Snowshovel
New member
I just bought an 03 Mountain Viper with 7200 miles on it, the previous owner is a guy in his 50's that road with his wife predominately on the trail and got off trail in the powder on occasion. I tested the compression and she is still very strong and well within specs, I am new to the Viper and was just wondering when i should consider getting the top end redone? at how many miles/hours? we are pretty close to having rideable snow here in Idaho so I dont want to mess with it this season and be waiting while my friends are riding. Should i just ride her till i sense a problem or compression starts to taper off?
She is almost bone stock the only mods the previous owner did to her was Boysen reeds and a Hartman clutch. I plan many many more down the road, but they will be during the off season. Thanks for any advice
She is almost bone stock the only mods the previous owner did to her was Boysen reeds and a Hartman clutch. I plan many many more down the road, but they will be during the off season. Thanks for any advice
OnDaTrail
New member
If your compression is well within specs, what do you hope to gain by a rebuild? I'd leave it alone.
staggs65
Moderator
ride it
Snowshovel
New member
I wasnt hoping to gain anything, just possibly prevent something, as I said i am new to the Vipers so i wasnt sure if there was a threshold or life expectancy on some of the engine parts. Like a track record of things going south on them at XXXX amount of miles, sorry it comes from my profession. I been wrenching on F-15 fighters for 21 years, we call it preventive maintenance on them, that is more what i was thinking. I guess i will take a if it aint broke dont !@#$ with it attitude with the Viper ha-ha.
GibViper
New member
Snowshovel said:
Now you get to fly one! You'll love the Viper...
staggs65
Moderator
preventative maintenance musts:
clean carbs
clean and adjust powervalves
drain that old fuel put in fresh stuff
clean carbs
clean and adjust powervalves
drain that old fuel put in fresh stuff
Snowshovel said:
LOL...It goes with the Aviation World...but with my sleds I find when performing my preventative maintenance I just end up "Fixin it til its broke!" LOL
Seriously, if its running good just ride it and assess what really needs to be repaired over the season. Trust me , you'll have a pretty long snag sheet by spring!
JM.02c
linemech31
New member
To relate the yamaha sled to aircraft mx it would best be described as all parts are on condition. They are well made sleds.
Last edited:
rx1jim
New member
Chances are the sled was rarely "beat on" by the former owner. I have 15000 miles on my 2000 SRX and the engine has not been opened. Have the power valves cleaned, give the carbs a good cleaning, get rid of any old gas in the tank, change the chaincase oil and go through the maintenance items in the owners manual. Be sure to check, replace or regraese the drive axle bearing loacted on the left side of the sled behind the speedometer drive. Also check, replace or regrease the jackshaft bearing. These two bearing take a lot of load and are often not checked or serviced until they fail. I take these bearings out, pop the grease seals, clean out the old grease and repack them with a synthetic waterproof grease. With this maintenance done , you should have a trouble-free season. Ride it this season then have a leak-down test done on the engine which will reveal much more about the condition of the rings than a compression test.
There are many "wear" parts on your sled. For us to advise on the condition of any of them is guessing at best. The obvious ones are the hyfax, carbides, bearings (wheels, shafts, etc.) and bushings. In the engine the rings and bearings are also wear parts, but they can last a long time. There is no way to know for sure without measuring the parts. However a leak-down test may be a better indicator than the compression test. Looking at the piston sides through exhaust ports can indicate blow-by.
If you are a mechanic then tearing down the top-end is a 1 hour job or less. The cylinders do not usually wear as bad as pre-Nikasil days.
Many on here ride them until the break, but I am convinced that replacing rings when worn yields more total mileage out of them.
If you are a mechanic then tearing down the top-end is a 1 hour job or less. The cylinders do not usually wear as bad as pre-Nikasil days.
Many on here ride them until the break, but I am convinced that replacing rings when worn yields more total mileage out of them.
Snowshovel
New member
Alot of good advice thanks all, I will do the carb cleaning and old gas shouldnt be a problem it was about empty when i bought it. I will take the ride it till stuff breaks mentallity and make my list of improvements for spring. If it breaks too hard i always have my 700 MM or 600 MM to fall back on 
staggs65
Moderator
make sure you do the powervalves too very important (powervalves on a yamaha are exhaust valves not carb powervalves)