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Post by cristian on Aug 28, 2018 7:31:01 GMT -5
Boy, am I happy I found this forum. I need some pieces of advice on how to improve top speed and pulling from stand-still. I live in a city where drivers are not that used to seeing scooters and motorcycles. Hence, you need to keep up with the traffic, otherwise drivers will just try to push you to the side one way or another. I bought in March 2017 a brand new Kymco Like 50 4 Stroe. I chose Kymco because they are very realiable. I went for the Like model because it has that Classic Italian look at half the price of a Vespa. And I chose the 4 Stroke because it is said to last longer, as I ride the scooter 11 months a year. So, 6 months after buying it, I installed some improvements: 1) Derestricted CDI and derestricted variator boss; 2) A 72 cc kit from Naraku (47 mm, cast iron, high compression). Pulling was OK until a reached 30 kmh or so (that's 20 mph). Afterwards, the speed increase was very slow, while top speed was 65 kmh (40 mph). And the engine was revving very high, it was trembeling under my feet. And to my big surprise, I was not able to kick-start again. And during winter, this was a big issue because I killed the battery one morning. I tried to improve things, so I installed: 3) Multivar 2000 Variator from Malossi, with the 6g rollers and white contra spring. There was no change in the pulling from stand-still position. Top speed increased a bit, maybe 70 kmh (43 mph). It was still revving like hell. Engine was very loud. 4) I changed the main jet, from the stock 75 to 82. Engine was not that loud anymore. But pulling was not impressive.Top speed 70 kmh (43 mph), but I needed like a mile of free road to reach this speed. And it was revving hard. 5) Afterwards, I installed the 49/17 secondary gear kit from Top Racing. Pulling was worse, but I expected that. Top speed was easy at 75-80 kmh (46-50 mph). And it was not revving so hard anymore, in fact the sound was very pleasant. Instead of calming down, I wanted to install a bigger bore for two reasons: improve the pulling, make my kick-start work again. 6) I installed the 80cc (50 mm) from Airsal (aluminum). In fact, this bore was even worse than the Naraku. I was barely moving from stand-still. And top speed dropped to 65 kmh (40 mph). 7) I went back to my stock secondary gear kit. Now, pulling from stand-still is fairly decent, but not impressive. Maximum speed is 65 kmh (40 mph). And it revvs like hell again. Please, give me some piece of advice on what to do, as I am desperate. I want better pulling and 75 kmh (46 mph) top speed, together with the ability to kick-start the scooter. The only thing I like about the current set-up is that I can kick-start the scooter. What should I do? ? I was thinking to go back to the 49/17 gears and maybe do a 90cc kit (there is a 52 mm aluminum from Malossi, also there is a 52.44 mm cast iron from Naraku which comes with a new and improved cylinder head). But I would like to avoid this because it is very expensive now. Would that do the trick? Thanks, Cristian.
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ratdog
Scoot Enthusiast
Posts: 342
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Post by ratdog on Aug 28, 2018 8:48:29 GMT -5
WOW! Lot of work to get nowhere! When you say it revs like hell, do you mean that when you take off the RPMs go way up before you start to move? Can you tell us how many RPMs? You mention you can’t kick start the scoot, why? By that I mean dose it kick thru just fine, but just won’t fire? Do you have, or can you get a compression tester? The Airsal piston is supposed to be very high compression. Are you using premium fuel?
The “ preformance” CDIs I have had contact with do not retard the timing at low rpm. This makes the scoot very hard to start, even more so if you try to kick start it. Have you tried putting the orginal CDI back in it now that you have BBKs? There are aftermarket CDIs out there that do restart/advance the timing. Don’t know what brands you may have advaible to you, but the important thing is that they MUST advance the timing not just keep the timing fully advanced all the time.
You mentioned you changed the jet, did you try to read the plug? Can you pull your plug, and take a closeup so we can see what the “white part” looks like? May give us a hint as to how your jetting is set.
In all this modding, I don’t think you told us what carb you have, stock?, 20 mm? 22 mm? Do you have the stock air box and stock exhaust on it?
I know nothing about the mods you did to the CVT, do you still have the stock stuff? What I’m thinking here is let’s go back to stock and set a baseline. Then we can make changes one at a time and work up. By doing that, we can see how what is effecting your preformance. As it is now, you have made so many changes and introduced so many variables that it’s the shotgun approach to fixing stuff.
If you didn’t give us the actual RPMs because you don’t have a tach, GET ONE! It is impossible for us to help “tune” your bike if we don’t know where the RPMs are and what’s happening to them as you increase speed
Also might help if you let us know how you have your tune up. (Valve lash, spark gap)
Please DO NOT buy another BBK. You have other problems that a bore job will not fix.
