Finally figured out my Dellorto problem...

ducktape · 06-05-2010, 04:23 PM

And it's all my dumb fault, as usual.

Anyone at the DGRR probably saw the car running badly. Dellorto DHLA 48 ON A 12A. It was rich as hell at idle, and wouldn't rev over 4500rpm.

The problem as I saw it was the main-jet circuit would never work. I had hogged out the idle jet, and that would allow it to rev to 4.5k at maybe 10% throttle, anything more and it would lean out completely and just cease running.

My buddy Kevin spotted the problem after a couple hours messing with it. I'm kind of ashamed to cop to it, but it was my dumb mistake...

I had modified an IDF air filter to fit on the DHLA...

The carb:

The filter:

So what's the difference here? Notice the hole in the filter baseplate between the two barrels? That's where the IDF jets get air. Now look at the DHLA, notice the hole above the left barrel? That's where the DHLA jets feed. That port was COMPLETELY blocked by the baseplate of the air filter!

It took 2 seconds to drill a hold in the baseplate to feed the jets, and now the car runs like a champ.

I can't believe I didn't catch that the first time. Duh.

hecmanortiz · 06-05-2010, 05:21 PM

Great stuff man. I'm grinning because I'm just now starting on an FB revival and can't wait to see what boneheaded stuff I'm going to do to it.
Glad to hear your ride is running better.

06-05-2010, 04:23 PM	#1
ducktape Hardcore Join Date: Apr 2010 Location: Louisville, Ky iTrader: (0) Posts: 88 Rep Power: 15	Finally figured out my Dellorto problem... And it's all my dumb fault, as usual. Anyone at the DGRR probably saw the car running badly. Dellorto DHLA 48 ON A 12A. It was rich as hell at idle, and wouldn't rev over 4500rpm. The problem as I saw it was the main-jet circuit would never work. I had hogged out the idle jet, and that would allow it to rev to 4.5k at maybe 10% throttle, anything more and it would lean out completely and just cease running. My buddy Kevin spotted the problem after a couple hours messing with it. I'm kind of ashamed to cop to it, but it was my dumb mistake... I had modified an IDF air filter to fit on the DHLA... The carb: The filter: So what's the difference here? Notice the hole in the filter baseplate between the two barrels? That's where the IDF jets get air. Now look at the DHLA, notice the hole above the left barrel? That's where the DHLA jets feed. That port was COMPLETELY blocked by the baseplate of the air filter! It took 2 seconds to drill a hold in the baseplate to feed the jets, and now the car runs like a champ. I can't believe I didn't catch that the first time. Duh.

06-05-2010, 05:21 PM	#2
hecmanortiz Rotary Fan in Training Join Date: Aug 2009 Location: Hamilton, Ohio iTrader: (0) Posts: 40 Rep Power: 0	Great stuff man. I'm grinning because I'm just now starting on an FB revival and can't wait to see what boneheaded stuff I'm going to do to it. Glad to hear your ride is running better.