crankshaft rebuilding
Moderator: rztom
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- Posts: 157
- Joined: Wed Oct 05, 2005 6:09 pm
Re: crankshaft rebuilding
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
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
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RD350 YPVS 1990
F2 converted to N2 Red/white 1986 - Figaroli pipes
RD350 YPVS 1990
F2 converted to N2 Red/white 1986 - Figaroli pipes
Re: crankshaft rebuilding
The two center pieces are splined, so not adjustable.
Re: crankshaft rebuilding
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.
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
F2 converted to N2 Red/white 1986 - Figaroli pipes
RD350 YPVS 1990
F2 converted to N2 Red/white 1986 - Figaroli pipes
Re: crankshaft rebuilding
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
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
Re: crankshaft rebuilding
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
2 1984 RZ350s
1985 RZ350
9 1986-1990 RZ350s
2000 ST2
2005 749
2005 749 with 999 engine
2 1984 RZ350s
1985 RZ350
9 1986-1990 RZ350s
2000 ST2
2005 749
2005 749 with 999 engine
Re: crankshaft rebuilding
Welcome back! I hope all is well and we see more posts from you.
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
Ken's Garage
https://www.youtube.com/c/KensGarage1
https://www.youtube.com/c/KensGarage1
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- Posts: 1373
- Joined: Tue Nov 12, 2013 2:34 am
Re: crankshaft rebuilding
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.
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.
Re: crankshaft rebuilding
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;
https://www.bansheehq.com/forums/index. ... lkthrough/" onclick="window.open(this.href);return false;
----------------------------------
RD350 YPVS 1990
F2 converted to N2 Red/white 1986 - Figaroli pipes
RD350 YPVS 1990
F2 converted to N2 Red/white 1986 - Figaroli pipes
- T.RexRacing
- Posts: 1318
- Joined: Fri Nov 01, 2013 8:34 pm
- Location: back in the hills
Re: crankshaft rebuilding
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
Salvador Dali
Re: crankshaft rebuilding
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. :)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;
Steve
Fuel Injected RZ350
- OldTZracer
- Posts: 240
- Joined: Thu Aug 05, 2010 2:21 am
- Location: Alberta Canada
Re: crankshaft rebuilding
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..."
- T.RexRacing
- Posts: 1318
- Joined: Fri Nov 01, 2013 8:34 pm
- Location: back in the hills
Re: crankshaft rebuilding
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
Salvador Dali
Re: crankshaft rebuilding
Agreed. They have to be checked before you plunk them in!
Rory
2 1984 RZ350s
1985 RZ350
9 1986-1990 RZ350s
2000 ST2
2005 749
2005 749 with 999 engine
2 1984 RZ350s
1985 RZ350
9 1986-1990 RZ350s
2000 ST2
2005 749
2005 749 with 999 engine
-
- Posts: 1373
- Joined: Tue Nov 12, 2013 2:34 am
Re: crankshaft rebuilding
Also make sure all go through my engine building. Key to a smooth revving engine.