bbk

[teddy554]

i installed my bbk and motor wont start now it also seem like the intake vavle is hitting piston not sure also i dont have a spark anymore and seems like no gas is being suck in line to carb i took off hose and turn motor over no gas came out

[jmkjr72]

if you think a valve might be hitting a piston pop the head off and put some clay on top of the piston and crank the engine over slow
it will push the clay out of the way and you will see where the valves are going down if you see piston in any of these spots you have an issue if not you are good to go

as for the no spark back track every thing you did to see what is unpluged
the no gas try pulling vaccum on the vaccum line and see if you get fuel then

[90GTVert]

I just replied to a PM about this, so I'll just quote myself here as well. lol

"Take it one thing at a time. Start by figuring out for sure if the valve is hitting the piston. Disassemble and see if there are any signs of contact. Even if not, try putting a piece of modeling clay on top of the piston. Then reassemble and turn it over by hand. Pull it back apart and looking at the clay should show you if it's hitting or close to hitting. You can cut the clay with a razor and measure the thinnest bit if you desire. Use just enough clay to put a very thin layer over the parts of the piston where the valve would hit. If it does hit, you'll either need to add a base gasket to gain more clearance, basically moving the piston down in the bore, or grind a valve relief into the piston. If you mod a piston, you must be sure it's thick enough to accept the new relief and not cause weakness in the piston crown.


Next, make sure you have spark. There is a troubleshooting guide for that here...

49ccscoot.proboards.com/index.cgi?board=basicstuff&action=display&thread=647&page=1

If you get all of that straight and it still doesn't fire, then worry about the fuel issue. Easiest way to check is to spray a quick shot of starting fluid in the carb and crank it over. If it fires up that way, there's a fuel issue. Do it a couple of times and it might sort of prime itself. If not, check the lines, filter, petcock, and float height.


If it won't start after trying this stuff, post in the appropriate troubleshooting section of the forum so more than just me can try to help you out."

[speedy1125]

smear some oil on the clay with your finger to keep it from sticking to the valve. did you turn it over with the starter and it stopped turning? CLUNK! It might have a bent valve now.

[teddy554]

i got it running needed to use stock heads and stock cam,rocker assembly to work. none of the other part work correctly. stock cam and rocker ass would make motor either hard to turn ever or cause vavle to hit piston