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Post by cristian on Aug 28, 2018 10:47:41 GMT -5
Hi and thank you very much for taking the time to reply.
So, to answer the issues you have kindly raised:
- "When you say it revs like hell, do you mean that when you take off the RPMs go way up before you start to move?"
No, when I take-off, revvving does not bother me, it feels ok. Once I reach 60 kmh, I fell the scooter trembeling under my feet.
- "Can you tell us how many RPMs?"
I do not have a tachometer. I know it's not expensive, but I would not like the looks of it on my dash board. I like my scooter nice, clean, simple and classic.
- "You mention you can’t kick start the scoot, why? By that I mean dose it kick thru just fine, but just won’t fire?"
The mechanic who installed the 72cc Naraku kit warned me that due to the high compression, the kick-start might not work. So, I was kicking, but the half moon (or how it is called) was slipping and did not manage to turn the engine.
The 80cc Airsal kit I have now is ok from this point of view. I can easily kick start the engine. Does this mean, maybe, that the previous kit was not installed properly? I have some suspicions regarding the mechanics here.
- "Do you have, or can you get a compression tester? The Airsal piston is supposed to be very high compression."
I do not know what this is. I am not a mechanic, just a scooter enthusiast reading blogs and forums :-)
- "Are you using premium fuel?"
No, should I? I am using 95 gasoline, not 98 as this is what the dealer told me when I bought the scooter. The gas tank is full, I will ride it tomorrow to empty it.
- "Have you tried putting the orginal CDI back in it now that you have BBKs?"
Yes, it starts and works ok. It just limits the revving. The restriction my scooter is withing the cdi and variator boss. Now, I have a Naraku racing CDI and works fine.
- "You mentioned you changed the jet, did you try to read the plug? Can you pull your plug, and take a closeup so we can see what the “white part” looks like? May give us a hint as to how your jetting is set."
The plug is fairly black, I know the mixture is a bit rich. I installed a sport air filter and it pulled better. I just went back to the stock air filter because I ride the scooter when it rains, sometimes.
- "In all this modding, I don’t think you told us what carb you have, stock?, 20 mm? 22 mm? Do you have the stock air box and stock exhaust on it?"
I have a 19mm carb (the stock was 12mm) with 33 pilot jet and 85 main jet. Stock airbox and stock exhaust.
- "I know nothing about the mods you did to the CVT, do you still have the stock stuff?"
I have a performance variator from Malosi with 6g rollers and white contra spring.
What I’m thinking here is let’s go back to stock and set a baseline. Then we can make changes one at a time and work up. By doing that, we can see how what is effecting your preformance. As it is now, you have made so many changes and introduced so many variables that it’s the shotgun approach to fixing stuff.
- "Please DO NOT buy another BBK. You have other problems that a bore job will not fix."
From your questions, I tend to understand a few things. I think I should put super unleaded gasoline. Perhaps go back to the sports air filter. This would solve the take-off.
And maybe heavier variator rollers to diminish the revving and increase top speed?
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Post by jbjhillbilly on Aug 28, 2018 11:49:24 GMT -5
I’m trying to remember, but I think there might be a restriction on the exhaust header.
As for the tach, I understand wanting a clean look, but without a tach, you are tuning blind. Tuning a scooter is a balancing act between the engine, fuel delivery, and CVT. Trying to get your engine to be in it’s powerband, you need to know the RPMs. You can take it off after you get your bike dialed in, but it really is an important diagnostic tool.
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Post by fugaziiv on Aug 28, 2018 11:58:36 GMT -5
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ratdog
Scoot Enthusiast
Posts: 342
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Post by ratdog on Aug 28, 2018 12:30:22 GMT -5
It is Really, Really, Really important to get a tach if just to tune the bike and take it off later.
the weights in the Variator needs to be balanced with the Spring and any other changes you may have made. this one of the areas we need a tach for. the majority of the acceleration of the bike is controlled by the Variator. The weights control what RPM that part of acceleration uses. If you could tell us "well from about 5mph to 30 mph(at WOT) im getting 6000 rpm, we could suggest you are too heavy and go to a lighter roller. If you were to tell us "well im at 8500 RPM from 5 to 30, we could tell you that your weights are too light.
