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Old 07-21-2004, 08:11 PM
jameskirk1 jameskirk1 is offline
Join Date: Mar 2004
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Attn: Demon Owners

Thought that this might help some one out at one point or another; and I also know that "BG-Tech" may read this as well so they might put it in their memory banks...

I've got a 625cfm Road Demon Jr. on my mouse equipped S-10. It hasn't EVER ran right at idle. Truly awesome response at all other engine speeds, but ALWAYS a rich idle that I could never figure out or tune out of it. I had initial timing set everywhere from 6 to 18 degrees before; no help. The air bleeds were clean. The power valve wasn't leaking. I reset the butterflies/transfer slot so many times I could do it in my sleep. I could shut the idle adjustment screws in all the way and it wouldn't die. I sent Barry Grant Tech e-mails, and read a LOT of posts on this forum, but to no avail...


I had pulled down and cleaned the metering plates and bowls off numerous times on both the primary and secondary side to clean/inspect thoroughly. Something I never did was pull the base plate off of the main body. Well, I was at my wits end, and decided to pull this off as a last resort, just to check before I ordered a fuel injection system (ha ha)...WELL, from the Demon factory, the gasket that seperates the baseplate from the main body was "off"!!! It was scooted over and "rotated" by a few degrees, and this was allowing the idle discharge port to pull all the extra fuel mixture it wanted from the transfer slot!!! (The sealing surface between these two holes is less than a 1/8") So I "re-aligned" it, and have put many test runs on it since, and let me tell you, it truly runs great. I have cured my problem.

I'm not bashing Demon, it is an AWESOME carburetor, worth every penny. And I figured even if I helped even one poor soul scratching his head out there, it would be worth writing about...Cause that's what forums are about.

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