My first project - 1974 CB360 K0

[Craizeehair]

You can get replacement pattern diaphragms from the likes of NRP. Not sure how well the originals will stand up to E10 fuel even if NOS.

Thanks, am I best to replace the whole thing rather than just the diaphragms though given the damage, or will that make no difference to the operation?

[Oddjob]

I was reading somewhere recently which said the original rings and stuff in carbs were viton based.

[AshimotoK0]

Genuine Keihin OEM slide/diaphragm assemblies NOS are going to be very expensive, that's even  if you can find them NOS.

Interested to hear what others say but even though the bottoms of your slides look grotty, I don't think that will affect the operation. Maybe gently file away anything that is above the flat surface.

I would be wary of any replacements with the slide included from China... better to use your originals. The DS ones don't really state the origin and he has been subject to selling some junk repro stuff recently. That's not to say the diaphragm assemblies are no good but need more info from them.

These people have a good reputation and state that their diaphragms are Viton™ and don't require cutting of the plastic ring.

https://nrp-carbs.co.uk/shop/index.php?route=product/product&product_id=5660&search=honda+cb360

[K2-K6]

Agree with assessment already posted, looks like the main jets and needle had become stuck in old solidified fuel, then someone has got a lever in there to  pry them loose.

Damage looks worse than the effect it will have in practical use. The primary air control is with the butterfly plates, these slide just responding to relative vacuum below and above the slide to hold parity and place the needle metering in proportion.

Cleaning off the raised bits carefully to bring the profile back to original would be my planned course of correction.  Their mass and overall dimensions likely only affected in such a minor way as to be insignificant in operating accuracy.

[Craizeehair]

Thanks for all of the responses, very helpful indeed.

[Oddjob]

Whilst I agree with both Ash and Nigel he's going to have to replace them as at least one of the diaphragms has a hole in it. I'd replace both just to make sure they act the same. Unless the replacements are genuine of course.

[Craizeehair]

Now the shed is finished I have been able to get a few more hours in and bits are coming off. I have been undecided what to do with this but have made my mind up to use as much from this bike as possible. Strip, clean, paint, keep some patina and make do to buy as little as possible, a safe rustic rider if you will and try to keep the spend to a minimum. As I have never attempted anything like this before all the emphasis will be on learning as much as I can by stripping and rebuilding it and move on to something else with more experience under my belt.

It’s pretty minging in places.

[Craizeehair]

Can anyone shed some light on this rogue piece I found on the bench? I would be very grateful for any help.

I managed to remove the engine from the frame today, after I had wrestled it free I noticed this piece sat on the bench. I’m not sure what it is, where it came from or what it is for. Didn’t take long for me to come unstuck!

[McCabe-Thiele (Ted)]

That looks like an upper engine mount spacer if it's a bit like a 400 one.

[Craizeehair]

Thanks Ted, I did think it may be a spacer but no real idea from where, if it was.

Just remembered the parts books are listed here, maybe shown there. I’m off to take a look.

[Craizeehair]

Found it, spacer for the lower left bracket.

[McCabe-Thiele (Ted)]

A similar spacer was missing on my 400 the PO replaced it with about 8 washers!

Max came to the rescue with a SS one - cost less than a replacement from CMS.

[Craizeehair]

I got into the engine tonight to check the cam bearings and cam shaft as advised. I think I’ve been lucky, everything seems to be in good shape there. A couple of the rocker arms appear to have some substantial pitting. If anyone has any advice as to the actual condition of these bits and if I’m wrong about the condition, I would be all ears.

On the down side, I think I may have found a problem. I cleaned up the engine a bit and found what looks to be a crack, as a complete novice  I’m unsure of what to do or if I have this wrong, again, any feedback would be greatly appreciated.

[AshimotoK0]

I don't think that's a crack it's a mould flash mark.

Some wear on cam flanks typical of that model. Journals don't look too bad ... again for that model as I have seen some real horrors..

May be worth sending cam and rockers to Newman cams for assessment.

[Craizeehair]

I don't think that's a crack it's a mould flash mark.

Some wear on cam flanks typical of that model. Journals don't look too bad ... again for that model as I have seen some real horrors..

May be worth sending cam and rockers to Newman cams for assessment.

Thanks Ash, much appreciated.