just bought 01 426 need help and advice


18 replies to this topic
  • trey03

Posted May 13, 2009 - 09:00 PM

#1

do i really need to do the decomp cam mod does it make it easier to kick start im a novice rider and on my first ride i couldnt kick it over my leg was spent from stalling it on trail all day if yes is the answer does anyone have instructions for the mod with step by step instructions with pics ive never worked on a dirtbike but am mech inclined dont know how to check valves or anything no expierance could use alot of help:confused:

  • yzf426f

Posted May 13, 2009 - 10:28 PM

#2

hey mate.as for doing the decomp mod its really a choice.once you get the method to using the decomp lever its easy.tho if u stall it on a hill its a pain.i have rode bike's with the decomp mod they are easier to start but ive heard that they give a shocking kick back.anywayz let me know what you choose.and how much its gonna cost you coz i was thinking of doing it aswell.cheer's

  • grayracer513

Posted May 14, 2009 - 06:35 AM

#3

i have rode bike's with the decomp mod they are easier to start but ive heard that they give a shocking kick back.

Kick back has nothing to do with the presence or absence of auto decompression. Any big 4-stroke has potential to do it.

  • DrThumper

Posted May 14, 2009 - 06:50 AM

#4

Having the decomp lever can have it's pros too. Like bump starting it when still in a slow roll (after stalling it).

Also after you flood it (a rookie tendency). You can hold that decomp lever and hold the throttle wide open and kick it over several times to air it out.

  • grayracer513

Posted May 14, 2009 - 08:34 AM

#5

Having the decomp lever can have it's pros too. Like bump starting it when still in a slow roll (after stalling it).

Also after you flood it (a rookie tendency). You can hold that decomp lever and hold the throttle wide open and kick it over several times to air it out.


The bump start procedure with manual decomp is to pull the comp release, let the clutch out, ease the release out, and hope the engine doesn't lock the rear wheel before it starts turning over, or the whole process take so long that the bike simply coasts to a stop. Requires skill and practice, but yes, it works most of the time.

With Auto Decomp, all you do is let the clutch out. No brainer. Nearly instant restart at ridiculously low speeds. Like a 125. Seriously.

Opening the throttle and turning the engine through a couple of times is easier with a manual release, but it is not any more effective at clearing a flood than doing so without it.

  • trey03

Posted May 14, 2009 - 06:29 PM

#6

called local dealer about decomp cam (hot cam kit) 207.56 with tax/ & labor to do it 226.70 with tax so all togather for mod 433.26 plus they said smoothier perfm. curve more power what im still wondering is has anyone had it done recently & is it worth it im really after the easier start and less stalling power just a plus dont really need it till i get more seasoned i like the bike its a little heavy but a beast on power already. My big question will it be alot easier to kick over cause i know i will still stall.IF so cool ill grow into the bike in skill bieng im already grown up.And how much easier will it be im 37 just dont have the leg to kick that comp. all day & ride too get too tired already happened.Ive already figured out the sweet spot can start on second kick on fresh leg.Will it ease up enough to matter??Otherwise im considering trading for a 250 2 stroke thats whats its all about. i want to ride mostly trails and be able to easly kick it over with out getting stuck to tired to kick it back over thanks for your comments all are welcome.riding should be fun not o sh-t i hope i dont stall it and or get stuck 3-4 miles in the woods wore out to tired to kick it. ps not a weakling im 5 9" 196lbs this bike just has alo-t of compression

  • MOTOXTREME222

Posted May 14, 2009 - 06:38 PM

#7

I had a 426 with the decomp lever and it was hard at first to figure it out and i was tired for a few days but once you get its trick down its easy to start. I got a newer kxf now with auto decomp and its nice too. I would figure out the lever unless you have the $500 to spend and you dont think it could be best spent elsewhere. Good luck with the bike!

  • yz450fast

Posted May 14, 2009 - 07:09 PM

#8

give a few more rides to find the sweet spot. you'll get it down. if your gonna spend that much coin, think about suspension or something you will be better off in the long run with.

  • buzzgrizz

Posted May 14, 2009 - 08:39 PM

#9

I rode with mine left alone for a few years then having to screw with the decomp during a rough race made me want to put the auto decomp in. I'm doing it now http://www.thumperta...ad.php?t=776291

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • Family Man

Posted May 14, 2009 - 09:41 PM

#10

Man two strokes are just way easier to start. Give it some gas and a little kick and they come to life, awsome. On the other hand, 4 strokes require finding top dead center and giving it a healthy kick, being in neutral helps also. And thats a four stroke with a stock auto decompression.

