Have a 425 that performed great till last year, then it got to the point it would crank slow and pop back threw carb. If i pulled the rope starter while cranking engine it would go ahead and start. Replaced battery and starter and got it to crank faster but still had a lot of trouble with it kicking back. I did a compresion check, a leak downd test on the cyl, checked the cam lift, set valves and replaced the coil. still had trouble. Let it set for about six mounths and decited to get it going, put in new fuel and fresh battery, gess what it started right up. Went to three diffrent atv parks and ran it hard, about 100 miles, never mised a beat. last night i ran it abour one hour and shut it off and it would not restart. Turns over good but pops back into carb, cant get it to restart,,,i am a small engine mechanic for john deere for thirty years,, but this one has got me stumped....

 

Most of the time when I've had popping back through carb usually would idle good and pop back when trying to increase throttle, usually turned out to be cam or valve related. Posted that you set valves,could you see if exhaust cam lobe scored/worn or does it appear good and plenty of "meat" on lobe. Just a thought! Never have had intake valve lobe problems,just exhaust lobes on cams. Dont know if this has anything to do with your problem,but the popping back through carb has me wondering? Only other times were from partially fouled plugs that can do same thing. Keep us posted.

 

Camshaft looked good, tryed new plugs. was told cams failed so i checked it good.

 

any news? I have similar problems with the exact same bike. I am at a total loss..

 

i also have a 96 425 same problem compression release was not working so i put another wrap on the spring it starts but still pops through carb been through just about everything i to am going nuts i noticed after running i have to give it throttle to start it again i replaced the needle and seat help

 

I feel you pain........

 

Whenever I had a question (or others) there was one member here that knew the 1995 Magnum425 in-and-out.

His user name is "ftwflh".

Drop him a PM.

I hope he is still around.

~MT

 

FTWFLH (use lower case letters for your member search to leave him a PM)