Honda CB750 Cafe Racer FIRST START after Engine Rebuild | Honda Cafe Racer Project Bike | 25
In this video I finally try to start my CB750 SOHC Cafe Racer project bike following major work on the engine.
Things that I used.
Motorcycle Auxiliary Fuel Tank: https://ebay.us/7aeVud
Battery Jumper Cables: https://ebay.us/opZgON
It has seemed like a long time since I started work on this bike, and to be honest I did expect to be riding it this year 🙁
When I first started the bike, I expected the engine to be working quite well. It had definitely had quite a bit of work before I got it. The PO did however say, he had never had it running, and felt that it would need to be worked on further. He didn’t tell me that it was a big bore engine, maybe he didn’t know.
When I started the engine for the first time it actually ran relatively well. But it had quite an oil leak that seemed to be coming from the cylinder head. This led to me removing the engine and stripping the top end. I was in for quite a surprise, as I found what I originally thought were 812cc Yoshimura pistons.
It actually worked out that although marked 812 these were 823cc pistons, apparently Yoshi used the same blanks, but machined them bigger. I think this had led to the previous builder making a big mistake. The piston rings that were fitted were for the 812cc, which meant they had ring gaps that were far too big, and were actually scoring the bores.
In the end I had to source a completely new (used) top end for the engine. I also had to get the barrels bored to work with the pistons. This meant quite a delay and a lot more expense than I originally thought would be needed.
In this video I have the engine back in the frame, and I just need to fit the oil tank and lines as well as the carburettors before attempting to start the bike. This all goes quite well, but when I actually pull the bike out and try to start it it seems that the starter is not working correctly. At first we thought it was just a weak battery issue, but after trying to address that we came to the conclusion that it was an earthing issue.
There still seemed to be a problem, but when I earthed the battery directly to the engine it turned over quite well and we did get it to start. In fact it does start quite well, but it is obviously not running on all cylinders, all of the time.
I will have to spend some time investigating the starter/earthing issue and the uneven running before I go any further. This will be in the next episode, it looks like refinishing and putting the tank on, and sorting out the seat is still a long way off 🙁
I would still like to think exciting times ahead 🙂
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