KX Riders

Maintenance & Technical => KX500 Original => Topic started by: dave916 on June 08, 2010, 09:14:34 AM

Title: window piston on prox
Post by: dave916 on June 08, 2010, 09:14:34 AM
is it ok to do the window mod on a Prox piston?
did a search but all the info seems to be related to wisco
thank in advance
Title: Re: window piston on prox
Post by: BDI on June 08, 2010, 10:47:07 AM
I wouldn't go cutting any big holes in a cast piston.
Title: Re: window piston on prox
Post by: 3Razors on June 08, 2010, 04:11:02 PM
I wouldn't go cutting any big holes in a cast piston.

Yep X2
Title: Re: window piston on prox
Post by: dave916 on June 10, 2010, 03:08:07 AM
so i will take that as a NO,  
a lot of the older 2 stroke cast piston used to have windows standard 
http://www.yambits.co.uk/catalog/product_info.php?products_id=313&osCsid=d8103f8df3a5347f34ee332849e16f09

Title: Re: window piston on prox
Post by: cbxracer30 on June 10, 2010, 03:16:09 AM
What I learned from the bigbore pistons the big hole doesnt work but then again the hole doesnt have to be that big cut the length in half , also if you have somewhere on that side of the pond that does cryogenic treatment , I can't preach enough about how much stronger this process makes new metals & it also helps used parts to , just something to look into. CBX
Title: Re: window piston on prox
Post by: BDI on June 10, 2010, 04:52:05 AM
If a guy were to do it He would want sand smooth and polish the edges of the hole to try and get rid of micro cracks. Even the method of holing the piston should be considered. I definitely would change the piston after 20 hours if it makes it that long. You could just buy a forged piston from J-fab or stewart and not worry about it. This is one of those things you shouldn't recommend someone to do.
Title: Re: window piston on prox
Post by: dave916 on June 10, 2010, 09:46:07 AM
thanks guys for the info,  going to give the widow idea a miss not worth the risk for a few extra hp,  already have a new  PROX piston, dont really like the forged piston as will be running on the road and dont like the extra warm up time,
 cbx is the cryogenic treatment something i should still do  [with no window]
Title: Re: window piston on prox
Post by: kwakman on June 28, 2010, 01:59:07 AM
gonna be using my 86 on the road eventually, and because of that I'm gonna use a forged Wiseco.Its worth thoroughly warming them anyway, so the extra piece of mind is worth having another cig while she warms up....Make sure your jetted properly for the road.Usual practice is to run a little richer than you would normally, as traffic speed dictates what you can do with the loud handle so take account of the lube required on your mains and keeping the piston cool.
Title: Re: window piston on prox
Post by: don46 on June 28, 2010, 03:02:12 AM
since this was up I thought I'd add my .02, I just did a bottom end for a guy that did the window in a cast piston. When the piston let go, it wrecked the cases, rod, and cylinder. The tranny, clutch and head were only things salvagable. What's crazy is he wanted me to do the window for him again, fortunately I talked him out of it.

There is a moral to this story, and I hope it will open some eyes
Title: Re: window piston on prox
Post by: kwakman on June 28, 2010, 01:18:38 PM
I bet he wishes he'd forked out the relatively cheap ?100 for a wiseco, compared to the cost of crank, cases etc;Would of thought he'd have learnt his lesson his self after that Don.