Surging Spree, and full throttle issues....

[Mattedroom]

So I did the pulley mod (.09 off) and belt, and felt as if I needed more power. (a weak 35mph) So I pulled the Cylinder and ported the exhaust and intake. Milled the head .018. Cleaned the muffler.

I put it back together and noticed a good power gain. Only gave me 1 plus mile per hour, from 35 to 36mph, but it gets there much quicker.
It also surges, feels like it wants to take off even at 35mph. It starts to feel like this after 30mph.

The thing is, that when accelerating, I can't have it at WOT until about 20mph or it gets really weak. It actually runs better 3/4 throttle at first.
Pulls almost like it doesn't have the pulley mod.

I also notice that the air filter is some home made crap, made out of two furnace air filter elements that seems to work. I also noticed (major) that the cylinder and the piston are scorched badly. I've never seen one like this, but I can't complain. It still goes 36mph! I haven't done a spark plug check, it's raining out side so I can't drive.

How big of a deal is this air filter? Do you think that is what is causing the surge? (maybe a vacuum leak?) You think that I should invest in a new cylinder and piston? I don't drive it much....

Just conversation...

Looks like the rain stopped, I am going to go play...

[SPREEtown]

im not sure if the filter would cause the surging, but you probably want to run a stock filter anyways($4 at your local honda shop.) then do a plug chop.

[happyman]

surgeing i think would indicate a lean condition. go up in the jetting and see how it feels. may gain some top end like maybe 5 mph total

So I did the pulley mod (.09 off) and belt, and felt as if I needed more power. (a weak 35mph) So I pulled the Cylinder and ported the exhaust and intake. Milled the head .018. Cleaned the muffler.

I put it back together and noticed a good power gain. Only gave me 1 plus mile per hour, from 35 to 36mph, but it gets there much quicker.
It also surges, feels like it wants to take off even at 35mph. It starts to feel like this after 30mph.

The thing is, that when accelerating, I can't have it at WOT until about 20mph or it gets really weak. It actually runs better 3/4 throttle at first.
Pulls almost like it doesn't have the pulley mod.

I also notice that the air filter is some home made crap, made out of two furnace air filter elements that seems to work. I also noticed (major) that the cylinder and the piston are scorched badly. I've never seen one like this, but I can't complain. It still goes 36mph! I haven't done a spark plug check, it's raining out side so I can't drive.

How big of a deal is this air filter? Do you think that is what is causing the surge? (maybe a vacuum leak?) You think that I should invest in a new cylinder and piston? I don't drive it much....

Just conversation...

Looks like the rain stopped, I am going to go play...

[Kenny_McCormic]

Too lean. Lean running WILL MELT THE MOTOR!

[Mattedroom]

Where do I get a larger jet? Honda dealership?

[keithw]

Honda bike dealer and also Honda power equipment dealers. The same jets are used in some of the industrial stationary motors.

keithw

[gobucks]

if a bike is running lean, how big of a jump in up jetting would you recommend, lets say it presently is a 68

[Kenny_McCormic]

I would try a 72 and close the airscrew down as far as you can keep it running at(richens the pilot jetting).