Honda PS125i low top speed  By  xylon (Read 12,585 times)

Very doubtful unless they were really worn enough to not properly push the belt out enough? Do you know the specs on the rollers? if so then the only way to know how bad they are is to open her up again and measure the OD of them.

Have you considered a good carb cleaning, at 15k in miles it could have tarnish buildup and such which can hamper the engine. Also need to remember 15k is a few miles and if the PM was good on the previous owner then the engine should still be tight with good compression but if the PM was suspect this can add to loss of MPH.

Little things also have an affect, rider weight, carb adjustment, even tire pressure has an affect. Little things can add up to a loss of overall MPH and be frustrating also. Have you checked the sparkplug to see if it's running rich or lean, this can have an affect on it. ?

JR

PM- Preventive Maintnance

Then this has proboably taken it's toll and I'll look to see if I have a manual on this scooter to see if there are any other recommendations for this problem. You might consider adding a recommended amount of a fuel cleaning solution to the gas tank, here people use a product that some will tell you is the best and it's called Seafoam. Good stuff.

JR

This scooter doesn't have the same engine or characteristics of a Chinese GY-6 and the top end should exceed the GY-6 by about 8MPH if all is correct.

This engine has PGM-FI electronic fuel injection along with digital transistorised electronic advanced igniton which alone makes it out perform a typical carb GY-6 Chinese engine.

Add small size, light weight and 13" tires if all is well it'll do in the high 60's and actually be in the high 60's unlike a lot of Chinese 150's that claim to go this fast.

This is a fine scooter.




JR

62mph on a 125cc scooter is pretty good actually. That would be better than I would expect. Many years ago I remember a friend of mine had a Honda 305cc motorcycle and it would only go 70 to 75mph tops. Now maybe if you went downhill with a tailwind, you could get more speed out of it.

My Roketa 150 scooter would only do maybe 60mph after a long run at it. I had to get a little bit of downhill help in order to get it over 50mph though. But then it was about a three mile run WOT to get up to 60mph.

There's a limit on what anything can do and debating what we think or might not think it can do is not the issue here. The OP has asked for help on trying to see why the scooter is actually slower than the 62 MPH you mentioned and suggestions as to how to help him increase his top end is what he has asked for.

Now given the facts that he gave us that the scooter has not been shown any TLC and that it has quite a few miles on it at 15k tells us that he needs to continue doing some of the things he is doing as far as getting the scooter back in good shape.

The poor condition he found it in hasn't helped his cause and a good fuel cleaning additive may also help his situation. After he does all of the things he can and it shows no improvement then I would suggest that he check the engine for compression and this will tell us if the 15k in miles plus the poor PM has decreased the engines top level of performance and he will have to decide to live with it and ride on or possibly re-work the top end for a better engine top end.

In comparing any two scooters that are not the same as far as weight, style, fuel delivery one cannot accurately say that it should or should not perform like any other scooter. The difference between 125cc and 150cc is so slight that at the most 1 MPH would be the difference. This scooter is small and compact and may out run some 150cc larger scooters?




It's like with any engine one can take and change the variables on a apples for apples scooter and they will not top out the same. One cannot own a scooter in Florida and tell one that it will perform exactly the same in Washington state.

In this case his scooter is apples and the 150 you mentioned is oranges.

Another suggestion that may help a little is replacing the possibly worn rollers with sliders of the right weight.

JR

The scoots always say they do more than they actually can.
Try BP Premium fuel, and put 10W30 or 5W30 in the engine.

Quite often wind direction, and slight hills can trick you into believing you're actually going faster (or slower) than normal.