at some point your variator is as large as its going to get, the the rear is as small as its going to get. with stock gearing, that seems to be in the low 30s mph. I call this full lock up, but I guess the more common term is "over rev" once you get this point, the variator and clutch no longer have any work to do. Is like you have a direct drive from the engine to the rear wheel. at this point, power and RPMs are everything. Again here the tach is so important. If your bike can pull 8500/9000 rpm you are most likely good. if you are going over 9000, then its time to go to your lower gear set (49/17)
Of course the 49/17 gear set makes it much harder to pull from stop. Its sorta like you have elimated "1st gear" So you may have to move the rpm up by lightening the weights and/or go to a heavier clutch spring (clutch spring not torque spring)
NO, changing air filters is not going to fix your problem. there is very little performance difference from the stock airbox to the pod filter, and it dose effect your jetting. I use a pod filter, not because it gives a big HP boost, but because it makes it much more simple to take the carb on and off. as Im always experimenting to get better performance, I take the carb off a LOT to switch jets and such.
Top speed will come after full lock up. The only job of the weights is to push the drive plates together inside the variator. Once we get to full lock up (overrev) the weights no longer have any effect. The only way the weights would effect top speed is if you were not getting the drive plates as close together as they are limited to go. again, if you had a tach...
to get the power right, we have to get the jetting right. the only way you have to do that is by looking at the plug. we can help a little if you take a ride with as much as possible wide open throttle (WOT). as much as you can, don't let the bike idle. then let us see the plug. you can't get max performance without getting the mixture set right.
I think the biggest block we have is that you have someone else doing the work for you. there are so many things we can experiment with but if you have to have someone else do the wrenching, its going to cost a fortune.
A compression tester is nothing more then a pressure gauge that has a flex neck on it so you can screw it into the spark plug hole. I would love to see what your getting for compression. if the piston was installed right and the engine is in good shape, that airsal piston should be producing something close to 200 psi. If the reading is a lot lower, you may have a sick engine. When you went to the piston, was it a "kit" with the piston and cylinder?
This is one of those things that if I had the bike in front of me for 15 min, we would have so many answers and know where to go from here.
Just wondering, what was the Multivar 2000 Variator from Malossi suposed to change? One of the advantages of being able to do your own work, I would be swapping that out for the stock part to see what, if anything, it was "improving"
I so much would like to go back to stock on the CVT and work on tuneing the engine, then try changes to the cvt to get better acceleration.
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Post by magoconnor on Aug 28, 2018 13:04:41 GMT -5
A 19mm carb is probably too small however. With the 50mm Airsal kit, we've been having quite a bit of success with a stock GY6 carb. Matt Hi Matt. Why do think the airsal works better with a 24mm carb? I only ask because I have just bought the airsal kit, I was thinking maybe going with a 20mm carb.
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ratdog
Scoot Enthusiast
Posts: 342
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Post by ratdog on Aug 28, 2018 13:18:59 GMT -5
IMHO, to get more top speed, you are going to need a bigger carb. top speed is where we need all the top end power we can get. I would very much recommend replacing the plastic intake tube with a metal one. the one we are using on all three scoots is made by Hoca, but I'm sure there are others out there.
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Post by fugaziiv on Aug 28, 2018 13:22:15 GMT -5
A 19mm carb is probably too small however. With the 50mm Airsal kit, we've been having quite a bit of success with a stock GY6 carb. Matt Hi Matt. Why do think the airsal works better with a 24mm carb? I only ask because I have just bought the airsal kit, I was thinking maybe going with a 20mm carb. Actually, we find that all of the 50mm kits we sell run well with the 24. It's an affordable option that pairs well with 50-52mm kits. The results of in-house R&D. We've installed and tested and on a street build... it just works. Matt
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Post by fugaziiv on Aug 28, 2018 13:24:41 GMT -5
IMHO, to get more top speed, you are going to need a bigger carb. top speed is where we need all the top end power we can get. I would very much recommend replacing the plastic intake tube with a metal one. the one we are using on all three scoots is made by Hoca, but I'm sure there are others out there. This is a good recommendation. The HOCA product has been replaced by SSP-G, so you won't find HOCA anymore. Aside from the branding change, they are the same product. We even still have HOCA in the URL. www.partsforscooters.com/169-336-Hoca-Intake-ManifoldMatt
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ratdog
Scoot Enthusiast
Posts: 342
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Post by ratdog on Aug 28, 2018 14:14:57 GMT -5
I was thinking it might be a good idea to insert a comment here
Of the 3 scoots I have been working on, two are run-a-round drive every day bikes. these have benefited from a bunch of bolt on parts and a bit of special hand work (head). these bike are well behaved and don't make a lot of noise. we get a comfortable 45-47mph from them. We can make them faster, but i think that's about what you should expect from these guys if you want something you can just turn the key and go and use every day with out having to work on them. The third bike is the earsplitingloudenboomer If you want to know whats up with this bike you should read my "new project" thread. This bike has a lot of very special work into it. Frankly, if we didn't have the resources we have, this would be an impossible bike to build, simply because all the custom machining we have done. Yesterday, Walt made a two way 1/2 mile run at 59 MPH (per GPS) We will get this bike into the 60s. But this not the kinda speed you should be thinking you are going to get by swapping out bolt on parts. I guess I'm saying, you have to manage your expectations. If you really want your bike to do these speeds and be driven day to day, get a 150! you can actually buy fully assembled 150 cc engine packages for maybe less then you have dumped into this little 50.
