Well I thought it was a carb issue...

[Stoneman]

Hi all and thanks for the add to the forum

Not one to post up a how ya going my name is.....
Great forum a a great sense of humour

Leads me to my problem

What tool do I use in this picture to tune this carb
I'm running a .55mm jet and still a little lean
Down bottom it it will run until it just stops unless I have the choke on

Any direction or a sort it yourself would be much appreciated

Oh and I should mention I've modified it as well, dunno if I've just straight out ****ed it or what

Cheers

 

[Frankenstein]

Hi all and thanks for the add to the forum

Not one to post up a how ya going my name is.....
Great forum a a great sense of humour

Leads me to my problem

What tool do I use in this picture to tune this carb
I'm running a .55mm jet and still a little lean
Down bottom it it will run until it just stops unless I have the choke on

Any direction or a sort it yourself would be much appreciated

Oh and I should mention I've modified it as well, dunno if I've just straight out ****ed it or whatView attachment 76845

Cheers

The screwdriver opens the carb bowl, use another screwdriver to remove the jet, out a 60 or 65 in and see if it's less lean. Make sure the carb is seated well on the intake along with the intake to the cylinder.

Then give it another shot.

 

[Stoneman]

I've had it on and off that many thimes
A 60 is to big for it for some odd reason even a 55 is starting to be to much

I just can't get the low end to work, no matter what it seems lean

I'm chasing an air leak to start with and make sure I'm not just chasing my tale
Recently my son split the boost bottle hose and ran hot how long I don't know.
But internally looks fine
So far used 400 grit on glass to clean the head up

What goes with the squish ring and using the original gasket? Will it still squish?
Or should use a new one

And I have to confess I bored the carb to 15mm

My pilots is lined up as it should be, I had to mod the slide to get to close properly
Also I've gone to .9 on the pilot and it barely made a difference!

Btw the little emulation tube just taps out from the other side , no need for an oxy!
Just in case any one is interested

 

[Stoneman]

First time pulled apart, no wonder there cheap

I think something is a miss here, piston is the wrong way!!!

Should of pulled it down before I started it

 

[Street Ryderz]

First time pulled apart, no wonder there cheapView attachment 76861

I think something is a miss here, piston is the wrong way!!!

Should of pulled it down before I started it

No it's right! Where are the retainer pins for the ring gap?On the intake side is the only way it should be!

 

[Stoneman]

No it's right! Where are the retainer pins for the ring gap?On the intake side is the only way it should be!

Yep intake side?

Everything I've seen and done (years ago now) it should point to exhaust..

I think you might be wrong

 

[Stoneman]

Hang on you might be wright in a way

Ring pins should not line up with any port from what I'm finding
Yep arrow to the inlet

Thanks back to square one now

Is the gasket good to re use?

 

[Steve Best]

Nice granite work surface you have there!
Your selection of tools looks familiar, needles to size the often unlabeled jets, a puffer for when you are stressed and a hammer for when you give up! I normally go for a beer and just toss it when I am frustrated. My work surface was the car hood...

Yup, the ring retainer pins go toward the intake side (as it appears in the picture) and you are right all other engines have the arrow point to exhaust.
Gary55 pointed out that he has seen a few of these engines with the arrow backwards as yours is. These engines will run either way, but the ring retainer pins need to point to the intake side or they will come loose.

The gasket is good for several uses, or you can cut up a soda can, or even use aluminum foil in some cases. I use a twisted string of plumbers teflon tape held in place with a bit of grease for assembly. The stock head is quite soft and warps easily if over torqued or you up the compression and power. I give it a quick sand every time I have it off. I'd suggest to try to modify your head to this shape and set the squish to about 0.030" by adding additional or hand cut paper base gaskets. You also gain rpm by raising the cylinder slightly.

Stock at the top, aftermarket to the left, modified stock to the front (recommended).

As for the SHA carb, I own a couple but haven't run them yet so I don't know much about them. Getting good results out of the standard NT.

Yer gonna fit in well here I think...

 

[Stoneman]

Thanks Steve, I see what your've done with the stock head and I think I've seen your post about how you did it. A little bit worried about the filling though during the process
I've just finished cleaning the ports with not actual adjustment just taking the lips off and a chamfer here and there at the bottom of the transfer ports. The casting are shocking and gasket are a bit off in places
The spare cylinder I got wasnt half as bad except for the usual hard to reach spots.
I'll have to look into this squish stuff a little more and how to get it right I think, or can I just put it back together for the time being and not stress to much about it until I learn a little more?
As it looks it doesn't look like it will squish bugger all when looking at the head and cylinder mating without the gasket. It like the head could be warped more the the squish ring if I, saying that right

I think after this I might put the NT Carb back on and play with that, little more used to the needle set up on them than this Chinese thing
I may of jumped the gun a little

Thanks for the welcome.

 

[Steve Best]

I file the burrs off the transfer ports as well. Hard place to get to, and to be honest, I didn't see (the expected) big power boost.

You will not file through the head doing the mod I suggest. Only sand the headgasket surface just enough to get it flat. These heads are too thin and warp prone as is to take big amounts off. Look for an aftermarket head with a moderate amount of squish area if you want to avoid warping. Too much squish area kills rpm and top speed. All the aftermarket heads resist warping well. All work well for cooling in my cool climate but some may not cool well in warm climates.

Squish is this area between head and piston, not the gasket crush area like one member was saying:

Another view:

What I did on the head below was enlarge the squishband width and match the angle and diameter to the piston.
The white grease and aluminum plate are for doing a cc volume check.

The volumes are almost exactly the same but the lower head makes much more power throughout the entire rpm range.
Small change, big effect.

The NT carb works surprisingly well for as simple and cheap as it is.
I am running the stock 44t sprocket, my bike will take off from a stop with no pedaling and will motor up any highway hill. Top speed is 35-37 mph at present but I was able to achieve 40mph with a differently ported cylinder and this cylinder head. That is 10,000 rpm with the 44t sprocket! That rpm not recommended for long term durability.