Production Racer AMA Twins Bike

I just ran across this picture of my Production Racer in it's final metamorphosis at the 1991 Daytona AMA race. The picture is from an article in the Japanese bike magazine Bikers Station. I scanned the article a while back and posted it, but just realized when I cropped the picture out that it was high enough resolution to post by itself. I was riding the bike, and my friend, Rob Tuluie was riding my monoshock Norton. Both bikes had 920 engines. When Rob blew the engine on the monoshock, I switched him in as the rider on the PR. He was a much better rider than I was, and I thought we had a chance for a really good result. Unfortunately, that engine blew also. Both failed from broken crankcases. Wish we'd had Maney cases available back then! I think this was the last race for the bike. I tore it apart and sold all the original PR parts (I'd saved all the good bits as I made changes to the bike) to a friend who restored it, and it now sits in a local collection.



I still have a lot of fond memories of the bike.

Ken

Neat flash back for sure Ken. Born too late eh. Sorry but do ya remember where/how the cases failed? Do you have a shelf dedicated tp sacrifices to speed?

Both cases failed pretty much the same. Cracked from the drive side main bearing bore back through the upper part of the case to the joint between case halves. Basically, the engine was just trying to pull the top end away from the crankshaft. I was using a 7200 rpm red line, and that was probably to much for a long track like Daytona. I had run my 750 there with the same red line with no problems, but it made significantly less horesepower.

Ken

Whew wee, I knew our twins were allergic to rpms but them 920's go into anaphalactic shock. I've seen that 7200 number mentioned world wide as tops to press to last a race. I would sure like a way to measure crank flex at flywheel. I'll be dialing out a few more 100 rpm on Peel's rev limiter. Why does this stuff suck us in so easy...

What a beautiful machine.

Thaks, Paul. I had a lot of fun on it over the 19 years I raced it. I've been tempted several times to re-create it, but there are just too many new ideas to try instead.

Ken

Wow, ditto to what Paul wrote ... and kudos to you for posting and sharing. Cheers !!!

I'm sure you all noticed this, but I'll make it explicit anyhow. This is the same bike as in my avatar, only many years and mods later.

This is a picture of it in an even earlier iteration. I think this was the third or fourth paint scheme I tried. I eventually decided I liked the original yellow submarine look the best, so that was the final color.



Ken

I'd stick with the "Yellow Peril" as well.

That's an interesting exhaust system, fat pipes and short megs. What gearbox is that?

RennieK said:

That's an interesting exhaust system, fat pipes and short megs. What gearbox is that?

Click to expand...

The pipe size and length, as well as the megaphone dimensions, are what Axtell developed on the dyno back in the late 60's and early 70s. That's what I mostly used on the race bikes, although I did later fit a Maney 2-into-1 high pipe on my 750 AHRMA bike for better midrange drive. On most tracks the extra drive out of corners more than made up for the loss of top end power.

The gearbox is a heavy duty Quaife 5-speed, which I fitted with a hydraulic clutch.

Ken

Sweet history. Nice bike.