Head kit problems

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topdog802

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Hey, I just installed a race ported 28.5 head kit from ddm. I can't get it started. I've gone through the engine many times double checking everythng, got good spark, no air leaks that I can find, gas and such. One thing that I noticed is when the engine is at BDC I can't see the top of the piston on the intake side so the gas is going into the crank case. Any help would be great. Thanks
 
This happens to a lot of people including me. I put mine together, couldnt get it started, gave up, came back later, got it started. Check your to and from lines on the carb. Check your spark. I don't have the answer for this phenomenon, it just happens. Keep trying. Is your mark on the piston to the exhaust? Theres lots of things it could be....Id say set it down and look at after your head clears. It may even be flooded.
 
http://www.davesmotors.com/s.nl/c.885035/n.1/it.A/id.4170/.f.


This is the head kit I got, i'm running a brand new 668. The arrow on the piston is pointing at the exhaust port. I've had time to sleep on it so I'll put it back together and try to start it again. It anybody has anyother ideas please post. Another question i should see the top of the piston on the intake stroke at BDC?
 
Did you check spark condition/quality? Coil gap is correct? One time I couldnt get my carb to prime the new head kit so I had to do it by mouth but make sure you take off the fuel cap if you do it :p Ive always got them started by giving up the first time and coming back in an hour 2. Is your air filter unobstructed? Carb needles 1.5 1.25? Like I said this is a phenomenon. Brand new headkits even when assembled 100% correctly usually don't like to start the first time.
 
Try putting a little 2 stroke oil in the cylinder, it helps a new motor make enough compression to start for the first time....... :D
 
Thanks for the pointers, I gapped it correctly, it has a new spark plug. The carb gets gas as the primer bulb is full, when I look into the intake when the piston is BDC I can't see the top of the piston, is this right?
 
BDC you mean bottom dead center? Ive heard some people say before dead center. When my engine is assembled I can see it at top dead center through the plug hole but not bottom. The piston will go up and down like it should as long as you put it together right. Make sure you put in the bearing, pin, and circlips, aligned the piston ring correctly, connected the piston to the rod, and got the marking to exhaust. If your piston isnt moving up and down you probably forgot the pin. If assembled correctly you don't need to worry about seeing the piston. With headkits its rarely a parts defect so keep checking, listen to everyones advice, try again.


don't forget to check/retitghten those headbolts once you get it running! Sometimes they loosen in the first .5 to 2 tanks.
 
topdog802 said:
when I look into the intake when the piston is BDC I can't see the top of the piston, is this right?
Click to expand...
You should not be able to see the top of the piston through the intake. the piston does not travel that far down. fuel gets to the top of the piston for ignition via the transfer ports.
 
Thanks for all of the help, I finally got it going. It runs good but is a pain to re-start. Is this normal with this head kit, will it get better as it runs more?
 
That's right I plan on breaking it, ummm, I mean break it in (haha). I got a CPI big bore on the way from sprint, should be here tomorrow or Tuesday. I can't wait! Again thanks for the help!
 
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