Author Topic: cant go over 35 mph!  (Read 2263 times)

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parkline

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on: June 23, 2014, 08:45:15 pm
I'm having a problem even the local techs can't figure out. I have a 2007 bullet ME with the AVL powerplant with 1300 miles, I did some mods, D slide carb, free flow exhaust, K&N filter, upgraded TCU. I can go 35 all day long but over that it burbles down and dies, will start up again in about 30 seconds or so. I switched back to the orig carb and TCU and it's still doing the same thing, already checked float adjustment, went through carb, checked timing and adjusted pushrods, techs checked out a dozen or so more technical and electrical things. anybody heard of or had this problem before? I really need to get on the road again.


barenekd

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Reply #1 on: June 23, 2014, 08:55:00 pm
One of the TCU senders is screwy. Sorry I can't be more specific as I'm not that familiar with the specific ECU.
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boggy

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Reply #2 on: June 23, 2014, 09:00:32 pm
Make sure you don't have an air leak at either your carb manifold or exhaust port.  I suffered from a throttle-bog on my AVL.  I tried all the typical carb/fuel line fixes over and over until I found the leaks.  The carb's manifold had a hair-line crack in it, on the underside and never noticed it.  After sealing that I realized I had a leak from my header.  The bike idled fine, and was ok at low speed, but the leaks were so minor they were only noticeable at half+ throttle.

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Arizoni

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Reply #3 on: June 24, 2014, 12:26:20 am
It sounds like a timing problem to me. 
If I were to guess, it's running very retarded.




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DanB

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Reply #4 on: June 24, 2014, 01:13:14 am
I'm thinking air leak as well... it maybe timing but since its got a tci and is an AVL the timing cant be adjusted. Another thought, make sure your engine breather is clear and the motor can breathe.
« Last Edit: June 24, 2014, 01:22:56 am by DanB »
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parkline

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Reply #5 on: June 24, 2014, 03:30:59 am
thanks everybody, the exhaust leak is something I will check out can probably spray some colored nonflammable powder around while running, I did find the hose barb on the carb manifold wasn't plugged after the rest of the EGR stuff was blocked off but I plugged it and still have the problem.. both TCI's are doing the exact same thing so I kind of ruled that out, of course they could be bad in the same way.


DanB

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Reply #6 on: June 24, 2014, 04:28:37 am
Also, check the carb manifold. It sounds like you still have the stock rubber there. This stuff does crack and I'd suggest a new one. What carb did you put on it?
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High On Octane

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Reply #7 on: June 24, 2014, 05:05:47 am
Sounds like your rubber carb intake manifold has a split in it as others have mentioned.  Pull the carb and the manifold off and give it a good look over, I bet you'll find a crack in it.

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RGT

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Reply #8 on: June 24, 2014, 06:23:38 am
I would check fuel flow to the carb, disconnect the fuel line and run it in to a container and see how much fuel flows through in a minute once you open the petcock


ace.cafe

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Reply #9 on: June 24, 2014, 11:53:03 am
I would check fuel flow to the carb, disconnect the fuel line and run it in to a container and see how much fuel flows through in a minute once you open the petcock

+1
Restricted or partly plugged up fuel delivery.
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Kevin Mahoney

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Reply #10 on: June 24, 2014, 06:07:52 pm
The carb rubber is a wear item. Often time they look good but have cracked under the clamps. You need remove it to fully inspect it. Fuel flow is also a good idea. The other question is "did you make any kind of changes or adjustments before this started?
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Arizoni

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Reply #11 on: June 24, 2014, 08:09:11 pm
Fuel flow is a good candidate.

I can see where a cracked manifold or inlet or a poor seal between the duct and the carburetor or engine would cause all sorts of idling and starting problems I can't see where they would limit the top speed to 35 mph.
That (I assume) is a wide open throttle problem where small leakages aren't a factor.

With the problem existing with two different carburetors, that sort of rules them out as the cause.

A blocked fuel filter, blocked fuel valve,  plugged fuel tank vent in the filler cap or a breakdown of the inside of the fuel hose that causes the hose ID to become blocked would do it.
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rtillery02

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Reply #12 on: June 28, 2014, 02:30:02 pm
That sound like a familiar problem I had that eventually was found to be a distributor flyweight problem,
  It idled great, would accelerate but not too quickly, & since the flyweights were "stuck in one place", I couldn't get any advance curve under a load & would just fall on it's proverbial face.   I ride a classic iron barrel so, I'm not sure if AVL even has a mechanical flyweight setup.
  Sometimes humidity & downtime will cause it, I hope some WD40 & finesse will get ya up & rollin',
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Reply #13 on: June 30, 2014, 09:17:41 am
Are you sure you're not running uber rich after the slide mod? Because I faced similar sorta stuff after plonking a VM34. It had 260 mains and super rich needle so it used to bog down at around 40mph or so, as if it was running out of fuel. My case is very much similar to yours. In my case I fixed the carb by getting the right set of parts, in your case I think it's the Carb acting up.

Did you start facing this after installing the carb? :)