Engine Performance but for how long

How long do these engines last when given at least a fair amount of maintence, oil changes at a proportional interval to riding style? I have a 00 WR400 and change the oil frequently: after 3 days of hard riding or 500 mi. I have not adjusted the valves yet because I have not noticed any loss of power or heard any valvetrain noises from the top end. I ride this bike pretty hard and have never experianced the woes people have talked about. Hot starts after a get off, jetting and carb adjustments,accell pump timing ect.Am I setting myself up for a catastrophic failure.I bought my bike at NCY and they put my pipe on and did the jetting and carb tweaks.Is it my good fortune and maintenence or should I tip my hat to NCY for giving me a bike thats dialed in. What would be a good compression test result be and how many kicks does it take? The cam timing is stock WR so does changing it to YZ bring along a bunch of headaches. I am considering the YZ timing but have read that people switch it back to WR or put after market cams in. Does anyone have a trouble free engine and what if anything did you do to keep it that way?

what is this USFS license you speak of,is it good for entire U.S. or just CA?

I have a hard plate so I can ride on any public road paved or primitive, but to ride forrest trails that is open to traffic you better have a forrest adventure pass $5.00 a day or 30 something a year(parking permit)even if you never stop for a minute.Now that the forrest burned up last year in So Cal I was turned away and was told I could not ride because of the fire danger and also I could not ride even with the hard plate.I also had a approved spark arrestor wich the ranger wanted to ticket me if I did not show the usfs stamp on the muffler skin. the ranger thought he knew the law, then a couple on a Harley chugged by W/ strait pipes and I said you better give them the same lecture you gave me.I told him I will be back when the forrest recovers.

If I were you, I'd be doing my oil changes more often (300mi is recomended I believe). Never hurts to check the valve specs. Only takes a few hours to do, 95% of that time is removing and refitting all the parts that are in the way.

Can't advise on the compression test, I always use a leakdown tester.

How long do these engines last when given at least a fair amount of maintence, oil changes at a proportional interval to riding style? I have a 00 WR400 and change the oil frequently: after 3 days of hard riding or 500 mi. I have not adjusted the valves yet because I have not noticed any loss of power or heard any valvetrain noises from the top end. I ride this bike pretty hard and have never experianced the woes people have talked about. Hot starts after a get off, jetting and carb adjustments,accell pump timing ect.Am I setting myself up for a catastrophic failure.I bought my bike at NCY and they put my pipe on and did the jetting and carb tweaks.Is it my good fortune and maintenence or should I tip my hat to NCY for giving me a bike thats dialed in. What would be a good compression test result be and how many kicks does it take? The cam timing is stock WR so does changing it to YZ bring along a bunch of headaches. I am considering the YZ timing but have read that people switch it back to WR or put after market cams in. Does anyone have a trouble free engine and what if anything did you do to keep it that way?

Given the technology behind the new "Four Strokes" (which were adapted from Factory Raced Sportbikes), I'd say a very long time. I have approx. 3000 miles on my '02 WR426 and I ride the piss out of it. I have changed oil approx. every 300 miles, and checked the valve clearances three times. Each time they were in spec! I just recently did a top end (piston ring replacement).

The motor on these four stokes are strong ane reliable. :thumbsup:

Can't advise on the compression test, I always use a leakdown tester.

whats a leakdown tester?

a leakdown tester is a box that you connect to a compressor. It had a hose coming out of it that screws into the spark plug hole. The box has a pressure guage on it, marked in %. Basically it fills the cylinder with compressed air (engine on TDC. you need a friend to hold the crank in poisition with a socket otherwise the air will push the piston down, opening the valves) and measures the % of air pressure that leaks past the rings and valve seats. 10-15% is a good figure for a 4 stroke. Up to 30% is still usable. After that you have problems. If you remove the header pipe and air filter you can hear where the air is leaking from. Noise from exhaust or carb = valve seat problem. Noise from crankcase breather = rings/bore problem.

thats a great tool, makes much more sense then using a compression tester. But using both would give a good indication of the motor.

I have the compressor, so where can i get one and how much do you think one of these tools is worth?

The unit I have access to is a snap-on brand, and therefore probably cost a shitload. Most bike/car mechanics will have one. Save yourself the $$$$ and just pay someone to do a leakdown on your engine if you are suspect. If you can get youyr hands on a leakdown tester, forget the compression tester.

Thanks for the info,

Hopefully I won't have to worry bout it just yet, ive only done 960km's on it.

:thumbsup:

Hey,

I was wondering how the 426 rides with the new piston and rings? Did u put a high compression piston in it?

thanks

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