Engine won't rev all the way while riding

[Soflowrider]

yeah, start at a 63 and go richer from there.

do actual plug chops.

around here our da can be as low as -1500 ft during the winter and as high as 2500 during the summer.

Ok sound good, I live in south Florida so it's always hot (80-90+) except for 3 months out of the year.
Thanks for your input

 

[Frankfort MB's]

35mph is not a bad speed with what upgrades you have is pretty good, I had the same upgrades but with a NGK b8hs plug and major port and polish job. I could only get 40 mph out of mine... I like my MZ pipe sounds awesome lol

 

[Jay dee]

yeah, start at a 63 and go richer from there.

do actual plug chops.

around here our da can be as low as -1500 or even -2000 ft during the winter and as high as 2500 during the summer.

that can easily be a 10% difference in power

3300 here in fort worth texas where should i start with my jet

 

[Just_plainspicey]

I have the same head but I can’t get it to work either but I’m going to try higher octane gas like 93 or something mine will not go high in Rpms it goes till like half throttle and pings

 

[Steve Best]

I have the same head but I can’t get it to work either but I’m going to try higher octane gas like 93 or something mine will not go high in Rpms it goes till like half throttle and pings

You are replying to a 4 year old thread, but I'm stuck at home and may be able to help.
These engines do not survive high compression and/or detonation well.
This will overheat the piston and take out the rod bearings quickly.
If it is pinging, get more chamber volume NOW. Octane is a band-aid (although I generally use the gold grade stuff)

This is sort of the ideal chamber shape for us. See that gap between the piston and the head?

It should be no less than 0.020" and no more than 0.060" with 0.030" about ideal.
Check it out with a bit of 0.040" (1mm) or 0.060" (1.5mm) electrical solder. Rosin core is ok to use.

You can measure it like this (bolt the head on) or in through the spark plug hole:

So once that "squish" is set to between 0.020" and 0.060" your engine should run with no "ping".
If it does, try opening the squish up toward the 0.060" side, or even better, open the chamber volume up.
How? A bit of polishing with sandpaper and a drill can do wonders on these motors.
Just get all the grit out before re-assembly.

Stock head here, I'm greasing it for a chamber volume check with the piston sealed to the head by the grease, and allow for squish.

Anyway, about the "not revving" problem. It is usually from running too rich a main jet.
Manufacturer sells them this way to prevent lean and over-rev destruction.
Go careful on jetting or you can destroy it, especially if pinging now.

Good luck.