Honda-SOHC

Near to me (across the field from my house) but I have enough junk ... so deffo not me.

Cursing you today Mo ... 'cos I had to go to the bowels of my stash to find this to measure for you. 

4 mount holes around 9.7 mm Dia. Large centre hole 73.7 mm Dia.




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Quote from: Bryanj on May 17, 2024, 05:35:02 PM

That would mean you could regrind a crank, does anybody know if the journals are hardened cos i dont

If needing treatment after grind, process like this available https://aalberts-st-heat.co.uk/tufftride-qpq#:~:text=The%20Tufftride%C2%AE%20process%20of,the%20characteristic%20black%20surface%20finish. Suitable for materials that can't accept nitride treatment.

My mate Graham Curtis refurbishes Honda cranks of the pressed together variety  (must have done at least 100) and I asked him about the depth of hardening on those. He reckons it's around 2mm on the crankpins  ... yes I know it's not a plain bearing crank but gives an indication.  He told me the crank parts are copper coated in areas where the parts are not hardened as part of the hardening process.

This was from the USA site ! Wonder if Oddjob is following it ... he had an obsession with collecting shells 

Quote from: MauiK3 on May 17, 2024, 04:07:29 pm
"I would not risk an Sohc four crankshaft to unknown bearings."


Reply from me:-

I agree but interesting that someone other than Daido would tool up to make shell bearings for a model 40 years out of production. People fit cheapo Cruzinimage pistons and rings,  so who can say that these are rubbish. Who is going to be the guinea pig though?
When i first got my K0750 there was an Australian firm selling undersize shells to fit a reground crank ...not sure on the depth of the hardening Brian. I have a scrap '69 K0 crank ...I could give it to Graham Curtis to determine the depth of hardening.

In the 1990's I designed a solenoid switch when I worked for Fenner (now SPX) fluid power based in Rockford Il. that we had made in Shanghai.. I chose some expensive precious metal contact tips made in France but the boss man found some at a  fraction of the price of Chinese domestic manufacture. I poo poo'd the idea of using them but the boss told me to make ten samples up using them and test them to destruction ... amazingly they passed all of the qualification tests.

I have often wondered if Daido would sell these shells direct as they are still in business supplying Honda etc.

HONDAMAN  ..had this to say :-

"The OEM bearings were (and still seem to be in the ones I've bought in the last year) Babbit alloy, both for the SOHC 750 and 550 I just rebuilt.
These bearings originally came from a Mitsubishi engine (rumored to be in a forklift engine made back when), Honda didn't invent them, nor their sizes. Honda made their cranks to fit commercially-made bearings, both the needle, roller (like CB450) and SOHC4 plain types - circa 1960s!

My local machine shop said they could probably find some bearings for these cranks even if Honda quit supplying them: they said they appear to be a common size, whatever that means? Someday I'd like to investigate that."



I always assumed they were made by Daido but i do know Mitsubishi made Honda valves ... Perhaps Trigger will know.

https://www.amazon.co.uk/INLIMA-35-75mm-Motorcycle-Connecting-Crankshaft/dp/B0C9JVJ6QZ

You still can't beat a seperate exterior h-drives to save important info.I use large capacity pen drives for photo's etc.

But with Dropbox you can share large files with others  ..like I am doing on here.

Amazingly after a week and then posting on here just now it's sorted  .... I just got this back.... despite the reply, I gave them no further info than I did a week ago.

"Kindly note that your answers have passed our security checks so we have temporarily disabled the requirement to enter the one-time verification code, as an exceptional one time case."

The treat of them losing £120 per year must have got through