Author Topic: CB500 Four K1 1972, currently mid mono-shock, working on engine (Read 9189 times)

Register · « **on:** August 31, 2018, 03:05:54 PM »

Hi, I’ve been getting lots of ‘input’ on caferacer.net. Much of it useful and informed.

On the basis of many minds etc. I could use some help with just about everything.

Bike currently as attached photos.

I’m getting on with bits but need to know what on earth is going on with the cylinder.

Glaze bust, re-bore, re-line, resign or what?

Thanks

MD · « **Reply #1 on:** August 31, 2018, 04:29:40 PM »

Hello from NE MN,

Need a few more post so that the pictures will show. So tell us more about the bike, where did get it from? What condition was it in before you started working on it?

-MD

Register · « **Reply #2 on:** August 31, 2018, 06:10:41 PM »

Hi, thanks for responding. Do you mean I need to post a few text based messages before photos are accepted?

I've tried to upload reduced size images without success.

Bought the bike 100% complete off eBay. 45,000 miles, non-runner.

I got all the electrics working and the bike to fire then stripped it down (possibly a bit previous).

I've assembled the bits (Ebay) for twin disk front end which included later forks for (UK) offside brake mount.

Mono-shock tacked in place and diy bump seat.

Ugly find in one of the bores. Not sure if I caused it whilst taking a friend's advice to soak everything in wine vinegar.

Maybe with photos?

Register · « **Reply #3 on:** August 31, 2018, 06:15:41 PM »

More photos

MD · « **Reply #4 on:** August 31, 2018, 06:38:56 PM »

Thanks for the pictures,

-MD

Register · « **Reply #5 on:** September 01, 2018, 05:44:06 AM »

No problem

Noticed I referred to wine vinegar when I meant white vinegar.

Attached photo shows related piston.

Looks ok to me. Any thoughts on what to do?

Thanks.

Register · « **Reply #6 on:** September 01, 2018, 06:18:42 AM »

Sorry can't get photos to upload

Register · « **Reply #7 on:** September 08, 2018, 01:52:15 AM »

Photo of piston from damaged bore

Register · « **Reply #8 on:** September 08, 2018, 01:54:05 AM »

Sorry should have said that's the face that's against the damage.

Must be something I did whilst cleaning. I could use some advice on what now

Thanks

calj737 · « **Reply #9 on:** September 08, 2018, 02:57:00 AM »

I’d strongly discourage you from using vinegar in any form in the cylinder bores. Vinegar is an acid and will indiscriminately eat the liners, not just any rust.

If it were me, I’d carry the cylinders and pistons (in their original sequence) to a machinist and have them measure the bores for tolerance with the pistons. Machine, hone, and deck the bores as required. The pistons are cast aluminum and if within tolerance, can be cleaned and re-used. A stainless steel brush and some oven cleaner spray works well on the carbon deposits.

The piston in the picture shows some wear on the skirt, plenty of blow-by in the ring grooves. Likely in need of any over-bore and new pistons, but let a machinist determine that properly.

Register · « **Reply #10 on:** September 08, 2018, 04:20:58 AM »

Thanks so much for the advice. I feared as much and will thank the guy who shared the tip with me.

Anyone know a good machine shop in SW London?

In the meantime still disassembling as photos.

Anyone know how much slack is appropriate in the primary chain?

Thanks

calj737 · « **Reply #11 on:** September 08, 2018, 05:46:39 AM »

You might follow this link and download the appropriate shop manuals for your model which will have all tolerances and procedures included:
http://www.honda4fun.com/materiale-documentazione-tecnica/shop-manual

Register · « **Reply #12 on:** September 08, 2018, 12:15:56 PM »

Thanks, I'm bound to be back with questions

Register · « **Reply #13 on:** September 08, 2018, 12:45:13 PM »

I think I've sorted the photo sizing so a few photos in case anyone can spot something I miss.

Also, am I ok to replace the broken clutch rod with a piece of 8mm stainless shaped to suit? Costs pennies.

Thanks.

calj737 · « **Reply #14 on:** September 08, 2018, 12:53:10 PM »

There’s a member Elan who sells an oil pump rebuild kit. I believe he’s in EU for your convenience.

