Cam timing adjusted.....should I weld them??

[Ronin 26]

I just finished an engine repair/build and I adjusted the cam timing by pressing the sprockets on and off to get them where I wanted them. The intake was easy.....the exhaust was not. The bike (03 450) runs great and pulls hard but I've spent a couple of nights sleepless in regards to the cams. I know there has been lots of talk about the sprockets slipping on the cams and I used some locktite when I reassembled but I think for the sake of getting my much needed rest I will probably fire up the tig and make sure they won't slip. What do you guys think???

[Pincushion]

What good is loctite going to do? Does the gear bolt to the cam?

I dont think I'd be sleeping either if I saw the gears removed from my cams.

[Ronin 26]

no, the gear presses on as I said. I remove sprockets all the time to install aftermarket bosses for adjustable sprockets. The reason I asked opinions is because of all the stuff floating around about the sprockets slipping on the cams. The locktite will LOCK the gear on the shaft, in theory.

[Pincushion]

I see. I certainly dont have any knowledge of the subject, but I'd be concerned about the intake cam, especially since you said the gear came off easy.

You could weld a small tack, but I'd worry about it changing the rotational mass and may lead to other valvetrain issues.

They are a pain in the ass to time, aren't they?

[02YZ426]

You mean that you just put the locktite on the shaft and pressed the gear over it? If its the red stuff it should hold up... I use that stuff to hold in bearing races in transmissions and it holds like a weld.

[Ronin 26]

Yes it was red, and I had the same thoughts about it, however if they do slip it gets ugly!!! The piston doesn't like it when the valves invade it's space. The intake was easy because it doesn't have the automatic decompressor. The press fit seemed tight, but I didn't measure it........should have. That's a good thought about the rotating weight Pin, but I don't think a couple of evenly spaced tacks would affect anything.

Anyone else??

[PumpkinHumper]

You could weld a small tack, but I'd worry about it changing the rotational mass and may lead to other valvetrain issues.

I had the intake cam gear spin on my YZ400 some time back. Enginedynamics hooked me up. And in the process at my request welded the gears onto the cams. They just put 2 small tacks opposite to each other. Hasent seemed to have any negative affect on my bike at all.

But I do have one thought about this. If for some reason a cam were to sieze for whatever reason while the engine is running. Something has to give. When the gear isn't welded it will spin. If it is welded....something is gonna break.

[Ronin 26]

Thanks for the info. If a cam seizes your already broken. I prefer the extra insurance.

[FFRacing79]

Don't worry about it...I have pressed and removed the gears many times with no problems and I am turning 13K rpm. Press it on and leave it! Tdub

Just out of curiousity...what lobe centers did you end up with??

[Ronin 26]

Thanks, I'm not at the shop right now I'll post them tomorrow. What do you usually run for lc's?

[FFRacing79]

On the 450 I ran last year at the nationals, I ran 100 to 105 on the small tracks and TTs. When I wanted peak HP for the 1/2 miles and Miles I ran 108 to 110 on the intakes. Stock exhaust works as good as anything out there at 107. Tdub

[Ronin 26]

I'm running the ex at 103 and the in at 105.5 I was shooting for something a little different but had the sprockets off a couple of times and settled here. It's fairly close to stock but I had to adjust it back here after milling.