How many people have twisted an 8/900 crank?

[Idcatman3]

Just curious as to how many people have twisted their crank on an 8/900 or associated big bore? We blew a belt on our 1500 triple 2 weeks ago and thought we had sheared the flywheel key, but it actually twisted the crank.

I was just curious whether this was a widespread problem. We've never had problems on our twins.

Needless to say, when we had it fixed, we also had it welded this time, like we should have the first time.

 

[Drifter]

I have seen two. It happened after a blowen belt.

 

[76FOMOCO]

i have herd of it but never seen it. but had mine welded anyway and tested the weld early this season with a belt letting go on the trail under full load. dam that,s loud and about scared the $$$t out of me!

 

[Idcatman3]

Yeah, I was climbing a hill with it when the belt blew. My first thought was that the chain had gone and that I was in trouble with no brakes Then I was just imagining all the other things that could have broken on it. I was relieved when I opened the hood and it was just a broken belt. Also blew a big hole in the bellypan :face-icon-small-fro It just didn't want to run right after that, popping and missing in the midrange. Even with two cylinders 30 deg out of phase, it still had way more power than our twins

 

[gus bohne]

I have a customer with 2 , a cpc unit that has had 4 cranks and is now on a ceramic bearing billet unit that has held up ok but is starting to go out of true on the mag end.
His other is a PSI 1800 that has not made it thru a full day of testing in 3 years..


JUNK,, balance factor, moment of inertia and polar moments are wrong for a triple period.

third engine is a cpc 1725 on its 4 th crank, runs like a really strong 340 fan,,


All three of these jewels are forsale.
14,000 each..


sorry it aint what you wanna hear.
Gus

 

[Idcatman3]

Well ours made it over 300 miles before it even blew a belt, so maybe we're just having better luck that you've had. This runs way stronger than our 975 twins and seems very smooth throughout the RPM range.

And I asked for it, if people have had bad experience, I want to know that too.

Are those all built on the cast crankcase that CPC used to make?

 

[CATSLEDMAN1]

blow'n belts

We used to figue the crank was gone when we used to blow belts on our modded old 580 cats. Twist about two cranks out and your cases are gone two.....no salvage, just the thermostat.

So if you blew a belt and only got the crank.........not bad. Looked at a M1000 last spring in Island Park that pulled the whole DD drive out of the tunnel and broke the secondary clutch when he tried a 100mph groomed trail run on the way back from Mt Jefferson. oops