  • grayracer513

Posted May 15, 2009 - 05:12 AM

#11

Man two strokes are just way easier to start.

Yeah, but why bother?

  • ROCKMOUNTAINTHUMPER

Posted May 15, 2009 - 07:39 AM

#12

i would spend some time figuring out the correct starting sequence. i own a '01 426 and had some fun battles with that kick-starter, but now i can get it to fire on the first kick almost every time. dont get frustrated quite yet. the 426 is a great trail bike imo. i used to own a 250 2stroke, just isnt the same on the trails as a 4stroke. good luck

  • jjsmx

Posted May 15, 2009 - 11:20 AM

#13

I have a 426 with the de-comp lever still on. Once you have ritual down it is easy to kick start or bump start. I like it cuz it is easy to find TDC. I have found with these bikes it is particularly important to first have the valves adjusted correctly and to find the right fuel / air mixture with hot start and choke. You will get feel for it. The de-comp exhaust cam just eliminates the ritual but you still have to get the thing to fire. If want to get the new cam, put it on when you or somebody does a valve adjustment. Good luck!

  • ROCKMOUNTAINTHUMPER

Posted May 15, 2009 - 01:36 PM

#14

I have a 426 with the de-comp lever still on. Once you have ritual down it is easy to kick start or bump start. I like it cuz it is easy to find TDC. I have found with these bikes it is particularly important to first have the valves adjusted correctly and to find the right fuel / air mixture with hot start and choke. You will get feel for it. The de-comp exhaust cam just eliminates the ritual but you still have to get the thing to fire. If want to get the new cam, put it on when you or somebody does a valve adjustment. Good luck!


curious, how tough of a job is the valve adjustment?

  • grayracer513

Posted May 15, 2009 - 01:46 PM

#15

Valve checking, which is usually all that's required, is pretty simple. Valve adjustment is more complicated, since the cams and lifters must be removed to access the shims.

Here's a look at the process. The write up is for a YZ250F, so the specs given are wrong, but the procedure is the same.

http://www.thumperfaq.com/valves.htm

  • Birdy426

Posted May 15, 2009 - 01:52 PM

#16

The autodecomp cam was the second best mod I ever did to my WR (ESP suspension was the best). Before I went big bore and hi comp, the kick thru was about like a 250 2 stroke...maybe a little bit firmer, but not much. Starts anywhere are easy, but that's really not the best part...I used to stall all the freakin time before the auto-decomp mod...stuff it into a corner a gear too high, lose too much speed, crack open the throttle, and ...blllaaahhhh...stall. With the auto-decomp, that's a thing of the past...and bump starting? What a breeze.

I went with both intake and exhaust Hot Cams, and it really woke the bike up. As far as paying someone a couple hundred bucks to install an exhaust cam, I would try to give it a shot myself first. Buy a 1/4 inch drive torque wrench with a small head (or a 3/8 drive that goes low enough (75 in-lbs) and one of these http://www.motionpro...partno/08-0134/ , a set of motion pro feeler gages http://www.motionpro..._feeler_gauges/ , open the manual and have a go. It really isn't that hard...and neither is adjusting the valves, Rocky. Just take your time, be careful with the cam chain, get a good set of feeler gages and follow the book. Stuff a couple of shop rags down the cam chain tunnel to keep the cam locator half moon clip from falling in, too. For what it's worth, if you are a good customer, many sops will swap "what you have" for "what you need" when it comes to shims, as well.

  • jjsmx

Posted May 15, 2009 - 03:26 PM

#17

valve adjustments are not difficult to do. the link greyracer posted should give you an idea of what it involves. you don't have to take the engine off the bike if that is not clear. though, if you do take the bike into a shop for a valve adjustment they can put the cam in for no additional charge.

  • wesherman

Posted May 15, 2009 - 04:10 PM

#18

I like the decomp lever. Once you get the hang of it starts first try. Save your money.

  • trey03

Posted May 29, 2009 - 02:05 AM

#19

installed the hot cam love it less stalling,easier starting,better power curve worth the money if for nothing else than to save energy and get more ride time just one good kick and go





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