my ride uk

 

[kevbo]

. Most attempts I have seen will not work, sound and shock waves travel in a straight line, a convoluted pipe just defeats this affect.

The folks who make brass instruments, trumpets for example, might take exception to that statement. Their products seem to work fairly well from what I've heard, and are certainly easier to transport than the old straight versions.....though much inferior for hanging banners

 

[Egor]

You don't have to convince me but working for a GP Yamaha racer you would never put any bends in the expansion chamber or else, and you needed every ounce of power. You don't want the shock wave to run into the bend it needs to hit the opening at the end or little effect. Everyone needs to know that the boost bottle was intended for a Reed Valve engine, and a twin at that. There is controversy as to whether they did work at all, a possible 1 to 2% gain at most and only at narrow rpm ranges. I got the most improvement from porting and a carb. I am going to make a reed intake next. One nice thing about reed valves are they enhance the low end power considerably, thats where these engines run best. These engines are so remedial you might ask, why do you mess with them? I have worked on every type of engine imaginable it is fun to make something this basic perform well. Have fun Dave

 

[MrCrowley]

All I can say is- crikey! What a nice setup you have there.

Something I would try if I could generate the power and speeds you are dealing with? I would take a funnel, tube, ride and hold the setup on a deserted section while hitting good speed, evaluate, and if I noticed an improvement, I would take some plastic and build a ram air setup. The faster you get, the more air youll get. Just a thought. With that, boost bottle, carb, porting, polishing, exhaust, you should easily see 50 mph!!! After that, you may have to find a hotter spark to see any increase. Also with more engine power, you may be able to run a taller gear which would weigh less anyways, still keep your acceleration the same, but add more top end speed.

 

[Alaskavan]

There are no roads where I live where 50 mph would not be exceeding the speed limit regardless of what you drive.

 

[sklein25]

Philcred

You have built the ideal motorized bicycle in my eyes!!!! In fact, I've been trying to figure out how to attach the engine sprocket to the left side of the hub (rear disc side) without having too many problems and having seen you do it already. I now know that it is all possible and very easy, just by attaching the hub directly to the disc. However; I think this is possible only with a very large rear disc rotor (203mm largest?) and a fairly small sprocket (36 or 34 tooth). I'm also a little concerned about chain lube over-spray or splash off from the sprocket/ engine chain contaminating the disc rotor & negating the rear wheel braking.
Anyways, congrats on your build and please keep us updated on your top speed challenge. You may need to take the bike to an airport strip and ride flat out to find out just how fast it can really go!!!!

Cheers..........
Steve

 

[fastboy9]

Love the bike mate! I'm sort of running the same set up, front suspension, front disc and aluminium frame with 80 cc happy time, hoping to fit a new mini moto exhaust with expansion chamber very soon. Not sure if I've just missed it but have you made a video like you said, a long time ago I know.
Cheers

 

[kjparker]

wow, love the sprocket mount! That is pure class!

 

[impression]

**** awesome.