weird Intake Leak Issue

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WaterDog

New Member
Sep 12, 2010
59
0
0
Miami / Fort Lauderdale, Florida
My bike runs ok at low/mid but bogs down at anything over 75% throttle (66cc Slant from Zoom Bicycles). Someone suggested the carb cleaner spray test and yes, there was an air leak where the carb connects to the engine. So i removed the carb and used silicone tape to make the seal. Replaced the carb and tightened the clamp. So no more air leak with the carb cleaner test. But now the bike bogs down at anything over 50% throttle!! It almost seemed like the air leak helped. I am using an upgraded air filter from Pirate Bikes, but the problem was around before the upgrade. So what could be causing the bog??
 

NunyaBidness

Active Member
Jun 29, 2008
1,062
2
38
memphis tn
It sounds as if you are getting to much fuel. Check the spark plug for color, if it's black and oily you're getting too much fuel.
 

WaterDog

New Member
Sep 12, 2010
59
0
0
Miami / Fort Lauderdale, Florida
The plug pretty clean and dry so I think I'm ok there. It may be a tiny bit off, but about right. Low end and mid throttle has great response with no hesitation at all. But at the half way point it just hits a wall. Acts just like it has a limiter built in. I can only get up to about 20 mph. Would an exhaust problem cause this? If it was partially blocked or restricted?
 

Mind_Reader7

New Member
May 1, 2010
392
1
0
Northam, Western Australia.
Rebuild the carb. Make sure there's no crap blocking anything up. When my engine was mounted on my old bike, the carb would overfill, so I bent the tabs. On my new bike it sits on a different angle, and as a result I need to press the fuel inlet thing for aobut 10 seconds, otherwise you need to peddle for about 20 seconds before the motor even kicks over.
 

WaterDog

New Member
Sep 12, 2010
59
0
0
Miami / Fort Lauderdale, Florida
Problem fixed....after making sure the air in was ok, I had to consider air out. My kit came with the catalytic converter sytle muffle. I lost my baffle a couple of weeks ago because the nut vibrated off. Anyway, I replace the baffle with the famous glade room freshener can trick. But the cat converter kept making think about restriction. Since I wanted to play with a better exhaust and would have to replace the muffler anyway, I decided to hack off the cat converter and just leave the top cap. So basically I cut the muffler about an inch past the point where the bigger section starts. Used a can opener to remove the bottom of the glade can. Popped out the spray nozzle and drilled 6 quarter inch holes around the nozzle hole. I figured I had about twice the opening of the original muffler and of course no restriction from the cat. Loosely packed a stainless steel wool kitchen pot scrubber in the can and attached the bottom of the can around the muffler pipe with a stainless hose clamp. Also drilled a 1/8 inch hole on each side and secured the can with screws to the left over top cap of the old muffler. The hose clamp just gave an air tight seal and the screws prevent the can from sliding off.

Anyway, the sound is deep and very quiet. Pick up is very noticable now and top end hardly bogs at all. I'm sure a real expansion muffler would best, but for two bucks, you can't go wrong....