The 50

[F5 Dave]

Sounds better, lighter, -Heck if it looks better, to ask for more would be just greedy.

[cotswold]

pipe of frankenstein

[Yow Ling]

Its only 45cc and 4 stroke , would get some attention though

[cotswold]

I have just got back from a top secret 2 stroke engine tuners in town. We fitted my spacer and as you would expect the deck height was in the negative. The head was machined to take the head inside the cylinder to the piston, we then set the squish to 0.54. Head gasket no longer wanted as we machined an "O" ring groove while we were at it, 47mm by 2mm viton. It's hopefully going on the Dyno in a week or so to see how we are going.

[cotswold]

https://www.youtube.com/watch?featur...&v=s4PA8VFpUlc

[cotswold]

Now I have a (hopefully) more powerfull engine I thought it had better look like a race bike, so I stole the bits off my F4 bike and dressed the 50 up a bit. The motor is now in one piece so will put it back together as
soon as I get time.

[TZ350]

Looking Good .....

[Buddha#81:Me]

50's dont feature too much down here, but motorcycling canterbury run a training class at their meeting for anyone starting out but as a 10year old its a way of keeping off the streets Its a rs50 with a carb Yow Ling fitted and is pumping out a massive 6.5 hp.

[cotswold]

50's dont feature too much down here, but motorcycling canterbury run a training class at their meeting for anyone starting out but as a 10year old its a way of keeping off the streets Its a rs50 with a carb Yow Ling fitted and is pumping out a massive 6.5 hp.

That is a very good idea, other clubs should look at doing something similar.

My F4 is sat in one of those frames.

[cotswold]

I got the engine back in the frame and connected all the bits that make it go, put it in gear and off she went. Very pleased, it certainly has more compression than before. Maybe a trip to the dyno is in order to see how she stacks up against some of the competition.

[F5 Dave]

or more to find a decent ignition point & nearest jet. Be off here & you can decimate power esp on a fiddy.

[cotswold]

Gave our local 2t guru a hand with the beast tonight and as a treat at the end we threw the 50 up onto the Dyno, sparked her up and gave her a couple of runs and behold the magnificence of the Dyno chart.

A Dutch friend pointed out

"I think it is plenty of things to do whith this engine.
But first of all the pipe is not right"

"Yes it shows that what you have is not right.
If the pipe is all right it starts to pull at 9000 and go ballistic to 14000 revs."

Ballistic sounds good

[cotswold]

After the dyno run (thanks Rob) it was pointed out by many that my pipe is not working as it should ( no suprise there ).
I put up a post on a different forum and Frits Overmars came to my rescue with a formulae that should help improve things, he even corrected a mistake I made re the speed of sound, it's greater when hot gas is involved.
Here is the result.
I have a nice new ignition on it's way as well so hopefully I will see some improvement.

[F5 Dave]

so. . . why so little ex duration? (if that 183 is).


First thing one should do is estimate the revs you are safe to turn and if you are likely to get the performance you require, else change components till you can turn the revs you need. So its all about the piston & then what crank you run as a result.

183* will suit a trials bike or a learners roadbike. So what sort of revs do you want peak power to be at?

[cotswold]

so. . . why so little ex duration? (if that 183 is).


First thing one should do is estimate the revs you are safe to turn and if you are likely to get the performance you require, else change components till you can turn the revs you need. So its all about the piston & then what crank you run as a result.

183* will suit a trials bike or a learners roadbike. So what sort of revs do you want peak power to be at?

see thats why I put my stuff ups up, so they can be pointed out before it costs me any money, 183 is port timing not duration, i'll correct that over the weekend when my brain is working.