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Author Topic: Removed air injectors/Jetting problems  (Read 1186 times)

boxerkerl

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Removed air injectors/Jetting problems
« on: June 26, 2008, 11:08:10 AM »
Over the winter I removed the emmission control air injectors on the recommendation of several friends. First, when everything is working properly, what will I have gained, other than losing a few pounds of weight and the ugly piping?

The real problem: the bike ran GREAT before, after it was way lean. On the recommendation of several knowleable folks, I increased the main jet and pilot jet and I thought I was close to getting it right, then I increased the needle jet. Again, I thought it was close, but after long test rides I find one cylinder lean and one rich, along with a lack of power. I did find an air leak on the lean cylinder, and there is less difference in the 2 now. Compression is OK 148/152 psi. Plugs are new. Both needles in middle position. I'm borrowing a timing light to check timing, but it was (seemed) OK before removing the air injectors...so before I replace all the original jets and start over, I'd like to hear from guys who have removed the air injectors, and how you got your bikes to run right afterward.

Thanks in advance!

Offline Justin B.

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Re: Removed air injectors/Jetting problems
« Reply #1 on: June 26, 2008, 01:06:27 PM »
I've not had to re-jet after pulling the smog hoses on three bikes I have done.
Justin B.

2004 BMW R1150RT
1981 R100RT - Summer bike, NEKKID!!!

Offline MrRiden

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Re: Removed air injectors/Jetting problems
« Reply #2 on: June 26, 2008, 07:35:21 PM »
You don't say so It begs the question: How did you plug up the holes left in the head & Airbox? Also did you plug the vacuume takeoff ports at the carb? Maybe silly questions but like I said above  :)
rich

who has a perfectly operating fresh air system on his bike.
"We can't stop here. This is bat country".

Offline Justin B.

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Re: Removed air injectors/Jetting problems
« Reply #3 on: June 26, 2008, 07:40:09 PM »
Wuss!  
Justin B.

2004 BMW R1150RT
1981 R100RT - Summer bike, NEKKID!!!

Offline MrRiden

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Re: Removed air injectors/Jetting problems
« Reply #4 on: June 26, 2008, 08:17:21 PM »
Quote
Wuss!  
I prefer purist! Now go change out some old light bulbs for the energy saving ones to atone for your carbon sins!  :)
rich
BTW I do agree with Justin, no carb fiddling should be needed!
http://www.webbikeworld.com/Motorcycle-technical-articles/pulse-air/
"We can't stop here. This is bat country".

Offline nhmaf

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Re: Removed air injectors/Jetting problems
« Reply #5 on: June 26, 2008, 10:55:31 PM »
I still have my air system in place, though the more I take the airbox off the more I think about getting rid of all that snorkely gear in there - also makes removing the
carb bowls easier.   I agree with all the above, that air injector system should not have any significant effect on your mixture - the air is injected at the  exhaust valve port
and not into the combustion chamber for ignition.  Without all that snorkely valve stuff crammed into the airbox, you will have slightly greater air-flow to the carb horns, but I
cannot imagine it is that much difference with the low vacuum the Bings pull while running, MAYBE need a very slight tweak to the air mixture screw at most, I should think.

Do you have non-stock exhaust on the bike ?    Normally, folks set the air/fuel mixture screw approx 1/8 turn or so to the rich side from the point where it is too lean
such that it stumbles a bit upon starting to crack open the throttle from idle, as a starting point.  A high-flow exhaust system can cause the system to run leaner.  
That air leak  you found can certainly greatly impact the mixture. Did you adjust the valves before tweaking the carbs ?    The points about how well you plugged up the carb and cylinder head holes is also important to note, too !
Airhead #12178 ? BMWMOA #123173 ?BMWRA #33525 ?GSBMWR #563 ?1982 BMW R65LS ?1978 BMW R100/7 1998 Kawasaki Concours

not-so-fast-ed

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Re: Removed air injectors/Jetting problems
« Reply #6 on: June 27, 2008, 08:11:10 AM »

boxerkerl

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Re: Removed air injectors/Jetting problems
« Reply #7 on: July 11, 2008, 11:05:45 AM »
Hew guys, thanks for all the replies. I thought I would get email not. like another board, but...

I plugged the holes with a kit I bought at Re-Psycle.

Re-jetting was a goose chase started by a well-meaning friend.

I thought the bike was running pretty well before taking the pipes off and thought just screwing with the mixture should fix it. BUT I found loose valves, timing WAAY off, one of the airpipe plugs had loosened up, float levels not right...and the real cuplrit: semi-plugged idle jets.

I went back to original all jets except I left the the 148 main jet in. Carbs balanced OK, after a couple hours hard riding the carbon from so much idling during all the attempts to sync carbs burned off, it runs smooth and quiet.


Thanks again,
Rick

Offline Ed Miller

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Re: Removed air injectors/Jetting problems
« Reply #8 on: July 11, 2008, 12:47:22 PM »
Congratulations!



Ed Miller
'81 r65
Falls City, OR

Offline montmil

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Re: Removed air injectors/Jetting problems
« Reply #9 on: July 11, 2008, 01:48:47 PM »
Quote
...Re-jetting was a goose chase started by a well-meaning friend. Rick

Hey, what are friends for anyway?  Does friend ride a Beemer?  Wrench on 'em?

Don't get mad, get even.  Use his name and address to start filling out junk mail requests for insurance, Russian brides, religious tracts, penis enhancement drugs...  you get the idea.   [smiley=ROTFLMAO.gif]  
Monte Miller
Denton, TEXAS
1978 BMW R100S
1981 BMW R65
1983 BMW R65
1995 Triumph Trophy
1986 VW Cabriolet

Offline Semper Gumby

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Re: Removed air injectors/Jetting problems
« Reply #10 on: July 11, 2008, 05:18:53 PM »
Late to the game but all I did was reset the idle mixture with a Colortune plug installed, put the regular plugs back in and off.  No problems there...
Bill Gould ?1980/03 R65 When at first you don't succeed....Moo!