Couple of questions on my new-to-me 2001 YZ426 - Pics inside

Here are a few pics. I posted earlier that I picked it up for $1300, and today I cleaned out the main jet because it has been sitting for about a year and bogged down when I tried to floor it when test riding it. Wow, what a difference! It runs great.

I have three questions on the carb. One is that there isn't a hot start 'button,' but instead a lever up on the throttle side of the bars. Is that aftermarket, or did the 2001's come with that?

The second is about something on the bottom of the carb. I assume it is the air screw, but it doesn't look as I would expect it to. I can twist it with my hand, so again, wondering if this is aftermarket or if they came this way in 2001. It seemed to run better when it was out 1 1/2 turns or so, but I'm wondering if it will vibrate itself loose since it doesn't have any kind of a cover or anything. It seems to turn pretty easily.

The third is there are some numbers inscribed on the carb, did they come this way stock or did this bike have some aftermarket work done?

Here is a pick of the carb dial thingy, just forward of the main jet cover bolt. (and two pics of the bike)

carb-1.jpg

carb-2.jpg

Here are a few pics of the bike. :excuseme:

yz426-1.jpg

yz426-2.jpg

The red 'thingy' is an aftermarket 'fuel' screw; it doesn't have an 'air' screw. The 'hot start' is indeed on the handlebar, whether or not it is original, I don't know; my 2000 had a 'button'. The inscribed numbers are some kind of manufacturer's codes and are not necessarily of any concern to you.

Hot start is aftermarket. The original was a red knob. Just got myself an 01 also, seam like good bikes .

Hot start is aftermarket. The original was a red knob. Just got myself an 01 also, seam like good bikes .

I haven't had a chance to ride it yet, and unfortunately don't know much about its history. It seems to start very easily, so I don't know if the previous owner did anything with the exhaust cam. (or the intake for that matter)

It seems to have great power, can't wait to take it out and play with it! It's my tenth dirt bike (sixth YZ), but the first one in quite a few years, and my first four stroke. :excuseme:

Here are a few pics. I posted earlier that I picked it up for $1300, and today I cleaned out the main jet because it has been sitting for about a year and bogged down when I tried to floor it when test riding it. Wow, what a difference! It runs great.

I have three questions on the carb. One is that there isn't a hot start 'button,' but instead a lever up on the throttle side of the bars. Is that aftermarket, or did the 2001's come with that?

The second is about something on the bottom of the carb. I assume it is the air screw, but it doesn't look as I would expect it to. I can twist it with my hand, so again, wondering if this is aftermarket or if they came this way in 2001. It seemed to run better when it was out 1 1/2 turns or so, but I'm wondering if it will vibrate itself loose since it doesn't have any kind of a cover or anything. It seems to turn pretty easily.

The third is there are some numbers inscribed on the carb, did they come this way stock or did this bike have some aftermarket work done?

Here is a pick of the carb dial thingy, just forward of the main jet cover bolt. (and two pics of the bike)

The red knob is an aftermarket air/fuel screw, and 1 1/2 turns out should be right in the ballpark. The hot start lever under the throttle is an aftermarket (most likely Dr.D) relocation kit (originally a red knob on carb), and the numbers on the carb are the factory Yamaha part numbers.

, but I'm wondering if it will vibrate itself loose since it doesn't have any kind of a cover or anything. It seems to turn pretty easily.

These aftermarket fuel screws come with a spring that prevents them to loosen up or fall out. You can take it out and look for yourself, be careful not to lose the little o-ring and washer that is on the top of the screw.

Note 1 : Before removing the screw, first turn it all the way in and count the turns so you can set it back afterwards

Note 2 : Many times the little o-ring remains sticked in the carb and doesn't come out with the needle

These aftermarket fuel screws come with a spring that prevents them to loosen up or fall out. You can take it out and look for yourself, be careful not to lose the little o-ring and washer that is on the top of the screw.

Note 1 : Before removing the screw, first turn it all the way in and count the turns so you can set it back afterwards

Note 2 : Many times the little o-ring remains sticked in the carb and doesn't come out with the needle

I actually did take it out and check it out, and didn't notice the o-ring or washer. I'll take another look, either it is up in the carb, or missing. Ruh Roh. (Edit: took it out and looked up into the bottom of the carb with a mirror, and I don't see it. Is it possible that some of the aftermarket ones didn't have the o-ring and washer? If not, then I'll have to buy them)

Grayracer, thanks I'll do some adjustments based on your links.

Edited by jcm3

"Is it possible that some of the aftermarket ones didn't have the o-ring and washer? If not, then I'll have to buy them)"

I have the same aftermarket fuel screw on my 2000 426. If I'm remembering correctly, the screw didn't come with a spring , "O" ring, or "O" ring washer but you need to have all three. The "O" ring is the smallest one I've ever seen and it can get easily lost. The washer is also very small. It usually comes out when you remove the screw.

If you can't locate yours, here's the PN's:

3TJ-14562-40-00 O-RING

3TJ-14952-40-00 WASHER

3TJ-14160-40-00 COIL SPRING

If you can't locate yours, here's the PN's:

3TJ-14562-40-00 O-RING

3TJ-14952-40-00 WASHER

3TJ-14160-40-00 COIL SPRING

Great, thanks for the info, guys.

Edited by jcm3

hi im new to TT just a few questions

i just brought a 426 01' seems to be in great condition

the last owner didnt know much about its history

had a quick spin great power

are there any major checks i should do

like valve clearances etc?

thanks

You can't copy links like that when they contain "..." in the string.

Thanks for the heads up grayracer. I just went ahead and deleted the thread so I wasn't giving a faulty link.

Bill

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