Idle issues HIF44

Started by bikewiz, September 09, 2022, 09:53:20 AM

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bikewiz

Motor specs 1293 mild cam (not entirely sure on cam spec) HIF44, BBW needle, LZX2085 damper red spring, MED stub stack with ITG foam filter, LCB RC40 SS DTM exhaust, mechanical fuel pump.

So I had a leaking float bowl so I while I had it apart I replaced the jet and float bowl gasket, set everything to spec float height, jet height etc. Had 94 octane non-ethenol gas in it. Fired right up and ran great, idle at 850-900 rpms.  Drove around 200 miles put 93 octane gas in, ran fine for another maybe 50 miles. Started the car Saturday ran like shiite, rough on choke, wouldn't idle off choke. Checked oil in damper OK (SU damper oil 20w) Checked vac advance for cracks, sprayed carb cleaner around pivots to check for leaks, nada. Ran the car a bit and adjusted the idle after warming to 850-900 ran OK but felt like maybe it was running lean around 2000-2500rpms. Started it today started OK but ran rough until it warmed but still had a unstable idle.

What should I check? Is it just crappy gas? I'm pretty sure the tank is clean, when I had the carb apart it didn't have any crap in it. I ordered a couple needles (BFY + BDL) to try but really I'm just guessing....

I feel like Elmer Fudd I'm hunting a stable idle huh huh huh......

MiniDave

Check the choke o-ring.....when they fail they do all sorts of weird running things.

Also, check the breather pipe if you have one, or block off the breather inlet at the carb just to check.

I wouldn't change a needle just yet - if it ran well before on this needle, unless it's broken or come loose or something, it should run fine on it now.
Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad

bikewiz

That may make sense, it would expand when it gets fully warm and change the a/f, I'll try and replace it.
I have the breather blocked off and the float chamber overflow piped away from the exhaust.

Thanks for that Dave.

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