de-compression valve

[matt kx500 (uk)]

hi i,ve i recently bought a compresion release valve wich was intended for a harley when pressed it alows pressure to pass through and once the bike is started it cuts off.does anyone no what sort of pressure harleys run at and wether i would be able to fit dirrectly on to the head of my k5 with a bit of machineing or is this a realy bad idea let me no what you think cheers matt

[AUS_KX5]

Most decompression systems operate by holding open the exhaust valve, so no the harley deal isn't going to work on your two stroke 500. Get a feel for bringing it up on the compression stroke before kicking it over.

[gwcrim]

We had a Sportster race engine with pop up compression releases.  They were either automatic somehow or we never used them.  But they were small and could most likely be used on a dirt bike.  They kinda sound like the ones that someone recently described on their Maico.

[mg82]

got one on my drag raptor from a harley application and works great.

[Paul]

got one on my drag raptor from a harley application and works great.

Harleys and Raptors have valves, I would expect it to work in that application.

[mg82]

the compression release that i have does not hold the valve open like AUS_KX5 was talking about. a hole was machined in the side of the head and an aluminum plug was dropped in and welded up. the plug was then tapped for the comp. rel. valve and thats it. its such a simple concept. if i doesn't work then just don't push the button in.

[Paul]

That type is in use on atleast one KX500 here, just search and you shall find

[matt kx500 (uk)]

cheers all! the valves in the post from the states so should be here in a week or so i,ll get some pic's up when its fitted. almost ready for the road. at last cheers matt

this is the type of valve if anyone else is interested ebay no.140106292210