Well, the rephasing would normally be possible along with the intstallation of the hi-comp piston. But I'm not sure that everyone wants to play with cam timing. However, I'm contemplating a making cam sets with re-phased timing on new cams for people to drop in. With maybe a couple of other needed improvements, like ramp change to deal with the excessive tappet strike when hot.
Looks to me like that CB450 would fit.
I'm not a big fan of doing stuff like that. It just makes me cringe. But it's one way to get cheap horsepower.
Well a new streetable re-phased camset will be optimal. I myself would never stuff a Japanese twin into a Bullet frame, just saw a few posts a while back about that SX650 engine in a Bullet and ran across this picture and thought it could be done quite easily if someone was wanting and willing. There seems to be a lot of interest in putting a vertical twin in the Bullet, I've read about it often. Some people are hoping & praying that one day soon RE is going to produce a new twin; I say wishful thinking at best. Think about all those diehard's waiting for the new GTO and look what the factory came up with, talk about cringing!
Blltrdr
I've noticed the discussions about twins too.
There's a few different ways to skin the cat.
Let's look at an Interceptor twin engine, which was known "in the day" to have plenty of power for a 750 twin, and fits right in our Bullet frame.
Alright, it has about 52hp, or somewhat less as a Super Meteor or Constellation.
But, let's take the 52hp.
It weighs about 90 pounds more than a Bullet at 450 lbs. And it's wider and more top-heavy than a Bullet, and it costs more to work on than a Bullet.
It's weight-to-power ratio is about 8.65:1.
The Bullet can be made to have about 40hp at the rear wheel as a 612(dynoed and proven), and I'm shooting at doing that similar power level with the 535 in streetable form, and I think I can do it.
At 350 pounds, a Bullet with 40rwhp has 8.75 weight-to-power ratio.
Very close to an Interceptor twin.
Yes, the Interceptor will be a touch more powerful, and just a touch faster, but will be less nimble and more "weighty" to move around.
In the Cycle Magazine test of the Interceptor, it managed 106mph as a top speed, even though it claimed top speed of 117 mph.
A Bullet can do that with a 19T gear on it, or do 102mph with an 18T at 6k rpm, if it is modded to around the 40hp level. So, top speeds are also in the same ballpark.
Essentially, it's within spittin' distance of an Interceptor, with the nimbleness and low weight advantages of the Bullet.
I thought about putting an Interceptor engine in my Bullet at one time, but after cranking those numbers, I just didn't think it was worth the effort.
I think a properly modded Bullet would be just as good, or better.