KymcoForum.com
Scooters - 50cc => Super 9 => Topic started by: TheAmishSasquatch on September 10, 2014, 05:56:08 PM
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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.
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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)
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Ohh and airscrew dont affect topspeed
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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
Pressure Testing a Minarelli Horizontal 2-Stroke Scooter Engine (http://www.youtube.com/watch?v=ySu2NC1X7s4#)
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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
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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.
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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.
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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.
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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
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#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.
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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 (http://www.kymcoforum.com/index.php?topic=11422.0)
I know... Pimping aint easy Bro!
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#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**.
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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 ;D) 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 8) After alot of trial and error I got the carb in a near usable spec and took my first ride up the street today ;D 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?
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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?
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That jet night be the restricted one, normally that engine derestrcted takes an #82 main.
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Thanks for the help guys. I think you might be forgetting the fact that the scooter was running peak & perfectly with the jets and tune that I'm currently trying to replicate. Even faster then most people claim on S9's with mine running a consistent 75-80kms on level ground. The bike was perfect until I started cutting open the air box, changing jets and drive boss's. I am still trying to source and original box cover as I think mine may still leak (which would cause som of the symptoms I'm still having) If anyone has one they would sell please let me know. I do have a jet set ranging from 80-100/105 The factory claims a #78 or #92 IIRCC depending on AC or LC and restricted or not. An area of confusion for me is the roller weights. I've purchased the $3.99 black Chinese and Koso weights and both seem to vary significantly from roller to roller. For instance a roller A. "7g" Koso weighs 7.4g actual, while roller B. "7g" Koso weighs 7.1g actual and yet roller C. "7g" Koso weighs 7.8g actual (and everything in between) Whats up with that!? Are Dr.Pulley rollers more accurate? The roller that I pulled out on the bike were an off white color with one end of the brass painted yellow. These appear to be factory Kymco or possible Dr. Pulley rollers. I noticed that material and quality seems higher on the original rollers as well. The $3.99 China trash is hard plastic outer shell as are the Koso's. The stock rollers feel like rubber or Teflon or something??? Anyway, thanks so much for trying to help me out. BTW I'm in NE Philly PA
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I personally did forget those tid bits.
The rollers you have a a graphite compound. Garbage.
Get 6-7 gr Dr Pulley or Polini rollers. They are Nylon, and can last thousands of miles.
Contact Josh @ www.thescootergarage.com/ (http://www.thescootergarage.com/) Ask him for a drive boss. Yours might be too long/short. He can hook you up w/ the rollers, and most likely has a lid for your air box.
Sorry for all the confusion.... Talk to him, and put a "solved" sticker here.
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Thanks. I'll contact him and see what he can do for me. I guess I'll just keep tuni9ng and tinkering until I get it tip top again.
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Tell him I sent ya. He's the S 9 super hero.
Don't disappear on us. Updates are what keeps the forum working, and all of us learning. Thanks! ;)
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I spoke to Josh yesterday and did mention you sent me. He was happily surprised you still throw his name out there and is thankful for doing so. Unfortunately he didn't have an airbox/cover. Ive been in contact with my local dealer to see how much a replacement will cost. I also plan to buy the original factory 7g rollers. I will try to update as progress occurs. The forum seemed kinda slow/dead for a while and I wasn't really doing much to the scooter anyway, so I took a leave of absence 8) I have tracked down a used airbox out of the UK but it looks beat and my scooter is very clean still so... ::)
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Ordered a new air box cover and the correct factory rollers yesterday. $45.57 out the door wasn't as bad as I had imagined from the dealership. Should be here in a week. I'll update as progress is made.
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Update: The new airbox cover and roller weights arrived yesterday and were installed last evening. The cover was a real PITA to fit, even though it is an OEM part. I attribute the poor fitment to the fact that the original cover has been through the same heating and cooling cycles and expansions as the original air box; where the new one was fresh off the boat. After it was finally affixed to the air box, I used a heat gun to soften things up a bit and let it cool/conform to the box. While everything was apart I decided to reseal the inlet tube from the airbox to the carb. A little fine tuning to the carb and I was off!! The bike runs well and I was able to ride about 10 miles of shake-down testing. The scoot does eventually get to 80+ Kms but not as fast as originally. This has me a bit befuddled as I'm not sure if its leaning out or the mix is too rich. Once it finally changes into top-gear the familiar hard pulling/fast accelerating performance I'm used to is restored. It used to accelerate from a dead stop in such a way as it seemed very low geared for about 3-4 seconds and then kick into a higher gear that seemed to pull and pull for days all the way up to 75-80kms. Again I;m curious as whether the carb needs more or less air/fuel??? Any help or insight is very much appreciated. I will keep updating as updates become available or until the bike runs as it used to originally. Thanks
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The way you find out what the carb jetting is doing is to do "plug chops". Get 3-4 new spark plugs, and install one. Ride the bike at WOT for about a mile, and hit the kill switch. When you pull out that plug look deep down to the base of the insulator. There will be a colored "ring" right at the base. It should be a dark tan to coffee color, and in a complete ring. If it is lighter in color the main jet is too lean. If it is darker in color the jet it too rich.
