how 2 remove auto decomp

7 replies to this topic
  • goofour

Posted May 01, 2006 - 05:02 PM


Has anyone tried this on a 650r mine is wearing out and I am to cheap to buy a Hot Cam.

  • qadsan

Posted May 01, 2006 - 07:41 PM


I've done it plenty of times for other people. It's just a matter of removing the cam, pulling off the cam gear (NOT by the ears or they'll break!) and removing everything between the cam gear and the lobe. There's a drilled hole in the stock cam directly underneath the auto decomp mechanism that provides oil to the mechanism and you simply weld it shut. Two seconds with a mig welder and its done, or you can epoxy / JB weld it shut, etc, but I prefer to weld it shut. If you leave it open, then the oil from that hole takes the path of the least resistance, which is back down inside the cam chain cavity and I'd rather make better use of the oil / pressure, which is why I weld that hole shut.

Once the auto decomp mechanism is removed, make sure the only way you start your bike is by kicking it over from just past TDC. If you kick it like a 2 stroke or try to start it from the middle of the stroke, you run the risk of kick back and or possibly injury. Start it right and you won't have any issues.

  • suharianu

Posted May 02, 2006 - 06:59 AM


it wont be easy to separate the shaft from the wheel.i did it on my 600 and
it took a lot of fiddling around until it came loose.if you have a press it much easier

  • luvmythumper

Posted May 02, 2006 - 07:17 AM


How do you know it is wearing out? What are the symptoms?

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

Posted May 02, 2006 - 12:46 PM


Thanks for the info I have more time than money. My bike is a 2001 with unknown milage sometimes I can find the compresion stroke after two or three kicks sometimes it takes ten or more and I am to old for that kind of workout.

  • HawkGT

Posted May 02, 2006 - 01:47 PM


I too sometimes find that TDC is "missing". I've found that a slow kick (way slower than you'd normally do) one or two times helps undo whatever is letting compression out.

  • skyriver

Posted May 02, 2006 - 08:42 PM


Are you kicking it 10 times to actually start it? You do little easy kicks until it stops dead about mid-stroke and then come up one click and give a nice firm (not fast!) kick. Should start 1st or 2nd kick cold, full choke or 1st or 2nd kick hot, no choke. If you know what the deal is I apologize.... Just seems kinda drastic to remove one of the best features on the bike if it's just a matter of knowing how to kick the pig.
Again, I apologize if this comes off as arrogant. Just tends to be a lot of 2-smoke kickers out there that think you hop on and start hackin'. :crazy:

  • goofour

Posted May 03, 2006 - 11:33 AM


Thanks skyriver I am kicking slow just tring to find TDC. Last year it worked fine. This year the auto decomp won't release or when I find TDC and give it a big kick the motor won't even turn over so I hit the manual decomp lever and try a kick after TDC. I am getting tired of guesing I thought without the auto feature I could spend more time ridding and less kicking.

Related Content


Which thumper motor for a street tracker? by woz

Dirt Bike   General Dirt Bike Forums   General Dirt Bike Discussion
  • * * * * -
  • Hot  29 replies

What was your path to Beta? by officialhopsof

Dirt Bike   Make / Model Specific   Beta
  • Hot  79 replies

Can anyone identify this xr600 piston? by ms_mtn24

Dirt Bike   Make / Model Specific   Honda   XR600/650
  • 4 replies

1993 XR600R rebuild by ove

Dirt Bike   Make / Model Specific   Honda   XR600/650
  • Hot  41 replies

FCR40 Tuning Woes- XR600R by aTuWitty

Dirt Bike   Make / Model Specific   Honda   XR600/650
  • Hot  37 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.