What happens when a Vitos stuffer crank explodes?
- Thread starter slickerthanyou
- Start date
i'm going to guess that the crank being bent, put the gear at an odd angle and had an affect on gear mesh
Oh yeah, dur! I forgot he rode it for a little while before it finally gave up.
Is the brown on that other stuffer into it or just a layer on top?
That i don't know, yet haven't removed the crank, looks like it's layered but i don't know!
Is it possible from running too rich that it could discolor them?? Just thinking out loud!
I wouldn't *think* that the plastic would turn from gasoline or 2t oil but I guess it's possible. I only pointed out the color of the stuffer because that's the same dingy brown that the cases get when they're sucking in transmission fluid....
I had some Lucas semi-synthetic left in my gas jug when I FIRST installed my stroker crank, I have now burned through nearly 8 gallons of premix 32:1 Klotz.
I use super M! The brown doesn't wipe off i even tried a liitle straight gas is not coming off!
Super M is supposed to be silly clean burning stuff too.....
Well, I'm convinced!
That your crank flew apart for some reason or another.... I'll be listening and watching for anything silly on mine. Not going to stop me from running mine (or another in the future) but it'll be in the back of my mind just in case my engine ever starts doing anything stupid....
Well, I'm convinced!
That your crank flew apart for some reason or another.... I'll be listening and watching for anything silly on mine. Not going to stop me from running mine (or another in the future) but it'll be in the back of my mind just in case my engine ever starts doing anything stupid....
I'm not yet! When I seperate the cases and pull the crank out and look at it up close, maybe then! Gotta be thorough!
Non-Blaster photo - This is a KTM factory stuffer block crank that runs over 10,000rpm:
This crank is in my bike at the moment so I cannot remember how the blocks are fastened on.
The effect is mainly on low end torque, and this is a lighter crank than the non-stuffed one I was using, so it revs quicker.
This is my "asphalt engine" for my bike. Quick revving 2-stroke with a close ratio gearbox.
One of the posts questioned the effect of the stuffer block, about it affecting compression.
While I didn't try a before and after compression test (might not have been valid anyway, too many things changed)
the stuffer blocks seem to increase low end power and torque slightly. Another post commented on the stuffer blocks
making up for the volume increase of the spacer plate. I think they more than make up for that very slight increase.
Good post Slick, thanks for the picts and putting it up for discussion.
This crank is in my bike at the moment so I cannot remember how the blocks are fastened on.
The effect is mainly on low end torque, and this is a lighter crank than the non-stuffed one I was using, so it revs quicker.
This is my "asphalt engine" for my bike. Quick revving 2-stroke with a close ratio gearbox.
One of the posts questioned the effect of the stuffer block, about it affecting compression.
While I didn't try a before and after compression test (might not have been valid anyway, too many things changed)
the stuffer blocks seem to increase low end power and torque slightly. Another post commented on the stuffer blocks
making up for the volume increase of the spacer plate. I think they more than make up for that very slight increase.
Good post Slick, thanks for the picts and putting it up for discussion.
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Well, some good and bad! Finally got the bottom end out and apart, I even got to make a case splitter tool out of an old pitman arm puller (YZ otis style!)
Any how, Upon final diagnosis and looking at the crank, and cases, I honestly think this is an isolated incident.
The stator side bearing is toast looks like it overheated bad, I think it took the brunt of ground up plastic. The bearing on the clutch side is smooth and no play at all, the crank seals are entact and look undamaged to me but, must of gotten some damage as when I tried to perform the air leak test it wouldn't hold any air at all and was pouring out the vent, I attributed it to a broken case (blancer area) but i was wrong. The cases have no damage at all! I could find a crack or anything. Well ok the crank webbing did rub on one side of the case but shouldn't affect anything!
Now for the bad and weird part! When i was removiong the bottom end, I found that the front motor mounts and the lower motor mounts were completed broken off! Not sure what happen with that or what could cause that, I can't see how that could atrribute to the crank damage, or if it was a cause of the crank siezing? Thank goodness I have a spare frame from Kenny Gibson ( thanks!)
