Background.

Firstly this follows on from Thunderbike Steve's thread on here a couple of years agao and his nod towards a thread on the FZR Achives site. I read about this conversion in Performance Bikes a long long time ago but I'd forgotten most of it, so thanks to Steve.

I bought a 600 4JH quite a while back (a couple of years) off Das Bay, then reading Steves 720 thread I also got a 3HE crank but with the Bimota taking a lot of time it just sat there. When I got the Bim's engine finally sorted ... it folded a valve and I had to start again.



worth the hassle though



Since then I started a course (Motorcycle Mechanics Level 2) at Lambeth College. Then came the 400/4 I finished that and had a buyer ready but the head leaked oil so with the confidence from the course I changed the head gasket, static timed the engine and set the vavles, so it sold.



So with no more excuses I got the 4JH down to college and started to rip it down a bit. This was supposed to be a quickie job but then I though ... why not clean up the head casting a bit. Of course I forgot the camera so the before shots are a bit scant.

You see I'd started smoothing out the head in the last pic ... that contiued for another 6 hours. The other guys laughed cos all they hear was a wizzzzzzzz of the dremel (which is really a mini tool ) Oval holes are inlets round holes are exhaust.



I got that finished on a Tuesday night and got it and the barrels home late that night. Got up early Wednesday to get them to an engineering company (Motortech in Dulwich) before work. They skimmed the head and barrels, and I picked them up again on the Thursday and back to college for the evening.

So this is where I heard about the FZS600 rods being a fit for the 660 conversion. Remember I already had the 3HE crank so I scooted over the Achives site and printed off the thread, I read it a couple of times travelling to / from work and of course college. That ended up in a buy it now FZS crank and rods.

So now I had to get the engine broken right down - it took a bit of doing but now it really is in bits. Anyway here's the meat of the thing 3 cranks from the top 4JH / FZS / 3HE



Notice the machining on the left ends - this is the generator end. The main seal internal diameter is the wrong size for the 3HE crank



So that was about as far as I got before being interupted by getting married, honeymoon, and college closing for the week. I did manage to get the crank home with the rods, pistons, starter clutch to be sent off to Basset Down Balancing - they lightend and balanced it and I got it back today.



So that's me up to date, the next college lesson is on Tuesday evening we'll see what I can get done.

Do you have a before and after for the weights?

Not really - I had to get the crank home and then sent out the next day. I had to meet my father coming in from Germany for my wedding so it was all a bit rushed. At a rough gess though .... 1/2 kg ???
This isn't a race tune remember I want the pick-up to be better but not bog down at low revs. Not that I know how the engine feels anyway.
The balancing will help at higher revs, although I'm really sure where the red line should be, I guess I'll with the 3HE's and go from there.

So I got to college this evening and took a couple of pics



This is what the fuss is about - Fazer rod



I cleaned up the pistons before they were ballanced



The 3HE (left) and Fazer (right) crank ends. The 3HE is slightly shorter than the later one.



3HE (left) and 4JH (right) - I need to know about the crank end seal. The 4JH looks like it's a wider seal than the 3HE ... I need to know if I can fit the 3HE into the crankcases.

The good news - after measuring the crank and rod journals they are give or take 0.01mm the same so I can use the existing shells.

This is going to be cool.

I do like how Yamahas are like Lego bikes - they all kind of fit together!

Suzuki's too

CMSMJ1 wrote:This is going to be cool.

I do like how Yamahas are like Lego bikes - they all kind of fit together!

Yep! We've got an SZR frame with an SRX engine, 3TJ front end and TRX rear on the lift at the minute...

This is looking really cool Boris

Evilchicken0 wrote:

The 3HE (left) and Fazer (right) crank ends. The 3HE is slightly shorter than the later one.

Looking at those tapers, the 3HE looks to be the fatter. Could there be enough material to turn the taper down to match the 5DM?
I still want to use the 4JH electrics, but will not be starting until the winter...

Alex.