I have a GO 25 3 port it has .036" of clearance with one headshim and I want to run 20% fuel. My question is that to much clearance for 20%?

hello!i bought an go gx-7r engine.The engine runs byron 25% nitro and 11% oil.i have a problem.when opened the engine the piston was black...i cleaned it and ran it 2 fuel tanks.then i opened again the engine and the piston it was again black.i haven't change the headshims.can you help me?the engine settings are ok ...

what colour is the underside of your head button?

if running 20 % .3-.4 mm head shim will be what you need to run on 20 %

to me sounds like you have a very rich setting if the piston is black , regardless the piston will go a little black due to carbon build up does the engine run okey

I took the head off my motor and the head and piston was a gold color that I've never seen that color before. I use Byron 30%.

Then your runnning lean. Like matt said, your gonna have SOME black from carbon but if it's excesive then your running too rich. if your too lean then it'll be more gold in color with no build up on the piston. Just curious, are you going through alot of plugs?

No I am still using the same glow plug. I had one heat I ran it got to 270 and then I richened it up, a little too much and didn't have enough bottom end in the main. Motor ran great at 270 I'm going to have to work on my tuning to get the performance that running lean on HSN gave the motor . Next race I will work on the LSN I suspect its a too rich. What do you think.

im not sure how many ltrs you have put through your motor but to me i would start again with bothe needles flush warm it up a little and get a 6 sec pinch on the bottem end at idle, remember on the the gx series carbies 1/2 hour adjustment on the top end is huge no more then this at a time , i would how ever suggest you take aread of the massive mods web sight on tuning it may shed some light on the problems you are having check it out

http://www.massivemods.com.au/produc...roducts_id=275

if your motor is still rather new hold off trying to lean it out to much and remember no smoke no good you want good consistant smooth power from start to finish :nod:

the underside of the head button is black and the glow plug.the carb setting are all ok.when i change the settings the engine drys...(it has no fuel and has flameouts)can you help me ?

It's too rich if that's the colour of it.

I tune mine to an even golden brown colour. Even with this colour i found there to be slight carbon build up on the side of the piston and sleeve, but none on the button or plug.

MM
The motor got to 270 when I changed pipes. I went from a JP2 pipe to Dynamite 053 but I used the JP2 header before that it was under 220. The motor really liked that combo the best. I race dirt oval so the motor never really gets a chance to rest and the races are only 5min long even the main. I read your tuning guide and I think it will be a big help I printed out so I can reread before next weeks race!

I don't have a GX series motor the motor I have is a modded 3 port
R2500-M00HSG that has 1/2 gallon through it. Does this motor adjust the same as a GX series? I know I'm using a sport motor for a racing application but the club I race with most guys run Dynamite sport or platinum series 21. I don't want to get too get our club into a high dollar motor war so basically we have a gentlemans agreement to keep the motors under $200.

Muahahaha yeh right...we have lotsa "gentlemens agreements" at our club too..then we get out on the track and everyone becomes an instant bastard!
Is that photo the engine? Is it even a Go motor.doesn't look like any I've run,and who was a bit heavy handed with the silicone sealant.You might want to make sure you haven't got any of that orange gunk inside the motor.

Now that's an old go sport 3 port. One of the first ones made? Any hoo you can find parts for it at amain hobbies believe it or not.

http://www.go-engine.com/in-products/R2500-M00HSG.htm

Looks like his motor, I am sure it has a long low speed needle.

Rex