S9 AC trouble.

[TheAmishSasquatch]

I picked up an S9 a few months back. The bike seemed stock other then the Technigas exhaust. The bike ran very well. Pulling hard out of the hole and all the way to 70Km. I wanted to get just a little more out of it (80km) because it would certainly help me not die in the traffic areas I ride. I bought an unrestricted Boss, thinking this would move the belt higher on the variator and give that slight increase I need. I disassembled everything and installed the new CVT boss. I noticed my stock boss was the same length and was void of the "restriction ridge" (it did have a grove though). The installation was strait forward but I also noticed that there were only 5 roller weights in my CVT    I installed everything as should be and the bike ran more poorly. I  rode the bike for a few days at the slower speed and then switched bosses back. Still ran poorly.  After a month or so of playing with roller weights, carb adjust ments, larger jets, drilled airbox, etc.. needless to say the bike was waaaay out!!!  I've since ordered the correct 7.5g rollers that were originally in the CVT, I've taped off the airbox cut-out, reverted back to the #75 main jet that was in the carb, and have been trying to adjust the air screw and throttle stop screws to the correct settings. The bike is for all intent and purposes is returned to stock as I bought it. ....The bike runs like crap still! WTF? 

My questions are:
Would TQ specs on the main variator nut &/or clutch nut affect performance?
What are the proper turns for the air-screw & throttle-stop screws?  (manual says 1.5?)
Does air-screw-throttle stop adjustments drastically affect the performance?  Seems like "duh, yes!" but the reason I ask is because I've never had an issues before and can tune scoot carbs very well by ear.
My bike doesn't seem to want to shift gears and bogs down. It revs, runs and sounds nice statically and when at 1/8-1/4 throttle runs very badly and seems stuck in gear.

Thanks for reading and I know Ive broken the most basic rules of tuning so please dont break my balls for it. I just really need help or my wife wants me to sell my scoot   Thanks in advance.

[Martfart]

Well to me it seems like your problem is cvt related.

Worn belt?
installed the cvt wrong?
Broken spring in secondary?
Belt slip due to oil/dirt
Check that every part in the cvt is counted for (the small triangels that always fall out)

[Martfart]

Ohh and airscrew dont affect topspeed

[zombie]

Hello,
I would start with a new set of 6 gram rollers. Either Polini or Dr. Pulley rollers are good. Also a Malossi RED rear control spring. Get yourself a NEW Bando drive belt too. These are improvements over stock, and are the first things I would do on a used bike bike.
Torque settings on the Var nut make no difference in performance...

As suggested by Martfart, check/replace the small triangular bushes on the ramp plate in the var.. They are a wear item that needs replacing just like a belt.
When you replace the rollers use a small drop of motor oil or grease on the crank shaft, and inside the variator bushing. This is only to help these parts seat, and after that they "self lube".
Use a drop of Blue Lok-Tite on both the crank nut, and the clutch nut.

Get a new spark plug, air, and fuel filters, and start the bike.
Turn the idle mix screw clockwise untill you get the Highest rpm you can. If it only falls lower turn it Counter clockwise for the highest rpm. That's when you turn the slide control screw to get th recommended idle rpm.

i would carefully check the intake coupler to the carb for cracks or air leaks. These are the first part that fails on most Kymcos.

All of this will cost well under 100.00US, and will most likely have you going.

IF you have access to a leak down tester I strongly recommend testing for case leaks. The crank shaft seals do go bad, and most people sell bikes that have bad seals because they cannot figure why the bike runs sh**ty.
I would also do a compression test. You should see at LEAST 120 psi on this

[TheAmishSasquatch]

Thanks for the advise. I've ran all 6g rollers during my roller experiments and they did nothing but rev the engine higher. I ran a compression test and I'm consistently getting around 120-121. The triangle bushings in the CVT are all fine and move as they should. The scoot has a Bando belt already installed and the bike itself only has 1554kms on it from new. I ran it for about 400-500kms before I had any issue. I highly doubt anything is wore out at this point. I will check the intake manifold-tube as I have removed it in the past and its possible its affecting the bike. Beyond that, my brain is frapped and have no idea where to look next. Any other suggestion's?  Thanks everyone

[zombie]

120 is boreder line compression. The top end should be rebuilt. Head, and base gaskets/Piston/Rings.

I would also do the leak-down pressure test. I understand you think it's a simple screw out of wack or a fitting fell out but the reality is a bunch of little issues combine to make what seems to be one big issue.
Any 2t 50cc scooter running properly should see 130 - 145 psi on a compression test. 120 indicates it is time for a rebuild.

