crankshaft rebuilding

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MBoyett220
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#16 Post by MBoyett220 » Mon Dec 03, 2007 12:29 pm

They have both, clutch and rear wheel cush drive. Michael

kjellz
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Re: crankshaft rebuilding

#17 Post by kjellz » Thu Jan 18, 2018 2:33 pm

Hi
Can anyone shed any light on how to make sure the cranks stay 180 after a center bearing/seal rebuild?
I do have access to a hydraulic press and figure the outer webs and big ends should be achieveable, but center "180 degree truing" of the crank pins seems challenging since it cannot easily be measured by a runout guage?

Regards
kjell
----------------------------------
RD350 YPVS 1990
N2 Red/white - F2 conversion
Figaroli pipes

bitzz
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Re: crankshaft rebuilding

#18 Post by bitzz » Thu Jan 18, 2018 5:43 pm

The two center pieces are splined, so not adjustable.

kjellz
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Re: crankshaft rebuilding

#19 Post by kjellz » Thu Jan 18, 2018 6:36 pm

I am a little confused about that;
But, I probably should have stated that I was asking for a 1990 F2 specifically in case this matters.
- And in another thread I was pointed to Yambits for pictures of the centre webs;
https://yambits.co.uk/crankshaft-parts- ... pqck2nop12" onclick="window.open(this.href);return false;

I cannot see that any of the 350 centres has splines ?
And if they dont my question remains.
----------------------------------
RD350 YPVS 1990
N2 Red/white - F2 conversion
Figaroli pipes

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smurph
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Re: crankshaft rebuilding

#20 Post by smurph » Thu Jan 18, 2018 7:05 pm

When assembling a crank from new parts, a fixture (sometimes referred to as a "jig") is used to properly align the crank web for 180 degree offset pins on the center section. If you are rebuilding one, you might be able to get away without using a fixture, assuming you are reusing the crank webs that went with the center bearing. Just mark which web goes to which end of the center bearing shaft and be careful. Measure 8 times, press once. :) Otherwise, you will need to make a fixture.

Typically, the center section is not rebuilt, but replaced, as a lot more tools are needed to rebuild them. It is WAY more economical to buy the center section because you will invest more time and money making a fixture than what the center section costs. Make a fixture if you foresee rebuilding many cranks in the future.

Steve
Fuel Injected RZ350

hondaror
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Re: crankshaft rebuilding

#21 Post by hondaror » Thu Jan 18, 2018 7:46 pm

As above, unless you have all the tooling and knowledge to do the work, just buy a new crank and then have that trued.
Rory

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kpke
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Re: crankshaft rebuilding

#22 Post by kpke » Fri Jan 19, 2018 11:46 am

Welcome back! :smt045 I hope all is well and we see more posts from you. :smt023
smurph wrote:When assembling a crank from new parts, a fixture (sometimes referred to as a "jig") is used to properly align the crank web for 180 degree offset pins on the center section. If you are rebuilding one, you might be able to get away without using a fixture, assuming you are reusing the crank webs that went with the center bearing. Just mark which web goes to which end of the center bearing shaft and be careful. Measure 8 times, press once. :) Otherwise, you will need to make a fixture.

Typically, the center section is not rebuilt, but replaced, as a lot more tools are needed to rebuild them. It is WAY more economical to buy the center section because you will invest more time and money making a fixture than what the center section costs. Make a fixture if you foresee rebuilding many cranks in the future.

Steve
1983 rwb RZ350 Canadian stock (exc toomeys)
1985 rwb RZ350NC vm30,pods,porting,spec2 pipes
1985 yb RZ350 rat driver,fz/fzr parts,fox shock,vm30,pods,porting,toomeys
1985 RZ350 black? fz/fzr susp (in process)
more RZ350s on hold
1985 RZ500 (done, yah sure)

evan_calgary
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Re: crankshaft rebuilding

#23 Post by evan_calgary » Fri Jan 19, 2018 1:12 pm

Cranks are all the same be it 83 or 90 RZ or a banshee during their long run. Thankfully due to the banshee we have super cheap cranks available new.

Doesn't really make sense to rebuild. 11 years ago when this thread was started the cost of a rebuild was still almost as much as the cost of a new crank today....

Crank and barrel work are the only 2 items I farm out to other trades. Have seen crank jigs for sale before which were expensive and made of quite thick steel.

kjellz
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Re: crankshaft rebuilding

#24 Post by kjellz » Sat Jan 20, 2018 5:01 am

I agree with the pricing of new cranks. They are not to bad . But for the hard dyi guys, i found this on how to rebuild even the centers, by using a jig. But I believe it can be done without as well. The key is to check the 180 accuracy afterwards and this links shows how this can done. Even useful just for checking a good crank.
https://www.bansheehq.com/forums/index. ... lkthrough/" onclick="window.open(this.href);return false;
----------------------------------
RD350 YPVS 1990
N2 Red/white - F2 conversion
Figaroli pipes

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T.RexRacing
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Re: crankshaft rebuilding

#25 Post by T.RexRacing » Sat Jan 20, 2018 9:25 am

A Yamaha 'Shee crank is $404 and shipping. Why not?
There is only one difference between a madman and me. The madman thinks he is sane. I know I am mad.
Salvador Dali

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smurph
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Re: crankshaft rebuilding

#26 Post by smurph » Sat Jan 20, 2018 8:22 pm

kjellz wrote:I agree with the pricing of new cranks. They are not to bad . But for the hard dyi guys, i found this on how to rebuild even the centers, by using a jig. But I believe it can be done without as well. The key is to check the 180 accuracy afterwards and this links shows how this can done. Even useful just for checking a good crank.
https://www.bansheehq.com/forums/index. ... lkthrough/" onclick="window.open(this.href);return false;
Yeah, well... don't go measuring unless you want to find how bad out of spec the production stuff is! It can be downright depressing. But for the most part, it still works fine. Sometimes ignorance is bliss. :)

Steve
Fuel Injected RZ350

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OldTZracer
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Re: crankshaft rebuilding

#27 Post by OldTZracer » Sun Jan 21, 2018 12:36 am

It was a lot easier with the early RD & TZ cranks as they had large splines & the centre cheeks lined up pretty good. The downside was one would occasionally crack, which is why Yamaha went to the micro-splined centre pin. I hate that the crank pin is now part of the flywheel though...
"...its a 2-stroke ya twit - Its supposed to smoke..."

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T.RexRacing
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Re: crankshaft rebuilding

#28 Post by T.RexRacing » Sun Jan 21, 2018 11:58 am

I never install a crankshaft w/o measuring and truing. Even if was true from the factory who knows what UPS?USPS/FedEx put it through. Not to mention the trip from the east.
There is only one difference between a madman and me. The madman thinks he is sane. I know I am mad.
Salvador Dali

hondaror
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Re: crankshaft rebuilding

#29 Post by hondaror » Mon Jan 22, 2018 2:46 am

Agreed. They have to be checked before you plunk them in!
Rory

evan_calgary
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Re: crankshaft rebuilding

#30 Post by evan_calgary » Wed Jan 24, 2018 1:16 pm

Also make sure all go through my engine building. Key to a smooth revving engine.

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