Freshening an SRX Engine

T

Theicor

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I have to freshen my 1998 SRX 700 Engine in my mountain sled and I had a couple of questions I wanted to throw out to you guys. Basically the engine is stock, and I need to put in pistons, rings, etc. First question do I get Wiseco pistons or just stay with the Yamaha. I know the Yammies are good, but the Wisecos may be cheaper, are there any known problems with the Wisecos? As long as I have the motor apart what are some cheap mods I can do to it to maybe bump up the power? I have read about the tricks with changing gaskets around and I would like to bump the compression since the sled is ridden at altitude. I would like to get a Peak Head, but I don't think that I can swing it. Let me know, any opinions would be appreciated.
 

Someone correct me if I'm wrong, but most guys on here will tell you to run stock pistons as opposed to Wisecos. From what I've read, OEM pistons seem to hold up better than aftermarket brands. Also, the head mod is a favorite of guys owning 98-99 SRX sleds. Cut .030 off the heads and add 2-3 base gaskets to get a bit more power.
 
Go with the stock pistons and to get more life out of them and a little insurance get the pistons coated . While it is apart check your cylinders for waren nicasil might be time to have them redone
 
I am looking to pick up a set of used mega power or peak heads for the thing and I will be running it with more compression, and I was leaning toward a Wiseco top end and then get them coated for this application. Can anyone give me a reason not to run the Wisecos, I am aware they run tighter and that you have to warm them up quite a bit more than usual. They are more affordable and the kit comes complete, I don't have to piece everything together. Thanks for the input... ;)!
 
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Well, first off the wiseco runs more skirt to wall clearance as they grow when they come to temp, 2nd they use a ring that is thinner then stock and will not last as long, they do provide less drag but you comprimise length of service life. The stock yamaha pistons are able to be run tighter, giving you a better ring seal as the piston does not rock back and forth up and down. For a race sled, I run wiseco's, they are lighter also. For a trail sled that you want to mile up, run stock. If you want a little edge over the next guy, you can run wiseco wrist pins in the stock yamaha pistons, this will give you a slightly faster revving engine and take the weight of 1 complete wristpin from the rotating assembly. You can run just as much compression with stock as wiseco, the stock ones are powder forged, very good units for trail/mod sleds that are gonna get alot of use.
 
yea wiseco's seem to have a lot more problems with skirt failure. Yamaha skirts only seem to fail when they rev 10,500 for awhile...so i've heard...
 
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