Author Topic: Jet Euro bogs on mid range after ugrading air filter?  (Read 908 times)

fmscott2

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Jet Euro bogs on mid range after ugrading air filter?
« on: January 18, 2012, 07:31:42 PM »
I have a 2007 Sym Jet Euro. I have upgraded to a 70cc piston kit, an aftermarket tuned exhaust, and I just purchased an upgraded air filter (K&N type). Most likely my shop rejetted the carb after the 70cc and exhaust upgrade.

The scooter was running great before I changed the filter. Now the scooter bogs on the mid range. I've adjusted the carb to a richer setting (more fuel) but it's still not picking up speed in the mid range. But if I richen it too much then the scooter won't hold an idle (it dies out).

What is the problem? Could my carb be too small now? My shop thinks that the fuel filter may have been clogged and since it's drawing more fuel it's getting more constricted. Should I try a hotter glow plug?

phipsd

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Re: Jet Euro bogs on mid range after ugrading air filter?
« Reply #1 on: January 20, 2012, 10:58:47 AM »
If the bike was running great before changing the filter, the answer should be obvious. K&N's are not an upgrade. They don't do a good job of filtering compared to stock. The extra crud your engine will suck in compared to stock will not be good for engine life.

Testing done years ago by the late Gordon Jennings at Cycle showed that K&N's are inferior to stock paper or oiled foam air cleaners. Clean air is vital to engine life. It's way more important than 1/2 a HP more.

gitsum

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Re: Jet Euro bogs on mid range after ugrading air filter?
« Reply #2 on: January 21, 2012, 10:05:32 AM »
You will need to raise your needle jet a notch or two and possibly go with a bigger main jet.  Adjusting the fuel/air screw is only for the pilot jet, idle to 1/4 throttle. 

bazza9001

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Re: Jet Euro bogs on mid range after ugrading air filter?
« Reply #3 on: April 20, 2017, 02:46:33 PM »
were did you get the 70cc kit from ?