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-   -   Ironhead 69 xlch won’t start (http://xlforum.net/forums/showthread.php?t=2079722)

rykk69 5th July 2021 02:20

69 xlch won’t start
 
Hi folks- new member here. Bought a 69 xlch in Dec. It was not running when I bought it but seemed in decent condition. Pulled the motor and rebuilt top end, new rings. Sent magneto to joe hunt for rebuild. Put everything into a Flyrite choppers gunslinger hard tail frame and have been trying to get it started last two weekends. It has a vintage Mikuni vm38-9 carb. Last weekend I got it to pop a couple times. Pulled the plugs and grounded and kicked in the dark- I am getting a spark. I sprayed gas into carb throat and got it to pop a couple times, then almost start (had throttle held wide open)- ran for like 1 second. I pulled the carb and took apart, cleaned checked everything- seems fine. Tried again today, adding some starting fluid into the mix. Same thing. Rechecked magneto timing- seems correct. It pops and seems to pop out of the carb when it “almost” starts. I did have the cam gears out, but carefully followed installation instructions.

I am not sure what to try next. I know there is lots of knowledge and info here but sometimes hard to figure out what’s relevant for a magneto kick only xlch. Any help would be very much appreciated!

doodah man 5th July 2021 04:41

Still have the left grip advance/retard control? Is the enrichener lever pushed down all the way on the carb when kicking? Jack the throttle slide screw in a bit (faster idle) and see if that helps, if it’s too fast an idle you can always dial it back down.

kitabel 5th July 2021 04:51

Don't touch the throttle when kicking.

doodah man 5th July 2021 04:59

Quote:

Originally Posted by kitabel (Post 5903205)
Don't touch the throttle when kicking.

+1 the further you open the throttle slide, the less it meters through the starting circuit.

Whitewalls 5th July 2021 07:34

This brings back memories. I had a very similar problem on my bikes first start after rebuild. My dumb ass didnt have quite enough gas in the tank. The fuel level was just barely below the draw tube in the tank.
Disconnect the fuel inlet hose at the carburetor and hold it over a container then open your petcock to make sure you have good flow.

Also. I know everyone says to not touch the throttle when starting a VM38-9 with the choke/enricher on. When I have a difficult cold start after many kicks I hold the throttle open about 1/4 turn and it usually starts.

rykk69 5th July 2021 17:28

Thanks for responses. No, I don’t have the left side advance control, but have tried manually rotating the magneto to advanced position.

First thing I checked was fuel flow from tank - it is good.

I tried with enrichener down, not touching throttle. Played with idle and air screw. No joy.

Also, I did check intake manifold o-rings - seem ok. I am tempted to buy a new Mikuni vm38-9 (see them online for $125-$150) and throw it on.

Iron Mike 5th July 2021 17:47

If the idle speed screw is cranked in too far, you will not pull fuel through the enrichener circuit on initial prime kicks. That will hold the slide up too far and allow air through Venturi and not pull through circuit.
Try backing speed screw all the way out on prime kicks, to allow a full pull on enrichener. Three good primes with no throttle or ign. Then when fuel is primed, use throttle to raise slide 1/4 throttle.
If it coughs, restart procedure.
Sounds like your not getting enough fuel, if all else is correct.

brucstoudt 5th July 2021 22:35

rotating the magneto to the advanced position will not help it start.popping through the carb is a sign of being advanced. it will start easier slightly retarded.Mike mentioned prime kicks,are you familiar with the procedure?

Ferrous Head 5th July 2021 23:59

Back to basics.

3 things needed to start this engine.
1. enough compression
2. a spark at the right time
3. correct air/fuel mixture going in.

1. we assume with a rebuilt top end ( and you can feel it when you kick it) that no. 1 is not the problem.
2. I check for this problem with starter spray - just like you did. A full 2 second spray into the open throat should allow the engine to start and run for 1-2 seconds.
3. I have discovered a quick and simple sanity check for this. I bought a $59 Chinese "fake" S&S Shorty from eBay. I can substitute for any suspect carb and it tells me if that's the problem.

Two caveats.

1. These engines can and will "nearly" run with the timing out. Even by 360 degrees.
Just double check that your on compression on the front cylinder and using the narrow lobe on the magneto cam.

2. I check both cylinder with a compression gauge. This is the first tool I reach for as it will tell you so much, quickly. I know you rebuilt the top end but a check on your work can be done this way. Also tells you the push rods are correctly adjusted and your cam timing is good.

Of course, all of this is only my opinion, others may disagree.

Whitewalls 6th July 2021 00:22

My experience with the VM38-9 is it seems pretty fool proof. My bike typically starts within 3 kicks cold and 1 kick warm or hot.
I have never used prime kicks. My idle screw is turned in tight at cold start and I adjust it after warm up. My air screw is about 1 1/2 turns out.
As Brucsstoudt says it sounds like it's not getting fuel if all else is correct.


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