Suzuki GS550E — 673 Conversion.

Slight Misfire Halts Play!

It finally happened, I knew the engine was on borrowed time, but it's been happily running me around for the past couple of years, relatively drama free. Now, still running reasonably well considering, it's misfiring on one cylinder and after a quick compression test, no.4 was found to be sadly lacking. You could also hear the familiar chuff-chuff out of the righthand pipe from a burnt exhaust valve.

The reason, you may well ask, why this engine was on borrowed time was because there is wear in the camshaft journals, so not ideal to do a top-end rebuild with the original head. And finding another head for one of these seems to be impossible in Australia. Plenty in the UK and America, but postage wouldn't be worthwhile.

Gilbert's Cylinder Head Service — Gold Coast.

Skimming, guides, seats, porting... 
Having had several car cylinder heads overhauled by Paul Gilbert since being in Australia, I knew the service and quality was exceptional. That's no bull, they come back like a new part, and I was pretty amazed — especially for the cost.
So when I needed a couple of shims machined on the GS550, I dropped in to see if he could do them. No problem he says, come back in a couple of hours and they'll be ready to go. 
Once we got talking I realised he did a lot of motorcycle work too, and he showed me some of the heads he was currently working on.

This is one of two Rocket III heads that were being ported, one for a supercharger. He said that although he has a flow bench, the ports are now so big on this 2.3L engine that he's had to use someone else's larger version to check the flow. That's going to be one quick Trumpet!