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New 426 owner, anything I 'need' to know?

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I picked up a nice 2000 w/ a DSP titanium exhaust (only mod). I added a T-handle mixture screw, a new NGK plug and cleaned the UNI filter and she runs great.

I've been a 2-stroke Honda guy for 15 years and dont know too much about these bikes and my question is.....

What do I need to know?

is there any known problems with these bikes? Valvetrain issues? Tranny issues? Anything?

Thanks.

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Do the 01 clutch mod, and the BK mod and youll have a pretty sweet ride....just do a search and youll get a quarter million results on both topics. Reliability wise, most 426's were pretty rock solid as long as you change your oil regularly, keep your air filter clean and keep your valves adjusted.

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And do not ride it like a 2 stroke in the sense that you should not hammer the clutch. If you do, the clutch basket will explode.

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Use a bead of something under the chain slider to stop it from rubbing a hole in the swingarm. I use "Outdoor Goop" or "Automotive Goop" available at most hardware stores. Lasts longer than silicone.

There's been a bunch of people recommended purchase of an '01 stock needle for a little extra juice and cleaner jetting.

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Pretty wide open question, but the first and foremost thing you should know when owning a thumper is putting Thumper Talk on your favorites list! You should also know that there is a lot of helpful guys on this forum and will get you through anything! :)

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First of all congrats. on the purchase I've only had mine a few months so I don't know of anything anyone probably has'nt told you but to HANG ON. because I went from a 2-stroke life to a four stroke boy was I surprised. Not at the power just how quick it comes on. I had to wind up my 2-stoke not this thing I feel like I'm lugging it to were it does'nt want to run but then the front wheel comes up & it's still pulling hard so all I can say is HANG :D:) ON. :D :D

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is there any known problems with these bikes? Valvetrain issues? Tranny issues? Anything?

Thanks.

Yeah, a percentage of '00s (probably a pretty small % at that) had issues with the straight key that holds the counterbalancer drive gear in place on the crank shaft. Not sure if the key was too soft or just too small, but it would start to wear and create play. Due to the oscillating load placed on this gear by the balancer any play quickly accelerates the wear.

Nearly everybody, me included, who experienced this problem noted an increase in noise which they attributed to the valve train.

At some point you will want to check for play in the crank to balancer connection. If there is some slop buy some hardened key stock and replace the key. In my case the play was sufficient to eat the locking tab and loosen the main gear nut. As it spun off it ate the side cover, and came dangerously close to interrupting oil flow to the bottom end. That would probably be your worst-case scenario with this glitch.

As mentioned the clutch is also a POS, you can retrofit about fifty bucks worth of '01 parts if you want to improve your clutch's attitude by about 150%.

Also Yamaha goofed on the jetting initially with the '00, the best fifteen bucks you could possibly spend, and it ain't even close, is to replace the needle with the '01 stocker. Yamaha PN:  5JG-14916-JP-00

Finally, do another search on "BK Mod." This is an easy and (nearly) free mod that is as helpful to your throttle response as the needle swap.

Hope this helps.

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As mentioned the clutch is also a POS, you can retrofit about fifty bucks worth of '01 parts if you want to improve your clutch's attitude by about 150%.

Also Yamaha goofed on the jetting initially with the '00, the best fifteen bucks you could possibly spend, and it ain't even close, is to replace the needle with the '01 stocker. Yamaha PN:  5JG-14916-JP-00

Finally, do another search on "BK Mod." This is an easy and (nearly) free mod that is as helpful to your throttle response as the needle swap.

Hope this helps.

Thanks to everyone for the replies.

I've heard about the BK mod and brought it to the attention of the previous owner, but he assured me that this bike didn't need it!?!?

What clutch parts from the '01 are you referring to? And what are the problems w/ the '00 clutch.

I sure as hell hope I dont have any couterbalancer gear problems, the last thing I want to do is dive into the cases.

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Not all bikes need the BK mod...it has to do with jetting also...if it runs fine down low and doesnt seem to have a bog, then just ride it!

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I've heard about the BK mod and brought it to the attention of the previous owner, but he assured me that this bike didn't need it!?!?

:)

Of all the YZFs, the '00 benefits from the BK mod the most ('02 the least). The accelerator pump changed every year but nobody has ever been able to test the different parts in older bikes (besides, the BK is practically free).

What clutch parts from the '01 are you referring to? And what are the problems w/ the '00 clutch.

It is plenty durable, it is just grabby. For '01 Yamaha added another ring-type (?) "spring" that goes behind (inside) all the plates in the basket. The mod is you replace the first set of plates (1 friction & 1 steel) with these three '01 parts:

5JG-16321-00-00 (I think this is a different diameter first plate to fit the spring)

5JG-16383-00-00 (this is the spring thingamajig)

5JG-16384-00-00 (I think this is a different diameter friction plate to fit spring)

However, when you do this you change the clutch throw, I don't have the PNs but you need to swap the '01 ball, and perhaps the pushrod. The aforementioned ball sits between the "main" pushrod and "short" pushrod that actually contacts pressure plate. The '00 doesn't have this ball at all but I also think the pushrod is a different length. Different folks seemed to have had different results...

I sure as hell hope I dont have any couterbalancer gear problems, the last thing I want to do is dive into the cases.

No need for that, everything is accessible behind the side cover to check for excessive play, but you do need to remove the clutch basket to get at the gear and visually inspect or replace the key itself.

Hope this helps.

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Check your throttle cable !!! The 4 strokes use a push-pull dual cable arrangement. If it is frayed or hanging on by a single metal thread and it snaps your bike could hang WFO. If it happens at the wrong time you could wind up in an ambulance. Worth the 10 min it takes to check.

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You should also know that there is a lot of helpful guys on this forum and will get you through anything! :)

I can't agree more!! This is the best site for new owners I have ever seen, or used, the best thing is, there's 100's of YZ owners on here all willing to help others. Its amazing. What ever the issue, just search the threads and you'll find comfort knowing that loads of others have had the same issues, and all have had them solved using this site.

end of bum-lick now, sorry for that out-burst! back on with work now..... :D

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