How do I get more out of my 426???


40 replies to this topic
  • 642MX

Posted June 09, 2006 - 05:15 PM

#21

Does the wiseco high comp piston kit require race gas?




Only if your engine pings. I run Citgo 110 octane leaded fuel in mine (13.5:1)

  • 78sharpshooter

Posted June 09, 2006 - 05:31 PM

#22

What is the performance difference when a high comp piston is installed?

  • 642MX

Posted June 09, 2006 - 06:10 PM

#23

What is the performance difference when a high comp piston is installed?




It gives the bike more low end grunt and mid range punch.

  • 78sharpshooter

Posted June 10, 2006 - 10:09 AM

#24

What is the function of the lead in the gas? I remeber hearing that it helps with lubricity but am not sure. And can you get it at a citgo station?

  • 642MX

Posted June 10, 2006 - 04:29 PM

#25

What is the function of the lead in the gas? I remeber hearing that it helps with lubricity but am not sure. And can you get it at a citgo station?




The lead helps lubricate the valves and makes jetting the bike 100 times easier. It smells good too. I get mine from a gas station that happens to sell race fuel also. Regular Citgo stations probably don't carry it.

Sunoco would be my first choice in race gas, but its hard to find around here. The Citgo is readily available, so I use it.

  • weng842002

Posted August 04, 2006 - 11:40 AM

#26

It gives the bike more low end grunt and mid range punch.


Any risk? Will the engine last as long as normal comp pistons?

  • 426kid

Posted August 02, 2007 - 03:11 PM

#27

lemme tell you somethin those 450 cams are oonly good if you dont no how to kick the ****in thing hoonestly but i did the BKmod on the pump helped alot especially down low ahhhhhhhhhhhh i tried runnin 110gas outta mine it didnt like that very much butta i use 93 nn add a bit of octane booster into it maxima oil and cyclogic engine ice it all makes a difference in its own way bend the clip up on your floats that ell help ahhh thats it if any of this stuff helped out or ya need n more advice hit me up

  • klxnewguy

Posted August 02, 2007 - 05:42 PM

#28

I've been wanting to do the 03 cam mod but when I called two dealers here in town one said they do it all the time and the other said NOT to do it as the cams have a different pitch and will wear out the chain etc..

What do you all think? I can start it just fine with the decompression lever but does the 03 cam do more than just make it start easier?

  • klxnewguy

Posted August 02, 2007 - 05:46 PM

#29

426 Kid, does the engine ice really help keep the bike cooler? My 01 always seams to be running hot but I've been told that is how they run but if the Engine Ice works well maybe it would be worth a shot. Let me know, thanks.

  • King_Air

Posted August 03, 2007 - 08:30 AM

#30

lemme tell you somethin those 450 cams are oonly good if you dont no how to kick the ****in thing.


I found that besides easier staring, the decomp cam mod gave more useable low end, and less tendency to stall at slow speeds. That in itself was worth the money. Being able to kick start it like a 125 2 smoke was just a bonus.

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  • King_Air

Posted August 03, 2007 - 08:34 AM

#31

I've been wanting to do the 03 cam mod but when I called two dealers here in town one said they do it all the time and the other said NOT to do it as the cams have a different pitch and will wear out the chain etc..

What do you all think? I can start it just fine with the decompression lever but does the 03 cam do more than just make it start easier?


Read thru the stickys at the top of the page. There is a lot of discussion on the chain pitch. As far as I know there have been no reported failures due to the cam chain pitch. You can also use the Hot Cams setup and the chain pitch matches. Only on the oem yz450 cams does the pitch differ. Trust me and the other 1000 people who say that this mod is a must do. It provides more than just easier staring.

  • grayracer513

Posted August 03, 2007 - 12:24 PM

#32

The specific difference in the chains is not actually the pitch, pitch being the distance from any point on the chain or sprocket to the next same point (as in pin to pin, or tooth to tooth). The tooth profile is slightly different, which causes the chain to ride slightly higher on the sprocket. But as was said, there has not been one reported problem resulting from it.


lemme tell you somethin those 450 cams are oonly good if you dont no how to kick the ****in thing hoonestly ..... (if) ya need n more advice hit me up

Yeah, we'll do that. I can give a crashed and flooded 450 4 good kicks and have it running by the time you're ready for the first one with manual decomp. That, and if you kill the engine with the brakes, you can bump it back off just by bouncing the clutch once at anything over 5 mph. At low speeds, there just isn't time to do that with MD.

