I am not really well versed in this or these kits. Your answer depends upon how big you want to go. If you want to go to 650cc you'd be OK. If you want to go to 1000cc then I'd have to say no.

The carbs will work with any size engine, but they may not have enough flow capability for you to fully realize the increase in displacement. The higher the displacement goes, then the more this lack of power will be felt. So that when you get to 1000cc, the machine will probably perform with the zip of a 600cc machine.

However, it's a double-edged sword. The up-side is that you'll get FANTASTIC fuel mileage !!

Here's the technical background: Small carb sizes have a higher internal velocity, so the metering of fuel is much better. IOW, better fuel mileage. The down side is poor acceleration because of the inability to cram large amounts of fuel into the engine on short notice. Large carb sizes have a lower velocity and therefore poor fuel metering, but great acceleration because of the ability to dump huge amounts of fuel into the engine.

The next limiting factor is the intake ports and valve sizes. Even if you did "shoe horn" large carbs onto a big bore kit, the intake track will still limit your power. Then you'd need to add 2 cylinder heads... and on and on. It would never quit. Think of it in terms of a "total system". Changing one part will never increase the total performance of the remainder. If you put a larger mouth on a person could they run faster ? No. You'd also need to expand the size of the throat and lungs to take in more oxygen. But then you'd want a larger heart to pump the increased oxygen. And on and on. For the most part, this bolt-on power stuff is "fool's gold".

Let's look at this from the other end. If you did install the kit and finally got it to run, what would you have ? Not much. Because the value of the bike is to collectors. No one buys a 40 year-old bike except people in the know. But you wouldn't have a unique, one-of-a-kind R45 any more. You'd have a Frank-en-bike. No one wants one of those, just like no one wants a chopper. Your re-sale after investing $1500+ goes to zero. Why not simply go out and buy a running 1000cc bike if that's what you really want ? I see those locally for $1700 on up. And they RUN.

Just my 2 cents.

Hey Wobbly,

I see your point on the unique bike. It does go decently well now. i get to 70MPH/112KPH at 5.5K RPM. The kit would cost me around what you just said. I think looking at the website it gives it an additional 20HP's? it would bump it to approximately an 860CC. Doubtful that high honestly. Here's the link to the kit. It's also recommended to replace the camshaft. Make sense though. If you can find me an R100 for $1500 and its running fine, let me know!

:cheer: Thanks