Sym XS125-K

In other news - I had a puncture 2 weekends ago. Garage repaired by replacing the inner tube - all in for £24, which I thought was reasonable.
 
Tattysnuc said:
I'm not sure about using Super. It's a different, higher RON rating, which could POTENTIALLY damage the piston head. I'll stick to the regular stuff while the bikes under warranty
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No it won't. Using regular where super is specified could result in piston damaging detonation, but not the other way around. However, I've tried both in my RSV and couldn't tell any difference.
 
YarwoodUK said:
What's it feel like at 67 ? You mentioned bottling out - why?

For a 125 you should be averaging a lot higher than 50mpg! :eek:
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I was thinking that - should be getting closer to 100mpg I'd have thought? Big bikes will do 50mpg plus.

Sounds like you're having a lot of fun on it though, and that's what it's all about :)
 
YarwoodUK said:
For a 125 you should be averaging a lot higher than 50mpg! :eek:
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Does seem very low. My dad took my step-mums CG125 out on a long charity rideout a month or so back and thrashed the living daylights out of it keeping up with the larger bikes on the faster roads, but it still returned about 80mpg, and can do ~100mpg ridden more sedately.
 
Morbius said:
My YBR was getting 90+ mpg flat out along dual carriageways. You should be getting between 90 and 100.
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It's definitely not anywhere near that, nor has it been since I bought the bike. A top up is usually around the £11 mark, and that's for just over 300km, which still gives me around 60mpg - the trip down to the midlands I was expecting to be lower, so the bike's running fine - just not anywhere near as efficiently as your CBR by the sounds of it.

I guess that's part of the false economy of buying one of these cheaper Taiwanese bikes.
 
YarwoodUK said:
What's it feel like at 67 ? You mentioned bottling out - why?

For a 125 you should be averaging a lot higher than 50mpg! :eek:
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Not enough road - or rather a corner approaching that I wasn't sure how sharp it was.

It was also getting quite breezy at 60+ mph - I couldn;t even see in the mirrors they were vibrating that much it was just blurry!

So... I bottled it... :)
 
My Kh

125 two stroke does 80+ mpg with a pillion.
It is a real feisty little chap and will hit 80mph, although it did have to be "tweaked".
It smells like heaven as well.:D
 
I see lots of claims of 90+ mpg, but I cannot find any references to bikes being that efficient...

the KMX for instance,

http://www.motorcyclenews.com/MCN/b...e-Reviews/Kawasaki/Kawasaki-KMX125-1986-2002/

comes in at 55mpg, with a top speed of 71 mph.

How are people calculating their mpg?

I did mine:

367km = 228 miles (using 1mile - 1.609km)
Fuel was measured in Litres on refill = 20.7
1 gallon = 4.54609 litres, therefore 20.7 litres = 4.55 Gallons
228 miles on 4.55 gallons = 50.xx mpg.

You sure your mpg is calculated correctly? Is mine?
I'm using a UK gallon, not US - the US gallon is 5.69 litres, which should make the number even lower.
 
four strokes will be more effecient than two strokes,a lot of petrol is unburnt/wasted with two stroke engines
 
I'm sceptical that there are so many efficient bikes out there. My understanding was always that 2 stroke engines were not as efficient as 4 stroke engines. The only thing I can think of is it's my slightly larger-than-it-should-be-be frame.

I know I'm a fat blighter (17.5 stone) but are people on here THAT much lighter than me, and does it make THAT much difference?
 
it might make some difference,also you dont know how that bike compares to jap bikes in fuel/engine efficiency

also nailing the throttle everywhere and hard braking/acceleration add to things
 
wazza300 said:
it might make some difference,also you dont know how that bike compares to jap bikes in fuel/engine efficiency

also nailing the throttle everywhere and hard braking/acceleration add to things
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indeed. I'd really interested to find out what other 125 owners MEASURE their efficiency to be...

New thread time?
 
Tank size

On the kh 125 is 13.5 ltrs -I can do 240 miles and have a little left on a full tank.
I have recut the side valve and had to down size the main jet as a result, plus change over to a cooler running plug.
 
Tattysnuc said:
I'm sceptical that there are so many efficient bikes out there. My understanding was always that 2 stroke engines were not as efficient as 4 stroke engines.
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They aren't*, and I'm extremely skeptical that a tuned 125cc two stroke could ever return 80mpg, especially with a pillion.

The small four stroke engines are very economic however, there are plenty of scooters that can manage 120mpg, and the Jap four stroke 125 bikes should be approaching 100mpg if they are in a decent state of tune (and you aren't flat out all the time).

Weight is a bit of a killer on small bikes simply because they are so light to start with; the difference between say 10 stone and 17.5 stone is more than a third of the weight of the bike

Also the type of riding you do will have a big influence; is your commute only mainly open roads with few traffic lights, or do you spend a lot of time in heavy traffic?

Low tyre pressures, binding brakes and insufficiently lubricated chains will all impact economy as well.



*Apart from supercharged two stroke diesels which are one of the most efficient internal combustion piston engines.
 
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