Re: pushrod, depends upon the grade of stainless you use. 304 is too soft and the ends will wear. You need hardened ends, maybe consider some 4140, or if stainless, try some 416R and have it treated afterwards.

Register · « **Reply #15 on:** September 09, 2018, 03:47:19 AM »

Thanks for the advice.

The rod I bought is Stainless 316 for £4. Should I bin it?

Also I'm struggling to free the 3 xhead screws that retain the pump cover. Already over done it with impact driver. Any thoughts?

Thanks.

calj737 · « **Reply #16 on:** September 09, 2018, 04:08:40 AM »

316 can work. If going forward you have issues with wear, just replace it with something harder.

All the cross-type screws on your bike are JIS, not Phillips. Grab a proper set of JIS screwdrivers and an impact (Vessel brand makes a decent set for reasonable money) and you won’t have issues.

If you have stripped the pump bolts, time to drill a center hole with a small bit. The shank is 6mm. Using any bit smaller, keeping it centered, you can step up the bit size and drill out the center. There’s corrosion between the head and the cases, so it won’t take much to release. Or, you can center drill then use Lefthand drill bits to unscrew the stripped bolt. Please don’t use cheap EZ Outs!

I prefer the LH bits and have a set I use constantly. It was about $25US, and has probably a dozen or more bits. Takes seconds, always works, never damages the base. The trick is to step up the drill size. Start small, skip the next size, then repeat. The screw generally unwinds after 2 bits.

Register · « **Reply #17 on:** September 09, 2018, 10:43:49 AM »

Thanks, I've only tried one screw so will get some JIS bits and go from there. I'm guessing the brands you refer to are all US, but I'll find something.

I cleaned out the black stuff from the sump, nothing unusual except the bit in the photos that is clearly a piece of something. Looks like about 40% of a circle with the radiused end looking original. It feels like 'spring' steel but I really need to know what/where it came from.

Anyone got any ideas?

Thanks

Register · « **Reply #18 on:** September 16, 2018, 12:21:35 AM »

Best opinion I've had so far is that it's the tip of a feeler gauge.

I've not been able to find anything in the Honda engine/gearbox drawings that look anything like it.

Seems most likely as setting the rocker clearances is awkward at best with two hands and three tools.

Register · « **Reply #19 on:** October 23, 2018, 01:01:38 AM »

Not much going on since I came off my bike.

Poss not the best photos for this site but apparently chicks dig scars.

calj737 · « **Reply #20 on:** October 23, 2018, 03:39:33 AM »

Is that from a kerfuffle with your mate who suggested Vinegar? If so, I hope he looks worse

Not a lot of “chicks” on this site, some but not many, but many of us have ample scars. What’s the backstory on your misadventure? Life’s best lessons leave scar tissue I’m told...

Register · « **Reply #21 on:** December 05, 2018, 09:31:58 PM »

Back on my feet and in the garage again.

Left the engine/box for a moment to figure the twin disc front end.

I’ve looked at the usual sites but cannot figure out how to get the speedo cable to work - catches on the RH disc.

The photos are without the 3mm spacer for symmetrical discs.

Any thoughts?

Thanks

Register · « **Reply #22 on:** December 10, 2018, 10:59:29 PM »

Ok, figured that one out.

Don’t waste time making a shim to achieve symmetrical disc off set if you want analog Speedo.

Speedo drive and cable work fine if I throw my hard work away.

Spent a cold afternoon editing the triple tree top mount.

A bit to go yet.

Rims and spokes on their way.

Anyone know the off set for the rear hub please?

Thanks

Register · « **Reply #23 on:** December 11, 2018, 12:22:37 AM »

This time with photos

Register · « **Reply #24 on:** December 18, 2018, 11:05:13 PM »

Hi, I could use a bit of help please.

I've been advised the cylinders need a rebore of 0.5mm over size.

Can anyone advise the tolerance I need to let the machine shop know.

I have the pistons from David Silver but they don't provide the related figures.

Thanks.

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Author Topic: CB500 Four K1 1972, currently mid mono-shock, working on engine (Read 9189 times)