CAM MOD done... Bike has trouble starting

[trxsandman]

Just preformed the "CAM MOD" last night and now my bike is having a really tuff time starting. I got it to fire, but I had to choke the heck out of it and force fuel down its throat... Once it fired it sounded great no popping or backfiring so its definetly not the jetting. Spark plug is brand new too. If anyone has ever had this problem please help me out...

[TWILES]

The WR 450 and YFZ have the same exhaust cam but the WR is rigged where it can't be rotated like the YFZ. I've heard people who have put the YZ exhaust cam in their WR's say they have to kick-start them when cold and after they are hot the electric start will start it. I don't understand it. It seems like the electric starter would turn the motor over faster than the kickstarter.

[trxsandman]

All I did was move the stock exhaust cam over one tooth clockwise. I could definetly see that when the motor was TDC the exhaust cam was advanced a tooth which would be a legit mod to de-tune the motor. By shifting the exhaust cam one tooth over I can now see that the at TDC the timing marks are both alligned correctly. I don't see how one tooth would have such an impact on the starting. My thought process was a stock yfz isn't firing at the peak compression because the timing was advanced. By retarding the timing (going a tooth clockwise on the exhaust cam) the bike will now fire at its highest compression. Need help!!!! I guess if its going to be this tuff to start I might just have to put it back to stock timing.

[hoser 400ex]

mine started hard teh first few times after the cam mod. make sure your valve clearances are good. also, make sure your battery is fully charged. after a few times mine started no problem.

[trxsandman]

That sounds like a good idea I haven't checked the valve clearence yet, but I do know the battery is fully charged. I have a feeling that because the bike wants to fire at the highest compression its putting a little more strain on the starter. Once its hot it will probably start no problem.. I'll definetly check the valve clearnce though....

[Toadz400]

What's your jetting at? And what other mods do you have? Sounds like you need a bigger pilot.

[jtquad]

mine both did this then i found out i rotated the cams one tooth opposite way. I was having to put the quads on the battery tender everynight till i figured it out - JT

[trxsandman]

I rotated the exhaust cam clockwise one tooth. I don't think its the jetting cause I went one up on the pilot and the main is at 168. I think the timing might just be off a couple degree's. I'm actually taking the bike to CT Racing to get some help. I'll let you guys know what the problem is after I talk to Allen Knowles at CT. The guy works magic on bikes. He actually is in the final stages of developing the most reliable 512 kit for the YFZ..... Can't wait to see it in action. Thanks for the help guys I'll let you know what I did wrong when I find out.

JT I'm heading out to Glamis on March 23rd for the weekend. Write back if your gonna be out there... It would be cool to meet some of the people that help out on the Website....

My Mods are: CT Pipe, 168 Jet, and K&N Intake...

[jtquad]

Im only in glamis every feb for pres day week due to the fact i live in new york lol. Let us knwo how you make out - JT

[250r4life]

Originally posted by trxsandman


JT I'm heading out to Glamis on March 23rd for the weekend. Write back if your gonna be out there... It would be cool to meet some of the people that help out on the Website....



i just may be there... i will let you know if i am... i would like to meet up as well...

im interested in knowing the gain from the cam mod- i'll be doing it this summer...

[trxsandman]

Alright guys please don't laugh... When I preformed the CAM MOD I thought I only moved the cam one tooth, however after talking to Alan at CT racing he said that the cam had been moved over two teeth. He said I probably was fighting with the timing chain because its an 07 and its still pretty tight. He thinks by me struggling to get the chain pulled back over the cam I might have pulled an extra link and not even noticed it. Oh well... He told me not to feel bad because it was my first attempt. I really hope this thread helps others that attempt this mod...

Now let me get to the performance side of things. The mod really hasn't shown any extra power. However it gets thru the gears alot faster now. The bike feels alot more responsive. Overall if your looking for some extra quickness in your bike go for it... If your looking for flat out power look else where. The response is very abrubt now and if your not careful it will throw you on your back...

[Toadz400]

Originally posted by trxsandman
Alright guys please don't laugh... When I preformed the CAM MOD I thought I only moved the cam one tooth, however after talking to Alan at CT racing he said that the cam had been moved over two teeth. He said I probably was fighting with the timing chain because its an 07 and its still pretty tight. He thinks by me struggling to get the chain pulled back over the cam I might have pulled an extra link and not even noticed it. Oh well... He told me not to feel bad because it was my first attempt. I really hope this thread helps others that attempt this mod...

Now let me get to the performance side of things. The mod really hasn't shown any extra power. However it gets thru the gears alot faster now. The bike feels alot more responsive. Overall if your looking for some extra quickness in your bike go for it... If your looking for flat out power look else where. The response is very abrubt now and if your not careful it will throw you on your back...

Don't worry, we all make stupid mistakes like that sometime.

As for the cam mod, I felt quite a big difference but I also added a pipe and larger intake. I ended up switching the cam back to the stock position because of the abrupt power, it would wear me out way too quick. Found myself being able to make 5 laps on an '06 stock YFZ much faster on my '05 modded YFZ because I'd be winded after 1 lap on mine. It really does change the power delivery of the machine.

[trxsandman]

Thanks for the support man... I did feel pretty dumb, but this was my first time working on the YFZ. I figure its a machine and if it breaks it can be fixed so what the heck. You'll never learn unless you try. Its just funny cause I was so close, but just not perfect. Allen at CT was very cool about it and only charged me 20 bucks so it paid off in the long run I guess....

[07yfzdenial]

i have the 07 se model. So the hard starting was caused by this only? Im just comfirming this before i do the cam mod myself. I have read several posts from different websites and they all had starting issues also. Let me know, thanks.

[trxsandman]

Yep the exhaust cam was off by one tooth. I could push start the bike no problem, but it would not start with the push of a button.