Hi everyone, So after help from this forum, I up-jetted my Baotian 49qt-11 Retro, fitted a cone filter and technigas silent pro exhuast. The jet that was in it was a 72 and it would bog down at about 30mph, but weirdly after about 20mins of riding, there would be a jolt and it would then manage 40mph. I used a 90 main jet and this seemed to cure it and for a while it ran well. I did however forget to renew the exhaust gasket so it was loud with lots of pops and bangs! Then the ignition coil wire snapped so I decided to replace that as well as new spark plug, 4g rollers and 2k contra and clutch springs. Got it back together the other day and as soon as I revved it, it died. Started straight back up but had to dial up the revs gradually. Also, it now seems to take a lot longer to actually move. The revs build but it doesn't move straight away. I'm confused for 2 reasons; first, the springs and rollers shouldn't have any effect of fuel/air/spark so can't understand why its suddenly stalling out - perhaps cold weather and fact its been stood for a while? Second, I thought the idea of mods to the transmission was to make it "bite" earlier and take off quicker but this seems to have had the opposite effect. I've had to put it back in the garage as one of the exhaust stud nuts fell off, so whilst I wait for a new one, does anyone have any thoughts or insights? Thanks everyone, sorry for long post!
Usually people change the clutch springs to stiffer ones when a sports pipe has been fitted, as the new pipe will make less power lower down the rev range than the stock pipe, but more power higher up the rpm range. With stiffer springs the revs will be higher on initial take off, as more centrifugal force is required to throw the clutch shoes out against the tension of the stiffer springs. Lighter rollers will delay the opening of the variator keeping the revs higher throughout the range of motion. Having said all that... your pipe, The Tecnigas silent pro is a very tame pipe with good low down torque, and you may find it works pretty well with the stock clutch springs and roller weights, and no changes are needed to the transmission. Its all trial and error really.
Thank you for the response that makes things clearer. I have a couple of different weights now so will give it a go. Noticed that it still makes a decent top speed but has lost a couple of mph which is what I was expecting.
Just a bit extra, after driving for a few days, it seems to be quicker around 20-25mph and pulls better going up but from a standing start its worse than stock. I hit the throttle fully open trying for a quick launch or if I hold it just below biting point, when I try to take off its like the revs go all the way and bounce back a couple of time before it moves off and then its quite slow. Wondering if the belt or clutch could be slipping?
clutch or belt slip is a possibilty... but there could be a few reasons its not pulling away properly. maybe see if you can post a video of what its doing
Cheers dude. Its hard to do a video as it's just me and the issue is prevalent when I'm on it. I'm wondering If I'm just too heavy for a quick start! Ended up taking it apart again, new clutch with red springs (came installed) and clutch bell, new belt, slightly heavier rollers (5g up from 4g), original contra spring back in, "racing" variator (does seem to be less meat on it) CNC variator pulley (doubt it does much but looks cool!). Bolted it all back up and on the stand the wheel starts turning much quicker with less revs. Haven't managed to do a test ride yet as still need to get exhaust sorted. Any recommendations on this? Technigas one fell off! I think like you say, I'm gonna have to play about and keep changing and testing until I'm happy with it. Thanks for the input.
