426 just got easier to kick?

7 replies to this topic
  • Moto_Madness

Posted May 09, 2013 - 03:37 PM


I noticed the kick on my 426 became signifigantly easier after a good ride on it. I've only ridden this bike twice. Initially it felt like it had solid compression, and was very hard to kick through. Now it is nice to kick through and starts first kick every time, idles fine.

Was wondering though if this is an indication it may be due for a top end?

Many thanks :)


  • four-twenty-sixer

Posted May 10, 2013 - 09:44 AM


Could be a valve sticking open, could be piston rings, I would start with checking your valve clearance and go from there. Might get lucky and its just some carbon holding a valve off its seat. Also check you decompression lever isn't hold the exhaust valve open.

  • NitrousR1

Posted May 11, 2013 - 05:12 AM


I would buy a cylinder leakdown tester. this will tell you what is leak- intake valve- exhaust valve- piston rings...etc. It could just be time for a piston and rings. Start with the valve clearances though- work from easy to hard.

  • GottaHangOn

Posted May 11, 2013 - 10:44 AM


Has the auto decompression cam mod been done or does it still have the decomp lever on the bars?

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

Posted May 12, 2013 - 04:50 PM


Has the auto decompression cam mod been done or does it still have the decomp lever on the bars?

it still has the manual decomp lever on bars. I disconected it to test if it was affecting the compression. It wasn't. Have also been chewing a plug per ride. Can you recommmend a cylinder leak down tester?


  • GottaHangOn

Posted May 15, 2013 - 08:26 AM


My snap on was around $250. I have done a couple a day some days so Its justified, but motion pro offers a cheaper alternative. I'd do a simple compression test if I were you. Cheap and easy and then you can take it to a shop if need be.

  • grayracer513

Posted May 15, 2013 - 08:43 AM


it still has the manual decomp lever on bars.

That doesn't mean it doesn't have auto decompression. If you find a flyweight on the exhaust cam, it does. If not, it's as it was built.

  • NitrousR1

Posted May 18, 2013 - 03:39 PM


Id recommend a name brand leakdown tester like a snap on, matco or mac. I have a snap on one that has worked great for years. But there are other good ones out there. The guy in the bay next to me has a OTC and has been using it for years without problems. If its for home use or recreational I'd recommend the OTC or similar name.

Related Content


The "going back to the other darkside" adventure... by Monk

Dirt Bike   Make / Model Specific   KTM   250/350/450/505 SX-F & XC-F (4-Strokes)
  • Hot  113 replies

05 yz450f not fast enough by RedeyeYZ

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • Hot  38 replies

Snake pit oct 30th by The Anvil

Dirt Bike   Dirt Bike Regional Discussion   California
  • Hot  293 replies

Is it worth it? (Cam and High compression piston) by macgi77

Dirt Bike   Make / Model Specific   Honda   CRF 150/230 F/L
  • Hot  36 replies

Wilson the Blue Privateer by jetfuel

Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  50 replies

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.