SOHC.co.uk Forums > Project Board

CB500 K1 Rebuild

(1/8) > >>

Charlie J:
Just getting started on rebuilding my project Honda Four which I introduced in the new members section. The confusing Subject title is due to the fact that I don't as yet know quite what I've got. The crankcase is stamped CB500 whilst the cylinder block has 544cc stamped on it. I thought from info from David Silver spares that it was a K2 but BryanJ tells me we didn't get a K2 in the UK and it might be a K1.

Anyway, it is what it is and I'll see what I can make of it. First job was to see if I could get the engine running after the bike had been left in a shed for at least 30 years.
So jobs done so far;

Stripped and rebuilt carbs which as you would expect were completely gummed up. New needle, jets, gasket, airscrew etc. The biggest problem was trying to fit the non-shaped o-rings. I had to resort to the use of super glue in the corners to get them to stay in place

New plugs, point and condensers

New oil and filter

Static timing set

Valve clearances adjusted

Timing chain adjusted

Rigged up basic ignition and starter circuit wiring (a lot of the original wiring is missing/damaged

Rigged up temporary fuel supply

Connected to booster start battery charger

Hit my makeshift starter button

The bike fired up immediately  ;D ;D I almost danced a jig. What a wonderful feeling, but it didn't last long. The bike dumped half her oil on the floor, used 2 pints of petrol in 10 seconds and filled my shed and the surrounding neighbourhood with exhaust smoke.

Back to the drawing board. Traced the oil leak to the bolt inside one of the side covers on the cylinder head cover and got that sorted. The disappearing petrol was coming out of the overflow of all four carbs. When I rebuilt the carbs, I set the float height to the specified value of 22mm which just didn't work, I ended up with a height of 26mm using the clear tube method. Fired her up again on the button and the bike is running well but with clouds of grey exhaust smoke. Checked the cylinder compression and it's about 135 psi on all 4 cylinders which I hope is good enough. Next job is to change the valve stem oil seals whilst leaving the head on to see if that sorts the smoke problem.

Nurse Julie:
Sounds like fun 😁😁😁😁

hairygit:
550 barrels on a 500 bottom end was a popular upgrade back in the day, but it involved machining the crankcase mouths out to suit the larger diameter liners. You'll have a lot of fun with that bike, nice little middleweight that handles nicely. Never, ever stamp on the gear lever to shift down, the forms are easy to damage, probe to bending, and near impossible to get now at reasonable prices. Welcome by the way!

Sent from my POT-LX1 using Tapatalk

SPR:
Remember to do the compression test with throttle wide open ....

Charlie J:

--- Quote from: SPR on August 10, 2020, 10:08:49 PM ---Remember to do the compression test with throttle wide open ....

--- End quote ---

Thanks SPR. Throttle was wide open.

Navigation

[0] Message Index

[#] Next page