Subi.Nova
New member
I'm kind of at a loss. Spent the winter going in circles chasing a gremlin somewhere within the SRV. She's running again.... But now only on one cylinder....any help would be greatly appreciated.
The engine in my '89 comes out of my dad's '88 SRV as the one that was in the '89 was shot (blown cylinder walls, burnt pistons, etc) I had originially planned on fixing up both sleds but since my dad's sled was in shit condition tub wise we decided to part her out to make the '89 run.
Back in February we had the sled running good and then it died around mile 14 (roughly an hour into of groomed flat trail riding). Thought it was the rings as they had probably seen better days so we swapped them out. Once done we went out on the ice and did a test ride and, again she died after about 45 minutes of riding once she got hot, (decided to looked at the pistons and realized that one was burnt and the rings were the only thing holding back pressure. thus we said screw it....engine rebuild, pistons, rings, cyllinder rehone, gaskets, crank seals, the whole 9 yards) Just got the engine back together and in the sled and she fires up without issue but seems to be running on the one cyl. The sled does pull oil and fuel with no problems and since its a rebuilt engine we're treating it as a new engine so its running pre-mix at the moment. (this is the 2nd time in the engines life that its been rebuilt, the last time was probably the mid 90s, when my dad last did gaskets and pistons and installed the power reeds)
I don't want to give up on the sled as I've put so much time into it over the winter. These are my thoughts but I'm not sure.....
Whats been done over the winter
New top end gaskets
New crank seals
New pistons, rings and circlips
Freshly honed cylinders
New plugs
Cleaned carb w/ rebuild kit
New fuel, oil and vac hoses
New CDI
New Voltage Regulator
Rebuilt fuel pump
New fuel and oil filters
New belts
Replaced clutch (comet 102c)
Rebuilt fan
Thanks
The engine in my '89 comes out of my dad's '88 SRV as the one that was in the '89 was shot (blown cylinder walls, burnt pistons, etc) I had originially planned on fixing up both sleds but since my dad's sled was in shit condition tub wise we decided to part her out to make the '89 run.
Back in February we had the sled running good and then it died around mile 14 (roughly an hour into of groomed flat trail riding). Thought it was the rings as they had probably seen better days so we swapped them out. Once done we went out on the ice and did a test ride and, again she died after about 45 minutes of riding once she got hot, (decided to looked at the pistons and realized that one was burnt and the rings were the only thing holding back pressure. thus we said screw it....engine rebuild, pistons, rings, cyllinder rehone, gaskets, crank seals, the whole 9 yards) Just got the engine back together and in the sled and she fires up without issue but seems to be running on the one cyl. The sled does pull oil and fuel with no problems and since its a rebuilt engine we're treating it as a new engine so its running pre-mix at the moment. (this is the 2nd time in the engines life that its been rebuilt, the last time was probably the mid 90s, when my dad last did gaskets and pistons and installed the power reeds)
I don't want to give up on the sled as I've put so much time into it over the winter. These are my thoughts but I'm not sure.....
- Maybe needs new boyesen reeds? (the ones in it my dad installed in like 96). They look fine when held up to the light, no cracks or deformities
- Try another carb (I have 2 more floating around ready and rebuilt, just need to be cleaned again)
- Has spark but should I look at a new coil pack? (I have one from another SRV that I could try)
- Maybe a bad ground somewhere?
Whats been done over the winter
New top end gaskets
New crank seals
New pistons, rings and circlips
Freshly honed cylinders
New plugs
Cleaned carb w/ rebuild kit
New fuel, oil and vac hoses
New CDI
New Voltage Regulator
Rebuilt fuel pump
New fuel and oil filters
New belts
Replaced clutch (comet 102c)
Rebuilt fan
Thanks
check the stator. had an old et250 that once the coils got hot under the flywheel, it would loose spark.
Subi.Nova
New member
When we had the engine on the bench doing the crank seals we tested the stator and the resistance tested fine. Also ensured that it's not out of phase as well when reassembling everything. Prior to the rebuild the sled was running on both cylinders, then we realized that we needed to do the pistons due to the fan side piston starting to burn out and only the rings being what was holding back compression in one spot.
Right now the engine won't even let it get hot. Prior to the rebuild the engine would die because of a loss of compression due to the bad piston.
Couple of folks think it could be the coil pack and the reeds although they look good are sticking. The one that is on the engine is the original so maybe although it's getting spark and it "looks even" it's not even enough. Or is it possible that I got faulty top end gaskets and some didn't seal on the cylinder that's not running right?
Right now the engine won't even let it get hot. Prior to the rebuild the engine would die because of a loss of compression due to the bad piston.
Couple of folks think it could be the coil pack and the reeds although they look good are sticking. The one that is on the engine is the original so maybe although it's getting spark and it "looks even" it's not even enough. Or is it possible that I got faulty top end gaskets and some didn't seal on the cylinder that's not running right?
RON HYDRAULIC YAM
Member
story time .. i gave a trailfire to my nephew to work on at high school. Did all the work
put it back together . started , ran , then ran poor . found a piece of burnt shop
rag near sled.. They had stuffed the inlet of pipe to keep dirt out .Forgot to remove it !
Drilled many large holes and eventually removed all the pieces.
Just for giggles . take pipe off and try a shop vac . Should suck with little resistance.
If it whines up and restricted , it may be bunged with a rag ? or if you used pipe from
parked sled , a critter nest.
..
other wild idea , backfire when starting ? and blow a crank seal ?
If drawing fuel , the dead cyl should be black and unburnt fuel dripping
down the manifold .
Good luck
Ron
put it back together . started , ran , then ran poor . found a piece of burnt shop
rag near sled.. They had stuffed the inlet of pipe to keep dirt out .Forgot to remove it !
Drilled many large holes and eventually removed all the pieces.
Just for giggles . take pipe off and try a shop vac . Should suck with little resistance.
If it whines up and restricted , it may be bunged with a rag ? or if you used pipe from
parked sled , a critter nest.
..
other wild idea , backfire when starting ? and blow a crank seal ?
If drawing fuel , the dead cyl should be black and unburnt fuel dripping
down the manifold .
Good luck
Ron