Crank rebuild adventure

DB90

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So, it appears that in 1 of these basket case motors that I picked up, the crank needs rebuilt. I have decided that I am going to figure it out myself. I am confident that I can do it just need to tool up a bit.

With that said I need parts. Does anyone besides Mike's offer a crank rebuild kit or will I have to buy all the stuff individually? I am hesitant to get kit from mikes because we'll it's Mike's. I don't have much faith in their crucial motor parts. Has anyone ran them and have any insight into quality and longevity?

Also, if you have any good resources on this subject feel free to link em below! I will be going to the tech section and absorbing any bit that I can from there!
 
If I remember correctly I've read here that Mikes crank bearings and heavy duty 447 rods are good. If I remember right it was Grizld1 that said that. There are a few threads on crank rebuilding. Do a search before starting.
 
If I remember correctly I've read here that Mikes crank bearings and heavy duty 447 rods are good. If I remember right it was Grizld1 that said that. There are a few threads on crank rebuilding. Do a search before starting.
Ok cool. I will definitely be doing all the searches haha
 
Ok cool. I will definitely be doing all the searches haha
I would also check with Hoos Racing on parts. I know he's turning over his parts business to Roger Johnson, but I'd give him a call. Also, compare the cost of the heavy duty rods to Carrillo's, it may be worth it, depending on what mods you're making to the engine.
 
I would also check with Hoos Racing on parts. I know he's turning over his parts business to Roger Johnson, but I'd give him a call. Also, compare the cost of the heavy duty rods to Carrillo's, it may be worth it, depending on what mods you're making to the engine.

Thanks for the info! I don't plan on doing any mods really. I was entertaining a big bore kit but I'm not sure if I'll do that.
 
Tooling? Maybe some homemade. From here...
https://www.xs650.com/threads/homemade-and-unique-tools.37/post-358371


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Yeah I need to get some new calipers, a bearing puller, copper hammer for trying and I need to build a truing stand

I just watched a video of a guy using that homemade press jig. Looks like I'll be making one too!
Please show what you do. I've thought about rebuilding a crank but I do not want t make room for a 10 ton press.
 
Please show what you do. I've thought about rebuilding a crank but I do not want t make room for a 10 ton press.

I'll do my best. I'm REALLY bad at remembering to take pictures when I'm doing stuff lol

Luckily I have access to a 50 ton press at work 🤘
 
copper hammer for trying and I need to build a truing stand
While copper works, it's not ideal. Copper can work harden and, although unlikely, can damage the crank when you wail on it. Think missing your aim point and hitting the threads on the end of the crank. We always used lead at the places I worked at.
I had to true up the crank for the RD200, so I made one from a lead ingot... a 5 pounder. Pretty easy to do and likely a lot cheaper than buying one.


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While copper works, it's not ideal. Copper can work harden and, although unlikely, can damage the crank when you wail on it. Think missing your aim point and hitting the threads on the end of the crank. We always used lead at the places I worked at.
I had to true up the crank for the RD200, so I made one from a lead ingot... a 5 pounder. Pretty easy to do and likely a lot cheaper than buying one.


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Good call! I hadn't thought about the work hardening!
 
Lead is best. Back in the 80s I worked for a bit in a friends automotive machine shop. He did a lot of crankshaft work. He had a crankshaft grinder,welder and press. I normally just ground flywheels , bored and honed blocks to size. And other easy stuff. He wanted to teach me to do cranks. I couldn't do it. Grinding the mains was ok. The rod journals were a big problem. Do not what it is but seeing the rod journal stationery and the crank rotating around it caused me to get vertigo. I would almost fall into the grinder.
Anyway one day I was helping him and he had a crank that needed straightening. It was a 16 cylinder crank. I think it was from a Alison airplane engine. They were popular with tractor pullers at the time. Anyway normally it's not a big deal to get them close enough to grind. Pull them twice to the amount that they are out and beat on them with lead hammers. You beat them with lead hammers. The theroy as to realign the molecules normally it worked.
Anyway this crank did not want to get even close to being straight. We pulled it 5 times it's run out, beat on it and it never was close enough to grind.
 
Welp! No turning back now! Waiting on a manual to get here so I can check tolerances and what not. Until then I'll work on building press fixtures and a truing stand!
 

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For an easy truing stand use the bottom engine case it works really well.
Another tip is to scribe a line across the edge of crank wheels before you split the crank. The line is square to the faces and helps when setting it up again.
I found this guide really useful as well.
 

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