Engine Vibration

[chopperruck]

Hello All,

My 2004 ruckus died and I couldn't figure out what the problem was.  Tried literally everything.  So I dismantled it and rebuilt a 2015, 1800 miles on the motor.  I am having a few issues, some that stuck around from the 2004 Ruckus. 

1. When I hit the throttle at a light, there seems to be a shudder and the bike almost dies, sometimes it actually does.  I have to give it a little gas before the red light changes in order to have a smooth start.  This was happening with the older Ruckus as well.  I am not sure it this is an air/fuel issue or something else.  The carb was jetted, aftermarket intake and exhaust were installed.  
2. I noticed a strange vibration that I haven't felt before.  With a wide open throttle I can feel it slightly, but when I release the throttle and let it rev down, the vibration is A LOT more noticeable and I can feel it through the entire bike.
3. The bike is slower than it should be.  Granted, I am not the smallest guy in the world, but I am only hitting about 34-36 mph, while my buddy, around the same weight as me, same year bike, and almost identical mods is hitting mid 40's.  

Please let me know if you have any ideas.  Any and all help is greatly appreciated and I promise if fixed, I will let everyone know what was corrected!  

Safe riding everyone!

[scootergurl]

does it have good fuel pressure?

[maczulu]

so the carb is tuned to your set up? including the pilot screw ("D" air/fuel screw)? I think your right, it may be the mix for your problem #1.



The vibe thing is hard, I had a weird vibe when I was an idiot and hooked up my cdi wrong. I hadn't hooked the delimiter right but the cdi harness was tied into the coil right, which I would think is how the cdi advances the timing (I think it's advanced...). So I think my weird vibes might have been the timing being wacky do to my bad install, once corrected, it was all smooth. But my vibes didn't increase when I let the throttle off.



have you inspected your variator and clutch? I know it sounds silly, but I have heard sliders can get flipped and vibrate. If your even using sliders. if the vibes are the same as with a different engine and they respond to throttle there's not alot of suspects left.



as for speed I'm still chasing that dragon. I'm 210 lbs, but that doesn't have the impact I thought. My buddy is 170 and when I ride his yamaha c3 (which is considerably faster and almost stock) I dont seem to slow his much and he doen't get more out of mine.



I'm running

malossi variator with mixed weights. 4.1s and 6s
(malossi is more acceleration than top speed)
stage 1 race clutch from japan-webike

Original belt about 4000 kms, waiting on a gates
belt
daytona cdi with a posh racing coil and ngk wire

daytona exhaust/ 6" piece of radiator hose for an intake

jets 38/82 may go back to a 40, as I'm still tuning.



When I start off I'm straight to over 8k rpm and settles around 8800 as I gain speed. on flats will hold at 9k ish. Thats 63 kph/39 mph. that's totally flat, no tuck, just full throttle and steady. My acceleration and hill climbing are great now, and now with regular traffic I stay with the low better on inclines.



the fastest speed my ruckus has ever seen (before exhaust and cdi) was down a long steep hill and me keeping the throttle just off the limiter was 77 kph/ 48 mph. (that was the east side of SFU hill for vancouver area people)