Valve clearence smc ram 170cc

[Mshotta]

Hi people I'm new here just looking for a bit of help. I got a smc ram 170cc atv and I'm just wondering does anyone know the valve clearence?

Struggling to get it started, It will try and start and get the odd back fire but that's about it.

Any help would be appreciated thank you

[Mudflap]

Appears to have a CG engine so I would adjust them to .003" intake and .004" exhaust.

[Mshotta]

Appears to have a CG engine so I would adjust them to .003" intake and .004" exhaust.

Thank you I will try that and let you know if I can get it running. Appreciate your help

[Mshotta]

Appears to have a CG engine so I would adjust them to .003" intake and .004" exhaust.

Still can't get it to run with that valve clearence. I done a compression test as well and it about 76psi is that normal or low?

[Bruces]

Low

[Mudflap]

Yes, definitely low. Easy engines to work on but I haven't seen a 170cc CG engine so parts may not be a common as for a 200 or 250.

[Mshotta]

Yes, definitely low. Easy engines to work on but I haven't seen a 170cc CG engine so parts may not be a common as for a 200 or 250.

I thought that but I've had the top end off and piston and rings look fine.

How can I tell if its definitely a cg engine?

[krat]

CG engines are vertical. Cylinder nearly up and down. Overhead valves with internal cam. They will be in 125cc and larger, up to 275-300cc.

Qmb engines will normally be on the fully automatic models and are usually horizontal with no provisions for clutch or transmission attachment. Over head cam. They run straight into a variator (CVT). They are sized from 50cc up to 175-200cc. Most of the larger size designations are false with "200cc" being actual 165cc which is a 125-150 with a big bore kit.

The cub type engines are overhead cam. They will be on many semiauto and automatics and are also adaptable for manual shifting. They are not usually in the larger sizes above 125-150cc but go as small as 50cc.

Its a crap shoot with ATV engines and from what I have read none of them are as fast in an ATV as they are in a bike or scooter.

I am sure there are exceptions, I just have not read about them.

[Bruces]

If it has a shifter ,the engine info should be on a little flat spot behind the shifter .

[Mudflap]

I thought that but I've had the top end off and piston and rings look fine.

How can I tell if its definitely a cg engine?


Easiest way to identify a CG engine is to look at the left side of the cylinder. You'll see a round metal insert with a slot in it. That is the pivot pin for the cam followers.

[Mshotta]

Easiest way to identify a CG engine is to look at the left side of the cylinder. You'll see a round metal insert with a slot in it. That is the pivot pin for the cam followers.

You on about this?

[Mudflap]

You on about this?
Yes

[Mshotta]

Yes

Yeh it's got that on it so it's definitely a cg170cc engine then

[Mudflap]

I thought that but I've had the top end off and piston and rings look fine.

How can I tell if its definitely a cg engine?
If the piston and rings are good that leaves the valves or head gasket. When you had the head off did you try pouring gas into the upside down head to see if there was any leakage through the valves. One time I over oiled a foam air filter which caused a buildup of carbon on the back of the intake valve. A tiny flake of carbon came off and got stuck under the valve causing a loss of compression.

[Mshotta]

If the piston and rings are good that leaves the valves or head gasket. When you had the head off did you try pouring gas into the upside down head to see if there was any leakage through the valves. One time I over oiled a foam air filter which caused a buildup of carbon on the back of the intake valve. A tiny flake of carbon came off and got stuck under the valve causing a loss of compression.

I'll try pouring some petrol down the head tomorrow see if any comes through. Yeh when I took the head off I cleaned all the carbon from the top of the valves and piston.

I did find a smc ram 170cc manual online and the valve clearence in the manual says 0.05 in 0.05 out but I tried that and still won't start