Low top speed
Posted: 17 Jul 2017, 12:44
Hi!
I bought my 1993 Mk2 two years ago. The engine had good compression by feeling and measuring, but very hard to start cold and lean symptoms at cruising speed and not too great top speed around 130km/h. I tried to adjust the float level, jet needle, jet change and air screw with no luck. I decided to try a PWK33 carb. After jetting the PWK ( 45 pilot, leaner straight section needle, 128 main) the cold start problem is gone and starts 1-2 kick cold or hot. The cruising lean symptoms is gone too, but the top speed is same as before.
The engine has now completely rebuilt from top to bottom all seals, new bore, bearings etc. I hoped the best. But the top speed is horrible same as before around 130km/h with 17 inch wheels and 15-39 sprockets, this is near the same but slightly longer ratio as the original with 18 inch wheel and 14-42. The bike pulls great and has good power at lower gears but reach top speed in 4 gear and no more acceleration in 5-6 gear. Brakes, chain, sprockets, wheel bearings are all in good condition, power valve works and i am not too heavy weight with my 68kg. Ahh i almost forgot the bike has an aftermarket silencer which i cleaned and repacked, the front pipe is original but i removed some big dents and the inner sound dampening layer and carefully welded the pipe but again, no luck.
Does anyone have any idea what's going on here?
Thanks!
Denes
I bought my 1993 Mk2 two years ago. The engine had good compression by feeling and measuring, but very hard to start cold and lean symptoms at cruising speed and not too great top speed around 130km/h. I tried to adjust the float level, jet needle, jet change and air screw with no luck. I decided to try a PWK33 carb. After jetting the PWK ( 45 pilot, leaner straight section needle, 128 main) the cold start problem is gone and starts 1-2 kick cold or hot. The cruising lean symptoms is gone too, but the top speed is same as before.
The engine has now completely rebuilt from top to bottom all seals, new bore, bearings etc. I hoped the best. But the top speed is horrible same as before around 130km/h with 17 inch wheels and 15-39 sprockets, this is near the same but slightly longer ratio as the original with 18 inch wheel and 14-42. The bike pulls great and has good power at lower gears but reach top speed in 4 gear and no more acceleration in 5-6 gear. Brakes, chain, sprockets, wheel bearings are all in good condition, power valve works and i am not too heavy weight with my 68kg. Ahh i almost forgot the bike has an aftermarket silencer which i cleaned and repacked, the front pipe is original but i removed some big dents and the inner sound dampening layer and carefully welded the pipe but again, no luck.
Does anyone have any idea what's going on here?
Thanks!
Denes