For information, how many miles we can get on the stock crankshaft?
How long will a crankshaft last?
- Thread starter polarisperformance
- Start date
300 if not summerized.
If you grenade a belt you're crank is bent.
Lube that bottom end.
Iceman56...could be... have you checked for crankshaft run-out with a dial indicator??
SMF makes a good point.
To clarify (if you don't already know this)
"Grenaded" means a catastrophic failure... You are on a hard pull and your belt snaps violently with a heavy load....pulling threads or getting a flat spot in the belt is not typically called "grenading"
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SMF makes a good point.
To clarify (if you don't already know this)
"Grenaded" means a catastrophic failure... You are on a hard pull and your belt snaps violently with a heavy load....pulling threads or getting a flat spot in the belt is not typically called "grenading"
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Iceman56...could be... have you checked for crankshaft run-out with a dial indicator??
SMF makes a good point.
To clarify (if you don't already know this)
"Grenaded" means a catastrophic failure... You are on a hard pull and your belt snaps violently with a heavy load....pulling threads or getting a flat spot in the belt is not typically called "grenading"
Does going over the bars and landing in front of the sled face up because belt suddenly "grenaded" count as a hard enough pull and violent enough snap?
This is how they all go with a turbo unless you catch a cord pulled and change it before it goes.
Don't even know what crank shaft run out is or how to check it but sled grenaded belts throughout the year and ran like a champ the whole time
I don't know Ice.....that may not be enough to be labeled as catastrophic....You're going to need to step it up...Blow that crank...
But I will have to agree that the chances of crank failure go up exponentially with blowout from a 1115...
Been there with a 2010 Dragon.
But I will have to agree that the chances of crank failure go up exponentially with blowout from a 1115...
Been there with a 2010 Dragon.
Do you measure the run-out next to the block, at the outer end of the taper or at some point between the two? I would think it would make a difference on your reading. What is considered to be the maximum allowance?
Indydan's post.
Indydan's post.
Sounds like a nice warranty cop out..... Ummm so you need a PHD in clutching otherwise your a novice and don't know how, if you blow a belt ever its because clutching is wrong, and if you ever blow a belt warranty is voided.... Yeah okay
Washing the belt from brand new and every couple of rides... cleaning the clutch faces and keeping the clutches clean is key to long belt/crank life... and making sure that the clutching is correct for your application.
Make sure you are using good oil and you are using the right amount of oil per ride.
If you are constantly blowing belts on your turbo... even if you are running 12 lbs... with a 3211115 belt... then, IMO, your clutching is not "right"... weights, springs, helix, deflection, side clearance, bushings.
I have personal experience with sleds/tuning of sleds where the owners are running 12+ psi, the 3211115 belt and getting at least 500 miles from a belt... only changing them for preventive maintenance.
I'm not saying it's not possible to blow a belt with proper clutching...but if it's happening often.. then I would look into it further.
I do agree... regardless of motor... if you "grenade" a belt... check runout on the crank.
Checking Runout...Using a good dial indicator with a solid mounting point... no spark plugs in the engine and turning it over smoothly.
If you don't have the tools and know how to use them...best left to a good mechanic that does.
Checking runout in the sled is possible... but if suspect... out of the sled is best.
If you catch a bent crank right away...possible to correct/repair... if let go... good chance you'll be buying lots of expensive parts.
Overall... since 2013, we have not been hearing of many clutch/crank/engine issues with the PRO RMK engines... this forum seems to magnify them... if they were out there in any significant percentages... we would hear about it here.
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Make sure you are using good oil and you are using the right amount of oil per ride.
If you are constantly blowing belts on your turbo... even if you are running 12 lbs... with a 3211115 belt... then, IMO, your clutching is not "right"... weights, springs, helix, deflection, side clearance, bushings.
I have personal experience with sleds/tuning of sleds where the owners are running 12+ psi, the 3211115 belt and getting at least 500 miles from a belt... only changing them for preventive maintenance.
