Post by symcity50cc on Apr 27, 2013 15:02:57 GMT -5
Hello all,
I'm new here and hope you can help me with an issue I've been having for a full season+. If you can help me figure this out I will seriously buy you pizza and beer.
Specs:
2006 SYM RS50 (BS05W Series) 2 stroke 50cc 4Kmiles 2nd owner (Bought it almost new with 300 miles on it)
AKA SYM Shark in Euro market
Normal operation:
-Scooter would get up to 40MPH fairly quickly with one or two people, and then crawl it's way up to maybe 45MPH, at that point the engine is winding out and likely redlining, I don't drive like that for long. I've always considered it a pretty quick unmoded 50cc, it was faster than a rented new Vespa50cc. I tried to take care of it and avoided beating it. New spark plug and clean air filter every year kept it running great.
Problem (Compared to normal operation):
-Loss of acceleration and limited top end. North of 10-15MPH is slooooow and top end is between 30-35MPH, sometimes 25MPH in a headwind. Uphill is painful, I have to pull over to let cars pass me.
This came on rather suddenly last year and it has been ***stuck with this consistent behavior for all of last season*** and now this season. I've worked on this myself, and taken it to two local mechanics (who *seem* competent and generally willing to help) and I'm at my wits end. Everything I, and the mechanics tried has made no difference or change in it's behavior, it all goes back together with the same result.
Things to note:
-Engine starts and idles just as new, no issue there.
-No backfire, missing, stalling, electrical weirdness, or any other odd behavior. It's smoooothly slow, and almost feels like the bike is carrying 1000lbs of weight
-Acceleration seems about the same from 0 -> 10MPH, above that doesn't get up to speed like it used to.
-1/2 to WOT doesn't seem to provide very much power, it just changes the pitch of the engine lower.
-MPG significantly lower
-Brakes are not stuck on, tires spin freely
-Never run out of engine oil (separate reservoir), ran out of gas once a few years ago
-Transmission oil has never been changed
-Environment is Northeastern US coast, 40-90F, mostly city, some longer 50 minute trips
-It's in otherwise perfect working order and I've been very happy with it, but it really sucks to drive it like this, and it doesn't yet belong in a landfill.
1st mechanic:
-Tested compression - 140PSI, leak down either not performed or numbers not given.
-Cleaned/inspected carb - no issue found
-Inspected tranny belt and weights - no issue found
2nd Mechanic:
-Observed fuel dripping inside carb air intake while running near the throttle needle, suspected faulty seal in carb- replaced carb- no change
Things I've done with NO change:
-Swapped ignition coil with aftermarket
-Swapped CDI with used Sym Shark from eBay
-Cleaned carb twice, wasn't even dirty the first time
-Multiple fresh tanks of fuel - always 91+ AKI
-Cleaned air filter, new spark, new fuel filter
-Checked reed, metal looked new and sat flat and unbent, screws were tight, cleaned and re-installed
-Before issue even occurred: Removed exhaust and cleaned out small build up of oil in exhaust inlet, new gasket - this improved the scooter a tiny bit
I'm mechanically inclined and I work on my car to save cash but I have limited experience with small engines.
Help would be greatly appreciated. Any ideas?
Thanks,
SymCity50cc
I'm new here and hope you can help me with an issue I've been having for a full season+. If you can help me figure this out I will seriously buy you pizza and beer.
Specs:
2006 SYM RS50 (BS05W Series) 2 stroke 50cc 4Kmiles 2nd owner (Bought it almost new with 300 miles on it)
AKA SYM Shark in Euro market
Normal operation:
-Scooter would get up to 40MPH fairly quickly with one or two people, and then crawl it's way up to maybe 45MPH, at that point the engine is winding out and likely redlining, I don't drive like that for long. I've always considered it a pretty quick unmoded 50cc, it was faster than a rented new Vespa50cc. I tried to take care of it and avoided beating it. New spark plug and clean air filter every year kept it running great.
Problem (Compared to normal operation):
-Loss of acceleration and limited top end. North of 10-15MPH is slooooow and top end is between 30-35MPH, sometimes 25MPH in a headwind. Uphill is painful, I have to pull over to let cars pass me.
This came on rather suddenly last year and it has been ***stuck with this consistent behavior for all of last season*** and now this season. I've worked on this myself, and taken it to two local mechanics (who *seem* competent and generally willing to help) and I'm at my wits end. Everything I, and the mechanics tried has made no difference or change in it's behavior, it all goes back together with the same result.
Things to note:
-Engine starts and idles just as new, no issue there.
-No backfire, missing, stalling, electrical weirdness, or any other odd behavior. It's smoooothly slow, and almost feels like the bike is carrying 1000lbs of weight
-Acceleration seems about the same from 0 -> 10MPH, above that doesn't get up to speed like it used to.
-1/2 to WOT doesn't seem to provide very much power, it just changes the pitch of the engine lower.
-MPG significantly lower
-Brakes are not stuck on, tires spin freely
-Never run out of engine oil (separate reservoir), ran out of gas once a few years ago
-Transmission oil has never been changed
-Environment is Northeastern US coast, 40-90F, mostly city, some longer 50 minute trips
-It's in otherwise perfect working order and I've been very happy with it, but it really sucks to drive it like this, and it doesn't yet belong in a landfill.
1st mechanic:
-Tested compression - 140PSI, leak down either not performed or numbers not given.
-Cleaned/inspected carb - no issue found
-Inspected tranny belt and weights - no issue found
2nd Mechanic:
-Observed fuel dripping inside carb air intake while running near the throttle needle, suspected faulty seal in carb- replaced carb- no change
Things I've done with NO change:
-Swapped ignition coil with aftermarket
-Swapped CDI with used Sym Shark from eBay
-Cleaned carb twice, wasn't even dirty the first time
-Multiple fresh tanks of fuel - always 91+ AKI
-Cleaned air filter, new spark, new fuel filter
-Checked reed, metal looked new and sat flat and unbent, screws were tight, cleaned and re-installed
-Before issue even occurred: Removed exhaust and cleaned out small build up of oil in exhaust inlet, new gasket - this improved the scooter a tiny bit
I'm mechanically inclined and I work on my car to save cash but I have limited experience with small engines.
Help would be greatly appreciated. Any ideas?
Thanks,
SymCity50cc