Hi All,

Lately my gas mileage has gone to a point that I needed to look at getting it back where it should be. So I removed the J-Costa Variator and reinstalled the stock Honda Variator and took it for a ride and just got back. What a difference the J-Costa in performance. It is going to take a bit of getting used to not having all that get-up and go.

One thing I noticed during my ride was the RPM went down from 6K to 5.5K at speedo speed of 70 Miles an Hour. This alone should give me a little better MPG.

When I pulled the belt cover there was very little belt dust, looked surprisingly clean. Belt wear was hardly noticeable at 28.15 mm.

I'm going to run with it stock for a while and see how I like it and if I get the erg for speed I'll re install the J-Costa.

Have you thought about Dr. Pulley 26gr sliders instead of the stock Honda rollers?

I was out for a ride today and noticed the RPMs while at 70 mph would range between 5100 to 5400 rpm. I never saw it over 5500, let alone 6000. Do you think your pins have worn too much?

I have an '03 with a J Costa. About 11,600 total miles, and about 4,800 miles on the JC.

After reading DennisB's post, I also checked my RPM vs speed this morning on my ride. At 70MPH indicated on the speedo, my tach is showing a consistent 5100rpm. 5500rpm yeilds about 75MPH indicated. Everything except the seat is stock, about 4800 total miles at this point.

80mph @ 6100rpm w/costa

Starting to think it might be the clutch that's giving me the trobble. When I first bought the scooter, it was brand new and one thing I noted was the clutch always started to engage and role the bike at around 2200. Now it dosn't engage until around 2800. Just don't think the clutch is giving me 100% any longer.

What do you think, clutch experts?

I have 36k on my Swing Dennis and have stock cvt. Have only replaced the drive belt for the second time, I think? I just know when i bought it new, rpm's at 80 mph were exactly at 6k. At 16k I was charged for a belt replacement but as time went on, i started to notice an increase in rpm to maintain same speed. Right at 31.5k and ready to have 32k checkup i ordered the stock honda belt thru the dealer and had it ready for the 32k checkup. The rpm's had got up to 6300 to maintain 80mph. after honda did the checkup, i was told my belt was under min. tolerance in width and they were right, but never noticed any difference in the first 16k, kinda makes me wonder if i paid for a belt installation that i never got. I am now back to 6k rpms at 80 mph.

Jim,

Nice thing is, my mpg has generally maintained 50 mpg riding solo or with wife thruout.

Dennis:
If the clutch is slipping, it would definitely affect your gas mileage. Have you looked at the clutch springs? The engine rpms your referenced seem pretty high for those speeds. A slipping clutch could be the culprit.

Looking at the IPB (Illustrated Parts Breakdown), It looks like the springs hold the clutch pads in while resting and then they are forced out by centrifical force.

No matter what variator I use, stock Honda or J-Costa, the RPM's are to high.

Dennis:
If the engine rpms are too high regardless of which variator is installed, then it would seem that the variator is not the issue.

I sure agree with you and Thank you for you help.

I just wish more good people, like you, would give their RPM numbers at 70 MPH and what variator they have installed, sure would help.

Dennis:
I have noticed that my engine rpms at a given speed seem to vary a little. I think this is partially due to the fact that where I live, there are very few (if none) flat places to measure accurately. I am virtually always either going up a little hill or down one. However, I do watch my engine rpms and typically, when I am traveling at 70 mph, my rpms are around 5,200 to 5,500. When I travel around 80 mph, my rpms are around 6,000.

One thing I have noticed is that when my bike is cold, (i.e. in the morning) it seems like my bike keeps running at higher rpms when it should be transiting to lower rpms. It almost feels like the variable pullies are stuck in place. Upon hard acceleration this transition usually occurs from 55 mph to 60 mph. But when it is cold, sometimes it seems like it takes longer for the "gears/pullies" to transition to lower engine rpms. Has anyone else noticed this?

Just ordered a new clutch. Should take a few days to arrive. It will be great to get scooter back in the green.

I'm thinking...This just might be a good chance for a pictorial on changing out the clutch.

One characteristic of EFI engines is they idle quite a bit faster until the engine reaches operating temperature. I've noticed this on my Silverwing as well as my Goldwing, once the SW warms up it drops from an idle of 1500 or so back down to 1200. My GW idles at 1500rpm on a cold start around 1500-1600rpm and drops down to its normal idle of 600rpm once it warms up. I don't imagine this would be a factor when the bike is being ridden with a cold engine but it does make it take longer for the bike to slow down with the throttle closed.

When all my test are done the scooter engine is well warmed. When I place it on the center stand and rev the engine up to 70 MPH on the speedo, the RPM's goes to 5200. That's with no rider or the pounds added by the scooter itself. Just moving the tire at 70 MPH. I think changing the clutch is going to make a big diffrence in the way this scooter works. You never know...I just might see 56 MPG again from the old girl!

I just wish more good people, like you, would give their RPM numbers at 70 MPH and what variator they have installed, sure would help.


Dennis

sorry for late reply
5700 rpm @ indicated 70 mph stock clutch and variator with 28 gr
Dr pulley sliders

The scooter on his mainstand or on the road...

I think the RPM's in function of speed , are the same.

The sliders takes a position ifo rpm's.
They don't see the load.

So the diameter of the drive (and driven) pulley is determinated.

Just theoretical thinking....

Hi All,

Well I found out what the problem was after taking it apart and inspecting the clutch and clutch drive hub.....They are with in Honda specification! I think I did find the culprit tho...It is the J-Costa drive face, It has worn down to the point that I could see and feel the where the belt has worn down the surface. At higher speeds the belt moves to the outer edge of the driver system and stays in this location. The J-Costa drive face has worn down to the point of where the belt slips at a higher RPM causing the motor to work at a higher RPM to manitain the speed. The drive Honda face looks good and has very little ware. Here's a drawing of ware area I found on the J-COSTA drive plate surface.

By the way the clutch is in GREAT shape and the looks brand new. Any one need the new Honda clutch that I bought. Will trade for a new set of 28 gr. sliders.

9K and this J-Costa is ready for the Trash Can.

Hi Bill,

I bought the scooter new and it had only 2K on it when I installed the J-Costa. Yes, the belt is the same one that came with the scooter new. After spending $280.00 on the thing, I thought it would last a little longer. The pins still have the wear indents showing. The wear on the drive face is around a 1/16 of a inch and thats alot.

bigbird, It looks like J-Costa needs to look at the material they cast the drive plate from. If your MPG starts to go south, take a look to see if your J-C drive plate is the problem.

Now I'm going to have to tear my j costa to inspect

Wow Dennis, that is alarming news. I put my J Costa on at 4,000 miles and will turn 20,000 in a week or two, so I have nearly 16,000 miles on mine. I will have to take a careful look at it next time I have it serviced. Thanks for the heads up. But if you break it down to a cost per mile, it works out to only 0.0175 (a penny and 3/4) per mile. Yes it is a cost, but it also adds a lot of fun factor.
DCC

Dennis, is there a lip at the outer diameter of the pully where the aluminum is worn down????

If not maybe there was a double angle/ slope cut into the pulley at manufacture.

How thick is the outer edge of the pulley. If it did wear a 1/16 in. , there wouldnt be too much meat left out there as I recall.

Just wondering.

Nice diagram .....

MaxB