  • kid on a 426

Posted August 04, 2007 - 08:55 PM

#33

The specific difference in the chains is not actually the pitch, pitch being the distance from any point on the chain or sprocket to the next same point (as in pin to pin, or tooth to tooth). The tooth profile is slightly different, which causes the chain to ride slightly higher on the sprocket. But as was said, there has not been one reported problem resulting from it.


Yeah, we'll do that. I can give a crashed and flooded 450 4 good kicks and have it running by the time you're ready for the first one with manual decomp. That, and if you kill the engine with the brakes, you can bump it back off just by bouncing the clutch once at anything over 5 mph. At low speeds, there just isn't time to do that with MD.


I've had my manual decomp on my 426 for almost 2 years now and I doubt you could get your 450 started any faster than me, kicking or bump starting hot or flooded. I know my compression braking has saved me from some hairy S**t coming down the big hills at Carnegei and certainly wouldnt want to change a thing about that. The only downside to MD is on the starting line of a harescramble but so far I've gotten mine first kick everytime and have had good starts.

  • whyzee79

Posted August 05, 2007 - 05:14 AM

#34

Only if your engine pings. I run Citgo 110 octane leaded fuel in mine (13.5:1)




Sorry for the quick hijack, but where do you get citgo 110 at?

  • 642MX

Posted August 05, 2007 - 06:08 AM

#35

Any risk? Will the engine last as long as normal comp pistons?


I've had a high compression piston for about 3 years now. I'd say that the high comp pistons have no affect on engine life.

  • 642MX

Posted August 05, 2007 - 06:11 AM

#36

Sorry for the quick hijack, but where do you get citgo 110 at?


I used to get it at a place called Busler Enterprises. They switched to Monster race fuels, which haven't quite been the same quality.

I recently found a guy who carries Sunoco, its amazing how much better the bike runs on Sunoco. I'm going to keep using it. :thumbsup:

  • Fastest1

Posted August 05, 2007 - 12:43 PM

#37

yeah it's the exhaust cam btw, it also gives it a little more hit.

Far from it! It actually mellows the "hit". It does make starting much easier,allows restarting while rolling and doesnt lose any power overall but delivery is much more tractable. The 2000 model is abrupt to say the least. I would go back and clean the carb thoroughly first and see if it helps. If it ran great very recently and just changed for no apparent reason, probably something minor. Try the plug too.

  • Fastest1

Posted August 05, 2007 - 12:53 PM

#38

I've had my manual decomp on my 426 for almost 2 years now and I doubt you could get your 450 started any faster than me, kicking or bump starting hot or flooded. I know my compression braking has saved me from some hairy S**t coming down the big hills at Carnegei and certainly wouldnt want to change a thing about that. The only downside to MD is on the starting line of a harescramble but so far I've gotten mine first kick everytime and have had good starts.

KID, you are dreaming! WAKE UP! I have been around too long and personally tested it. The only thing better about the original cam is the abruptness of power! Yeah it is fun, but smooth equates to fast every time. The only reason NOT to install the cam is if you are broke. I wonder why Yamaha went to an AD cam since Tim Ferry should have been able to restart as fast as you or I?:banghead: BTW I didnt lose any engine braking and I run a Rekluse on top of all that! Maybe it isnt running right. LOL

  • 642MX

Posted August 05, 2007 - 02:53 PM

#39

I've had my manual decomp on my 426 for almost 2 years now and I doubt you could get your 450 started any faster than me, kicking or bump starting hot or flooded. I know my compression braking has saved me from some hairy S**t coming down the big hills at Carnegei and certainly wouldnt want to change a thing about that. The only downside to MD is on the starting line of a harescramble but so far I've gotten mine first kick everytime and have had good starts.


What does a 450 cam have to do with engine (in your words, "compression") braking? :confused:

  • 642MX

Posted August 05, 2007 - 02:55 PM

#40

The only reason NOT to install the cam is if you are broke.


Exactly. There is NO downsides to an auto-decompression cam.





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