use when we think they have a leak..so i pulled my plug threaded the end into it and started the machine up, i let it run for a good 5-6 minutes and the only spot smoke was leaking out of was the silencer. None of the gaskets, seals intake boot or anything was leaking smoke..so seems like i dont have any air leaks. So now i can go ahead and do the plug chop?

 

[blasterBruce]

That does not sound like a real leak down test , just because its a smoke machine doesn't mean it will show an Air leak , sounds like your new top end is junk already

 

[BlasterFreak860]

Its as close as i could get without buying a leakdown tester but i might end up having to. It works just like one, trust me we use them on big rigs at work all day and smoke comes out of the smallest holes that is creating an airleak. I mean once i pulled the airbox lid off it started to run differently but i just wanted to try and jet it like that and its not workin to well. Once it gets going and stops bogging i guess you could say, it pulls really hard and i wont have issues with it..it just seems to be wanting more fuel and its running a little hot..but when i go down on the clip position the the 4th position its like its almost to rich for the quad.

 

[Awk08]

/\
NO, that test you did, if it added pressure ? only tested the cylinder above wherever the piston was sitting at that specific time,
maybe TDC ? but probably starting downward on the exhaust stroke, exposing the exhaust port, as smoke came out the exhaust

there is no way to tell if it put 7lbs. pressure into the intake/reed gaskets,
or bottom end < checking for leaking base gasket, case halves and crank seals

what you used tests 4 stroke engines, as the valves are always exposed to the top of the piston, no matter what position it's in

for a 2 stroke complete leak test, you must pressurize the intake, with the exhaust blocked off

also...you do not mention richening of the main jet for the airbox lid off, only the needle
leave the needle in the middle and go up on the main jet a few sizes and try again
or simply put the lid back on before you fry it !

 

[blasterBruce]

Its as close as i could get without buying a leakdown tester but i might end up having to. It works just like one, trust me we use them on big rigs at work all day and smoke comes out of the smallest holes that is creating an airleak. I mean once i pulled the airbox lid off it started to run differently but i just wanted to try and jet it like that and its not workin to well. Once it gets going and stops bogging i guess you could say, it pulls really hard and i wont have issues with it..it just seems to be wanting more fuel and its running a little hot..but when i go down on the clip position the the 4th position its like its almost to rich for the quad.

Wow haha okay sounds good

 

[BlasterFreak860]

Yes sorry, It does put in pressure! i had 7 psi going through it and it held for 5 minutes i had a plug on the silencer but the smoke was leaking through a little bit. The first main jet i had in their was a 340 with the clip at stock position, it ran ok but i didnt think it was rich enough..so i dropped it down to a 330 with the clip at the 4th position, ran to rich and wasnt enough fuel? Im new to the jetting thing and big bore kits and everything. Ive always normally road stock quads and never really put mods on them..So if im doing something WRONG PLEASE TELL ME BEFORE I BLOW THIS THING UP. I just did about 2500 dollars worth of motor work to it!

 

[Awk08]

So if im doing something WRONG PLEASE TELL ME BEFORE I BLOW THIS THING UP. I just did about 2500 dollars worth of motor work to it!

no more 4 stroke truck testers, official 2 stroke leakdown testers only

 

[Blaaster]

But as Awk said, only 7psi, no more.

It is possible to do a leak down test by pressuising the cylinder at the spark plug hole, as pressure will seep by the rings into the crankcase.

But it will not test to see if anything before the reeds are leaky.

A leak down tester is the mechanics best friend, for the measly outlay it can save thousands of dollars.

 

[blasterBruce]

I bought a leak down tester before I bought a new top end ,

 

[BlasterFreak860]

Alrightly then, ill do a legit leak down test tomorrow at work. I mean its got brand new boyesen reeds and rad valve..all new gaskets,seals and bearings. Everything, i mean everything in this motor was replaced! all new bottom end and top end. I have a carb laying around from a 1990 cr125 its a keihin pj, not sure the size, but will it work on my blaster if i end up needing a carb??

 

[Awk08]

that cr carb will work wonders on that bbk, now look for a different pipe than that DG, thats gonna hold you back too

and the reed gaskets are a very popular spot for leaks, even brand new, most of us have found some sealent to help there, i like a light coat of hi temp copper perma-gasket,

 

[Blaaster]

Point of interest, you are running a DG pipe and a BBK 240.

That DG may hinder performance, it makes absolutly no difference in power to a stock motor.

Before you consider another carb, try to get your hands on a reputable pipe.

 

[Awk08]

here's the DIY leak testers...........

http://www.blasterforum.com/do-yourself-20/build-use-leakdown-tester-10663/

 

[Blaaster]

Ruddy slow keyboard!

 

[BlasterFreak860]

Alright my buddys gunna let me use his extra fmf pipe. My next question is for the cr carb..What do i need and can i use the vitos jet kit with it? and since its bigger its obviously not going to fit in the airbox opening so what do i do about that? Thanks for the help guys!