KX Riders

Maintenance & Technical => KX500 Original => Topic started by: ElliotG on September 21, 2004, 03:17:28 PM

Title: Detonation and Octane boost
Post by: ElliotG on September 21, 2004, 03:17:28 PM

Hello all,

My 5 hunnie has some detonation going on, and am thinking about trying some higher octane fuel.

I haven't cracked the head open yet, my compression is just shy of 115, so detonation isn't related to high compression.
I am probably due for a new piston/ring.; I have a trip coming up for SandMountain, and don't have enough time to freshen up the top end (parts availablity).

I really don't want to purchase 6 dollar a gallon stuff, so am considering using tuolene or xylene, depending on what is available . I have seen this done for other applications, was just wondering if this might be harmful for a two stroke?

I am worried about running in the sand for extended rides, don't wan't to hurt the bike with too much detonation, so the octane boost is a temporary fix.

Thanks

Title: Detonation and Octane boost
Post by: mikesmith on September 21, 2004, 08:46:03 PM

I wouldnt suggest using that stuff found in paint thinner,are you sure your jettings right?I would rather run my jetting a little fat (rich) and put up with the "blubbering" (how it runs)of the bike and not worry.

Title: Detonation and Octane boost
Post by: Kawadougie on September 22, 2004, 12:52:28 AM

I would definitely replace the piston and de-carbon the head.  Also check your ignition timing.  For a quick fix you can use any commercially available octane booster.  I used to use them when I raced high compression 125's.  The only downside is that it will stain the inside of the tank an ugly brown color.

Title: Detonation and Octane boost
Post by: alan on September 22, 2004, 08:31:29 AM

Here is a post on another site which talks about Octane Boost!

http://yz490.com/index.php?name=PNphpBB2&file=viewtopic&t=26&highlight=klotz&sid=3a79aaf81fbebcdcdfc9799ebae9de87

Klotz works great!

Alan

Title: Detonation and Octane boost
Post by: KXcam22 on September 22, 2004, 11:11:49 AM

I have had good luck with octane boost.  But....for riding in the sand I would definitely put a fatter main jet in.  The extra load is considerable in sand and you are better to be a tad on the rich side. Cam.

Title: Detonation and Octane boost
Post by: ElliotG on September 22, 2004, 05:54:43 PM

Thanks! You are right, I could have some carbon buildup on my piston. I am not sure when they were last done. I have seen advice from Paul to the effect of using compression as a basis of new piston/ring. Being as I am at 113 or so, I am probably due.

As far as the octane boost goes... I have used Klotz, was just wondering if anyone had actually used straight tuolene or xylene, mixed in with the gas of course  :!:

Thanks

Title: Detonation and Octane boost
Post by: Paul on September 23, 2004, 02:27:40 AM

These are called service limits. If you're at 113lbs of compression you are due for a new topend.

Quote from: ElliotG

I have seen advice from Paul to the effect of using compression as a basis of new piston/ring. Being as I am at 113 or so, I am probably due.

Check the FAQ under specs for the Service Limits (http://www.pitbull-racing.com/modules.php?op=modload&name=FAQ&file=index&myfaq=yes&id_cat=5#15)

Title: Detonation and Octane boost
Post by: ElliotG on September 23, 2004, 05:00:41 AM

Does is make any difference whether the bike is cold or not when runing a compression test?