RPM's versus Speed

Just recently bought a Silverwing. At 65 mph, the tachometer shows around 5000 rpms. Is this the normal range, or is the transmission possibly not changing? Mr. Bill

The transmission is a CVT belt rather than having gears.

If you want to improve the rpm / speed then install a JCosta Variator. It also reduces vibrations to very low levels.

Cheers,

Bill,

I am at 5,000 rpms at 70 mph. I installed the 28 gr Dr Pulley sliders and it helped decrease my rpm's at 70 by about 300-400. You may want to think about the sliders, but your rpm's are about right.

100kph (62.5mph) & it turns at 4750rpm as far as I can see while moving head to the left to get a straight-on view of the tach.

That sounds about right.

J Costa is a great performance part, but it wears and begins to perform poorly by 10'000 miles or so. After replacing the pins/rollers it still did not work properly, so I finally gave up on it last week. Rpm's were so high that my mpg was down to 45 or so.

I installed dr pulley sliders (24 gram) and found acceleration okay/disappointing but mpg's up tremendously. Took a trip to Mt. Mitchell Sunday, and got 55.1 mpg for 254 miles.

I also have 21 gram Dr Pulleys, and may try them sometime. I loved the acceleration of the J Costa!

If you'd like to join us on some day trips (mixed group of maxi scoots) let me know. Most of us are from the Charlotte area.

x

bigbird wrote:

buddy19520 wrote:

After replacing the pins/rollers it still did not work properly,

The J Costa inner drive face wears more rapidly than the Honda inner drive face. Was your J Costa inner drive face grooved or worn?

The two halves of the pulleys had touched and worn each other down a bit. Unlike the Honda inner pulley, the JC pulley is not splined, so it can spin on the crankshaft at a different rate than the outer pulley (at least momentarily upon initial throttle).

The real problem I was having is that the graphite and brass bushing would get sticky. The variator would hang up and not slide in/out like it should, and I would do ridiculous RPMs (when bad, it would hit 8000 RPM). Two drops of Mobil 1 during assembly helped a lot, but it only helped for 2000-3000 miles. At this point (15,000 miles on the variator and two sets of pins), it was just revving too high all the time. Everything was 5500 RPM or higher (at cruise speeds).

Expecting the demise of the JC variator, I ordered two sets of Dr. P sliders early this year. The 24 gram weights provided me with MPG that I've never seen before, but the acceleration is lacking (at least after being used to the JC). When I get the urge to work on it, I will replace the 24g sliders with my 21g sliders and report back.

If the JC had the durability of the Honda part, I'd still be using it.

x

Buddy:
I used to have the J Costa and when it wore out I switched to the 22g Sliders. With them the accelleration seems pretty close to what the J Costa did, so you should give the 21 g sliders a try. I think you will be pleased.

bigbird wrote:

buddy19520 wrote:

The two halves of the pulleys had touched and worn each other down a bit.

How is that even possible with the belt between them?

I suppose that that belt had worn enough that it would ride too high on the pulley, allowing them to get closer together than the design called for. Remember, the JC inner pulley is not splined, so it can slip a little when accelerating. If it is touching the outer half of the variator, they would grind each other down.

I just put the 24g sliders in Saturday and noted the worn area again, although it was not as shiny as it once was.

FYI,
JC went in at 6800 miles
belt replaced at 15917
JC pins replaced at 15917 also
Dr. P sliders installed at 22180

Andyman had the same thing happen to his variator when he used to use the J Costa.

The Scootist wrote:

Buddy:
I used to have the J Costa and when it wore out I switched to the 22g Sliders. With them the accelleration seems pretty close to what the J Costa did, so you should give the 21 g sliders a try. I think you will be pleased.

Your posts about the lightweight sliders are one reason I also bought a set of 21g sliders. I figured that it would be enough gap that mix-n-match might work better than 22g.

I was surprised at how low the RPMs were upon acceleration. My JC, when working properly/new, would hit 6800 rpm at WOT from a standing start. The 24g sliders hit 5000-5100 RPM. It just doesn't have the punch the JC had. I was a bit afraid that the 21g sliders were too light when I ordered them, but after using the 24g sliders, I am no longer concerned.

Buddy:
I had tried the 26g Sliders first and I liked them, but they just didn't have the extra punch I was looking for. The 22g are pretty decent. At WOT I hit 5,400 rpm right away then quickly rise to 6,100 rpm

I'm guessing that I will probably see 5500 RPM when I switch to the 21g sliders. Still not real high, but should be better.

I also noticed a non-stop vibration from the belt while using the sliders. The JC used to smooth it out very nicely. Not a real bad vibration, but a low level vibe coming through the floorboards and the seat.