Roller Weights on Like 50 2T (Malossi 70cc cylinder and Malossi Variator)

[blackrod]

Hello,

After a lot of research on youtube, modern vespa, aprilia forum, and the kymco forum:) and getting a better understanding of where my Kymco Like 50 2T needs improvement, I decided I just want to change out the roller weights.

As mentioned in a previous post, I upgraded to the Malossi 70cc cylinder and Malossi variator.  I am using the Like 50 as a commuter and am more than satisfied with max speed (only gotten up to around 40 mph but this it will go faster).  My only issue is the acceleration at low RPM and acceleration uphill.

Based on my findings and recommendation from my mechanic at Sportique Scooters in Denver, it was recommended that I use lighter roller weights.  I do not know the grams of the roller weights I have in my variator now but I assume they are most likely Malossi as I have a Malossi variator.  I know lighter roller weights might effect my max speed but I am in need of better acceleration in lower RPM when commuting to/from work in Denver.

Which roller weights brand do you recommend?  Dr. Pulley, Malossi, Polini?  I have heard many good things about Dr. Pulley.

Any feedback would be greatly appreciated.

Thanks,
Ross
 

[wheelsoffreedom76]

   The stock roller weight was 8.5 grams. The malossi variators I have looked at online are listed with 5 to 9 gram weights.

   When you pull the cvt cover off check if the belt is loose or tight. Look at where the belt is sitting in the front and rear pulleys. To acheive the lowest possible gearing on takeoff the belt should be riding out to the edge of the driven pulley (rear), to the bottom of the front pulley, and be snug in this position. The state you find it in is where it was riding when your idling scooter was turned off last. If you find the belt loose, and/or riding lower in the rear pulley, you may have a restricted driven pulley and/or stretched/wrong belt. These are important to check as they effect take off power, and top speed.

   As for the "roller" weights, if your 70cc is performing correctly then 7-9 grams would be in the ballpark, I hear great things about the DR.Pulley sliders but I have not run them before, maybe somebody else can chime in about the roller to slider weight change, as I beleive you go a few grams one way or the other from the roller weight.  Did you make any other changes from stock other than the bbk and variator? Do you have a pipe, different carb, bigger jets?



   

[blackrod]

Hi Wheelsoffreedom76

The only changes I made were the bbk and variator.  My mechanic recommends going up to the Arrehe 17.5 mm carb as it will provide better performance with the 70cc engine.

As a next step to maximize the 70cc, do you recommend upgrading the carb, pipe, or jets?  Which carb, pipe, or jets do you recommend?

Thanks
Ross

[wheelsoffreedom76]

     It looks like you will have a couple issues to address, both on the engine preservation and performance side.

 Your engine utilizes oil injection to add oil to the air/fuel charge. That system varies oil input with engine rpm, and throttle position. From the factory these are set at the higher end of the acceptable fuel to oil ratio, (higher ratio being less oil)  and that is on the stock 50cc setup. The injection pump cable can be adjusted for a little more oil, though it may fall short once you get your air/fuel ratio lined out.

  Your scooter probably has a Keihin PB 16mm carb, with a #35 pilot jet, and a #70-#80 main jet from the factory. If the kit to derestrict was installed it may have a #82 main jet, which would be ok on a stock setup, but will not be enough for the 70cc especially if you do any air box, or exhaust changes. There is a danger here of running too lean on the fuel/air ratio and causing the engine to run hot and even seize the piston in the cylinder. The stock carb can be rejetted, and needle shimmed/adjusted to acheive proper fuel/air ratio. The areche carb has good reviews, and may offer a bit more overall performance especially if you install a performance pipe, and it too will need to be jetted correctly. Here is a couple links to articles on jetting, and plug chopping that you should read.
http://scootrs.com/tech.cfm?tip=tunecarb
http://www.kawtriple.com/mraxl/carb/plugchop.htm

Jets for the stock Keihin PB carb
http://www.rockymountainatvmc.com/p/43/53/213/930/-/25594/Keihin-99101-116-Series-Main-Jet
http://www.rockymountainatvmc.com/p/43/53/213/930/-/25591/Keihin-N424-74C-Series-Pilot-Jet

   Another issue to consider is if you are going to run the oil injection, or switch over to premix. As your investment grows into your engine some people (myself included) have trouble trusting that the oil pump is achieving an acceptable oil/fuel ratio. It starts to make premixing your fuel a prudent idea. Acceptable fuel to oil ratios are usually between 32:1 and 40:1 with synthetic, or semi synthetic premix oil. Many people run lower or higher, but the general consensus is 32-40:1. If you do go this route it will effect your carb jetting as fuel AND oil will be flowing through your jets and the oil will displace the fuel to the ratio you are premixing. Read this link http://articles.superhunky.com/4/194

  There are many good exhaust pipes out there and it is important to consider how you ride your scooter and at what rpm peak power is important to you, as pipes are generally tuned to make power in a specific range. I personally have only run stock exhaust on my scooters so I know there are many other people here with more insight to the leo vince and technigas etc. pipes.