Topic: Restoring my k0 cb750

[edwardmorris]

What do i need to prepare myself to buy for measuring the crankshaft bearing clearances? Plastigauge? But what type and clearance range? What exactly is the purpose of measureing these clearances? Excuse my noobness  , i have never done precision work like this on a motor before. But is it to determine what size bearings I need to buy for the new crankshaft? Thanks!

Just curious, did you grab a copy of Hondaman's book?

[Cragdog]

What do i need to prepare myself to buy for measuring the crankshaft bearing clearances? Plastigauge? But what type and clearance range? What exactly is the purpose of measureing these clearances? Excuse my noobness  , i have never done precision work like this on a motor before. But is it to determine what size bearings I need to buy for the new crankshaft? Thanks!

Just curious, did you grab a copy of Hondaman's book?

I wish.. Been really tight on funds lately so no I don't have a copy. I've been following the clymer manual as much as I can.

[edwardmorris]

I wish.. Been really tight on funds lately so no I don't have a copy. I've been following the clymer manual as much as I can.

The book is 30% off right now http://forums.sohc4.net/index.php?topic=132433.msg1480103

I know we're all on a tight budget, but at this price, I highly suggest you grab a copy and re-prioritize some other (maybe cosmetic) things.

From what I've read around here, there are some errors in most other manuals. If you are really into getting this bike on the road, this book is an essential tool IMHO. Besides, you can always resell it when done

[Cragdog]

Cases are split








I'm thinking about the best way to begin cleaning off the cases. My friend has a blasting cabinet, but no gun or media to use. I've heard about those gravity-fed bead blasters from Harbor Freight that you can hook up to an air compressor, anyone have any luck with those or another cheap solution for cleaning off the cases? I have a week or so until I get my gauges and can measure the clearances for the new crank. If the new crank is within spec for the old main bearings is it ok to continue using them?

[754]

Uages. ? Do you mean plastiguage ? Did you check where crank exits case for cracks ?

[Cragdog]

Uages. ? Do you mean plastiguage ? Did you check where crank exits case for cracks ?

Yes, I meant plastigauge. And no, fortunately I didn't find any evidence of cracks in the cases!

I did however, find something a little disturbing at the tranny/front sprocket:


I had noticed this hard plastic-y stuff around the front sprocket years ago, but didn't think much of it, just thought it was some sort of protective layer between the chain and the engine case, but turns out it was some type of hardened material covering a large hole in the case! Kind of a bummer, but it didn't affect the functionality of the bike when it was running so i think it will be fine.

Still waiting on the plastigauge. Can someone give me some direction regarding that process? When I put the material on the new crankshaft journals to gauge the clearances how much reassembly do I have to do to get the right amount of torque/pressure on the crankshaft for an accurate result? Just put the two case halves back together and torque to spec? Or will I need to reinstall the whole top end as well? Thanks guys!

[edwardmorris]

Goes rather fast but here is someone doing it

CB750 K2 Engine Build 1a

[Cragdog]

Wow, that was an awesome video! Thanks edwardmorris. Man I wish I was performing the level of detail and cleanliness that a lot of other guys can perform in their builds, but I  really just want to be riding this bike again as quickly as possible.. 

[edwardmorris]

Wow, that was an awesome video! Thanks edwardmorris. Man I wish I was performing the level of detail and cleanliness that a lot of other guys can perform in their builds, but I  really just want to be riding this bike again as quickly as possible..

No problem. Bit of unsolicited advice from personal experience, "wanting to ride the bike asap" usually doesn't end well.

Just for fun, if you do decide to get it that clean and glyptalled, here is how

Glyptal Application Process

[Cragdog]

Holy crap! Haha, what a great video. Is that your personal work? I am planning on doing some cleaning, more particularly to the outside of the cases, but man anyone who's thinking of using glypyol in their engines should seriously watch this video as he covers nearly every end of the spectrum for pros and cons using this stuff. Very informative, I really enjoyed it!
With that said.. I don't think there's any chance I'll being doing this to the interior of my cases, too much time and effort for a bike that I want to ride as much as I can and I haven't had any oil flow issues in the past. Really talented and detailed presentation, I am glad to have learned from someone who is building at a seriously high level of work. Thank you for sharing!

[edwardmorris]

HA, I wish I had that kinda patience and discipline. I've been searching a lot about the k2 and saw some of these useful things.

[Cragdog]

Haha, okay.. Had me going there for a minute! Just caught up on your build thread, keep up the good work!

HA, I wish I had that kinda patience and discipline. I've been searching a lot about the k2 and saw some of these useful things.

[754]

 Your cases should be welded,. But it is up to you, it worked patched til now.
 Where did you get plastiguage from.. I would think a lot of autoparts places like Napa would carry it.

[Cragdog]

Your cases should be welded,. But it is up to you, it worked patched til now.
 Where did you get plastiguage from.. I would think a lot of autoparts places like Napa would carry it.

Yeah I was rather surprised and a bit disappointed when I saw that hole.. I don't have the means to weld myself,  but I have a buddy who might do it for me. I wonder what material was used to cover it up? It seemed to work well when the bike was running, I never noticed oil coming out from there before. I'm more curious as to how it happened? Possibly the PO had a chain that was very loose and was dragging on the case as it returned around the sprocket? I didn't find plastigauge at my local auto parts store so feeBay it was. Should be here soon!