You can do the exact same test at any/all throttle positions. I always do this at 1/2 throttle, and full throttle, and use a NEW plug for each test.
Nice job on the air box too. I liked the idea of heating it all up to get the correct fit.
Also... You bike may have seemed peppier because of the worn/lighter rollers. The first sign that they are worn is an increase in rpm so new rollers will have reduced rpm over worn rollers.
Most people will lighten the replacements by a gram or two to get that extra rpm, and torque. You might want to keep the new ones, as spares, and get another set about a gram lighter.
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Thanks Zombie. Ive been tinkering and keep getting very close. The scoot even has that punch I remember. However the bike still lacks the acceleration/pull to 70-80kms. I did notice (thanks to the digital tach I installed ;D) the pipe comes on at around 3200/3250-about 3300 RPM and pulls hard to a top speed 70-81.5kms maintaining 34xx-35xx RPM. When the bike is accerating I feel the certain punches and pulls I remember but then drops from 3050-3080 RPM out of the powerband/pipe band to 29xx rpm. Its at that point I need the bike to gain an extra 100-200 rpm , not drop em!!! I was thinking of using the cheapO ebay 6.5-7g rollers i have as spares and as you said keep the OEM rollers for back up (just until I order OEM 6.5-7g rollers). The absolute biggest question I have is "what is the effing idle supposed to be set at!?" Ive read 1900 +/- 100 (seems waaaay too high), and I've seen 900rpm. Today I set it around 1820-1880 (after the motor idled down to steady on center stand) and noticed at stop lights with the bike on the ground + me, it was idling around 16xx rpm. The bike ran great with the exceptions of top speed/pull noted earlier but these settings burned through a half tank of gas in about 15 miles!!! This leads me to believe 900rpm is closer to spec, but when adjusted to 900rpm idle, the bike is a slow turd and 55-60 kms is about all she's got captain. Any help would be great. Thanks!
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When the bike looses accel. from a reduced idle it is showing the idle jet is too small, and the bike is way too lean at such low rpm.OR the idle jet is too big, and the bike is flooding at low rpm. Have you been adjusting the MIX screw every time you changed the speed screw?
Set the idle around 1200, ansd adjust the mix screw for the best idle. Try that, and see how the accell. is. Then turn the screw 1/2 turn either way to see what result you get. If enriching the circuit helps then a larger idle jet will help or vice versa.
Also your slide needle should be adjustable. If you need more fuel to accel raise the needle 1-2 slots. If you need less fuel lower the needle.
In either event changing the pilot jet to match what the screw/needle indicate will get you back to setting the needle, and screw back to their standard settings. 2.5 turns out for the mix screw, and center slot for the needle.
I hope that all makes sense....
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Thanks it does make sense, and I have been adjusting both individually as well as in conjunction with each other (I'm trying every combo to see what works). The "Throttle stop" screw seems to have more of an effect on idle. The "air screw" has an effect as well but seems more important in WOT operation. I wish I could adjust the needles on the fly, while riding. This is what I have planned:
I will turn both screws in until seated. I'll adjust the throttle stop until 1200 rpm. I'll then begin to adjust the air screw and see where that take the idle/throttle response. I'll then adjust the throttle stop acordingly to the point where the back wheel just begins rotation (in the event the air screw adjustment sends the idle into the stratosphere as has happened). Looking for an idle of between 1200 and 1500 or is that too low/high? Is 1900 the correct factory spec? Once I'm happy with those settings I will swap to the cheap rollers 6.5-7g. Does this seem legit? Thanjks. BTW its getting cold as F*** riding the scoot :o
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You sort of have it right...
The idle Stop screw is the larger one. DO NOT turn that all the way in. Chances are the engine will blow.
