Author Topic: Air Filter Woes--Reversion?  (Read 249 times)

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AgentX

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on: September 19, 2019, 02:51:18 PM
Hey all.

My Fireball is running pretty damned well lately.  However, there's an issue I've been having with my air filter.  I have the Ace airbox mounted, and after ruining paper filters in the rain, I switched to a K&N and Spectre re-oilable cloth filters.  I never had a paper on for very long, but both the re-oilable filters exhibited the same issue: the rubber shrank and hardened, and in the case of the K&N, the oil on the filter medium disappeared very quickly, like within a ride or two.

My conclusion is that reversion is soaking the filter with gas.  Any advice on how to fix this?  It's the standard TM32 for a Fireball, with a 190 main (was getting fuel starvation WOT with the 185) and a P6 emulsion tube.  Forget the pilot size...perhaps 25?  I never changed it from the stock jetting provided by Chumma when I got it from Ace, anyhow, and it idles fine.

Do I just need to go to a bellmouth with a screen and forget my air filter issues???


ace.cafe

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Reply #1 on: September 19, 2019, 03:24:03 PM
Reversion is highly doubtful. The intake overlap period is considerably shorter than with stock cams.

Maybe try painting the rubber parts of the filter with Plasti-Dip to protect it. Maybe that might help.

You can go to a bellmouth if you want. It will shorten the time until you need a valve grind.



AgentX

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Reply #2 on: September 19, 2019, 04:31:54 PM
Well, something is getting gas in there and affecting the filter...if not reversion, I will need to find what else could be causing it.

I had a crumb of fuel line stuck on the float needle a while back and that killed the previous air filter (along with general sporadic overflow) but that's now fixed.


ace.cafe

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Reply #3 on: September 19, 2019, 04:33:15 PM
If float level is too high, gas can come out of the carb mouth.


AgentX

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Reply #4 on: September 19, 2019, 04:35:43 PM
Yeah, will definitely check that.  Need look up the spec float height for tm32.


AgentX

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Reply #5 on: September 25, 2019, 03:21:19 AM
Damn, thought maybe I caught the problem but incorrect.  Grrr.  Back to the drawing board.


*Whatever.  I'm dropping a mm off the current float height and seeing if that helps.  And putting in a paper filter.
 Done for now...
« Last Edit: September 25, 2019, 05:17:36 PM by AgentX »


ace.cafe

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Reply #6 on: September 26, 2019, 02:05:01 PM
Damn, thought maybe I caught the problem but incorrect.  Grrr.  Back to the drawing board.


*Whatever.  I'm dropping a mm off the current float height and seeing if that helps.  And putting in a paper filter.
 Done for now...
Watch your mixture. Lower float level can affect it.

Regarding filters, I always though the paper ones were best anyway.
You can make a better rain shield for the front if you need it. I just made a cheap one because most people didn't use it anyway.


AgentX

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Reply #7 on: October 05, 2019, 03:16:19 AM
Actually, I already made a huge Kydex rain shield for the front, but that doesn't really help when it's sitting outdoors in the rain...

Float level change was minimal, but didn't change anything.  It still gassed out the filter when I left the petcock open for a few hours as a test.  I just have to be diligent about shutting it off for now, looks like.  Maybe the needle isn't seating, but it seems to hold up to rudimentary tests I've done with both gas and air.


ace.cafe

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Reply #8 on: October 05, 2019, 01:53:39 PM
Check your oil for fuel contamination.
If the needle doesn't seal for complete fuel shutoff, the fuel can also run down into the engine.
It is always best to close the petcock at the tank.

One time on my Ducati, I left the petcock on, and it filled the crankcase with fuel because the needle/seat failed to seal completely.