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Bike dies off idle - 70' A65L Concentrics #8018
02/07/06 3:09 am
02/07/06 3:09 am
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JAX
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bsanorton Offline OP
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OK. One slide was sticking. Took apart & did the old channel lock & rag trick, then polished the slide & walls of carb. Put the carbs back on with new cables & all is moving freely. The bikes only barely idles. So I realized I didn't drop the bowls & clean them out! Which I always do, must have been in a rush!! Took the carbs off & found one badly clogged main jet. Cleaned all jets & bolted carbs back on, same thing. Do I take them off once again & check for clogged jets & passages? I'm usual very good at this, but have lost my patience. Used new plugs & wires. the gas is fresh with stabil in it, but the octane is only 87 could that be a problem? Battery is good & a tender is on it. Also checked for wet sumping, very little oil came out when I dropped the cover.


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Re: Bike dies off idle - 70' A65L Concentrics #8019
02/07/06 3:44 am
02/07/06 3:44 am
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Owego, NY, USA
Mark Z Offline
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Low octane gas will not cause the engine to not idle.
A clogged pilot jet, however, will. Later Concentrics have a fixed pilot jet, which resides in the hole vacated by the idle mixture screw. If you remove the idle mixture screw and shine a penlight in the hole, you will see the brass jet an inch or so down. The orifice is about .020 inches in diameter, a .017 wire is recommended for cleaning if it can't be simply blown out. Note that the passageway between the other side of the pilot jet and the fuel intake opening in the ceiling of the float chamber (where the earlier removable pilot jet use to go) must also be clear.


Mark Z

'65(lower)/'66(upper, wheels, front end, controls)/'67(seat, exhaust, fuel tank, headlamp)/'70(frame) A65 Bitsa.
Re: Bike dies off idle - 70' A65L Concentrics #8020
02/07/06 8:14 am
02/07/06 8:14 am
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Ger B Offline
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I found a good explanation, including sketches of this problem at
http://www.jba.bc.ca/Bushmans%20Carb%20Tuning.html

regards, Ger


Ger B

Re: Bike dies off idle - 70' A65L Concentrics #8021
02/07/06 10:38 am
02/07/06 10:38 am
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bsanorton Offline OP
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The bike will idle but for a very short time. If I attempt to open the throttle, she dies. These carbs have the screw in pilot jet in the underside of the carb body, I was able to clear them & visually see light thru them. I assume when I have this arrangment there is no pressed in pilot bushing I have to worry about, correct?


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Re: Bike dies off idle - 70' A65L Concentrics #8022
02/07/06 1:17 pm
02/07/06 1:17 pm
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There is a pilot jet oppostite the air screw. You just do not see it. It must be open otherwise idling is a problem.
In the drawing in
http://www.jba.bc.ca/Bushmans%20Carb%20Tuning.html
you see a screw; in your carburettors (and mine) this is a blind plug. The rest of the description is valid.

However, when your motor idles and only dies at the moment you open the throttle (this is what I understand from your message), it might be worth while to see if the needles (main jet) are in the correct position.

Ger.


Ger B

Re: Bike dies off idle - 70' A65L Concentrics #8023
02/07/06 1:35 pm
02/07/06 1:35 pm
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Thanks GER. Anybody know what postion the clip should be in? I think it's in the last starting from the top. Not home right now to get to manuals.


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Re: Bike dies off idle - 70' A65L Concentrics #8024
02/07/06 2:19 pm
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Ger B Offline
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In my A65 Haynes manual I find that for A65L with a R930/21 r.h and a R930/22 l.h. Concentric (after 1968) it is needle position 2. On the old R928/2 r.h. carb. of my A65 Thunderbolt (I replaced mine last year) which I have on my desk now this is the middle slot.

Good luck.


Ger B

Re: Bike dies off idle - 70' A65L Concentrics #8025
02/07/06 3:00 pm
02/07/06 3:00 pm
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Thanks GER, I'll check that. Just want to confirm that if i have the screwed in pilot jet, I will NOT have the pressed in pilot jet viewed from the air/gas needle, correct?


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Re: Bike dies off idle - 70' A65L Concentrics #8026
02/09/06 4:13 am
02/09/06 4:13 am
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Owego, NY, USA
Mark Z Offline
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That is correct, unless someone erroneously added the screw-in jet (even the later carbs still had the threaded hole for the screw-in jet). For peace of mind, you may want to still shine a light down the air mixture screw hole. If there is a fixed jet in there, you will see brass.


