Another Piped Viper burnt down!

U

underwood

New member
Joined
Dec 14, 2004
Messages
13
Age
43
Location
Fargo, ND
Ok so I will admit that this one was my fault as the sled ideled for 45 minutes as we were trying to get my buddy's ski-doo running. When we took off it ran fine for 4 miles and the started backfiring. Loaded it up and went home to check the compression and it was 120(PTO) 120(Center) 27(Mag). After this I took out the scope and checked the piston and there was a huge hole in it. I have never redone a viper so I was wondering if you guys think I should redo the whole motor or just the one piston and sleeve. Or should I redo all the pistons and just the one sleeve? Also is there anything else I should check? Also does anyone have a good site to order this stuff from as I want to get back on the trail soon? Thanks
 

you might not have to replace the cylinder, i would just put a new piston in it and replace the cylinder if needed,they are nicasil so yoiu would not sleeve it, renic is about200.00 by the time you do shipping, i have a used viper piston and cylinder in very nice condition for 300.00
 
I was thinking I needed a sleeve because I was browsing denniskirk.com and they have cylinder sleeves for an 02 viper fo $90. Is this not what I would need?
 
First off, take off the cylinder, and then if there is smeared aluminum on the cylinder, go to the hardware store and buy a bottle of muratic acid. Using a eye dropper, place drops of the acid on the smeared aluminum, this will eat it off and not hurt the plating, let it sit and bubble, it will do the work, when it all turns to grey bubbles, wipe off with a rag and repeat if needed till its all gone, you might have been lucky and just need a piston assembly. :o|


p.s. wear gloves and dont breath the vapors from it bubbling, its nasty stuff, it eats aluminum, so dont get it on anything you dont want gone, you can protect areas you dont want touched(aluminum) with a smear of grease!!
 
make sure u check with your dealer first. my dealer said he can get new cylinders for just about what it would be to get it nicasyld but i'm not sure with yamaha knowing them its double the price. i will find out tomorrow,i will be in need of some parts too. let me know how u make out there underwood. good luck
 
most likely you can reuse you gaskets,if they come of in nice shape, mine did and i used it twice already, i have reused the sxr style quite alot with no probs, not recomended by yamaha but they want to sell parts,just slam in a piston and go hard
 
If you are able to reuse the jug, take 800 grit wet/dry sandpaper and rough up the cyl walls at a 30 degree angle in both directions. This gives the new ring somyhing to seat to. Don't worry that niacil is harder than steel. Its only on there about .003" but after 10,000 km on my sled u can still see the crosshatching in the cyl's.
 
underwood said:
After this I took out the scope and checked the piston and there was a huge hole in it.
Click to expand...

Was this hole in the top of the piston or under the lower ring on the exhaust side? Sorry for your luck.
 
underwood said:
It is on the top side towards the handlebars.
Click to expand...

Detonation from being overheated would be my guess, Was you able to save the cylinder like the others said?

Hopfully you cut the exhaust manifold gasket into 3 pieces when you put the pipes on, It would save from pulling the other 2 pipes out to get the cylinder off.
 
Well after tearing the motor down tonight it is a lot worse then I thought. It looks as though the ring on the piston broke and all broke loose after that. It looks as if I will need a new cylinder, (hugh grooves) piston, head is all pitted, and the powervalve is gashed. Makes me wonder if I should just part out the rest and get a race motor or fix it and ride it. Also Bushman there is no hole as I once thought with the scope, but it is a little melted on the exhaust side. Any one have any insights as to what might have happened or can anyone suggest what I should do?
Darin
 
I just burned down my piped viper, also.

Took my newly Bender piped Viper out 2 sundays ago and it ran great! It was over-revving so I ordered a set of Heel Clickers. Went back to the pond on Thursday with a fresh tank of Sunoco Ultra 93 and my new heel clickers. Ran awesome until the 4th run across the pond....pop...pop...lost my mag and center pistons! Called Justin @ Bender right after it happened...we concluded that the Sunoco must have been oxygenated and caused me to run lean. (don't run any 93 in the Northeast...too much oxygenated additives..run 91)He had me send in my head and 2 cylinders to exchange them for reconditioned cylinders and a head that had been machined so that all the cylinders ran the same compression. Got credit for my damaged goods towards the new ones. Maybe you should try calling them...they have plenty of reconditioned engine parts in stock. Phone Sales: 585.937.6829
Tech: 585.937.6837 Ask for Justin.
 
CPR ceramic pipes with jeffs jetting. Stock head no cooler. Might just sell the pipes and put it back to stock now.
 
The exact same thing happened to me last year with CPR coated pipes. Its defenitly caused by a lean condition. With the coated pipes the underhood temps are lower so on a long pull (blew mine after 3/4 mile of WOT :o| ) the warmer air is sucked out from under the hood and replaced by a nice cool charge of fresh air making it much leaner than on short bursts of WOT.
If you are going to make long pulls of WOT you need to jet richer than CPR's recommendations and I would certainly put on a set of EGT's, they are cheaper than rebuilding a couple of times a year.
Just my .02.
 
Underwood, if you were running close to jeff's spec's you should not have burnt that down. His jetting is fairly conservative to save from that. I have been running much leaner than his spec's and have not even had temp's close to a burndown. My viper can idle as long as it want's but it may load up a little. Did you modify the airbox or run tpi's, or maybe a pipe that leaked, just check everything because I think most viper burndowns should be able to be avoided.
 
In 02 - Vipers were running uncoated pistons - Yamaha did a silent change and went to SRX pistons - change all your stock pistons and you will be ok. You wernt lean - it was a bad piston from the factory. I did 3 of these before I found this out - the part # for the piston silently changed in late 01.
 
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