[TheAmishSasquatch]

Thanks Zombie. I know for a fact its a bunch of little things. Too many lol. Not quite sold on the time for a rebuild bit yet as the bike has on 963 miles on it. Theres a combination of bad things playing out. First is: besides the pipe, I "thought" everything was stock. Upon closer inspection theres a bando belt, yellow clutch springs, #75  main jet installed (not 78 or 92 factory) and the 5 (not 6) original rollers. All this combined with my turning of the various air screws really adds up to a poor base-line to tune from.  My original plan was simple enough: Add unrestricted CVT boss, open airbox, upjet accordingly, go faster.  Well that notion flew rite out the window    I'm gonna also check the intake manifold/tube as I had removed it at one point and its possible its not seated properly and allowing air leaks. m=Might check the head gasket as you mentioned as I'm gonna look for carbon build up anyway. Thanks for the help, its very appreciated.

[zombie]

If the main is to small (lean) 1 mile of riding is too much.
Look at it the way I would. It's a second hand bike, and everything that could be wrong... is wrong.
I take it for granted I have to strip the bike down, and start from scratch.
S9's are a classic go fast scooter, and IMHO something worth having, and holding onto. I'd make it a restoration project, and have a hell of a finished bike.

[Areomyst]

Thanks for the plugs Zombie.   I don't check in here as often as I used to because family and business keep me more than busy... Good to see you're still kicking around.

 Any updates on your situation Mr. Amish Sasquatch guy?  The Super 9 is a great machine, and when they're running right they're really quite nice.   I hope you can get the issues sorted.

Ciao!
 
~Josh

[BettinANDlosing]

#72 main jet is too small you would be at #82-#85 oil the main. Also the oddest fuel mixture setting is 3\4 - 1 turn out. Running the bike with one weight missing it could have damaged your variator.

[zombie]

Thanks for the plugs Zombie.   I don't check in here as often as I used to because family and business keep me more than busy... Good to see you're still kicking around.

 Any updates on your situation Mr. Amish Sasquatch guy?  The Super 9 is a great machine, and when they're running right they're really quite nice.   I hope you can get the issues sorted.

Ciao!
 
~Josh

Love ya like a Brother J. The way you run your business is really my inspiration in helping here. You always help before looking to empty someones pockets.

I noticed one other bit I missed before. He stated there was a "groove in his original boss". That means thew bushing in the Var is worn, and I'm sure that is hurting the performance even w/ a new boss.
We haven't heard back from him, but this might help someone else.

If you know anyone capable of maintaining the ZX I still have it, and will throw a hefty "brokers fee". The complete list off mods is here,,,
http://www.kymcoforum.com/index.php?topic=11422.0

I know... Pimping aint easy Bro!

[zombie]

#72 main jet is too small you would be at #82-#85 oil the main. Also the oddest fuel mixture setting is 3\4 - 1 turn out. Running the bike with one weight missing it could have damaged your variator.

I wish he would have posted back. It's really just a bunch of little/easy sh**.

[TheAmishSasquatch]

Hi everyone. Sorry for the delay. Ive been very busy with class, work, wife and everything associated with both. not to mention lack of funding. So after weeks of not having a running scooter, I was finally able to source the correct parts/tools needed to get my S9 back to a 10.  What I've done so far: using a digital scale, I weighed the original rollers (7.5g) and bought new replacement rollers.  Purchased an electric impact from Harbor Freight (also started a new job working there )  Disassembled and cleaned the carb. Its a #75 main jet not #72 as someone mentioned earlier. I then tore the motor apart for inspection/cleaning. Bought a new gasket kit. Broke some piston rings (as usual) and bought a new piston w/rings kit. Installed new rings on old piston (better quality) and reassembled. I also installed a digital tach and neatly wrapped and tapped the pick-up around the spark lead.  All aces so far  After alot of trial and error I got the carb in a near usable spec and took my first ride up the street today    The bike still lacks that "get up & go PUNCH!" it originally had, but did finally climb and maintain 70kms. I adjusted the carb back to closed settings and will attempt to reset it later today. I still don't understand why the bike still doesn't have that hard hitting feel it used to?

[zombie]

Just to settle any second guessing... Get a new compression tester from HF, and check that. W/ new rings it should read around 130 with the throttle wide open.
Next the Main still sounds WAY too small. Try a set ranging from 80,82,84,86,88,90. Start at 90, and work down.

Also a leak down test. When a bike sits for months/years the seals harden. Just a few miles will wear out hard seals.

Where are you located?

[BettinANDlosing]

That jet night be the restricted one, normally that engine derestrcted takes an #82 main.