MODIFIED BLASTER JETTING HELP PLEASE!

[blastermx247]

Ok, i have a blaster i just rebuilt and am having trouble with main jet sizes, list of mods are: FMF fatty pipe with powercore silencer, 4 degree timing advance key, head rechambered to "hemi" style head, running approx. 165psi compression, bored .080 (68mm piston), stock vm26 carb with boyesen carbon fiber reeds, reed spacer, vitos jet kit with currently 360 main jet, uni pod off the carb( currently no air box) 200 feet about sea level
i built this quad mainly for something fun to mess around in the woods with, built mainly for bottom end power, not looking for peak topend performance although it seems a little flat on the top end, The lowend seems very snappy also coming up on the pipe, top end seems to leave a little to be desired, just wanted to see what anyones thoughts were, i know there are a lot of experienced blaster guys on this forum, any help would be very much appreciated, thanks!

nks!

 

[blasterkid1998]

that 360 main seems way too large. and jet kits are bad news. have you leak tested it?

 

[blastermx247]

yes, intake side is air tight

 

[Herpderplol]

what about other sides? have you leak tested it, or did you spray starting fluid or something else flammable on it?

premix fuel or stock oil injection?

fmf calls for 260

i would say try 310-270 MIKUNI JETS. dont buy the jet kit crap

 

[Awk08]

what led you to the 360 main ?
plug chops are the only way......
http://www.blasterforum.com/threads/how-to-plug-chop.53237/

 

[dirtysquared]

Ditto what everyone said above. Also only buy Genuine Mikuni Jets. Jetsrus or Carb Parts Warehouse are good places to get them at.

 

[Blaaster]

Are you using the stock needle?

The needles that come wit jet kits are usually garbage and do not suit the needle jet

Where is the clip on the needle?

 

[blastermx247]

engine is air tight, just a very slight exhaust leak where the pipe slips onto the flange bolted to the jug, needle is not stock, its a vitos jet kit need, i do have the stock one though, clip is in middle position, i had a 270 main and it ran fine prior to adding the pipe, timing advance, headwork, jetkit

 

[blastermx247]

i thought that with the much higher compression aprox. (10.5 to1) that i would need to jet it up some but i tried everything from a 300 main jet up to a 360 (currently) all with similiar results and no fouling on the plug, and i do have both mikuni jets and jet kit jets, but currently running a mikuni jet do i need to drop it below 300 maybe?

 

[Blaaster]

Compare the Vitos needle with the stock needle, you may find the taper is different.

I have never had any good results by using any other needle than the stock one in a stock carb!

 

[blastermx247]

currently running belray synthetic oil at 32:1 on 93 octane and lucas ethanol treatment added, i dont currently have the space right now to do a full plug chop on it, i tried doing a plug chop in 2rd gear but plug looked good

 

[blastermx247]

i think i may try the stock needle with maybe a 290 main jet and see where that gets me

 

[Blaaster]

Make sure the float level is correct?

Warm up the engine and set the idle as per specs!

#32.5 pilot, stock needle on middle clip, #290-#300 main jet.

 

[Herpderplol]

try to get in 3rd gear and go WOT and hold the brakes so it makes the engine work hard, try to get that for 7-10 seconds then kill engine