Yfz450 Cam Mod

[freshy21]

will a dealership do the cam mod im not reall yinto working on 4 stroke motor jsut yet

[Terse]

Yes the dealer can and will do it for you.

[NETHNGBTSTK]

ok so i did the "cam mod" yesterday and ran it today. Runs great but my god does it back-fire when i let off the throttle. Whats up with that??? I could really use some help.

[Alpha_Duner]

ok so i did the "cam mod" yesterday and ran it today. Runs great but my god does it back-fire when i let off the throttle. Whats up with that??? I could really use some help.[/b]

your lean

[NETHNGBTSTK]

your lean[/b]

main pilot jet??

[Alpha_Duner]

main pilot jet??[/b]

pilot i think, whats are you at? mods, and elevation

[NETHNGBTSTK]

pilot i think, whats are you at? mods, and elevation[/b]

Engine Mods= Stage 2 jet kit with uni filter and air box lid removed, white brothers exhaust, and now the cam mod.
Elevation= Not a factor, i live in NY.

[nzed]

Hi guys,

I read through this eariler today since i was feeling a bit maintenance frisky, i had decided it was time to check the valve clearances during the week and thought... stuff it, i'l do the cam mod!!!!

It's really great to see people here helping others out. As where i am, even in my whole country, their are only a select few people around here who know much about modding the YFZ. So to cut a long story short, the tutorial was a god send and you guys, and girls (if any) need a good pat on the back...

Once i got it done, it ran like a piece, so i bumped it up to the next pilot jet and it's running much smoother now, i'l get it tuned better during the week...

Many thanks

[Derrick Johnson]

Recently replaced head gasket and did cam mod all timing marks line up wont fire on time been apart five times in 3 days please help

[skatpex99]

Are u sure that u have the timing right because i THINK that on 4 strokes, one stroke is the combustion stroke and the other is the one where the gas and air come into the cylinder. Someone correct me if im wrong.

[Alpha_Duner]

Are u sure that u have the timing right because i THINK that on 4 strokes, one stroke is the combustion stroke and the other is the one where the gas and air come into the cylinder. Someone correct me if im wrong.[/b]

ya but what does that have to do with his question, he said his marks and timing is right. did you torque the head down right? got gas, spark? how does it turn over by hand?

[SprintCar24]

Thats for the write up, going to try this mod on my new 06 this week.

[Derrick Johnson]

ya but what does that have to do with his question, he said his marks and timing is right. did you torque the head down right? got gas, spark? how does it turn over by hand?[/b]

Ya I got good spark, gas , it turns over and I got a good Torque wrench. I've assembled the moter on both strokes, both ways it will not fire, also will burp flames out the carb both ways. I did have to take the magneto cover off to recover a circlip about the 2nd time around but I never disassembled anything and replaced the gasket. Ran perfect before replacing head gasket even when it was leaking oil. Even tryed stock cam timing again with no change. I'm lost!

[Alpha_Duner]

Ya I got good spark, gas , it turns over and I got a good Torque wrench. I've assembled the moter on both strokes, both ways it will not fire, also will burp flames out the carb both ways. I did have to take the magneto cover off to recover a circlip about the 2nd time around but I never disassembled anything and replaced the gasket. Ran perfect before replacing head gasket even when it was leaking oil. Even tryed stock cam timing again with no change. I'm lost![/b]

your valves are off, an intake valve is open, did you shim the valves? is so they are off or a shim slipped, go check to see if you thats the case, i am almost positive that is what your problem is. but if not you may need to bump the pilot up but still you shouldnt have flames out your carb

[Derrick Johnson]

your valves are off, an intake valve is open, did you shim the valves? is so they are off or a shim slipped, go check to see if you thats the case, i am almost positive that is what your problem is. but if not you may need to bump the pilot up but still you shouldnt have flames out your carb[/b]

I'll open it up again this weekend, it's very possable one of the shims didn't seat right. Best idea I've herd yet. probably hit u up next weekend when it's running I hope.

[myk]

You may have bent a valve if you had the timing wrong, the valve can hit the piston and bend, which would cause the valve not to seal properly and shoot flames out the carb. Did you roll the motor over by hand to make sure there were no interferences before you tried to start it?

Mike

[Alpha_Duner]

I'll open it up again this weekend, it's very possable one of the shims didn't seat right. Best idea I've herd yet. probably hit u up next weekend when it's running I hope.[/b]

cool just let me know but that sounds like your problem and he saidhis timing is on so its not timing or the cammod its most likely the valves the intake to be exact

[mudnuri]

I just got mine back from a mechanic and he did the cam mod. Now it will not start right up and it backfires when turning over.

[Duane]

I just got mine back from a mechanic and he did the cam mod. Now it will not start right up and it backfires when turning over. [/b]

I would have a little talk with your mechanic to find out exactly what he did. Maybe he rotated it two teeth instead of one.....you never know.

[mudnuri]

All you had to do was breathe on the start button to fire my quad up(before). Does anyone's do the same with the cam mod?