Rebuilt Motor And Wont Start... Why!!!???

[samv6912]

Hello to anyone who is willing to help. I have rebuilt a 4k motor to go into my Ke30. Everything went together as it was suppose to, nothing was out of place. Now the motor is back in and wont start. I have checked everything you can think of. It has plenty of spark plenty of fuel, distributor is in correct (checked 7 times, the firing order is correct. Any thoughts? Anyone? Its doing my head in.

[beerhead]

Does it crank over really quick? Could be the cam timing, a compression tester will tell you if its definitely out of whack.

[jono1986]

So you have fuel, spark and obviously air....Do you have compression when you should have compression, did you install the cam properly. One way to check is to take off the cam cover and rotate the engine til the little mark on the main pulley is at the 0 mark on the sprocket cover thingo. Both valves should be closed. Does it fire at all, like are you getting back fire.....Or I just thought of this if you put your hand over the carby and crank (with the coil unplugged so it doesn't blow your hand off) does it blow or suck when cranking.

[samv6912]

Does it crank over really quick? Could be the cam timing, a compression tester will tell you if its definitely out of whack.

 

Thanks.. Ill check in the morning.

[samv6912]

So you have fuel, spark and obviously air....Do you have compression when you should have compression, did you install the cam properly. One way to check is to take off the cam cover and rotate the engine til the little mark on the main pulley is at the 0 mark on the sprocket cover thingo. Both valves should be closed. Does it fire at all, like are you getting back fire.....Or I just thought of this if you put your hand over the carby and crank (with the coil unplugged so it doesn't blow your hand off) does it blow or suck when cranking.

 

 

Hey, I am pretty positive the cam is in correctly but I will check in the morning. it does back fire a little but thats all. thanks for your help.

[jono1986]

It could also be the valve clearance, not letting the valve fully close.

[samv6912]

so I have done every thing, the cam is in the right spot. Crank mark on TDC, No1 valves are both closed, rotor button is facing No1. valve clearances are all good, It has good compression... What else could it be?

[altezzaclub]

Can you see fuel being pumped down the carb when you work the accelerator?

 

or crank it over with your hand over the top of the carb and it should suck hard, wet your hand with fuel and fire up... the ultimate choke.

 

 

...and you're sure the ignition timing is correct, the dizzy turning the right way and the coil sparking about 10deg BTC. Has it backfired or coughed at all? or just completely dead?

Edited December 17, 2010 by altezzaclub

[samv6912]

Can you see fuel being pumped down the carb when you work the accelerator?

 

or crank it over with your hand over the top of the carb and it should suck hard, wet your hand with fuel and fire up... the ultimate choke.

 

 

...and you're sure the ignition timing is correct, the dizzy turning the right way and the coil sparking about 10deg BTC. Has it backfired or coughed at all? or just completely dead?

 

Thanks for your help guys... appreciate it.

 

Is it possible for the dizzy to spin the wrong way? it has back fired abit. I have twin 40 webbers on it so its hard to see if fuel is getting in there (you can smell it) and it was doing the same thing with the stock carby on it.

Edited December 17, 2010 by samv6912

[jono1986]

The distributor is connected to the cam shaft via a metal shaft so no, unless you have put the battery in backwards and the motor is cranking backwards. Make sure that you have indeed made sure that the timing is correct and you DO have spark. What your describing to us is impossible to fix with out going to a professional carby tuning place or seeing it in person.

What condition are the webers? are they both tuned in sync with each other or if it's even tuned at all? are you using an aftermarket fuel pump?

[altezzaclub]

No, dizzy can't spin the wrong way, and if you have cyl 1 on compression at TDC and the rotor points to #1 lead you're right. Easy enough to check the timing either with a light or ign on and cap off while you turn by hand and listen for the points spark.

 

I've also seen points set up so they were closing around TDC not opening, on the assumption the rotor spun the other way. Make sure the leads are 1,3,4,2 in the direction the rotor actually turns...

 

So if you have spark at the right time and tappet gaps to close the valves, it really only leaves petrol. You'd need a mirror to see the fuel jet in a sidie, but usually they pump so much fuel around its no problem. Do you have the chokes hooked up?

[samv6912]

the thing is that all is as you say... it has everything it needs to start (SO FRUSTRATING!!!). even if the carbs werent in sync it should still start and run ruff. I have a mate who is going to come over and brain storm with me soon so ill let you know how it goes.

 

Thanks again

[samv6912]

Well I have finally sorted the problem all that was wrong was that the dizzy was 180deg out. such a relief.

 

Thanks again for your help.