Crank failure modes

[RBrider]

Hard spirits required. Broken cage if you look.

Were the hard spirits part of the solution or part of the problem??

Good job on finding the problem. On my 200, it was the mag side that let go.

RB

 

[(F5)]

Yeah it was the mag side.. My race bikes never did that as several thousands rpm lower.

 

[(F5)]

Wow that was a slow day. Hangover city.
Still need to slip the inner of roller bearing off the crank and the outer from the case.

A mate dropped around bearing gifts. A genuine GG complete gasket set, mains and crank seals. Awesome. Bought for his old 07 and not used. Probably most would suit his 15 but ya know?.

Ordered the rock it and arrangements to do the crank in place with another mate. It's all getting there.

 

[Gasser Nate]

6206c3 is the replacement ball bearing for the silly roller one..

 

[Zman]

Thank you Sir

 

[(F5)]

One thing the roller bearing does offer is some axial movement. On race bikes I've been polishing the crank so there is some slip possible from inner to crank so the crank can center and expand without sideways loading the bearing. But we're talking small engines here not 300s so I might leave this tight.

 

[Gasser Nate]

One thing the roller bearing does offer is some axial movement. On race bikes I've been polishing the crank so there is some slip possible from inner to crank so the crank can center and expand without sideways loading the bearing. But we're talking small engines here not 300s so I might leave this tight.

I think they get around that by having both the mains having c3 bearings. (0.003? axial play when cold.) interestingly my old Tm had roller bearings on both side and the crankcase was just machined very accurately to limit float.

 

[(F5)]

Rod arrived

 

[(F5)]

Delay waiting for mate to do crank.
Bearings pushed in cases with new seals. Smoothed steps out of reed intake just because.

Crank apart. Thrust washers just starting to mark pin and wear evident. Ideal time to replace rod. Wossner pin 20 grams heavier but rod 6 grams lighter. Hopefully balance good enough to stay same which was minimal vibes on my bike.

 

[(F5)]

Bottom end back together. Got it to .02 on centers and bearing journals. He was impressed how strong crank was. Took some real belts to move it from almost perfect to damn near.
He made us a tool to pull the crank into the rhs bearing. Cool.
I dare not tell him I pushed it home by hand. . .

I'll slide it back in the frame to do up the crank and clutch nuts but off on holiday tomorrow for a few days.

Had to buy some 1mm thrust washers. conrod Kit came with 0.8 and 1.25mm washers.

 

[(F5)]

Just to report back. Vibration seems about the same; ie minimal on the new crank using Woosner rod and piston.


Am getting some hanging idle issues but sprayed some brake clean around everywhere and it doesn't affect idle.
Then as I cleaned the copious mud from crazy muddy ride I noticed that the fuel line was kinked pretty bad so may have been starvation. Or the new carb I just put on.

 

[(F5)]

Only just got to ride the bike again with fuel line unkinked. Perfect. Actually maybe I'll drop a clip position. But goes great and wheelies up hills.

Through an A section blasting up the hill. Then Buuuuurrr. Stop. Dead. Ugh.

. . . 1 min ago I'd dumped the bike over to help a mate out of a stream. . . And turned off the gas. . .

Turns back on.
Brinngggdingding! Sweet!