a working compresion release is here

[jfabmotorsports.com]

R&D....Rob and Duplicate...Got to love it. So easy a caveman could do it. Well the Rob part, the duplicate took a little more time. Thanks Larry, I loved the weld on bung idea. 

[jfabmotorsports.com]

Done deal. Works great. IMO, it is the best mod that you could do to the kx500 engine...except put it in an aluminum frame.  

[monster malibu]

I'll definately take one, after having my cyl. replated and a new piston installed on my 87 KX500 it was real bear to kick. The only good thing about the hard to kick problem was there weren't to many people in my area that wanted to ride my bike because they couldn't kick it.
This mod is worth it's weight in gold easily to me.

[DHregdovic]

I have mine on its way to larry right now. Can't wait for this mod to come back. Thanx again Larry!!!

[gortex]

Maybe I'll buy or make this one.


http://www.racebase.co.uk/item--Decompressor-Valve-Assembly--EH_VDE5.html



Dutchie

Just brought two of these, ones gone onto a yz490 and the other getting put on my kx500.  We putting these in the head on both bikes i'm getting the k5 done now and the 490 kicks over like a 125!!!
We got some nice hotstart levers and no one will ever know 

[jdb1989]

i have an 85 jug would it be possible for my head.

[Larry Wiechman]

No problem!

[Friar-Tuck]

 L.W. & JFab,
 Has anyone approached you guys on doing the big CR's?   or those big MX sidecar motors?
    I believe when this gets around you're gonna be swamped... 
  Tuck\o/

[Larry Wiechman]

The CR's really benefit from this modification, especially if the cylinder has been bored oversize. The stock decompression grooves near the exhaust port are removed by the over bore. Now you have additional cylinder volume being squeezed into a stock volume head.
 
Larry

[PowerFiend]

Anyone worked out a hotstart activated one yet? 

[Larry Wiechman]

Anyone worked out a hotstart activated one yet? 

 Do you mean cable/lever operated?
 
Larry

[jfabmotorsports.com]

Anyone worked out a hotstart activated one yet?  

 
 Do you mean cable/lever operated?
 
Larry

   I have been working out the details of this idea for some time. I just finished it up this morning and if the rain here ever stops I will take the K5 out and thrash it a bit.
     I think it was Dutch-K5 Fan that said he was interested in using this type of valve. The valve can be bought all over the internet and with very little head work and the little adapter that I am going to offer it can be installed on just about any head on any bike.

JFAB    

[Friar-Tuck]

 I hope you guy's  make a zillion with these.
   "Find a need, Fill a need"...
  Tuck\o/

[Dutch-K5 Fan]

Although it's not going fast now, I'm working on it bit by bit.
 It realy looks good Jerry!!!!!

Dutchie

[jfabmotorsports.com]

Thanks Dutch, I like the one built for chain saws that I put on my KX500AF but if you are running a stock K5 with an over size fuel tank it is hard if not impossible to use especially in a hurry. I just got in from some riding and so far so good. It starts easier than the AF but the engine is bone stock as opposed to 13:1. I think that is the difference. I used the same size hole into the cylinder. Thanks again for the idea Dutch.

JFAB