Forum

[Adrian]

That's a shame after all that work. Find someone who HAS got a Bullet with a broken engine and fit it with the biggest gearbox sprocket you can obtain. 20 or 21T might work.

A.

[Bulli]

....well, if you would build the engine in a standard frame to run without a sidecar.... and use a normal BNR beltdrive ( which makes it about 12% longer than the normal chaindrive...) and then use a (selfmade) 22T, it might be OK for some people. But even with this setting, a bike will not go over 73 mp/h at 3.500 revs.... and more then 3.500 (maximum 3.750) i would never ever give this engine...... So this engine is supposed to be used in a very pretty sidecar-project. Then you may use a regular 21T und the bike will allow you a travelling speed of 56 mp/h (63 mp/h with beltdrive conversion) at 3.000 revs.
But that is nothing for my temperament, i have fun in (sometimes) riding my bullet with revs over 5.000..... and on long distances i must have a travelling speed of 68-70 mp/h....

[Vince2]

Hi, what happens above 3000rpm? Vince

[Bulli]

....well, after getting an old bullet in my garage still having the german technical inspection tag beeing good for this season..... i built the engine in that bike and checked all the things i need for testing. Brakes, wheel bearings, gearbox with 20-teeth sprocket, good clutch and working suspension..... all these things had to be repaired... Last not least i managed to have the engine running. I didn`t fix the whole electric..., since i can drive with a big battery for testing purposes... https://youtu.be/ybfx6k7gUg4
>> and i did my first test ride...! That engine is really pulling from low revs on. I didn`t try any higher revs than maybe 1.800... So i can say so far, this engine is working..!
@Vince2: You may (after initial running in) run that engine over 3.000 revs... and it may run with 3.500 revs for a while.... but than the speed of the piston will be to high.... and the heat will be to high.... and the engine will... ups...

[Vince2]

Hi, at 4000fpm the engine will be at 5000rpm. Vince.

[Bulli]

Whatever that means.... today i made a few miles with the bike on the road. It is definetly pulling very strong from low revs on, even in 4. gear with the 20-teeth sprocket....

[Vince2]

Hi, the accepted limit for piston speed is around 4000 feet per minute. On the stroke you have that equates to 5000rpm. Even the old Big Four Norton with a 120mm stroke reached over 4000rpm. If your limited to 3000rpm then you top speed will be about 55 mph, this is assuming that you pull gearing similar to a 750 cc twin. Vince

[Bulli]

Yes, thanks. I gave the engine about 2.800 revs for a short time then, when it was pretty hot. And that was quite a normal feeling for the engine. If there had been a "real" technical mistake, it would have been broken down, i guess.
So that is what i wanted to know. > That engine is definetly running well... and will go back to my shelf the next days or weeks... to be used some time for a sidecar-bullet.

[Bulli]

Yes, thanks. I gave the engine about 2.800 revs for a short time then, when it was pretty hot. And that was quite a normal feeling for the engine. If there had been a "real" technical mistake, it would have been broken down, i guess.
After the trip today, engine is really hot. https://youtu.be/1OeKXQij4qw
So that is what i wanted to know. > That engine is definetly running well... and will go back to my shelf the next days or weeks... to be used some time for a sidecar-bullet.

[Bulli]

Since it has been a sunny , warm day today, i decided to go on a little 40 kilometer roundtrip with that bike + and engine before 1 disassemble it for storage. https://www.youtube.com/watch?v=Pn0ycZN48Zc&t=47s
No problems, the engine starts pretty good and goes smooth as it should do.