Honda-SOHC

That post was a comment and post from a friend of mine after I’d brought the subject up on another forum,  he was trying to clarify all the mistakes and myths regarding Ethanol. The only reason he did that post was in answer to my comments in relation to the problems ethanol could cause, not in our bikes though as they are all post 2000 models but in any other bikes the members may also own. Members were surprised that the government hadn’t bothered to warn anyone about what introducing this into our petrol could cause.
 

I'd agree that the better the chromers the better the result but none will cure the problem, I asked when I had mine done why the bottom of the fins looked dull and was told it was because they haven't got anything that can get deep enough inside the fin to polish the surface, the smoother the surface the better the nickel coating will be. If you've got 6 years old of yours then you must wrap the bike in cotton wool, my first set lasted less than a year before they were unsightly. My BIL has my K reg 500 and when he came round on it in the summer last year the engine looked great, the clamps were a real mess, so much so that I couldn't stop looking at them, they spoiled what was a nice bike with many thousands spent on it.

My aim in commenting on this subject isn't to say "Look at me I'm so clever" it's to advise members of the potential pitfalls of just throwing parts in a box and expecting the chromers to sort all of it out. They'll sort 95% of it if they are really good but they'll charge you the earth to do it. Or you can pay less and get an inferior result. The alternative is to sort the problem as well as you can before giving it to the chromers, they'll charge less and take less time as well. My current chromer charges me around £5 to chrome a gear lever off a 500/550. That's because all of his time consuming work has been done for him. He took a week to do it as well, which was really fast for a chromers these days.

That's my point Paul, they'll rust, and there is nothing you can do to stop it. Where they are located means they are subject to the hot/cold cycle of the engine, but even that wouldn't be so bad if they weren't so badly cast. The surface between the fins is like the moons surface, cratered to hell. It looks like they've been cast in sand and rough sand at that. Because the surface is so rough the nickel and chrome coating isn't intact, there are holes all over it, this allows water to get underneath, it evaporates due to the heat mostly but the contaminates in the water are left behind, these discolour the coating first off and then start to attack the surface. Very soon you'll have surface rust showing on the surface, this then develops into a deeper rust colour and very soon the clamp looks a mess, not even NOS are immune to this and they were chromed onto brand new metal.

Been there, done that and learned the lesson. Getting them chromed is like putting a band aid on a sucking chest wound, unless you cure the root cause it's a waste of time and more importantly money. Grind or sand the casting smooth and give it a chance to be a good job. Sure it's hard work and takes hours for each clamp but it's better than just having it rechromed every 2 years and eventually the chromer will polish off the fins and they'll become smaller and smaller every time it's done.

Interesting Julie. So if that is correct and I have no reason to doubt it, then only by being submerged or constantly exposed to fuel causes the Nitrile rings to deteriorate, exposure to vapours and such either doesn't or takes far far longer to become apparent.

I wonder as the levels of Ethanol increase whether the deterioration increases as well. A couple of years ago it was 5% now IIRC it's already at 10%. Saying that they have E85 fuel in the US and certain European countries, that's 85% Ethanol and only 15% petrol. You can almost see the orings melting can't you? 

It's odd, don't you think, that people and recommending we use Viton O-Rings because of the Ethanol in todays modern fuel. We are advised to replace all the O-Rings in the carbs due to the exposure to the new fuel YET no one says anything about the petrol tap O-Rings. Yet if anything the tap is exposed to more fuel than the carbs, we drain the float bowls in Winter be we don't drain the tank so the tap is constantly exposed to the Ethanol. We also say nothing about the inlet manifold O-Rings which are exposed as well, not as much as the carb and taps admittedly but they act as a seal against the outside environment so they must be exposed to some of the petrol vapour but we don't say anything about replacing them.

At 28 x 2.5mm I'd say the ring was 2mm oversize, which may explain why it needs to be stuffed back in. I'll see when the new rings arrived. I think the 23 x 2mm was pretty much spot on. I'll see though if 2.5mm would be better or worse.

Drill out the mudguard brace if you're binning the old guard Ted. You can actually use the brace and fit a different blade off another Honda that uses a 19" front wheel, I used the blade off a CB900F from the early 80s, 900FZ being the best one, the FA and onwards had a air scoop incorporated in the blade to deflect air onto the oil cooler and this can cause problems when fitted to a 500/550. The upside is that corrosion is a thing of the past being ABS plastic, the downside is you need to get it sprayed to suit the colour of the bike.

Even if you don't use the brace it can be useful to others who are planning to do something similar.

Pic of the guard, as the bike was being restored, guard still in silver



And after being sprayed to match the bike, the guard is still pretty much pristine even after 40 odd years but the front was an experiment that Dream Machine who sprayed it really mucked up. I intend to have it repainted to get rid of the front part.



Just remembered that the pic above was taken in the street Mick Hucknall (Simply Red) grew up in.

I missed the comment about having a chain already removed, was it there initially and I just miss it?

Just ordered a new bowl and doughnut seal from DS. Also after a re-measure with a digital vernier I concluded that the bowl O-Ring is more 31mm than 30mm, the thickness was around 2.67mm and concluding that it must have been squashed in use I think the initial thickness was more like 3mm, so I ordered some Viton O-Rings at 25 x 3mm and just in case some 26 x 2.5mm, I'll see which suit better when they arrive. The tap to tank O-Ring looks to be 2mm but again it's almost flat, so to cover all the bases I ordered some 23mm x 2mm and some 23mm x 2.5mm and again I'll see which suit better.

I'll wait for the new doughnut to arrive to see what thickness of Viton sheet I should order to make some new ones.