YZ426F Info.

Hi, my friend just bought a 2002 yz 426f with a fresh rebuild, I just want some other opinions whether the sound radiating from the cams or cam chain. i cam to the conclusion that it might be just the nature of the beast or that the cam chain is loose. i mean its a constant sound, it gets louder with the rpms. I havent delt with this model before. i just want some info on this bike and whether or not it could be the rebuild or just normal engine noise.

Thanks for your time!

KTMcolman41 the 426 is a noisy motor just like a RFS KTM is a noisy motor they both cluck and rattle I had a 2006 KTM 560 RFS it was a noisy motor also.

The best bang for the buck is swapping the Exhaust cam out with a Hot cam it has a compression release makes the bike very easy to start cold or hot get the jetting right on you love the bike.

Like I said I tried RFS KTM to heavy I think I also tried a Aluminum framed bike it handle nice but just did not feel at home I like the old steel framed bikes I use to ride back in the day the old 2 stroke YZ's it has the same feel and handles much better.

Thank you so much, I thought it was just the nature.of it but that takes a lot of the worries out but another question, is it poSsible to tighten the cam chain with the tensioner or does it automatically tighten it. If it is a full head rebuild should I shim them or see what the clearance is?

automatic

Thank you so much, I thought it was just the nature.of it but that takes a lot of the worries out but another question, is it poSsible to tighten the cam chain with the tensioner or does it automatically tighten it. If it is a full head rebuild should I shim them or see what the clearance is?

Did you own one and did your cams or cam chain seem loud?

Another question is it supposed to drip from a hole below the water pump on the side cover, it drips the coolant , is it for getting to hot?

No, the hole is an escape port. The pump shaft has an oil seal, since it comes from the engine, and a coolant seal, since it works in the cooling system. To avoid any possibility of a leak at either seal allowing these two incompatible fluids to mix, there is a gap between the two seals that is ported to the outside through the hole you see. If you see coolant leaking there, you need a water pump reseal, and possibly a shaft replacement:

http://www.thumpertalk.com/forum/showthread.php?t=940018

I just got my 2002 YZ426F a few weeks ago. Did some research,and saw that they're hard to start(stubburn). So I then went out and got the JD Jetting jet kit,and the Hot Cams exhaust cam w/ auto-decomp. I get it back from the shop tomorrow.Plus had valves adjusted.Should this help aide in the starting woes of my 426? I haven't ridden it since I got it. Thx

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