Mark Z

'65(lower)/'66(upper, wheels, front end, controls)/'67(seat, exhaust, fuel tank, headlamp)/'70(frame) A65 Bitsa.
Re: Bike dies off idle - 70' A65L Concentrics #8027
02/09/06 5:54 am
02/09/06 5:54 am
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North Georgia, USA
RF Whatley Offline
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BsaNorton -
Gee, what a shame you live in NJ. Down here in "God's country" we simply slide a banjo string (1st or 5th) into the pilot and wiggle it all around. You probably can't get those "good tools" north of the Mason-Dixon. :bigt:


Don't hide 'em, Ride 'em !!

RF Whatley
Cornelia, GA
Re: Bike dies off idle - 70' A65L Concentrics #8028
02/09/06 5:56 am
02/09/06 5:56 am
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North Georgia, USA
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PS.

Oh, and one other thing. Tell us what type of battery you have... Gell Cell, AGM, wet cell, sealed... ???

Thanks.


Don't hide 'em, Ride 'em !!

RF Whatley
Cornelia, GA
Re: Bike dies off idle - 70' A65L Concentrics #8029
02/09/06 10:28 am
02/09/06 10:28 am
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Not equiped with a Boyer, points. Wet cell battery. There is a zener/rectifier solid state replacement however, a Tympanium. My experience with a Boyer & bad battery is getting no spark at all or not enough to fire up the bike. This doesn't seem to be the case here. It will start up pretty easily, but as soon as I attempt to open the throttle she dies. Never say never though, as soon as I get a chance I'll go over the carbs & battery again. Yes, in NJ we have high tech tools, I've carried a 4 inch piece of guitar wire in my carb/jet drawer for many years now!


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Re: Bike dies off idle - 70' A65L Concentrics #8030
02/09/06 12:34 pm
02/09/06 12:34 pm
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Bega NSW Australia
Mark Parker Offline
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Are you sure the plugs haven't loaded up with carbon, if they are black, and you open the throttle you increase the load, (cyl pressure) and it can become easier for the spark to go down the carbon than jump the gap under the pressure.
If the plugs are good you might try putting your hand over the carb intake to choke them a bit and see if it'll pick up then.


mark
Re: Bike dies off idle - 70' A65L Concentrics #8031
02/09/06 5:41 pm
02/09/06 5:41 pm
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North Georgia, USA
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BsaNorton -
Well it was a long shot on the Boyer. You sound like a really sharp guy. So I can't conceive that anyone can take carbs apart several times and NOT find a problem big enough to keep the bike from running. "Running great", I'll concede; not running at all is a leap.

Therefore, I still believe you have electrical system issues adversely effecting the ignition or the timing has slipped.

When was the last time the timing was set, who did it, and was a strobe used?

:bigt:


Don't hide 'em, Ride 'em !!

RF Whatley
Cornelia, GA
Re: Bike dies off idle - 70' A65L Concentrics #8032
02/10/06 12:25 am
02/10/06 12:25 am
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New plugs were used, new plug wires. Not claiming to be 'the sharpest tool in the shed, LOL!!'. what puzzles me is that when I bought the bike, it revved real good. That's why I didn't drop the bowls to inspect when one carb slide was sticking, fixed that & replaced the cables. After the problem appeared, it was then that I opened to bowls to take a good, & boy was one carb really clogged! Still can't believe that it got so cloggeg within a month or so. I haven't been able to dig back in yet, but will go over the electrics & carbs soon. I haven't hit it with a strobe yet, cause I can't bring it up to speed! I'll have to do static timing 1st.


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Re: Bike dies off idle - 70' A65L Concentrics #8033
02/10/06 12:52 am
02/10/06 12:52 am
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If your carb got clogged in a month and your jets, what are your gastank petcock filters like? Could be they are almost clogged. Stalling off an idle usually is not enough fuel for the extra air. A serious tank clean might be a start.

Re: Bike dies off idle - 70' A65L Concentrics #8034
02/10/06 3:43 am
02/10/06 3:43 am
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North Georgia, USA
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Whiz Kid -
Yes, Pat most certainly has an idea there. If the bike sat for long enough, all the old fuel would have evaporated leaving a huge amount of scum lining the tank. The new fuel would have loosened all that up and allowed it to clog all the screens. The time span of one month is about right too.

Suggest you turn your tank up-side-down over a towel to catch all the scum and check it out. Then unscrew the petcocks from the bottom of the tank and clean their screens. While the petcocks are out a good wash might be in order as insurance.

While you're at it, check the breather vent hole in the cap. Not that I think that's a fact right now, but with that much fuel evaporating it may be the next issue.

:bigt:


Don't hide 'em, Ride 'em !!

RF Whatley
Cornelia, GA
Re: Bike dies off idle - 70' A65L Concentrics #8035
02/10/06 10:13 am
02/10/06 10:13 am
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bsanorton Offline OP
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10-4 on that, I will be checking it out.


