I've been talking with mechanics, people who know a lot about engines and a guy called Ed March who's ridden a Honda C90 great distances around the World pretty much all day today. I've been saturated with mechanical advice and I think I know what to do. I know that I have to change the cylinder I have in now, its seen too much damage, has had too many, probably bad rebore's, which also means that I need a new piston. I'm thinking that its highly likely that the top end of the engine has been damaged from the seven seizures on the St Louis-Bamako ride due to bad mechanical work I had done in Senegal. I'm hearing a 'clanking' sound when the engine is put under pressure and this may be a sign that the top end is starting to see the end of its days. I'm going to try and get to Ghana where I should be able to find a decent, new cylinder, piston and an English speaking mechanic. When we take off this cylinder I can check to see if the top end is okay. If its not then it is time for a new engine. No sentimentality about holding onto it, its going to die a death. But if there's no linear play from the top end then it all should be okay. We'll see.
My suspicion is that this is the end of my poor little 90 engine. This clanking sound isn't happening if there isn't anything wrong. I'm going to take it steady on the ride to Accra. It might take a week to get there. If the engine dies on route then it will be time to reverse the trend and get the Greek to give an EU member a bailout... Push my bike to Ghana! Either way, if I do need a new engine, Ghana will be the best place in West Africa to find one. If I can't get through the border though as I'm travelling without a Carnet d' passage and have to turn back into Burkina then I can do all these tests here, and may have to settle for an unknown Chinese engine. The choice isn't too great in Burkina.
So these are my options. Besides all the pain its all been one huge lesson in mechanics. Probably a good thing. Maybe.
Hi Liam,
ReplyDeleteSince you indicate you've had a couple of rebores:
You should be aware that the original Honda C90 piston (GB6 type) isn't available any more. So it is often replaced by the 126 piston. That is however the piston for the 12V 70cc models. Same bore, but piston isn't as high as the GB6 C90 piston and therefore less compression and loss of power. Here in The Netherlands, 'specialists' pretend you're crazy when you tell them this. They like to sell you the incorrect piston in stead of selling nothing at all. But the 126 piston could be part of the problem, or all of it.
Also, our fourstroke engines require a cylinder bore with less tolerance than 2stroke engines. You should always doublecheck if the rebore-company is aware of this.
I wish you all the best. If you fancy me shipping some stuff, let me know. I have loads of these engines and parts, I can also supply you a (slightly) bigger bore alloy cylinder & piston for more relaxed cruising and better cooling in those hot arreas. I also have a 108cc Lifan engine. 4 speed semi auto with electric start and multiple-plate clutch on the gearbox, so it endures more power than the C90 clutch.
I really hope you will be able to fix the engine though. This is something I would still love to do with my C90!
Regards,
Jaimy
www.facebook.com/jaimy.penders