customized my exhaust today

D

drewbob

New Member
I finally got around to putting an expansion chamber on my 66cc...grabbed a cheapo pocket bike exhaust on ebay - turned out to make it fit, I only needed to cut and rotate it in one spot. I used a 45 deg angle to connect the two pieces, sealed them up with silicone gasket maker (we'll see how long that lasts), wrapped it up with exhaust wrap, and voila! custom exhaust!

I like the underseat exhaust look, but think it would be even better with two pipes instead of one...Ducati style.

Have to wait 24 hrs for the silicone to set if I have the slightest chance to keep it from leaking. Will see how it sounds and runs tomorrow...
 

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Looks good Drew.

Is there enough clearance for the gas tank? Can't see the pic real well and am just asking.
 
enlarging the pic makes it look like he has about 3/4'' between the wrapped pipe and his tank, so he should be go on that part.

You make a good point though, I sure wouldn't want a hot exhaust pipe against a fuel tank strapped between my knees......ouch! that could get ugly real quick!

zpt


Dan said:
Looks good Drew.

Is there enough clearance for the gas tank? Can't see the pic real well and am just asking.
Click to expand...
 
That header wrap that is on that pipe keeps the heat way down , I have the same on mine an can grab the pipe right next to the jug an my hands only warm .
 
Thanks, and yes, there's a good inch or more from the tank. It sticks out a bit which gives it more clearance, but still far enough from my legs. The wrap is my extra safe guard...I wouldn't want anything to catch on fire!

The engine runs much better than before - it pulls well from low revs and seems to have a smoother pull up towards the high end.

I have a question if anyone is willing to impart their genius on me:
My engine has a tendency to 4-stroke (less so than before the exhaust change, and less so when warm) when cruising. Under heavy load (accelerating or going up hill), it behaves as it should. Do I need to adjust the needle in the carb, or do I maybe have a leak in the intake?

It's the generic carb, which I could upgrade if it gave better performance, but I've heard it's not necessarily worth it. Any help?

Thanks.
 
I would remove the spark plug, clean it back down to clean metal with a wire brush and some carb. cleaner, put the plug back in engine with a dab of anti-seize on the threads and go for a 2-3 mile ride where you can maintain your normal cruise speed for a good stretch of the way, try not to let the engine lug down for a long period of time if you can and return home, let the engine cool down for 20-30 minutes then remove the plug and look at the color of it, if it is lite gray or white looking in color you are running to lean and this will trash you engine in a short time, but if the plug is a nice medium brown or a bit darker you should be in good shape.

All of my engines 4 stroke a bit off & on when they have little to no load on them, but none of them 4 stroke under medium to heavy load or at wide open throttle, my plugs run medium to light brown since I run an approx. 80:1 mix with Opti2.

If your plug is brown, you have better power over the RPM range and less 4 stroking, these are all good things and shows you r exhaust mod has got the little china girl breathing easier now, just do the plug check and make sure you're not running her lean and you should be in great shape.

Peace, map

PS: Others may give you a different method for running the engine before checking your plug which is fine, I'm just posting here how I've always done it and it works just fine for me.

Best wishes
.wee.



drewbob said:
Thanks, and yes, there's a good inch or more from the tank. It sticks out a bit which gives it more clearance, but still far enough from my legs. The wrap is my extra safe guard...I wouldn't want anything to catch on fire!

The engine runs much better than before - it pulls well from low revs and seems to have a smoother pull up towards the high end.

I have a question if anyone is willing to impart their genius on me:
My engine has a tendency to 4-stroke (less so than before the exhaust change, and less so when warm) when cruising. Under heavy load (accelerating or going up hill), it behaves as it should. Do I need to adjust the needle in the carb, or do I maybe have a leak in the intake?

It's the generic carb, which I could upgrade if it gave better performance, but I've heard it's not necessarily worth it. Any help?

Thanks.
Click to expand...
 
Thanks Map,

The plug is a nice light chocolaty brown. Like you say, the 4-stroking only occurs at light loads, so I'll assume the engine is performing as well as it should. It runs noticeably better than it used to, so I'm going to call it a success.

Thanks for the help!
 
drewbob said:
Thanks Map,

The plug is a nice light chocolaty brown. Like you say, the 4-stroking only occurs at light loads, so I'll assume the engine is performing as well as it should. It runs noticeably better than it used to, so I'm going to call it a success.

Thanks for the help!
Click to expand...

Your very welcome, sounds like you got a winner going on there so far.... ride safe.

Map
 
shouldn't...it faces behind me and up...It's the usual location for most pocket bikes. I'm hoping it won't spit oil much at all, but I'll let you know if it does...
 
Run Opti2 and the heavy smoking and oil spitting days are over.........!

I'll never go back to the other stuff, Opti2 rules in my opinion and most others who use it.

Map
 
that is really cool. I am having problems getting an exhaust on my bike cause it is a schwinn with fenders /on and clearance is criticle. fender hits exhaust.
 
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