If the engine is too rich in the main jet it will never put out full power...........Like Bill said, If the engine is quite new i wouldn't push it too hard.......You may do damage before you ever know what the top end performance could be.
E: Engine Lame duck Comet
- Thread starter Black Flash
- Start date
Well I will keep you updated how things are developing.
Dieter is a well known man in the NSU club rebuilding tens of engines a year for club members. With the very slow gear change of the Comet against a NSU Max you loose every time you you need to change gear. He is certainly not racing the Comet, but he was quite miffed when he could not keep up with the Maxes when on a club run.
the Max is a 250 cc bike rated 17 to 19 PS [bhp], so I certainly feel with him being left behind on a 29 bhp 500!
Anyway I am waiting for his comments once he has fitted the shadow carb and changed back to the old ATD springs.
Cheers Bernd
Dieter is a well known man in the NSU club rebuilding tens of engines a year for club members. With the very slow gear change of the Comet against a NSU Max you loose every time you you need to change gear. He is certainly not racing the Comet, but he was quite miffed when he could not keep up with the Maxes when on a club run.
the Max is a 250 cc bike rated 17 to 19 PS [bhp], so I certainly feel with him being left behind on a 29 bhp 500!
Anyway I am waiting for his comments once he has fitted the shadow carb and changed back to the old ATD springs.
Cheers Bernd
I find the Comet Gearbox, Change is quick enough, Just the space between the gears, The down change is as quick as anything, To me.
I wonder how many people have been put off the Comet, Because of it ?.
I would love to get my new 560cc built, To see if the extra power would help with the gears.
I now know I have been silly trying to do it myself, It would have been quicker and cheaper to get a top man to make the Flywheels.
We live and learn !. Cheers Bill.
I wonder how many people have been put off the Comet, Because of it ?.
I would love to get my new 560cc built, To see if the extra power would help with the gears.
I now know I have been silly trying to do it myself, It would have been quicker and cheaper to get a top man to make the Flywheels.
We live and learn !. Cheers Bill.
I run 34 with a reduced throw ATD to give about 4 at full retard and i can get over 80 if I need to..John
I have certainly avoided the Burman box because of the shifting. I don't think it is horrible, but I don't like the length of the shift.
I have seen three Comets go on the dyno in years past and I think 26 BHP was the highest. The low was 22. Most riders have no idea how poorly their engines are running.
I did mention in another post that I believe that there is no benefit to running advanced timing on any bike. Advancing ignition does not improve performance and it makes the engine run hotter. (I am referring to ignition at full advance.) The goal is to get the most retarded timing with the best torque readings. That is hard to do without a dyno and I know that it is unlikely for most owners to do that type of testing. My guess, and it is just a guess, is that timings above 30 are getting pretty advanced. It is very difficult to generalize because there are no Factory stock Comets anymore.
As Greg says, most engines are set up too rich to get good performance. In general, the Vincent is not very sensitive to jet changes either way. This makes it hard to dial in the tuning. The Comet riders with a lot of experience seem to have closed in on the better tuning through the years and seem to have good performance.
David
I have seen three Comets go on the dyno in years past and I think 26 BHP was the highest. The low was 22. Most riders have no idea how poorly their engines are running.
I did mention in another post that I believe that there is no benefit to running advanced timing on any bike. Advancing ignition does not improve performance and it makes the engine run hotter. (I am referring to ignition at full advance.) The goal is to get the most retarded timing with the best torque readings. That is hard to do without a dyno and I know that it is unlikely for most owners to do that type of testing. My guess, and it is just a guess, is that timings above 30 are getting pretty advanced. It is very difficult to generalize because there are no Factory stock Comets anymore.
As Greg says, most engines are set up too rich to get good performance. In general, the Vincent is not very sensitive to jet changes either way. This makes it hard to dial in the tuning. The Comet riders with a lot of experience seem to have closed in on the better tuning through the years and seem to have good performance.
David
Something in my head , Going back to cars, Vac' advance, Gives better M.P.G. Cheers Bill.
Bill, I think what you are thinking about is something fitted to lots of 1950s/60s cars' distributors. The idea was that when one pressed down on the accelerator the suction in the inlet tract reduced and the 'vacuum servo' retarded the ignition, just like you might do with a manual advance/retard if one wanted to take a big handful on a bike. It is all some time ago so I might have it wrong.
If you take your foot off the pedal, You would get better MPG anyway !, But it did allow you to have more advance. Cheers Bill.