I found this bike on Craigslist with a damaged head.  The previous owner either did not change the oil, or let it get low.  The cams seized to the journals due to a lack of lubrication.  This bike is an 05, and when looking for a new head to rebuild, I could not find an 05-06 head at a reasonable price.  I did find an 08 head, valve train, cylinder, and piston all with very few hours on them since they were leftover parts from the recall Suzuki had on the 08 450′s.  The recall was to correct the problem where the cases were splitting at the kick start shaft.  Instead of Suzuki paying the labor to split the cases and replace them, they just replaced the entire motors.  So there was an surplus of 08 top end parts for a while.

Well there were several problems with trying to make this all work together.

1. The 08′s had a larger bore and shorter stroke than the 05′s
2. The 08′ is fuel injected

I saw the larger bore of the 08 combined with the long stroke of the 05 to be a good thing in theory.  The challenge was fitting the 08′ cylinder jug into the 05′ case.  The cylinder diameter is just slightly larger on the 08.  This was fixed by filing the case by hand while a vacuum is nearby to catch the shavings.  I also had to use an 08 head and cylinder gasket.  I modified the gaskets to allow oil passage to the valve train.  Without this important step, I would have the same problem all over again with no oil going to the valve train.

The intake boot is different on the 08′s due to the fuel injection.  It is not possible to change the boot to accommodate the 05 carb, but you can just use the 08 and bend it.  The only downside to this is that it pushes the air box boot back a little and is only noticable if you are looking for it.

There were some benefits and detriments to this modification.  The benefits are the mild bore and stroke but even more importantly is the increased compression ratio.  I have never ridden another 450 with this much raw power.

The downside is the difficulty to start it due to the high compression.  It requires a very specific process to start it and if not followed precisely, it will not start.  If feels as if it is so tight you could break the kick start lever instead of starting it.  Not good if you stall it in the middle of a race.

Despite that many said this conversion was not going to be possible, I was able to make this work well.  The bike has just over 20 hours on it since I did this and it shows no signs of wear.  The valves do not even need to be re-shimmed.

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