Pull cord tension so high after valve spring change

#1
Hey crew,

So I have a newer non-hemi 212 predator. I applied the stage 1 kit form OldMiniBikes and also added a flywheel to the equation. I added most of the parts and noticed that after the fact the pull cord was soooooo tense when trying to pull the engine by the valves. I did some trail and error and removed the valve spring and replaced with stock ones and it went back so a smooth pull. Can anyone shed some light on this if it is extremely hard to pull over the engine once you put on the 18lb valve springs? I thought it wouldn't be too bad as these are basically the lightest performance springs you can get. Maybe the valve lash is too tight? I set them at the stock specs but maybe they tightened up after an hour or two of use. I literally broke 2 pulls trying to start it and i usually need someone to sit on the bike when I pull it over so i don't pull the bike up with the cord...

Any advice or recommendations would be appreciated.
 

SAS289

Well-Known Member
#3
One thing for sure is that the valve lash adjustment is the same whether you have 10 lb or 18 lb springs. You need to double check the lash with the 18 lb springs installed. Find TDC and adjust the lash at that point.
 
#5
Thanks guys,

Ill start with the lash again. It was slightly difficult setting it and then tightening the lock nut. It would slightly tighten it more when tightening down the lock nut.

Also, would you expand on the potential of coil binding? I'm not familiar with what that is or what to do about it. Thanks
 
#6
To eliminate coil bind as your issue. Remove the spark plug and see if it is easy to pull over. If it is then it is not coilbind. Coilbind is when you compress the valve spring and the coils stack up with no space between the coils. It can happen with changing valve springs on the hemi predator. Most likely it’s a loose exhaust lash.
 
#7
Thanks guys,

Ill start with the lash again. It was slightly difficult setting it and then tightening the lock nut. It would slightly tighten it more when tightening down the lock nut.
It may take you some tries to get it right. You'll get a feel for it once you've done it enough times. I always go a bit loose as I know it'll tighten up some more once everything is locked down.
 

GustoGuy

Well-Known Member
#8
Thanks guys,

Ill start with the lash again. It was slightly difficult setting it and then tightening the lock nut. It would slightly tighten it more when tightening down the lock nut.

Also, would you expand on the potential of coil binding? I'm not familiar with what that is or what to do about it. Thanks

I also needed to adjust my valves a few times on my modified Predator 212cc since my bike kicked back sometimes when pull starting it. I played around with the adjustment and rotated the engine back and forth a few times while adjusting and measuring with the feeler gauge and right now it pull starts smoothly with no kick back at all.
 
#9
To close out this thread I have found the issue and learned a few things. It was not coil bind as a member stated pull the spark plug and the engine should move freely which it did. I did some research online and did some toying around. Apparently there is only one top dead center. The piston raises twice in the actual combustion of the engine and you need to make sure it is at the top of the cylinder after the intake valve has collapsed and released, not after the exhaust valve has collapsed. This was not good as I was driving it around with some seriously loose valves and I hope has not caused any permanent damage. Once I found that out, I adjusted the valves to the correct spec and it pulled over at a pretty much normal resistance. I should have known and am a little embarrassed about it but its all good now and hopefully this can help people in the future.
Thanks to all that commented suggestions.
 
Top