Cam decompression mechanism

[2SlickNick]

Hey guys,

I recently pulled the gov on my 6.5hp clone.
Put everything back together reset valve lash at TDC.
Occasionally now on about every 3rd pull, the pull cord is pulling back; hard.....
Once started it runs as it should.
I have read this it the compression relief mechanism causing this.
Is this true?

So...Back into side cover huh?

Can I or do I pull and remove the mechanism or just adjust it?

 

[OND]

Nick, I would check your valve lash, If the exh. valve is loose It will kick back. Valve adjustments are .003 on Int and Exh but I run mine tighter.

 

[ole4]

Make sure you are at TDC or a few degrees after TDC. The decompressor holds the exhaust valve open slightly till right near TDC so if you just turn the motor onto compression and are not quite at TDC and then set the ex valve clearance it will wind up being too much decreasing or eliminating the effect of the de-compressor.

 

[2SlickNick]

True...
Thanks.
I was thinking maybe the mechanism was stuck open. Because it doesn't do it with every pull. I was thinking it only doing it on the compression stroke.
I will recheck my lash first.
I did set it to the .1mm as called by manual.
But will go with the tighter .003"

 

[2SlickNick]

Make sure you are at TDC or a few degrees after TDC. The decompressor holds the exhaust valve open slightly till right near TDC so if you just turn the motor onto compression and are not quite at TDC and then set the ex valve clearance it will wind up being too much decreasing or eliminating the effect of the de-compressor.

Thanks,
Makes sense... I will try again.

 

[davidlamb78]

I had the same thing happen, and I couldn't figure out what was going on. I set the lash correctly, but it was ripping the pull start out of my hand. I ended up going back just to check the lash, and, sure enough, it had loosened. That was when I learned that after setting the lash, spin the crank a few times and continue to check lash several times.

 

[lawn-boy biker]

That was when I learned that after setting the lash, spin the crank a few times and continue to check lash several times.

Is this not standard practice? Just sayin.

 

[davidlamb78]

Is this not standard practice? Just sayin.

Oh, I'm sure it is. But, nobody ever taught me how to do this. I learned on my own. They always say, "Experience is the best teacher." In this case, I have to agree. I know exactly what it feels like to have that damn pull start ripped out of my hands. When someone says they're having the same problems, it helps me relate, and hopefully, diagnose their problem as well. I grew up in a home where nobody changed the oil in the car. Mechanics did everything. I always liked the oil and grease. I totally swapped out the front suspension of my first truck in my parents' garage with nothing more than a socket set and a borrowed spindle fork. I always try to do my own work when it comes to maintenance (and just about everything, for that matter). I usually learn from doing. We didn't have YouTube when I was a kid. I had a knowledgable neighbor who enjoyed seeing a kid get his hands dirty. My clone was the first motor I've ever totally disassembled and reassembled, and I didn't have a manual for that. I did have YouTube, but there were many videos out there on these little motors at that time. I hope to pass all of this down to my kids, and helping out folks like 2slicknick is always fun. So, Let us know what you find out Nick. I hope it works, and, if it is valve lash, I bet you'll never forget to spin that crank a few times and recheck it before you slap that valve cover back on.
Ride safe,
Dave

 

[Norcalputput]

If you remove It the is no chance for it to come loose and reek havoc in the engine
A lot of guys hate starting the engine with a pull starter and no compression release there's a learning curve to it but once you have it down it should be no problem


Sent from my iPhone using Mores code

 

[2SlickNick]

Funny thing.... I did not happen again; weird.

I did reset my valve lash at .003"
Even cycled through a few times back to compression stroke and tdc.
It did remain the same.

Looks like I will not be messing with cam.

All seems to be well now.

Thanks guys.

 

[Dragbikemini]

When release is sticking it will run but with no power and will not kick back. If you run oil level high it can mess with it. It is taking out when you want to make sure it wont mess with the engine running. like low oil sensor in turns on a kart.