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Crank Repair


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I pulled a bike apart becuase of trans problems and found a crank problem. The crank has good bearings and the rods appear good. It is starting to come a part. it measures 6.186 with a caliper over all. The web measures 2.102" clutch side and 2.136" fly wheel side the rod clerance is .020" clutch side and .051" fly wheel side. So it appears the fly wheel side is coming apart. Can it be pressed back togather and trued and welded or is it junk?????? :confused: pm me a ball park price.

 

Thanks

Tim

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It can be trued and welded.Now the cost..i havn't a clue.If you have a stock stroke crank.You may be able to just buy a good used T&W crank from Kevin (Herr Jugs Racing).I believe he usually sell em for around 125 or 150 shipped and he trues and welds them.He might work something out with you...good luck

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problem with repairing cranks is by the time your done paying to have it fixed you could have bought a new one.i am saving old cranks to take a truckload to the scrapyard....

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I pulled a bike apart becuase of trans problems and found a crank problem. The crank has good bearings and the rods appear good. It is starting to come a part. it measures 6.186 with a caliper over all. The web measures 2.102" clutch side and 2.136" fly wheel side the rod clerance is .020" clutch side and .051" fly wheel side. So it appears the fly wheel side is coming apart. Can it be pressed back togather and trued and welded or is it junk?????? :confused: pm me a ball park price.

 

Thanks

Tim

 

 

Yes it can be repaired but probably not cost effectively if you send it off. We have done several like with good results. You can do it yourself if you understand TIR and machinist lingo. You will have to first press the thing into width tolerance, then get the TIR down below .001", then weld, then recheck true. You would have to make a simple stand and get some mag bases and indicators for the job though.

 

 

 

 

B

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Any pressed crank that tries to seperate will always tend to do so. Welding can slow this down, but at a later date it will break the weld and seperate again. no big deal ,normal behaviour on some multi -piece crankshafts...Jim

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I'm a welder but work in a machine shop with some great machinist. What kind of stand do you use. I have access to dial indicators and mag bases and a hydraulic press. T.I.R. I would guess is total indicated run out. Do you remove the outer bearings before doing any work if so I guess you would need a bearing seperator to do that.

I would like to just send it out if possibly and the cost are reasonable.

 

Thanks

Tim

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Yes if it needs a rod or bearings I would buy a new one. This one was running and the bike has 170psi compression. I caught it becuase of the trans problem. you can see it with your eye and the measurements tell the story. If it can be put back togather at a resonable price i will send it out if not I will buy a good used one or a new one and have it welded.

 

Tim

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I pulled a bike apart becuase of trans problems and found a crank problem. The crank has good bearings and the rods appear good. It is starting to come a part. it measures 6.186 with a caliper over all. The web measures 2.102" clutch side and 2.136" fly wheel side the rod clerance is .020" clutch side and .051" fly wheel side. So it appears the fly wheel side is coming apart. Can it be pressed back togather and trued and welded or is it junk?????? :confused: pm me a ball park price.

 

Thanks

Tim

In Phoenix, Metaltech will true and weld them for like $35.

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