Only runs at half choke

grv7

New Member
Dec 6, 2010
29
0
0
New Hampshire
Ok, so I've been all over this site reading threads and trying to get my Blaster running. Doing better, I can get it to run half choke but when I close it the engine starts to cough and cuts out. Its set up with an F7 pipe v-force reeds, UNI filter w/ no cover. The carb is clean and has a 300 main, 32.5 pilot, the clip is in the #3 slot and the mix screw is at 1.5 turns. It would be great if someone could chime in and help. Thanks...
 
same pipe and intake setup as my sons bike, which has been running the same carb settings as you, that should be close, theres gotta be sumthin clogged up in the carb, or an airleak somewhere, have you leakdown tested it ???
reeds good ?? no chips or cracks ???
you wouldnt happen to be running a reed spacer between the carb and reeds are you ???? thats trouble !!!!!
tear the carb completely down, every part, and clean it good with carb cleaner and blow out with compressed air
check the float setting while in there, 20 - 21.5mm from where the gasket would sit, to the top of the float, while at a 45 degree angle, just touching the float valve needle, adjust to specs if needed

clean carb, check/adjust floats, inspect reeds, and leakdown test,
then report back your findings
 
is the carb clean? no clog jets?
start there.

also your plug what color is it?

The main and pilot are clean. I put a new plug in and ran it 20 min. The tip is a very light brown, lean. Maybe I should put an air box cover on. It was missing when I bought it and I dont know if the guy was using one.
 
you can try an airbox lid, i even have one if your interested, it's got some holes drilled in it, but i've used duct tape to open and close them trying different air flows, but i'm telling you, my sons bike has the exact same setup, open airbox and all, that jetting should be close

answer the rest of my questions now...reeds good, floats in spec, reedspacer??
and most importantly airleaks ???? leakdown test, < trust me, and everyone else on here that have fried a $120 wiseco piston kit, thats the most important thing you can do ......LEAKDOWN TEST for airleaks
which is where i'm really leaning, choking it just adds extra fuel to compensate for the airleak, which v force reed cages are famous for

i even have one you can borrow if you wanna pay shipping, way cheaper than a piston !!!!!!
 
same pipe and intake setup as my sons bike, which has been running the same carb settings as you, that should be close, theres gotta be sumthin clogged up in the carb, or an airleak somewhere, have you leakdown tested it ???
reeds good ?? no chips or cracks ???
you wouldnt happen to be running a reed spacer between the carb and reeds are you ???? thats trouble !!!!!
tear the carb completely down, every part, and clean it good with carb cleaner and blow out with compressed air
check the float setting while in there, 20 - 21.5mm from where the gasket would sit, to the top of the float, while at a 45 degree angle, just touching the float valve needle, adjust to specs if needed

clean carb, check/adjust floats, inspect reeds, and leakdown test,
then report back your findings

The floats are set, the reeds are good. I do think there is a gasket between the reed cage and intake boot. I took the reeds off the orignial motor and I thought it needed a gasket. Could this be a big enough spacer to mess it up?
 
a stock reed cage doesnt need a gasket, i think it has a built in rubber one????
been a while since i fooled with stock components,
but in the "aluminum reed spacer" case, it was allowing the center part of the v-force to push backwards when rev'd
did someone cut the lip off of the stock intake like described in the v-force instructions ???
a lot of us have had to use some type of sealant on the v-forces to get them to seal, some use yama-bond, i use permatex hi temp copper
 
Yes, the boot was cut. So I should have the intake boot to the reed cage with spematex and a gasket between the cage and intake port?
 
only if it's leaking, you really need a leakdown tester, they're invaluable to our motors, like i said, i have one you can borrow, or for a few more bucks, holeshotman sells a very nice set-up on here, and there is also a "diy" on here to build your own i think for around $20
do a search for "leakdown tester"
 
only if it's leaking, you really need a leakdown tester, they're invaluable to our motors, like i said, i have one you can borrow, or for a few more bucks, holeshotman sells a very nice set-up on here, and there is also a "diy" on here to build your own i think for around $20
do a search for "leakdown tester"

Thanks AWK, I pulled the reeds out and I see what you mean about them getting sucked out when rev'd. Thats were I had installed a gasked that was not needed and the reeds could not seal. I try to fire it up again and get back to you. Thanks again.
 
cool !!!!!! invaluable lesson about spacers and gaskets on vf3's learned at slickerthanyou's expense
 
i had the same problem, i was basically chasing airleaks and fixing the previous owners screwups. make a list of all the possibilities even the far out ones and correct all of them. chances are when you fix one youll find 2 more:p

also leak down test it; theres nothing more disappointing than when you restore an engine and it blows up:p

whats youre altitude?
 
i had the same problem, i was basically chasing airleaks and fixing the previous owners screwups. make a list of all the possibilities even the far out ones and correct all of them. chances are when you fix one youll find 2 more:p

also leak down test it; theres nothing more disappointing than when you restore an engine and it blows up:p

whats youre altitude?

Don't know my altitude, but its cold. 28 degeres and your right I am finding all the previous owners screwups. I just have to find the right one. I'll have some time later in the week and get back to you guys them.
 
how did it run before it got cold??? if it ran good before it got cold and now it will only run on half choke you need to jump up the pilot to alow more fuel at idle, same with the main jet, if it ran good when its warm its to lean now
 
how did it run before it got cold??? if it ran good before it got cold and now it will only run on half choke you need to jump up the pilot to alow more fuel at idle, same with the main jet, if it ran good when its warm its to lean now

Thats the thing, its a rebuilt motor from Ebay (:o I Know) but the seller garanteed it to run. Soooo with that said, I took everything else off the origanal motor and put it on this one. The carb had a 300 and a 32.5, how bigger can I make them?