Engine blown already?

Message

WJR · #11 Post by **WJR** » Thu Sep 25, 2003 4:21 am

Eric,

Dude, this sounds like your connecting rod bearing. I know because the same thing, from the sounds of it, happened to me--stalling, tires locking, rolling in neutral, etc. When you stick a wrench on the main crank nut, it will turn a bit, then be ok for a while and then jam up. The good news is there are more cranks available, the bad news is they probably suck too. If you do need a crank, I'd check out Diamondracing, at least that is what I am going to do. Good luck.

WJR

thomez · #12 Post by **thomez** » Thu Sep 25, 2003 4:38 am

There is a used crank on Ebay that hasn't got a bid, starts at 100 bucks. You could buy that and then send it off to get balanced somewhere (100 bucks at Southbay) and you would be good to go. Just a suggestion.

WJR · #13 Post by **WJR** » Thu Sep 25, 2003 5:29 am

Thomez,

FWIW, I thought about doing that, too. But I couldn't convince myself that it would be a quality fix. First, the older style ran without a bearing race. That is, they just ran the crank pin on the carburized rod surface. Apparantly, this was not to carillo specs. Second, there are different length cranks out there. I am not sure which goes with which. Third, the newer style cranks have a con rod bearing that is rated for 11000 rpm, and most of our engines tach out at 11600. I dunno, it was too shakey for me.

WJR

thomez · #14 Post by **thomez** » Thu Sep 25, 2003 5:56 am

Makes perfect sense, some info I didn't know in there. Some part of a fix has got to be balancing the crank though, I would think. Wobble wobble wobble = bearing problems.

What did you end up doing?

EricM · #15 Post by **EricM** » Thu Sep 25, 2003 3:33 pm

The crank on ebay says it is for a cable clutch and will not work on hydraulic (which mine is). What would how the clutch is disengaged have to do with the crank design?

WJR · #16 Post by **WJR** » Thu Sep 25, 2003 6:12 pm

Eric,

I dont know how it would affect anything, maybe just a wierd thing. But at least that guy is shooting people straight.

Thomez,
Unless something wierd happens, i.e. an aftermarket crank shows up, I am going to send my crank in to diamond racing sometime soon.

cannondale27 · #17 Post by **cannondale27** » Thu Sep 25, 2003 10:42 pm

Yep it sounds like that is the way to go.Mr.Winkelbaur is a class act and seems to be the crank expert around here.I started a thread on the subject.Seems like we need another insurance policy.When does it end?

Big Winky · #18 Post by **Big Winky** » Sat Sep 27, 2003 1:09 pm

Sure sounds like Eric will be giving me a call.

EricM · #19 Post by **EricM** » Sun Sep 28, 2003 7:38 pm

I havent taken anything apart to see if the problem is the crank, but i was looking in the manual and I dont see how the rod comes off of the crank? If the bearing is bad how do you change it?

cannondale27 · #20 Post by **cannondale27** » Sun Sep 28, 2003 8:05 pm

Rebuilding crankshafts is a form of art.Really.They are pressed apart and then pressed back together after changing rod and bearing.That is where the art comes in you have clearances to meet,it has to be perfectly straight and it all has to be in sync and I think you have to get it right the very first time.All while working with tons of pressure.It requires a "feel" that most will never have.It is something I have always wanted to try to learn.
A good example to explain this is we have a guy who works in a old garage a few mi north of me.He does every single factory recalled or failed crank for Yamaha snowmobiles under contract with Yamaha.They have tried others but his success rate is best.By the looks of his shop most would turn around and leave but like I said he has a nack for it.