KX Riders

Maintenance & Technical => KX500 Original => Topic started by: SupermotoFan on February 08, 2007, 04:25:09 AM

Title: Quite possibly the stupidest question ever--but I'm ready!
Post by: SupermotoFan on February 08, 2007, 04:25:09 AM
Joking around with my friend: I said I wanted a plonker trailbike as I'm pretty inexperienced, and I end up with a KX500.  He replies "just put two base gaskets on it--that'll make it easier to ride!"

Now, I know he was joking.  But upon further thought--Is this a reasonable option?

Perhaps, it would start easier, and make less horsepower...

It's got me thinking.  Has anyone out there heard of such a thing--or better yet tried it?

Thanks in advance.
Title: Re: Quite possibly the stupidest question ever--but I'm ready!
Post by: alan on February 08, 2007, 04:36:58 AM
Easier starting can be accomplished by adding flywheel weights, also reed spacer helped mine. If you were going to do trail riding weights would be the way to go! Adding gaskets will lower the compression ratio which will lower the HP, however I don't think it will do anything for starting except make a little easier to kick. :-D :-D
Title: Re: Quite possibly the stupidest question ever--but I'm ready!
Post by: gowen on February 08, 2007, 05:11:26 AM
Easier starting can be accomplished by adding flywheel weights, also reed spacer helped mine. If you were going to do trail riding weights would be the way to go! Adding gaskets will lower the compression ratio which will lower the HP, however I don't think it will do anything for starting except make a little easier to kick. :-D :-D

Actually it is close to using a thick head gasket and it does actually give more HP up top at the expense of down low. I never doubled the base, but I did use thick top-end gaskets..

Now this is of course you have the porting set up and the ignition set to accept the placement of the jug.. (huh?)
Title: Re: Quite possibly the stupidest question ever--but I'm ready!
Post by: don46 on February 08, 2007, 06:13:40 AM
installing 2 base gaskets will reduce compression, of course it also affects the squish are and the port timing, when done correctly it can make more horsepower. what year K5 are we talking? from about 90 on the flywheel was heavier, in fact it's quite heavy, you could add more weight to smooth out the power some, might help with the starting.
Title: Re: Quite possibly the stupidest question ever--but I'm ready!
Post by: gowen on February 08, 2007, 07:30:44 AM
Flywheel weights??  :-o :-o :-o  :evil:
Title: Re: Quite possibly the stupidest question ever--but I'm ready!
Post by: hughes on February 08, 2007, 07:37:12 AM
I'm getting me a flywheel weight just the for the stalling issues in tight woods. Off topic sorry.  :-)
Title: Re: Quite possibly the stupidest question ever--but I'm ready!
Post by: KXcam22 on February 08, 2007, 07:44:43 AM
SM fan,
  There are two really easy ways to detune that I have used.  The first is to remove the reedvalve and bend the mteal reed stops inward so that the reeds can't open as wide.  Set them for a 1/4" opening to start.  The second is to remove the pipe, find a large industrial sized washer with an OD the size of the pipe flange and about a 1-1/4" hole and place it flat in the exhaust port, sandwiched between the port and the pipe.  The inner hole of the washer will restrict the exhaust. My sons PW50 came with one of those.  A flywheel weight is also a great idea.  Hope this helps.  Cam.
Title: Re: Quite possibly the stupidest question ever--but I'm ready!
Post by: SupermotoFan on February 08, 2007, 10:22:02 AM
Excellent replies people!

Yep, I'm on my way to buying one of the Steahly flywheel weights, and for sure I will try the washer in the exhaust port.

Part of the reason I was going for this particular mod was because the engine is currently apart, and I figured it would be a cheap and easy way to lower the compression.


P.S. '86 KX500.