Honda-SOHC

I think Nigel he is going off experience with using Cruzinimage rings rather than  testing hardness in a lab, it's my experience though that the cheaper the product the more likely it is to be inferior to the dearer product. I read in one of Mikes posts about him removing a piston after just 5k miles and finding they'd worn considerably, on a bore that he'd done to Hondas specs, as in really really tight. As you say though it's a difficult thing to say what caused that wear, however it should be easy enough to test as ring wear should show in the compression readings, test after fitting, test again after say 3k and then do periodic tests to see how the figures compare.

As the old saying goes, you tend to get what you pay for and Cruzinimage do seem suspiciously cheaper in comparison to other brands.

I don't  think you will go wrong with genuine Riken rings Ken. Same with ART pistons. Not sure that Cruzin are the same quality as the genuine Riken items. Having said this, Yamiya sell 750 Riken rings a way lot cheaper than CMS and don't badge them as Honda. I just wish Yamiya would start selling 500/550 parts.

Mike Nixon doesn't rate Cruzinimage rings at all, reckons they are almost out of spec within less than 10K miles and that was with a really tight bore done. Reckons they are really soft metal in comparison to the Honda rings.

I wish Yamiya would as well Ash.

The rings are made by RIK not RK as I first detailed. CMS have responded with a statement saying if the packaging is really bad they will rebox them but these a genuine RIK boxes, brand new, look like they were made yesterday. They’ve asked for pics and have also said they had sent genuine rings so we’ll see what happens now. In my experience of fitting hundreds of sets of genuine Honda rings they came either in red boxes with the part number on the edge and the Honda wing on the top/bottom or if they were re manufactured rings in white boxes with a genuine Honda part number with the Honda sign on it on the top.

I've got a few Queens Park Motor stickers still left on my Snap On tool box. Still look new TBH.

Just some points to consider.

Mike Nixon was a trained manufacturer instructor. When mechanics go on training courses he's the guy who's training those mechanics in proper procedure and the manufacturers thoughts on problems that the training was there to try and cure. Not only was he a trained Honda instructor, he was also a trained Kawasaki instructor IIRC. As such he'd have had access to information from the manufacturers that mechanics, even trained mechanics wouldn't. This I feel qualifies him to pass on this information which should be at the very least be considered for thoughtful consideration. Far too many people think that because it doesn't match exactly with they think that they should either ignore it or start to criticise it. I'm not saying his word is gospel, just that it should be seriously considered.

Some of the points raised may not be 100% Honda, some may be things which happened whilst at Kawasaki. I think he adds them just in case they will be of use to others reading his thoughts.

I personally didn't find it a long read, short in fact considering the subject matter. I've been on training courses that spent 7 hours on a subject that should really have been 2 hours at most and that would include a hands on training part.

As Mike says the nylon washer was fitted to dampen vibration . Where I think he went wrong was in his description of it as a gasket. What I think he was saying is that it's possible to fit an alternative where a washer that thick would be a problem, something much thinner is required and he found some plastic coated cardboard worked as well but didn't last as long as the nylon washer.

Same things apply to fitting a similar gasket between the disc and the hub, it was fitted to later models but not to the SOHC bikes AFAIK, it just dampens out the metal to metal vibration and may be of use to even some SOHC bikes, just because Honda didn't fit it doesn't mean it can't be of use. TBH not a point I had considered but worthwhile information I think.

I found the brake fluid page very informative, didn't consider going silicone myself but after reading his thoughts on the subject, especially the lack of use these bikes are subject to these days, it may be something that you should at least give some consideration.  All my brake parts are new so for me going silicone will be easy. However if you're one of those who insist on having original rubber brake hoses I can see why that might be a problem. However you now have some information that may make you feel you should reconsider that stance.

As for disc warpage, Bryan is correct, I personally haven't seen a SOHC disc warp but did see other manufacturers discs warp, Suzuki for instance. But they were later models, in the 80s for instance when discs were getting thinner and thinner. As Mike says, the lack of metal due to their thinness meant they overheated easily, this caused them to warp, hence why they started to mount the discs on bobbins, to allow this to happen but the bobbins would try and allow the disc to straighten out afterwards. As Mike says, it doesn't always work.

Interesting to note Mike saying sintered or ceramic pads work much better on these old stainless discs than the softer organic pads, these old systems were great back in the day but compared to modern brakes they appear to be really bad, getting them to work better and for longer whilst retaining safety is always a good idea. That may involve fitting a second front disc or maybe having them slotted or drilled, fitting different composition pads which weren't available back in the 70s, maybe fitting different lines like braided to try and avoid the expansion of the old rubber hoses, a different MC maybe, more fluid for less pressure? All points to consider.

500 or 550 Peter and what model.

Any work done recently?

Uneven as in the engine isn’t quite running right, that could be just because it’s not setup properly, maybe timing slightly out but it’s more likely to be carbs, they need balancing and getting the mixture spot on. Sometimes that can take a while as everything starts to settle down.

If the engine will start from cold with no choke it’s clearly running too rich. Try another 1/4 turn out on the air screws, see if that makes a difference.

For a first start though Dave it’s pretty good.

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.