Gx240 build issues

[Yamahama]

So I took my gx240 apart this weekend to install some 50lb valve springs, HD push rods, gx390 clone cam and gx390 clone carb.

I got the motor all put back together with no problems and installed it back in my g2 with a slightly used Gator primary clutch.

Motor started with some difficulty but fired up after putting a little bit of gas down the air cleaner.

The motor ran OK but was down on power and would barely move the cart up a small hill.

I pulled the rocker cover off and backed off on the rockers a bit thinking that maybe the weren't closing all the way. Motor seemed to run much stronger but then the exhaust rocker fell off.

So, the main problem I'm having is that the motor has very little compression when I setup lash to the correct setting. Seems like the compression release is working too well... So well I can't get the motor to stay running unless I open the exhaust lash up way too big.. Like 1/8"...

Is my Chinese 390 cam a POS? Could something what be wrong?

I'm kinda pissed off about it. I really don't want to pull the clutch and side cover if I don't have to.

My carb bowl is also overflowing with gas and I think I'll need to add a return line or use a smaller fuel pump. I'm sourcing my order signal from the unused governor hole in the motor.

[sho305]

I know you can bend something on the cam to change how it works, otherwise I don't know. You can see the valve pop up a little if you turn it by hand. You may have to jet the carb richer. Most kart people run near zero lash no problems.

I tried to run the pulse there it will fill the line with oil and the pump will quit. I put a fitting in the rocker cover and it works great. I did another clone into the carb spacer and it needed a return line it would overflow at idle. Both G9 pumps.

[Yamahama]

I spent some time messing around with it Saturday morning but I had to work outside and it was barely above freezing and pouring rain.

I checked push rods and they're not bent. Rocker arms look fine. The lash cap came off when the exhaust valve rocker arm fell off but it stayed in the top end and I fished it out with a magnet. I can turn the motor by hand and watch the valve train and everything seems to operate properly. I didn't check the timing key.

With the lash set to like .010" on both intake and exhaust the motor has barely any compression and will start for few seconds and die. I can barely feel the compression stroke when turning the motor over with the recoil or turning the clutch by hand. If I back off the exhaust lash the point the rocker is almost falling off the motor suddenly has great compression and I can get it to start and stay running.

Everything I can think of points to a cam issue. Could the settings for the 390 compression release just not work with the smaller motor?

I'll be headed back up to where the cart is in two weeks with a gator clutch puller and a new side cover gasket.

Could I completely remove the compression release? I want to be able to start this thing with a starter/generator.

[general01]

You will need the compression release or even the starter/generator will struggle turning it over
I speak from experience on this with a vc460 from Vegas carts

[Yamahama]

Just to update, I pulled the compression release off my cam and my gator starter/generator turns the motor over easily but the gator starter does have a smaller pulley compared to the golf cart starters..

I also found that my choke flap had some how broken off and was bent and stuck in the carb. I'm guessing it broke off when my motor backfired a bunch when the exhaust rocker fell off. I just pulled the choke plate and left the shaft. It seems to start ok cold but I have the low speed jet turned way out.

With the minor mods, the little 240 climb hills just as well as my dad's g2 with stock gx390 clone even though his belt is new and mines badly worn and sitting way down on the secondary. Both have 22" tires.