Hi guys new to the forum, I have a Sr 125 2t and acceleration is perfect and open throttle is perfect top end is perfect, but say I hold it at 40mph,50mph or 60mph it’s starts spluttering slowly pull the throttle more it’s fine balance off and hold it at a steady speed it starts spluttering again any ideas.
Cheers tom
Hi guys new to the forum, I have a Sr 125 2t and acceleration is perfect and open throttle is perfect top end is perfect, but say I hold it at 40mph,50mph or 60mph it’s starts spluttering slowly pull the throttle more it’s fine balance off and hold it at a steady speed it starts spluttering again any ideas.
Cheers tom
Forgot to mention it’s got a stupid cheap looking cone air filter thing and don’t know if it’s been jetted for this
Thats a wierd one.......
If acceleration and top end is fine I would rule out the air filter, that would affect the entire range.
Maybe the air/fuel mix screw needs playing with or maybe the slide needle could do with raising one notch on the circlip (put the clip on the next slot down the pin).
Thats a wierd one.......
If acceleration and top end is fine I would rule out the air filter, that would affect the entire range.
Maybe the air/fuel mix screw needs playing with or maybe the slide needle could do with raising one notch on the circlip (put the clip on the next slot down the pin).
I just took my carb off and had a look at the main jet and it’s a 100 surely that’s way to big for a standard bike
Not really, as an example, the vx125 has a 108 main jet as standard.
I’ve jus
Not really, as an example, the vx125 has a 108 main jet as standard.
so hopefully it’s the standard jet and the last owner just put a filter on without jetting it
Can’t get my head around it put standard air box on won’t go past 30mph and bogging really bad, so thought take air filter out see if the filter is causeing it didn’t make a difference tried it with the air box case open still the same took the air box off completely and was running fine up to 70mph no problem so why is it like that with the air box on also this air box is off another bike off eBay I’ve never owned this bike with a standard air box on it it’s always had a come filter on it
That's because the airbox is causing a restriction.
You might well find that the cause is actually the cone air filter itself.
Had it a few times on a Neos I did some years ago. The K&N type filter looked good but was actually blocked, changed the filter, away it went again.
If the bike is running fine with no filter on, as in you can hold it steady at 50mph without problems where you couldn't before, then that points to the filter.
Swap to a sponge filter. The metal bit at the end of the filter is upsetting the air pulses within the carb
That's because the airbox is causing a restriction.
You might well find that the cause is actually the cone air filter itself.
Had it a few times on a Neos I did some years ago. The K&N type filter looked good but was actually blocked, changed the filter, away it went again.
If the bike is running fine with no filter on, as in you can hold it steady at 50mph without problems where you couldn't before, then that points to the filter.
It runs exactly the same with the cone filter on or off stills has the splutter when holding at a speed I was trying to find the standard size main jet but can’t find any info so I had a look at a gilera sp 125 2t because they both rolling nut engines and they run a 86 main jet so my guess it’s way over jetted and it’s running rich
The std 125 typhoon on a mikuni carb uses a 82.5 main, and yes the runner 125 has a 86 main with std airboxes, a good place to start plus needle second from top !
