Despritly need help!

joedirt5724

joedirt5724

New Member
Mar 2, 2009
295
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westmoreland, ny
Two days ago i had a new .40 piston installed and bored cylinder. My mods are a cmf airbox, boysen power reeds, and factory seven exhaust with no packing. I went through all of the break n steps and have been riding lightly and was going to for the next week. It was about 90 degrees and humid as hell out today. The wheeler was running a little rich but very smooth. I was goin down the road(not wide open) and the cylinder seemed to seize to the piston. I thought it over heated and heat locked. So i let it cool down and i was able to get the piston moving smoothly again. Problem is it wont start and seems to have low compression than what it had before. And i have spark. So i need your thoughts on why it locked up and why i cant get it to start. Please help, ive put in almost $2500 into this wheeler over the summer and this is what i get.
 
my first thoughts are check the reeds, check compression with a tester, and if low, your gonna hav'ta pull the head and cylinder, i think i've read about a bore job that they didnt chamfer the ports and a ring will catch it and break<< that'd suck
let us know what ya find
 
if i broke a ring in gunna fk'in tweek. Ive been down all dam summer because of a broken ring. It sucks cause ive been sent wrong parts and everything has taken forever to get here and now this. bye the time i get this fixed im gunna be back to school and will have no time to ride.
 
if it sstuck take a small screw driver or pick and twiiter it out and then tak a small file and fill the ring slot then take the ring and go around and if it doesnt get stuck put it back on and if it doese get stuck file it down more
 
well i do know that my bike ran like sh*t when the packing was blown out of my silencer, they definately need backpressure to run correctly... i just dont know the releovence of that to a piston seizing. i wouldnt think that could do somthing like that, just throw off the mixture a lil. any chance of the piston being the wrong bore? just a thought...
 
rings r melted into the piston, im gunna say cause of no packing not enough back pressure and got hot. so i need a hole top end now. A top end i just replaced with a $60 bore and $130 piston. f*ck my life.
 
joedirt5724 said:
Two days ago i had a new .40 piston installed and bored cylinder. My mods are a cmf airbox, boysen power reeds, and factory seven exhaust with no packing. I went through all of the break n steps and have been riding lightly and was going to for the next week. It was about 90 degrees and humid as hell out today. The wheeler was running a little rich but very smooth. I was goin down the road(not wide open) and the cylinder seemed to seize to the piston. I thought it over heated and heat locked. So i let it cool down and i was able to get the piston moving smoothly again. Problem is it wont start and seems to have low compression than what it had before. And i have spark. So i need your thoughts on why it locked up and why i cant get it to start. Please help, ive put in almost $2500 into this wheeler over the summer and this is what i get.
Click to expand...

What color is your plug? it should look like cardboard- not too light, not too dark. My first guess is that your jetting is off. I have been told by a couple of builders know that many people do not jet their midrange correctly. They also told me that the Blaster is usually too lean in the mid-range and this make for a dangerous combination when cruising or coming off of a hard run on the top-end. I do not know what carb you are using but if you have left the pilot jet and needle alone (on stock carb) and only jetted the main then that is why you burned your engine up. I was told to up my pilot by one, drop my clip one position, and to go to a 290-310 main all just for adding an after market exhaust. Please let us know what carb you are using and how you have it jetted- otherwise you might have an airleak that is causing a lean condition. I doubt your silencer packing is doing this much damage as the pipe on a 2-stroke creates most of the backpressure for the engine. As far as it being hot and humid these could play into causing a poorly jetted engine to melt.
 
burnin'_oil_2001 said:
What color is your plug? it should look like cardboard- not too light, not too dark. My first guess is that your jetting is off. I have been told by a couple of builders know that many people do not jet their midrange correctly. They also told me that the Blaster is usually too lean in the mid-range and this make for a dangerous combination when cruising or coming off of a hard run on the top-end. I do not know what carb you are using but if you have left the pilot jet and needle alone (on stock carb) and only jetted the main then that is why you burned your engine up. I was told to up my pilot by one, drop my clip one position, and to go to a 290-310 main all just for adding an after market exhaust. Please let us know what carb you are using and how you have it jetted- otherwise you might have an airleak that is causing a lean condition. I doubt your silencer packing is doing this much damage as the pipe on a 2-stroke creates most of the backpressure for the engine. As far as it being hot and humid these could play into causing a poorly jetted engine to melt.
Click to expand...
I have to go with burnin'_oil on this, plus all a silencer does is silence.... its not a 4storke.
 
plug is a darker brown. Ive got the stock carb. Im not sure on pilot jet size but the needle is in the center position and ive got a 270 main. im definitely gunna say thats my problem. I talked with a sled builder today and he said it looked like a cold seize because of running too lean. So now i need to know what jet sizes should i run. And needle position. Im fortunate enough that i need just a new piston and i can save my freshly bored cylinder. Can i buy different jets in a kit
(both pilot and main)????
 
you really shouldnt have to worry about the pilot to much you should be ok with just air screw adjustments and maybe a changed clip position but you'll probably need a bigger main most siezures happen when you let of the throttle after an extended hard load like flying down the street i say start with maybe a 320 and go down from there
 
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