I don't know the OEM rpm but 12-15 is normal for mine. 18-19 is ok. same for 9-11.
Anyway get it around 12k, and then turn the air screw either direction to the highest rpm. If you have to turn down the stop screw that is a GOOD sign. Keep doing that until the idle is around 12k, and no matter which way you turn the air screw the idle goes down.
That air screw has a very limited effect on wot. Because it only corrects the air/fuel ratio at idle, and maintains that ratio only up to about 1/4 throttle. The needle manages that ratio from 1/4 up to about 1/2-3/4 throttle. From 3/4 it is all on the main jet.
Yes they all interact, and are very dependent on each other. To some degree they can/do compensate for each other but not in a perfectly tunned bike/carb.
It is a bitch riding/swapping/riding/swapping but it is worth the effort for a long lived engine.
Besides having about 20-30 jets for each carb type I also have around 10 needles for each one. Thinner/thicker/taper rates.
What I do is set the idle, and ride ONLY on 1/2 throttle or less. Do this w/ a brand new plug, and look inside for the coffee colored ring. Tan is too lean, and black is too rich.
Once I get a good plug chop I will start playing w/ the main, and repeat the plug chop but this time at 1/2 throttle, and again at wot. 3-4 NEW plugs, 5-6 jet swaps, and it should be good to go.
Pick a WARM day for all this. If you jet below 50ish degrees it will be wrong when it warms up.
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Thanks for the clarity on the adjusters. I know its close, but still could be perfect IMO. I'm just trying to get it ride-able as a back up means of transportation. I figured with such low temps and cool dry air the mix would be lean but still wanted to try and get it running as close as possible. It's probably gonna have to wait until spring, but come spring I'm hoping to get a left over stock SR50 lol. Love the S9 but I love the Aprilia more hahaha :P
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Then you will need to talk to Richard from High Gain Tunning!
He's built the fastest SR-50 there is. They are his bread, and butter. All in figure around 5k for a 7o mph beast
He has never posted the real number but the bike pictured is near 25k in parts/labor.
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Turbo setup? If so, thats a very clean install. The bike I'm after is an SBK. $3200 with dealer de-tune/flash. 55+ mph off the show room :)
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That's a great bike, and the price is very fair. I was seriously considering one. I wound up building up my ZX 50 instead. 5k, and 82 mph but I havent riden it in close to a year. Just a few rides now, and then.
Rich's SR took about a year to build, and it wound up that every part had to be hand made. It is a turbo (Zenith I think). Every part was machined/fitted/tuned to his design. Right down to custom built injectors, and the software that runs the computer.
At one point we talked about me replicating all the body panels in CF for the bike but another 5k put that out of the ball park. Plus I couldn't travel to Texas for 3 weeks (seven mean ass dogs to take care of).
If you do go for the Ape, talk to Rich first. He may be able to help you out.
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Thanks. The S9 was my second choice but since I couldn't secure financing on the SR, I passed. Plus I got my S9 for cheap money considering its practically brand new.
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Even tho they are completely different bikes, they are both capable of competing w/ each other. depending on the builder it is anyones guess which would win in any sort of contest.
I sort of would have liked to get my mitts on one but it would (once again) be money I would rather spend elsewhere.
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Update: So after a very long and cold PA winter, the weather has finally warmed up enough to break the bike out and get to tinkering. The last several days have been in the 60s/low 70's here so it's perfect Temps to finally get the carb jetted and adjusted properly.As you may recall I atempted this endeavor last fall with poor results (attributed to 30s- 40s degree temps) Well I am very excited to say that I have the PB 14 dialed in to perfection! With the help of my installed digital tachometer and a digital scale courtesy of harborfreight, I have even been able to get the mysterious stock roller weights identified and total weight known. Since I'm limited on my "on hand" roller selection, I made a few ball park weight combos. According to the stock weights I should be In the 50g range. After weighing each of my weights for true weight I was able to better fine tune my total mass. Despite what the manufacturers say, the weights are pretty varied from one weight to another (not just labeled weight) I've found "6.5" weights to be 7.0 and "7.0" to be 8.3 etc... I'm not just talking the cheap China weights. I've found this on a set of Dr pulley rollers as well. So I strongly suggest getting a cheap scale and take to time to weigh and group your rollers/sliders. Any-who I tried a few groups in the 51.2g range and a 42g range. The 42.5 was a great base and after tuning a bit I'm in the 44.3 range and it seems to respond nicely. I suppose now all I have left to do is ride the crap out of it 😊