Crank issue...

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bondra131

Thaat's braptaastic!
Location
Coeur d'Alene, Idaho
Soooo just got brand new oem 62t cases from Blowsion. New "true and welded" SBT crank. Crank felt nice by itself. Sealed up the cases, wouldn't turn... Super stiff. Could force it to turn a bit. Pulled it apart and cleaned up this sticky mess and tried again. Crank turns fine when snapped into just the upper half case. Popped the bottom on and tapped it down tight but didn't put case bolts in, crank turns but comes to one tight spot. Same spot every time it binds. Never seen such a thing... This the crank bunk or what? Anyone know? This is horse poop I'm getting pissed. Been down a month with problems lol
 
eastcoastjumper

eastcoastjumper

James
Site Supporter
Location
Long Island
Did you try putting the case bolts in and torque to 11lbs/20lbs ?

Then the bed plates to 17/34


I haven't had to tap cases together.


You have any pics of how you sealed it up?

Was the crank new out of the bag & coated
 
B

bondra131

Thaat's braptaastic!
Location
Coeur d'Alene, Idaho
I didn't even get to the point of bed plate bolts... Torqued the 8 middle bolts to 6 pounds because that's what factory specs say... And realized the crank wouldn't turn. I only had to tap the halves together because the two dowel pins fit snug that's all. It was fresh out of a bag all oiled and felt fine. I pulled it back apart and the thing turns fine when just inside the top case... Pop that bottom one on though and it turns and hits a tight spot every rotation. Sbt crank... I think shonet block technologies licoriceed this crank up
 
eastcoastjumper

eastcoastjumper

James
Site Supporter
Location
Long Island
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B

bondra131

Thaat's braptaastic!
Location
Coeur d'Alene, Idaho
They seem normal from any other cases. Found it. Rubbing the back wall wall right before the rear case seals... Lobe rubs. It's abnormally tight to the case there. Front lobe clears case by 1/16 inch more. I can see the scuff marks on the case just from me hand cranking... Wtf is that all about? And doesn't constantly rub. Only at one point of the rotation. And ONLY on the bottom half case. Not the top. Yep... Gotta be a whack crank
 
Freakie

Freakie

Location
Cape Town
take the crank out and put it between centres or both ends on v blocks and measure the run out at each centre bearing with a dial gauge.....machine shop will do it for you in 2 minutes....u will kno for sure then
 
Roseand

Roseand

The Weaponizer
Site Supporter
Location
Wisconsin
If it's for sure a crank issue they'll give you a new one at least. Plenty of us are running sbt cranks with no issues..
 
B

bondra131

Thaat's braptaastic!
Location
Coeur d'Alene, Idaho
Idk about it not being assembled right being that it snapped in to all 5 pins on outter race holes but it's like something's bent. I can see the lobe get closer to the side of the case until it touches then move away from it. Yea I know there's a lot of these cranks out there and has a warranty. Just gotta wait another week or something now... Sucks
 
2StrokeLife

2StrokeLife

If the crank measures straight, I would suggest grinding/sanding the cases where the crank webs are making contact. Castings are never perfect and case volumes/forms are likely to be slightly different from case to case.
 
Breese08SJ

Breese08SJ

Location
New Jersey 732
2StrokeLife said:
If the crank measures straight, I would suggest grinding/sanding the cases where the crank webs are making contact. Castings are never perfect and case volumes/forms are likely to be slightly different from case to case.
Click to expand...

Don't mess with a brand new set of oem cases. It's 99.9% likely an sbt issue. Oem Yamaha parts even castings arejust not that far off. Talk to Chris before you do anything he will help get to the bottom of this. I think he's at the rip and ride now so be patient if you can't get in touch w him
 
Breese08SJ

Breese08SJ

Location
New Jersey 732
Sorry apparently I was wrong I could have swore I saw it somewhere that he was away. As for the cases I meant don't mess with grinding on them as someone else said earlier. Glad he took care of it. You will be back riding in no time.
 
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bondra131

Thaat's braptaastic!
Location
Coeur d'Alene, Idaho
Oh hell no yea I'd never grind them lol. Good call. I know that wouldn't be right. It wasn't a consistent rub so that meant the crank wasn't true. Could watch it wobble a bit while hand cranking it
 
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