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Re: Bike dies off idle - 70' A65L Concentrics #8036
02/10/06 3:40 pm
02/10/06 3:40 pm
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Have been following this thread with interest as I've been experiencing a similar situation since winter set in. It'll idle somewhat, but as soon as I try to give it throttle, it'll die.

The only differences that I was looking at were that I'd put some Sea Foam in the gas tank & had been riding less due to the winter weather, which would leave unused fuel sitting in the carb.

It was giving me fits, but eventually it would fire-up, warm-up & be just fine. Turned out the air mixture screw an additional turn & got better response in fire-up (tho' still difficult), but once fully warmed up, had to re-adjust the carb settings back to original as it was now idling much too high.

Weather permitting, was only going to drop the float bowl & have a look, but have decided to pull the carb & do a thorough cleaning.

An in-line fuel filter would also be a good investment & I always run one on my bikes for the added protection of catching any junk that might get past the petcock.


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Re: Bike dies off idle - 70' A65L Concentrics #8037
02/10/06 4:03 pm
02/10/06 4:03 pm
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In my experience, clogged petcocks either permit no running at all or dying under heavy acceleration. Flicking the throttle shouold work. I've had this problem quite a few times with different causes:

1. Clogged main jet
2. Needle jumped off the clip upon installation
3. Air leak at top cover (displaced cable, removed air valve hole not plugged)

You can check if the idle circuit is working simply by turning the mixture screw. If it has ANY effect on running, I would say the idle circuit is not clogged. OTOH, if turning the screw does nothing, the circuit may be plugged or you have a vacuum leak. Have you tested for vacuum leaks?

Oh yea, poor throttle synchronization on dual carbs can make 'em stumble pretty badly, too.

Hang in there, man. You'll get there :bigt:


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Re: Bike dies off idle - 70' A65L Concentrics #8038
02/11/06 1:40 am
02/11/06 1:40 am
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FIXED!!!! DAMN!!! What GER & Alex said was sticking in my mind. So I decided to check the position of the needles & for leaks. Opened the top of the left carb & the needle was in the third position so I moved it to the second (think it has to go back), then I opened the top of the right carb, pulled the slide out, compressed the spring, went for the needle, but it wasn't there!!!! The needle was sitting in the carb body & the clip was loose in the slide, it must of popped off while assembling. When watching to see if the slides were adjusted right I wasn't paying attebtion to the needle!!!! She runs like a beast & idles like a kitten (for now, knock wood, LOL)!!!!! Thanks for everyones help, great thoughts on all counts.


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Re: Bike dies off idle - 70' A65L Concentrics #8039
02/11/06 11:53 am
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Ger B Offline
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Congratulations.
It happened to me a number of times that the retaining ring jumped of the needle when I wound the slide spring around the cable.
Good that you discovered it.
What I find annoying in some manuals is that they talk about 1st, 2nd and 3rd slot. I allways wonder then which is 1st: top or bottom? Why not say: top middle and lowest or bottom.

Ger.


Ger B

Re: Bike dies off idle - 70' A65L Concentrics #8040
02/11/06 12:21 pm
02/11/06 12:21 pm
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I have these little ferrules on my A65 with the slots in them on my carbs. (same deal as on clutch cables). These make setting the needle position real easy with no chance of the whole works jumping out of your hand. Unfortunately I cannot remember where I bought them as i need one for my other bikes. Anyone know what i an talking about and where to buy these things. Makes carb spring assembly a snap.

Mr Mike

Re: Bike dies off idle - 70' A65L Concentrics #8041
02/11/06 1:41 pm
02/11/06 1:41 pm
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Mike, I sent you my email address in your mailbox of this forum. If you have a sketch or photo of your ferrules, pls send it to me as I do not understand what you mean, and this realy is a problem.
Thanks,
Ger


Ger B

Re: Bike dies off idle - 70' A65L Concentrics #8042
02/11/06 3:03 pm
02/11/06 3:03 pm
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Quote
Originally posted by ger:
Congratulations.
It happened to me a number of times that the retaining ring jumped of the needle when I wound the slide spring around the cable.
Good that you discovered it.
What I find annoying in some manuals is that they talk about 1st, 2nd and 3rd slot. I allways wonder then which is 1st: top or bottom? Why not say: top middle and lowest or bottom.

Ger.
Agree. my manual says it should be in the second or middle slot. Mine were in the third or LAST slot. The manual says that if you have a 930 21/22 series with a 2.5 throttle slide, the clip should be in the MIDDLE position. Putting it in the third or last slot would lean out the main jet settings correct? For better gas mileage?


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