Yz426 best year/mods


15 replies to this topic
  • Tevonini

Posted June 27, 2012 - 11:21 PM

#1

Ok I've been determining what kind of bike to buy, and ive dicided it's going to be a 426 now my question is what year is the best year to buy with the the least amount of problems and easier mods,
I do alot of trail/woods/fire road riding(mountain riding)
One thing that has me worried is my father in law said that 426's are a B$#ch to start is that true, what are the mods I can do to fix this, I've here somthing about a 450 cam mod I think what Is that? But than again my pop-in-law has a wr450.... He has a button so are they actually hard to start or just harder thAn the button lmao...

And the bk mod? Dose it work on the 426?

Thanx for all you'd help
Tevon

  • grayracer513

Posted June 28, 2012 - 06:49 AM

#2

They're hard to start (if not impossible) if you don't follow procedure:

http://www.yamaha-mo...troke_vid_a.mpg
http://www.yamaha-mo...troke_vid_b.mpg

They're also harder than they should be if the idle circuit isn't adjusted right. People tend to make them richer than they should be, and that doesn't go over too well when the bike's hot. They like nice fresh iridium plugs, too. Old, worn out or dried up carbs on these can cause problems, too. Otherwise, experienced riders can light them right up without much trouble.

The '02 was the best one, but any of the 3 years, '00-'02, are OK. The '01 and '02 are the best choices for reasons of parts availability on certain things and the revised balancer gear. But neither of these things is a huge reason to avoid a 2000.

Aftermarket manufacturers like Hot Cams make stage 1 (near stock) cam grinds with an auto decompression unit built into the exhaust cam. It updates the engine to eliminate the manual decompression lever and simplify starting. Very popular mod.

The BK Mod is for 426's only.

  • Tevonini

Posted June 28, 2012 - 09:17 AM

#3

So the auto decompression makes starting alot easier when hot?
Dose it make the procedure easier or kicking?
Do the wr426 have electric start?

  • grayracer513

Posted June 28, 2012 - 09:40 AM

#4

Only the WR450 has e-start, and the others can't be converted by any practical means.

The AD cam simplifies the process, but the bike will still be fussy about throttle, hot start, pilot adjustment, more so when hot. Once you figure it out, it's not bad.

With manual decompression, you push until you hit the compression stroke (the sudden "hard spot" you feel in the starter lever, often incorrectly called TDC). It's either nearly or actually impossible to kick through an entire compression stroke if the engine is healthy, but you need to be able to kick it from a point before TDC, past the ignition point, and past TDC as it fires. To do that, you stop when you hit the hard spot, pull the decomp lever, and advance the kick crank about 1 to 1.5 inches farther. That puts the piston closer to TDC than it was, so you have less air to compress when you kick it. Then you kick from there.

Auto decompression holds one exhaust valve slightly off it's seat for the first part of the compression stroke, so when you feel the hard spot on a bike so equipped, you are already at the right piston position to start the engine from. So instead of the above process, you simply push until you feel compression, draw the kicker back to the top, and kick from there. You can just flail away at the crank like it was a two stroke, but it works better if you do as I just explained.

Bump starting is also much easier with AD.

How auto decompression works

  • Tevonini

Posted June 28, 2012 - 11:17 AM

#5

Ok thank you do much, now this may be a stupid question but I ride where it's really hilly. With the compression so bad is it easier to do a rolling start? (pop the clutch in gear while rolling)

  • grayracer513

Posted June 28, 2012 - 11:44 AM

#6

Bump starting with manual decompression requires that you pull the clutch, pull the compression release, roll the bike, release the clutch to get the engine turning, then ease off the comp release to fire the engine. Takes practice to avoid locking the rear wheel with the compression.

With auto decomp, you pull the clutch, roll the bike, release the clutch, and it starts like a 125. Almost.

  • Tevonini

Posted June 28, 2012 - 01:36 PM

#7

Sweet thanx Gary you've given me lots of valuable info it is very much appreciated

  • Tevonini

Posted June 28, 2012 - 01:38 PM

#8

Oh and I've never had to deal with decomp is it a lever or a button and where is it located on the bike?

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  • grayracer513

Posted June 28, 2012 - 02:01 PM

#9

A second smaller lever on the clutch side.

Who's Gary?

  • marv02

Posted June 28, 2012 - 03:52 PM

#10

Hi Jacking just for my own info whats bad about the year 2000 YZ426 so I have heads up.

What to be looking out for.

  • ZGILBERT93

Posted June 28, 2012 - 04:48 PM

#11

Pick the 426 that is in the best shape, and has the lowest hours. All other mods can be done at your own expense because then you know they are done right.

  • grayracer513

Posted June 28, 2012 - 07:58 PM

#12

Hi Jacking just for my own info whats bad about the year 2000 YZ426 so I have heads up.


Other than usual annual suspension refinements, the '00 used a square key to locate the balancer gear on the drive end of the crank. In these models, the balancer gear can work the crank nut loose, after which the gear beats up the key and the keyway until you finally figure out what all the rattling is about. By then, you've wrecked the crank. The '01 model uses the current splined design and doesn't exhibit this behavior.

Beyond that, no one makes an aftermarket clutch basket for the '00. The '00 and the '01 have the same gear ratio, and as far as I know the later OEM basket/gear fits the '00, so it's more an inconvenience than anything else.

  • marv02

Posted June 28, 2012 - 08:43 PM

#13

So I taking it if the crank go's south I can put a crank out a 2001 and a better clucth Basket Thats no big deal I think if I had to spit the cases I put a WR gear box inb the bike at the same time I would like the WR trans I ride Desert longer legs would be nice.

Other than usual annual suspension refinements, the '00 used a square key to locate the balancer gear on the drive end of the crank. In these models, the balancer gear can work the crank nut loose, after which the gear beats up the key and the keyway until you finally figure out what all the rattling is about. By then, you've wrecked the crank. The '01 model uses the current splined design and doesn't exhibit this behavior.

Beyond that, no one makes an aftermarket clutch basket for the '00. The '00 and the '01 have the same gear ratio, and as far as I know the later OEM basket/gear fits the '00, so it's more an inconvenience than anything else.



  • Tevonini

Posted June 28, 2012 - 08:54 PM

#14

Who's Gary?


Oh crap tells you how much attention to detail I pay... Lol I thought you screen name was Garyracer513 lol I'm sorry lol thanx for all the info GRAYRACER lol

  • Tevonini

Posted July 01, 2012 - 03:21 PM

#15

For some reason this videos you posted wont come up on my iPhone or computer you any where else I can find them

  • grayracer513

Posted July 02, 2012 - 08:16 AM

#16

For some reason this videos you posted wont come up on my iPhone or computer you any where else I can find them


The vids require Quicktime. Download it free from Apple to a computer near you.





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