212 hemi misfire

[aham2003]

The 212 on my kart is running rough. It's a brand new motor. Stage 1 kit and governor removed with an 8 degree timing key. The first thing I can think of is when I removed the governor the cam came out and the pushrods fell out. Got everything back in right, but do I need to check the valve lash? The only thing that happened was the push rods came out. I put them back in and put the valve cover back on. Ran great the first 2 or 3 days. Now after coming out of a hard throttle I get some serious missing in it. Any ideas?

 

[mckutzy]

Re check the lash...
What is this stage 1 kit you bought....like whats in it?
Why a new timing key?

 

[aham2003]

Stage 1 is intake, header and bigger fuel jet. I used the timing key really just because it came with the kit. I did this exact same thing on my previous mini bike build and had no problems at all. The only other thing was that it had 18lb valve springs. The lash should be .003 on intake and exhaust while at TDC, correct?

 

[leesiel]

Not saying this is your problem.....but I recently sheared an 8 ° timing key took me months to figure it out.
Takes 5 min to check; that's where I'd start

 

[aham2003]

Not saying this is your problem.....but I recently sheared an 8 ° timing key took me months to figure it out.
Takes 5 min to check; that's where I'd start

Ill definitely check that in the morning. May just put the stock key back in it.

---------- Post added at 05:31 PM ---------- Previous post was at 05:28 PM ----------

When I set the lash to .003 at TDC and pull the cord to cycle through the compression stroke, the lash goes way way out. Almost out enough to make the push rod come out from under the valve. The last motor didnt to this when I set the lash. Pulling my hair out.

 

[Bbqjoe]

You put the rod back in, but it's not properly seated in the lifter.

Go fix it.

 

[Jfive]

Lash is adjusted when valves are closed. So if one valve is partially open you need to turn it over to adjust so that your adjustments are when the valves are closed. If a valve is closed and you adjust and lose lift then I'd suspect a bent push rod or cam has a flat spot or is bad. You would need a magnetic dial indicator to verify though. I'd pull the rocker arm off and try to spin and verify this somehow. Things like this justify buying a dial indicator. http://m.harborfreight.com/clamping-dial-indicator-93051.html

 

[aham2003]

Lash is adjusted when valves are closed. So if one valve is partially open you need to turn it over to adjust so that your adjustments are when the valves are closed. If a valve is closed and you adjust and lose lift then I'd suspect a bent push rod or cam has a flat spot or is bad. You would need a magnetic dial indicator to verify though. I'd pull the rocker arm off and try to spin and verify this somehow. Things like this justify buying a dial indicator. http://m.harborfreight.com/clamping-dial-indicator-93051.html

Are both valves closed when at TDC?

 

[Bbqjoe]

Are both valves closed when at TDC?

Yes.

 

[aham2003]

Can't even get it to turn over now. I've checked everything. Tried the lash at .003 and even tried it at 0 lash. I really don't wanna take the engine off and pull the crank cover off of it but I guess I'll have to.

 

[Bbqjoe]

Can't even get it to turn over now. I've checked everything. Tried the lash at .003 and even tried it at 0 lash. I really don't wanna take the engine off and pull the crank cover off of it but I guess I'll have to.

It won't pull, or it won't start?

 

[aham2003]

It won't pull, or it won't start?

Won't start. It rolls over fine. I took the 8 degree key out and put the factory key back in.

 

[Bbqjoe]

Have ya got any spark?
Is there any compression?
Are you sure it's filled with gas?

 

[Jfive]

On off switch, fuel petcock, lots of variables to consider.

 

[Bbqjoe]

Here's what I'd do.
Pull the engine out, and set it on the shop floor, vowing to get back to it.
Run to HF, buy another predator, leave it the fund alone, slap it on the Kart, and have fun with some worry free riding just as it is.

 

[SLJ2137694]

Yes.

TDC on the compression stroke ONLY!

 

[Bbqjoe]

TDC on the compression stroke ONLY!

SLJ2137694? How do you even pronounce that?
Is that what all your friends call you?

Do you have any friends?
Do they even call?


Just curious.

 

[bob58o]

I think I remember reading something about the 18lb springs in the Hemi????
Don't remember what it was... Some people had issues IIRC.

Anybody?????

---------- Post added at 01:20 PM ---------- Previous post was at 12:59 PM ----------

Or was it the 22lb springs in the non hemi? I don't know. Did you check for coil bind?

 

[aham2003]

I think I remember reading something about the 18lb springs in the Hemi????
Don't remember what it was... Some people had issues IIRC.

Anybody?????

---------- Post added at 01:20 PM ---------- Previous post was at 12:59 PM ----------

Or was it the 22lb springs in the non hemi? I don't know. Did you check for coil bind?

I did a Hemi with 18lb springs a few months back. Didnt have this issue.

Can you explain coil bind?

 

[bob58o]

As far as I can tell.... When the valve springs are installed and the camshaft lifts the pushrod to open the valve, the valve spring compresses. If the spring compresses where one coil is touching the next one, this is no good. When at max lift, there needs to be space between one coil of the spring and the next one. Not sure the the exact spec, but a feeler gauge can be used to check spacing between the compressed spring coils.

I remember the 18lb springs being longer than the stock ones and the 26lb ones. They need to be compressed more to install, so I was just wondering. I have some 18lb springs but never used them as my cam wanted 26lbers.