My tadpole trike won't exceed 45 mph or 4200 rpm By coji (Read 1,469 times)

[coji]

   I have a DF300TKB.  If you look at the specs on the bike, it says 55+mph, and I regularly cruise a 60-65 on the way to work.   .sunnymotor.com/product_info.php?cPath=28&products_id=134#descr" rel="nofollow" target="_blank">.sunnymotor.com/product_info.php?cPath=28&products_id=134#descr
  I recently changed the back tire from a 130/60-13 to a 130/70-13 because I was told it would fit.  (Also I had a rear tire blowout and this was the only tire they had, so maybe that is why they said it would fit.)  Anyway, it barely goes on, and when the bike reached 50 mph, the tire rubs the rear of the engine case and the bike kicks in the governor after a few minutes of this, stalls and then starts running normally.  Ok, I just changed where I rode and adjusted to the slower speed.  Then, I checked and changed the factory spark plug which looked like it had been through 50000 miles and not 2200.  I set the gap, installed the spark plug, and on the jack everything ran normal.  Could max rpms if I wanted and ran good.  I set it down, went for a test run, and the bike would not exceed 45 mph or 4200 rpm.  No what, on the ground the bike won't do it.  On the jack, it runs just fine.  The only other thing I have done is refill the tank, but I have never had issues with this Shell station before.  (I use it on the bike and all 3 cars.)  Also the bike does not overheat, just won't exceed 4200 rpm.
   So I am wondering if the cheap shocks on the back of the bike, which are not adjustable, have settled some and the rubbing on the tire is capable of reducing the rpms enough that it will not exceed 45mph?  If so, does anyone know of a shock spring stiffener I can place on the coil springs to make the bike not lay back so much due to the shocks?

Thanks in advance for the help.

[alleyoop]

I suggest you put on the correct tire size: You stand a chance of a blowout from the heat it creates rubbing. Don't forget as any tire rotates it actually expands and the faster you go the worst it gets.
Alleyoop

.motorcycle-superstore.com/5/32/404/12010/ITEM/Avon-AM63-Viper-Stryke-Rear-Scooter-Tire.aspx?SiteID=Google_PLA404&WT.mc_ID=10012&esvt=0-GOUSC&esvadt=9-0-3886819-1&esvaid=30548&kw={keyword}&gclid=CNvSorGunroCFdFcMgodgQUAcw" rel="nofollow" target="_blank">.motorcycle-superstore.com/5/32/404/12010/ITEM/Avon-AM63-Viper-Stryke-Rear-Scooter-Tire.aspx?SiteID=Google_PLA404&WT.mc_ID=10012&esvt=0-GOUSC&esvadt=9-0-3886819-1&esvaid=30548&kw={keyword}&gclid=CNvSorGunroCFdFcMgodgQUAcw

[coji]

Yeah, I am kind of angry that they told me the wrong tire would fit. Haven't had time to go chew them out yet because they are exactly opposite of the direction I head for work. Had no choice other than that to get home though.

And that was the exact tire I was looking at ordering.

[fflintstone]

Yup--if that tire is rubbing it is doing damage to itself--and slowing you down--trouble ,trouble--get the right tire on there quick--IMO--good luck,fflintstone

[coji]

OK. Officially checked the tires today by tested another tire the right size and testing my tire on another bike. My tire on another bike worked fine. No decrease in speed either getting there or maximum speed. The other tire, 103/60-13 which is what it should have, made no difference. My bike still will not exceed the 4200 rpm or 45 mph mark. Actually with the correct tire, my bike would not break 35 mph. Nothing has been touched on the carb, so anyone got any ideas?

[alleyoop]

Well that is hard to believe, reason I say that is the 1st number is the WIDTH of the tire the 2nd number is the HEIGHT from the rim to the top of the tire so a 60 in either tire would not change the diameter of the tire. The tire which was 70 was rubbing because it changed the diameter of the tire. Now the width can also make the tire rub but on the sides.

Have you changed anything on in the CVT? Have you adjusted the Carb?
Only a few things will limit the RPMS on a motor, Fuel Mixture, Low Compression, To heavy of weights in the Variator or a bad CDI.

1. CHECK your compression? And let us know what it is.
2. Take the CVT cover off and rev it up and see how the belt climbs up the Variator.
3. Adjust your carb After it warms up at least 5 minutes idling.
Here is how to adjust the Carbs Fuel Mixture:
thescooterprofessor.proboards.com/thread/3001/4-stroke-carb-tuning

4. The CDI no way to test just would need to replace it.
Alleyoop

[new2scootn]

Hey coji, I've got the same trike and had a previous bout with loss of power(and eventually stalling out) on prolonged full or near full throttle. Is it stalling? Mine turned out to be a defective fuel tank pickup tube(crappy weld inside the tank). Quick way to find out would be to pull fuel line off of tank and cap off nipple then put the fuel line down inside tank(with a spare fuel filter on the end if you've got one) duct tape it in place to cap off tank and hold line, then ride. If that fixes it 1) I'll be shocked!, and 2) pm me and I'll tell you how I fixed it without replacing the tank(but I have a new spare!).

[coji]

Haven't got to check most of the stuff Alley suggested, but the carb is fine and adjusted correctly. Gas is not a problem because the bike feeds gas correctly and nothing is stopping the flow. The shop I got the scooter from is going to call the importer tomorrow, but he thinks it may be a slipping clutch/transmission. He will work on it for free for me, but I have to get it 25 miles from here to his shop. It may not happen for a week or two the way things are going, but I will update what I find out from the shop.

[alleyoop]

Well I have to tell you a SLIPPING clutch will NOT limit your rpms As a matter of FACT it will increase your RPMS. So I have to say they are full of it if they say it is a Slipping Clutch. Now if they said maybe the Clutch Pulley was not opening up to allow the belt to drop down that would cause a load on the motor and low rpms and low top end speed.

These people do not know squat and I keep telling the folks you are better off finding a Lawn and Tractor shop than taking it to a scooter shop. But be it as it may, as long as they say FREE then go for it and hope for the best.

Forgot to mention if there is a lot of restriction of the Exhaust that will also cause those conditions.
Good Luck and May the Force Be With You.
Alleyoop

[ellpee]

Man, I'm the ultimate newbie and mechanical doofus, but I agree with Alley. Slipping ANYTHING in the drive train would result in HIGHER RPM, like having the pedal to the metal in the ol' '57 Chevy but holding the clutch halfway in or having the emergency brake set. I'd be looking at the engine end, everything BEFORE the CVT.

[coji]

Will do and check this out before taking it to the shop. Can I run the bike without the exhaust pipe on just to test and see if there is a restriction in it? Already feel like I messed it up enough without doing it more. (Hear this a lot from the wife atm)