What happened to this Crank? What are my rebuild options?

[vinpie1]

I just picked up a 03 Edge 800 144" with ~2200 miles and a blown motor. I have been trying to figure out what happened to it. The pistons look to have four corner seized, but one jug looks good the other has a bb sized spot where the nikisil flaked off right above the intake ports. The crankshaft spins smoothly and all the bearings feel smooth. The pto inner bearing has a little wiggle side to side. The rods look new and are very smooth and tight. The cases have a few marks from the bearings spinning. Do they need fixed? What are my options for the lowest cost to get up and running? I just need one bearing replaced and the rest inspected. I am in Colorado, anybody in the state (or the west) you can recommend? Thanks !

 

[Jay]

I'll guess the "seized" piston is the pto? The cases in those pics are completely hammered. There is so much slop on the center bearings the crank has actually been touching the labrinth seal in the cases. Where the pto bearings are sitting in the cases there is so much damage I'm not sure you could even clean that up with line boring. Those are classic polaris BB 800 crankshaft failure pictures, the only pic missing is the one of the 2 piece crankshaft. Send your cases to a reputable shop and they can tell you if there is enough left to line bore them, if not you need new cases. Exchange the crank for a rebuild. You'll need 2 replated cylinders and a top end kit. Hardass on here does replated cylinders. SPI kits are available almost anywhere and work well. Is the head ok? usually they get pounded out also on the pto side. I guess it depends what you want to spend to repair it, maybe look into a rebuilt engine instead of doing it yourself, might be cheaper. If you plan on keeping it send the whole thing to Indy Specialties and Dan will send you back an engine you can beat like a redheaded stepchild for years to come, guaranted. If you want to spend a little more throw a set of slp heads on it and a set of slp twins, if you want it all send the renicked cylinders to Doug Ruth for porting and you'll have a REAL strong engine. I have a soft spot for the old BB 800's, they are a good engine with lots of potential and when they are done right they pull like a freight train.

 

[vinpie1]

Jay- Thanks for all the great info.

 

[LoudHandle]

I'll guess the "seized" piston is the pto? The cases in those pics are completely hammered. There is so much slop on the center bearings the crank has actually been touching the labrinth seal in the cases. Where the pto bearings are sitting in the cases there is so much damage I'm not sure you could even clean that up with line boring. Those are classic polaris BB 800 crankshaft failure pictures, the only pic missing is the one of the 2 piece crankshaft. Send your cases to a reputable shop and they can tell you if there is enough left to line bore them, if not you need new cases. Exchange the crank for a rebuild. You'll need 2 replated cylinders and a top end kit. Hardass on here does replated cylinders. SPI kits are available almost anywhere and work well. Is the head ok? usually they get pounded out also on the pto side. I guess it depends what you want to spend to repair it, maybe look into a rebuilt engine instead of doing it yourself, might be cheaper. If you plan on keeping it send the whole thing to Indy Specialties and Dan will send you back an engine you can beat like a redheaded stepchild for years to come, guaranted. If you want to spend a little more throw a set of slp heads on it and a set of slp twins, if you want it all send the renicked cylinders to Doug Ruth for porting and you'll have a REAL strong engine. I have a soft spot for the old BB 800's, they are a good engine with lots of potential and when they are done right they pull like a freight train.

Indy Dan is the man! Could not have said it better myself.

 

[Goinboardin]

That motor has been apart before. The PTO oil hole was drilled for better oiling, and it has a wide bearing installed already.

My take is that the motor broke previously, that's when the case was trenched from spun bearings, and someone either didn't know better than to reuse that case or someone cheaped out fixing it to sell it, then it failed again. Maybe, its tough to know/tell.

I'll add you should have the clutch balanced and shimmed, but probably need cover and moveable sheave bushings as well as weight bushings.

Probably need a replacement case (or line bore), exchange for a rebuilt & trued crank, have the clutch balanced (IndyDan does a great job, more of a clutch overhaul + balance). Top end, Hardass treated me well with cylinders. I liked my Wiseco pistons, but have heard good things about SPI too.

I'm about to go through my motor again, 0.0105" runout on PTO side. Calling Dan this time for the TM3. You can make the stock setup last, but detonation (buy fuel at Gunnison Tire to avoid this), imbalanced clutch, poor bearing/case fit and she'll not be long for this world.

 

[Jay]

Damn, good eye on the big bearing and the drilled oil passage. I just kinda focused on the labrinth seal and the rest went right past me.

 

[Goinboardin]

As for a recommendation, I've had two from JJMachinery in Utah. The first one was great, I was very pleased with it, the second was sub par. They probably would have taken care of the issue I had with the second one, but I was impatient and just tried to make it work. The flywheel threads were cross threaded and the PTO clutch bolt threads were rougher than I should have accepted. I can't comment on how true the second crank was as I didn't check it until riding a while and noticed a vibration. That first crank had very little runout (0.0015") after 900 miles. I'm not trying to knock them as no business/person is perfect, but just mentioning my experience. They are fast shippers, and low on price. I didn't give them the chance to make things right, so I don't think I'd be in line saying they're sketchy. Most everyone else says positive things about that shop.