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wahlman
Scoot Enthusiast
Posts: 111
Location: Miami, Florida
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Post by wahlman on Aug 28, 2018 15:25:09 GMT -5
I would question the competency of your mechanic if he allowed you to proceed with so many upgrades at ONCE and getting poor end results. Some of the advice you are seeking...... the same professional mechanic should have rolled the changes back on his own, go back to full stock (baseline) and then make upgrades one at a time.
Im starting to wonder if that guy really knows what he is doing? There is nothing worse than paying thru the nose for expensive repairs and then your scoot runs even worse then before? Thats no good
I am running a very cheap China Bike (IceBear 50cc) and its all stock except for the NGK sparkplug. Mine is not "optimized" and I can hit 42 to 45 mph on flat land. So that Kymco should be running like a top with all the money you are throwing at it. I think you should take your bike back to the shop and if he refuses to roll back the changes for free than I would find a new mechanic.
I think that guy should roll back ALL upgrades back to stock and then do things one at a time. We are talking about a brand-new Taiwanese scooter. That thing should be getting 45 mph top speed just on stock configuration if its tuned correctly. (I think......I know a Honda or Yamaha scooter would be seeing 45 mph top speed and beyond unless we are talking about a rider over 185 lbs).
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ratdog
Scoot Enthusiast
Posts: 342
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Post by ratdog on Aug 28, 2018 15:50:27 GMT -5
Just wondering, how many RPMs are you turning at 45mph.
from my experience, expecting a stock 50cc 4 stroke to go 45mph is a bit much. but my experience is limited to 3 new stock bikes, but all three of them were "all in" in the high 30s stock, they just couldn't pull the 8500 RPMs these bike need to get over 40. (that's why I'm wondering what RPMs you are turning)
BTW, one of those bikes is a new icebear "falcon" which I would guess would have the same overall gearing as your bike. just thinking, what size tires do you have. mine has 10 inch, so if the model you have has 12 inch, that would effectivly give you a lower overall final drive (less rpms at say 40 mph)
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Post by pinkscoot on Aug 28, 2018 18:01:26 GMT -5
I always put a tach on my scoots to tune. I just run the wire on the outside and zip tie it to the mirror so I van see it when I ride. It looks like hell but once the scoot is tuned I move it to where I need it. I do the same with my temperature sensor.
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wahlman
Scoot Enthusiast
Posts: 111
Location: Miami, Florida
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Post by wahlman on Aug 28, 2018 18:47:59 GMT -5
Just wondering, how many RPMs are you turning at 45mph. from my experience, expecting a stock 50cc 4 stroke to go 45mph is a bit much. but my experience is limited to 3 new stock bikes, but all three of them were "all in" in the high 30s stock, they just couldn't pull the 8500 RPMs these bike need to get over 40. (that's why I'm wondering what RPMs you are turning) BTW, one of those bikes is a new icebear "falcon" which I would guess would have the same overall gearing as your bike. just thinking, what size tires do you have. mine has 10 inch, so if the model you have has 12 inch, that would effectivly give you a lower overall final drive (less rpms at say 40 mph) >>>>>>>>>>>>>>>>>> Im not really sure Rattdog, I dont have a tachometer on mine. Its a used 2015 IceBear 50cc scooter. It rode like crap when I first bought it with 900 miles on it (struggled to reach 30 to 35). But i took it to local mechanic who performed valve adjustment, oil change, adjusted the brakes (Which did not work very well when I bought the scoot) and advised me sparkplug had already been upgraded to NGK. Maybe its because I only weigh 130 lbs and I removed the trunk box. But it definitely gets 42 to 45 mph top speed on flat ground. It gets up to 30 pretty dog-goned fast (But not fast enough for some cagers behind me). Everything else is still stock even the carb. And the idle is set pretty low when I listen to it at red lights. But I would not call the turning "optimized". When letting off the throttle I hear WANG,whoa,whoa, whoa, WANG, gow,gow GOW, gow Its standard 10 tires
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