Venom ghost

[Thunderduck32]

Venom ghost should be here tomorrow. Any tips for me?

[Thumper]

I think this model now has a carburetor. If so, it is probably jet kind of lean which makes the engine run a little hot and it will back fire when you are decelerating (let off the throttle, slowing down in gear)... So it is probably a good idea to increase the pilot and main jets. There is probably an air/gas mixture screw that will need to be exposed (drill out the cap). Most carbs on 167FMM CG clones allow more gas in when unscrewed/opened, counterclockwise. It is the opposite (airscrew), lets more air in when you open it on the carb that comes on most 172FMM engines. Tell us what you have when you get the carb off (pics would be great).

If it has EFI, then you won't be able to just change jets. Maybe someone here has a hack to modify the enrichment curve.

Also, check/set the valve clearance. They are often shipped too tight, even with no gap! If this is a push rod engine, gap to ~ 0.002-0.004" on the intake, and ~0.003-0.005" on the exhaust. If it is an OHC engine, then those clearances can/should be a little tighter: intake no more than 0.002", and exhaust no more than 0.003".

To adjust the valves- open the side port on the left side (stator cover, probably a wide flathead slot) and remove the sight port on top of that case cover to see the timing marks. Remove the spark plug so it turns easy on the compression stroke (you will be stopping at the top of the compression stroke). Remove the caps on the valve cover so you can see the rocker arms to determine when the valves are closed. You can put a socket (14mm or 15mm) on the stator nut and rotate the crankshaft counterclockwise to the |T mark (TDC mark through the sight port). One or both valves will be closed. Rotate another 360 degrees and one or both valves will be closed. When you figure out which is the both valves closed position, you can set the gaps. You do not need to gorilla tighten the lock nuts-just snug and then another 1/16th turn. Also, they close the gap when you tighten them if you don't hold the stem in place while tightening. Verify the gap after you snug down the locking nut. Here is a nice valve tool that works on the 167FMM head from Amazon for under $8 (click on the thumbnail to see the full sized pic). It does a nice job of holding the stem in place while you tighten the locking nut:



These values depends a little bit on the engine, but these are normal clearance ranges for the CG clones. Is this a 167 FMM engine? The engine model stamp should be visible behind the gear shift lever. Knowing this will help with jetting/valve clearance advice.