RPM question

[mrmike]

     I currently own a '21 X-Town 300I ABS. I'm 79 years old and probably 80% of my riding is about 40MPH. I ride mostly in urban areas. On both my previous scooters, I switched to a lighter slider to increase low end pick up to deal with city traffic. Last fall I ordered a set of Dr. Pulley sliders for my X-Town. They ended up sending me 2318-16g sliders. I wanted 17g but got sent these instead. I believe the stock set-up is 18g rollers. When I cruise now at 40MPH, the tach shows 5000RPM. The question is how much will my cruising RPM's increase if I install these sliders? What would be my estimated top end?

[Iahawk]

the new ones are ~11 or 12% lighter...it will be interesting to see just what kind of change that makes to your rpms. I don't know if anyone can tell you exactly what will happen to your rpms at a given speed (?) I would suggest trying them and then letting us know if and how your rpms changed.  I went from 24gr rollers to 21 gr sliders on my Helix...didn't notice an increase in rpms and I went from 14gr rollers to 13gr sliders on my People S200. Same thing, didn't notice an rpm change. Both scoots felt a bit quicker off the line (real or imagined, who knows?)

[NorWeWa]

Different engine and variator in the Downtown 300i for me. I put a set of Dr Pulley sliders in about 200 miles ago. Stock rollers are 15.5 grams and the sliders I installed are 15 gram. Closest I could get to the stock 15.5 gram.  Looking at the part # for your X-Town 300i. Kymco 22121-LFG2-305 the rollers are 23X18 - 17.5 gram.  I'm seeing some increase in rpm around town and under 50 mph, and it's smoother. Out on the highway which for me is 55 and 60 mph posted speed the rpm will drop down some compared to the stock rollers.  So far the mpg seems to not have changed in spite of using more rpm around town. 
Your sliders are more of a decrease than what I installed, but a different engine. Interested to see the results with your sliders. 

Art 

[Neil955i]

That’s interesting Mike, from memory, my 10K miles 2019 X-Town delivered an RPM which matched the speedo pretty well i.e. 30 mph = 3,000, 40 = 4,000 and so on up to 70 being about 7,000 RPM.

[mrmike]

That’s interesting Mike, from memory, my 10K miles 2019 X-Town delivered an RPM which matched the speedo pretty well i.e. 30 mph = 3,000, 40 = 4,000 and so on up to 70 being about 7,000 RPM.

       Neil955i

       I thought that tach reading was a little high for that speed (40mph) also. I'll double check at different speeds, install the new sliders, and compare them. I'll wait until my next oil and diff change and do it then. I'll report back when I get the results. Thanks all for your replies.

[Stig / Major Tom]

       Neil955i

       I thought that tach reading was a little high for that speed (40mph) also. I'll double check at different speeds, install the new sliders, and compare them. I'll wait until my next oil and diff change and do it then. I'll report back when I get the results. Thanks all for your replies.

I put a set of Dr P sliders in my Burgman....and watched the revs drop 800+ rpm when cruising at 80mph. Other than that, I noticed nothing in the scooter's performance. So the engine was a bit more relaxed at the top end, which I liked.
Stig

[NorWeWa]

There is a lot said about sliders verses rollers that doesn't quite compute.  Like quicker response from start, but the sliders seem slower to respond, takes more rpm and this seem so for wanting to accelerate.  On my DT 300 once it's up to 60 mph where I ride the tachometer settles around 5500 rpm. 

Art 

[Stig / Major Tom]

There is a lot said about sliders verses rollers that doesn't quite compute.  Like quicker response from start, but the sliders seem slower to respond, takes more rpm and this seem so for wanting to accelerate.  On my DT 300 once it's up to 60 mph where I ride the tachometer settles around 5500 rpm. 

Art

I ride all my scooters in a fairly relaxed manner  - esp. with my throttle hand! which probably makes me a lousy test subject in  the slider debate 🙂.....but looking down at the speedo at 80, I clearly saw a reduction in rpms.
I pulled the sliders from my Like because of the increased rpms at 35mph. I didn't like that - even though the increased engine speed mimicked an increase in HP.
So, I went heavier...and the result was more to my taste!
Stig

[monkeybongos]

Local dealer is not a fan of sliders.  Said they were more suited to racing.

I'm perfectly content w both my scooters acceleration and top speed, see no need to mess w the rollers.
Figure the engineers experimented plenty and put is what worked best for the scoot.
But plenty of people sweat by sliders...

[CROSSBOLT]

There is a lot said about sliders verses rollers that doesn't quite compute.  Like quicker response from start, but the sliders seem slower to respond, takes more rpm and this seem so for wanting to accelerate.  On my DT 300 once it's up to 60 mph where I ride the tachometer settles around 5500 rpm. 

Art

Me, too. 1000 rpm/10 mph ~40 to 55 mph, then less than 1000...70 mph about 6200 - 6500 rpm if memory serves....crossover at 55 mph.
Yes, stock, original rollers.

[NorWeWa]

I'm going to post here, even though it relates to my Downtown 300i.
First the Downtown 300 to me does feel better around town. Smoother and more responsive with the sliders, ( 15 gm wt ).  The rpms are up quite a bite around town and any slower speed.  Varies between 4000 to 5000 for speeds 30 to 40 mph. Grab some throttle and it will show 6000 rpm.
Once out on the highway it acts like it has an overdrive.  When you get to cruising at 60 mph the rpm settles back to 5500 and changes little with pulling a grade, but will drop even more going downgrade 60 mph at just over 5000 rpm.  Nothing linear about the rpm and mph. 
When I look at the HP and torque for the 300i it's max at 8000 for HP and 6500 for torque.  The sliders seem to work into a better hp/torque range. Just an guess there. 
After running a tank of gas entirely with the new sliders the mpg came out at 72 mpg and that's the same as I have been getting.

Art 

[mrmike]

Okay! I just ordered a variator removal tool. I'll be trying the Dr. Pulley sliders in a couple of weeks. I'm debating putting a heavier clutch spring in at the same time. Is this advisable? Would it help? Where could I buy one?

[Stig / Major Tom]

Okay! I just ordered a variator removal tool. I'll be trying the Dr. Pulley sliders in a couple of weeks. I'm debating putting a heavier clutch spring in at the same time. Is this advisable? Would it help? Where could I buy one?

It is generally recommended to make one change at a time....gives one a better idea of which change caused which result.

Stig

[NorWeWa]

https://www.monsterscooterparts.com/selecting-scooter-clutch-springs   As posted do one change at a time.  Here is a brief article on scooter clutch springs. 

Art 

[mrmike]

  Thank you for all the replies on this subject. I'm waiting for the variator puller tool I ordered on Amazon to arrive. When I get it, I will be installing the Dr. Pulley 16g sliders I have. I'll post the results when done.