So i friend of mine wanted me to do the cam mod to his yfz 450 so i said no prob strip it down for me and ill do the rest. So in the process of taking his plastics off he notices that his subframe is cracked. So he takes it to a welder friend of his gets it all fixed and it looks good too. So i go to his place after work do the cam mod with no probs go to start it and it just cranks and cranks wont start. So im like well lets undo the cam mod and see what happens. Switch it all back and no better. So i ask him if he disconnected his cdi box when the guy welded his subframe, he says no. So my question is this is the cdi fried or do we have some other problem?

 

He didn't have it running ealier before you did the cam mod?

 

I've welded on my frame without disconnecting the CDI. My guess is it's somthing amiss with the cam change. IE timing. Check all the wireing that might have been in your way that you moved out of the way. Check all plugs and connectors etc.

 

My buddies LE YFZ is the same way. With the cam mod it's hard to start. He even added a dyna fs and it's still a pain to start. But when he holds it WOT it will start up.

So try pumping the throttle some on your buddies YFZ, and if it won't start, then hold it WOT and crank it. It could start.

 

I welded my frame without disconnecting the cdi and the battery. (stupid I know, you dont have to remind me[img]i/expressions/face-icon-small-mad.gif[/img]) My cdi was fried. At the time there were no aftermarket replacements, so I ended up paying 300 bucks on an oem cdi...

 

I was saying that because I had no problems afterwords when I welded it. Twice now, need to do a 3rd. Call me stupid but why would it matter?

 

ok now I'm confused...

I quoted you because you stated you didnt unhook and didnt have a problem. I didnt unhook and I did. That was the comparison, and I was saying that I knew it was stupid for ME not to disconnect the battery...

 

Try pull starting it, if it starts and runs like crap the timing is off. If it still doesn't start swap the electronics with someone else's to see if that fixes it.

 

Was it Tig welding?

 

No need to be confused, you understood me correctly. I didn't have any problems with my CDI when I welded my frame twice now. I'd still like to know how welding the frame can screw up a CDI. How/why did it mess up yours? Maybe I was just lucky and I should be disconnecting my CDI. Can anyone can give me a good example of how it will mess with the CDI? TIA