This sled has 6k miles on it. It still runs and starts good. Its a 99 air cooled phazer 500. It seems a little underpowered on take off and the bottom end. How long before this motor needs a refresh? And would you just replace the rings and hone it out or replace pistons rings and everything?
For Cheap insurance it would be wise to put fresh pistons in "IF" it needed to be rebuilt.
The main key when it comes time to rebuild is to have the bores measured to make sure that they are true and not tapered or out of tolerance spec. When the tolerances start reaching the large side the pistons starts wobbling or rocking in the bore and the piston will have a tendancy to beat itself to death. This is where the term piston slap comes in and when the piston has reached its breaking point it will fracture and send all kinds of debris through the rest of the motor. This is the reason why I state "cheap insurance". Its no fun splitting the cases and having to wash or have the bearings replaced on the crankshaft because of trying to not repalce a part that takes alot of abuse. My $.02 T
The main key when it comes time to rebuild is to have the bores measured to make sure that they are true and not tapered or out of tolerance spec. When the tolerances start reaching the large side the pistons starts wobbling or rocking in the bore and the piston will have a tendancy to beat itself to death. This is where the term piston slap comes in and when the piston has reached its breaking point it will fracture and send all kinds of debris through the rest of the motor. This is the reason why I state "cheap insurance". Its no fun splitting the cases and having to wash or have the bearings replaced on the crankshaft because of trying to not repalce a part that takes alot of abuse. My $.02 T
X2
rebuild the entire top end
rebuild the entire top end
RJH
New member
I ride the heck out of nine..new pistons at close to 10K seem to be common??
It is fast ..for a 500...I have it clutched to lug on the trail..so easy on gas..
It is fast ..for a 500...I have it clutched to lug on the trail..so easy on gas..
The Phazer 500 engines I have torn down did not seem to wear the pistons very much. I would measure and only replace them if they are near the limit on tolerance. The rings do wear, so I would replace them for sure. This engine does not have anywhere near the horsepower of it's larger liquid cooled cousins. Thus rebuilding at 5K may be premature. However, the newer 500 engine has had more rod failures than it's predecesor the 485. The 2 engines are very similar, so I don't know of any reason why this should be the case. One thing to note is that the cases are real hard to find, as are used engines. So I would check all crank and rod bearings out very closely if your are tearing into it.
Now, if it seems slugish, I would first make sure all is well with the engine and ignition. Then I would suspect that you are losing efficiency somewhere in the clutches or drive train. Make sure all bushings, bearings and the chain are in good shape. Make sure the skid is in good shape and the track not too tight.
Switching to 8-tooth drivers and a Ripsaw track makes this an entirely different sled. The 11% gear reduction is exactly what this sled needs. I don't know why it is so over-geared from the factory. I experienced much improved acceleration, better sustainable top speed except in optimum conditions, and better fuel mileage to boot. I am still trying to find the downside. You can get used 8 tooth drivers for less than $100, and a used ripsaw for $200 or less. Be sure to put plastic skis on it. For less than $500 in upgrades this sled can really be impressive for a fan. Sell your old parts and it is very cheap.
Now, if it seems slugish, I would first make sure all is well with the engine and ignition. Then I would suspect that you are losing efficiency somewhere in the clutches or drive train. Make sure all bushings, bearings and the chain are in good shape. Make sure the skid is in good shape and the track not too tight.
Switching to 8-tooth drivers and a Ripsaw track makes this an entirely different sled. The 11% gear reduction is exactly what this sled needs. I don't know why it is so over-geared from the factory. I experienced much improved acceleration, better sustainable top speed except in optimum conditions, and better fuel mileage to boot. I am still trying to find the downside. You can get used 8 tooth drivers for less than $100, and a used ripsaw for $200 or less. Be sure to put plastic skis on it. For less than $500 in upgrades this sled can really be impressive for a fan. Sell your old parts and it is very cheap.
opsled
Active member
Ding said:
Exellent Ding, Exellent!!
opsled