Honda-SOHC

Could be the K2 has a different route for the pipes than the F2? As Bryan says the tanks are different. I have a spare F2 tank you can have if Bryan can't find his. What about connecting to the tank first then measuring the o-ring end to see how much too long it is, then you can have the guy remake that hose.

Okay. Back to the shells. Have done some very careful measurements. Have torqued up the crankcases and measured the two outside journals with telescopic gauge and micrometer. I agree with Honda they are B&C. Cant check the inners with a telescopic gauge as I cannot get the gauge out after the measurement. An air gauge would be perfect for this job. So will assume the other three journals are correct.

Measured the crank journals, mains and big ends, and they are all exactly 1.2590" not even a tenth thou in them. Checked for taper and ovality and all bang on. Top marks to Honda for managing to build a crank to those tolerances. Impressive. Torqued up the conrods and measured them, they are as Honda states all No.2s

Checking the tolerances in the manual with my measurements I get the following, Mains 1-3 are green  4-5 are brown. Big ends are all green.

Using the crank etchings, Mains 1-brown, 2-green, 3-4-brown, 5-black.  Big ends are all yellow.

Colour coding on existing shells is still clearly visible (paint on side), Mains 1-4-brown, 5-black.   Big ends all brown.

What an utter load of nonsense that lot is. Very little correlates together. Either Honda have put the wrong shells in this engine or (more likely) it's been rebuilt before and the mechanic used the wrong bearings (or whatever they had on the shelf). Well I trust my own judgment and measurements so am going with the top line which is what the ACTUAL measurements are. In any case if you go from the largest bore size to the smallest crank size there is only 1 thou and 8 tenths difference anyway. Just goes to show it's never wise to just trust somebody else, always check and double check. Mistakes get made.

Decision made now so I am going to get the shells ordered tomorrow. I've been so careful with this I am confident I am right.

Checked through the rest of the engine parts and all appears to be in extremely good nick. All the bearings feel like new, no wear on the selector forks etc. Am very impressed with the engine in general, there are some very well made parts in there. Top marks Honda.

Now the engineers bits finished, time to put the mechanics hat back on (this is where things may get tough).

Hi all.

More on the shells later when I get a chance to measure up. Been using the fine weather to get the engine painting out of the way. Had all the castings bead blasted then a really good clean out with heavy degreaser and a flush in hot water. Got everything masked off ready.

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Spray painted everything with Simonize aluminium finish engine enamel. Looks okay and a nice finish. It sprays really well without runs etc and dries fully within 30 minutes. Gave everything 3 coats.

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Wife's away this weekend visiting daughter No.2. So whilst theres the opportunity to get it all in the oven to cure.

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What she doesn't know she cant complain about. Got in real bother last time with the 750. Had a price to stove enamel the castings £225 plus VAT so that's a big saving. £21 for the paint, £15 for bead blasting, £12 for degreaser. Well pleased with the results. Next installment will be the engine going back together.

That guy's got too much time on his hands. Very impressive but a finished bike would be better.

I had a DOHC CB750K years ago (1980 me thinks) that did a similar thing. The oil leak on that strangely showed up by keeping blowing the gear change shaft seals. Ended up selling the bike for a song as I knew nowt about engines back then. Actually sometimes, I'm not too sure I know anything about engines now either.

Had a quick look that seems promising. Will have to do a bit of research to establish which size is going to be best. Cheers.

Thanks Bryan will give them a go.

Ash. Is Nitrile rubber good for these parts. Aren't they supposed to be Viton? The ones you softened for me are working pretty good, but cant seam to get rid of the last tiny leak on No.2. Cheers.