I will say this I do believe my son experienced some issues/problems, and maybe lack of knowlegde or inexperience, he continued to ride it for a while, until it locked up, and caused the other damage, clutch gear, stator, flywheel. He says as soon as he started to smell plastic burning he turned it off but i think it shut off! He rides hard and i have no problem withthat, just wish he would learn a bit more about them as I am not always there when he rides!
So here are the pics enjoy gonna need two posts for them i took alot!-
motor mounts-
first few are the bottom-
front mounts-
Stator side case-
Clutch side case-
next page........
Any how, Upon final diagnosis and looking at the crank, and cases, I honestly think this is an isolated incident.
The stator side bearing is toast looks like it overheated bad, I think it took the brunt of ground up plastic. The bearing on the clutch side is smooth and no play at all, the crank seals are entact and look undamaged to me but, must of gotten some damage as when I tried to perform the air leak test it wouldn't hold any air at all and was pouring out the vent, I attributed it to a broken case (blancer area) but i was wrong. The cases have no damage at all! I could find a crack or anything. Well ok the crank webbing did rub on one side of the case but shouldn't affect anything!
Now for the bad and weird part! When i was removiong the bottom end, I found that the front motor mounts and the lower motor mounts were completed broken off! Not sure what happen with that or what could cause that, I can't see how that could atrribute to the crank damage, or if it was a cause of the crank siezing? Thank goodness I have a spare frame from Kenny Gibson ( thanks!)
I will say this I do believe my son experienced some issues/problems, and maybe lack of knowlegde or inexperience, he continued to ride it for a while, until it locked up, and caused the other damage, clutch gear, stator, flywheel. He says as soon as he started to smell plastic burning he turned it off but i think it shut off! He rides hard and i have no problem withthat, just wish he would learn a bit more about them as I am not always there when he rides!
So here are the pics enjoy gonna need two posts for them i took alot!-
motor mounts-
first few are the bottom-
front mounts-
Stator side case-
Clutch side case-
next page........
Crank pics-stuffer missing-
stuffer intact-
Bearings stator side-Ya that got super hot and is the cause of the squeeking noise!
Clutch side-
seals entact but had to be leaking-
I'm gonna contact Vitos send all pics I have and see if they will reimburse me a crank for this build! Will post what they say!
stuffer intact-
Bearings stator side-Ya that got super hot and is the cause of the squeeking noise!
Clutch side-
seals entact but had to be leaking-
I'm gonna contact Vitos send all pics I have and see if they will reimburse me a crank for this build! Will post what they say!
Here's what I think. The broken motor mount tabs are an indication that the front bolt loosened up. Now here comes the boy, beating the crap out of the Blaster as the engine sends crazy harmonics into the engine. The stuffer blocks are pressed in. They're made of plastic and nothing is holding them in other than the interference fit between the block and the crank web. The vibration from the loose front engine mount caused the stuffer block to rattle out of its pressed in fit. I will say this. Tons of bikes and quads use stuffer blocks. Theses cranks are the only ones that don't secure the blocks with something other than a press fit. This is the first one I've seen go bad. I don't think this is a Vito's issue.
Not a vitos issues, seems to be the concensus! I'm not one to put blame where it doesn't belong. I don't know what really caused this, but i do believe that my son rode it longer than he should have!
I can say the bolts when I removed the motor were not loose at all!
Even thought they have that locking tab on the nut, when I reuse them I always use blue locktight, I don't take a chance.
I am still going to send Vitos a concern letter, and if they feel the need to replace it, awesome! If not, Then I will just have to purchase another crank, bearing, seals, have the bottom end gone through rebuilt, cylinder bored, new piston, new clutch basket gear, new crank gear (which I have), rebuild the stator, check the flywheel, may need a new one if bent, new seals and gasket kit. Ya that's gonna take a while!
I can say the bolts when I removed the motor were not loose at all!
Even thought they have that locking tab on the nut, when I reuse them I always use blue locktight, I don't take a chance.
I am still going to send Vitos a concern letter, and if they feel the need to replace it, awesome! If not, Then I will just have to purchase another crank, bearing, seals, have the bottom end gone through rebuilt, cylinder bored, new piston, new clutch basket gear, new crank gear (which I have), rebuild the stator, check the flywheel, may need a new one if bent, new seals and gasket kit. Ya that's gonna take a while!
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