Build or buy expansion chamber?

[Deleted member 12676]

since it turns clockwise by making it more CCW causes the spark to happen later (retarded which is better for top end power)

yes there is 1mm play there but if the fit between magneto and shaft is good then just the tightness from the nut keeps it in place.
check it this way: remove the woodruff and put the magneto on the shaft and then rotate it without rotating the shaft.
either on the magneto or the shaft you will see telltale marks where the high spots met. If that happens then they aren't mating well and you need to use valve grinding paste. Put it on the shaft and manually rotate the magneto. that will grind down the high spots.

 

[Steve Best]

My testing with a GPS speedo on a hill with a 2015 GT5A and 2013 GT2A indicated more power with baffles in.
My round trip to work is 50 kms. I often do a 50 to 100 kms tour in the evening. Takes an hour or two.
I'm racking up the miles pretty quick. Still running stock Grubee exhausts so far.
The chromed exhaust is quieter and faster than the supplied black catalyst exhaust.

Steve

 

[Deleted member 12676]

Interesting. I'll bet bikebuilder did his tests on level ground.
Probably these engines like more back pressure at mid range RPM and less back pressure at top RPM.

 

[BikeBuilder43]

I thought if you are looking at the shaft from the left side of the bike where the magneto is then it turns counter clockwise( same direction as the wheel)

 

[BikeBuilder43]

Or am I missing something?

 

[Frankfort MB's]

I have the 2015 epa approved grubee exhaust and it is so stopped up I can't breathe through it lol!

At low rpm it doesn't have as much power w/o baffle but mids seem to be better.... Top end isn't that noticeable, didn't effect top speed though

 

[butre]

I thought if you are looking at the shaft from the left side of the bike where the magneto is then it turns counter clockwise( same direction as the wheel)

the mag turns clockwise, the gears in the clutch side reverse the rotation

 

[BikeBuilder43]

OOOHHH thats true. Good info. Lol

 

[Deleted member 12676]

on motorcycles the shaft turns CCW. this engine is opposite because it doesn't have the extra shaft that motorcycles have for the gears.

 

[BikeBuilder43]

Jag i knew you gave good advice. Found the right piece for the dremel and cleaned up the exhaust port and pipe. Got a better match. Dremeled the little woodruff key near the magneto. Man it feels like the faster i go the harder it pulls. I love it! Starts much easier too. Right when i engage the clutch it fires right up. Thank you for the good info.