I'm not saying it's not possible to blow a belt with proper clutching...but if it's happening often.. then I would look into it further.
I do agree... regardless of motor... if you "grenade" a belt... check runout on the crank.
Checking Runout...Using a good dial indicator with a solid mounting point... no spark plugs in the engine and turning it over smoothly.
If you don't have the tools and know how to use them...best left to a good mechanic that does.
Checking runout in the sled is possible... but if suspect... out of the sled is best.
If you catch a bent crank right away...possible to correct/repair... if let go... good chance you'll be buying lots of expensive parts.
Overall... since 2013, we have not been hearing of many clutch/crank/engine issues with the PRO RMK engines... this forum seems to magnify them... if they were out there in any significant percentages... we would hear about it here.
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The belt wont bend your crank, BS
I just always listen for pulling strings.
Changed 4 out since i put the LR in.
Have not blown a belt since the old 01 700 summit days.
That thing ate belts like a 12 proclimb.
I've seen a sled that had blown a couple 115's snap the clutch off between the sheaves.
Whatever causes crank failure ( I've seen a few. ) blowing belts eff's things up.
Call bs all ya want.
I could care less what happens to you're motor
Changed 4 out since i put the LR in.
Have not blown a belt since the old 01 700 summit days.
That thing ate belts like a 12 proclimb.
I've seen a sled that had blown a couple 115's snap the clutch off between the sheaves.
Whatever causes crank failure ( I've seen a few. ) blowing belts eff's things up.
Call bs all ya want.
I could care less what happens to you're motor
A crank shaft is pressed together... 7 pieces...
Violently unloading the crank, on a sled with all 100+ HP pulling hard, from a a belt breaking... you can certainly throw a crank out of true.... No BS there.
Blowing a belt under load can also bring the cylinders out of phase... even with the PTO end remaining true.
HUGE forces going on there.
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Violently unloading the crank, on a sled with all 100+ HP pulling hard, from a a belt breaking... you can certainly throw a crank out of true.... No BS there.
Blowing a belt under load can also bring the cylinders out of phase... even with the PTO end remaining true.
HUGE forces going on there.
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better do some more studying before posting stuff like this^^^
happens all the time I knocked a welded black magic 1010 out of index with a belt explosion.
now pinned and welded is only option
G
geo
Well-known member
Pretty common problem on sleds (crank runout-phase issues) during rebuilds (if you look) no matter what brand. Way back when too.
Must be some reason this is more common on sleds lol.
Really good info from Indy Dan. Wish I didn't have to learn things the hard way all the time lol. Even before I got into this lightweight CFI motor.
On a side note, I've read complaints about vibration on the Pro. Mine is one of the smoothest 800's I have every owned. Lucky I guess lol.
I have less than a thou. on both ends (crank) and as best as I can tell with pistons installed a perfect phase.
I still have a degree wheel I used in the 70's to time CZ's and Bultaco's lol. Used to see one hanging over every mechanics bench when I was young. Along with a dial indicator, magnetic stand and plug hole adapters. Just daily "tune up" tools lol.
Some things never change eh.
Must be some reason this is more common on sleds lol.
Really good info from Indy Dan. Wish I didn't have to learn things the hard way all the time lol. Even before I got into this lightweight CFI motor.
On a side note, I've read complaints about vibration on the Pro. Mine is one of the smoothest 800's I have every owned. Lucky I guess lol.
I have less than a thou. on both ends (crank) and as best as I can tell with pistons installed a perfect phase.
I still have a degree wheel I used in the 70's to time CZ's and Bultaco's lol. Used to see one hanging over every mechanics bench when I was young. Along with a dial indicator, magnetic stand and plug hole adapters. Just daily "tune up" tools lol.
Some things never change eh.
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EH !!
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I've heard of guys checking their runout after blowing a belt to find out that it was either out of spec, or just barely in spec. Checking it again after a few rides it seems to have healed itself. Is that possible or should they buy a new dial indicator?
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