Throttle Response

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MikeL
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Throttle Response

#1

Post by MikeL » Tue Oct 23, 2012 3:21 pm

I am not sure if I am missing something easy but my bike is a 52FL mostly stock and when I crack the thottle wide open the bike wants to die and then it back fires through the exhaust. I thought it may be a problem with the carb (S&S Super E) and when I opened it up to clean everything I discovered there was no O-Ring on the ejector nozzel. I have since cleaned all the jets, etc and installed the o-ring and although I had to change all the settings to get it back idling decent it still has the same issues when cracking the throttle. I have bubble tested my intake and everthing is good. The bike idles fine and runs okay if you ease in to the throttle. Any thoughts?



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Re: Throttle Response

#2

Post by DuoGlide62 » Tue Oct 23, 2012 3:32 pm

New condenser is cheap. Try that.

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Re: Throttle Response

#3

Post by DuoGlide62 » Tue Oct 23, 2012 3:32 pm

that's assuming everything else is spot on.

Cotten
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Re: Throttle Response

#4

Post by Cotten » Tue Oct 23, 2012 4:10 pm

MikeL!

If you have solid replacement pushrods, I would inspect their adjustment, suspecting some may be loose.
And strobe-timeing the ignition is a good double-check.
I know nothing of the Super E, other than it is a lot bigger than the Pan ports require, or can handle.

...Cotten
PS: When you bubble-tested, did you check the pan cover screws over each intake port?

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Re: Throttle Response

#5

Post by Bosheff » Tue Oct 23, 2012 5:07 pm

To much fuel being delivered to quickly....bosheff

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Re: Throttle Response

#6

Post by steve_wood » Tue Oct 23, 2012 5:07 pm

Is the accelerator pump enabled on the super E?

How quickly are you going to full throttle? To put it another way, when you gradually roll on to full throttle, does the engine respond smoothly?

Backfires in the exhaust means you have fuel and air in the exhaust. Perhaps the super E is providing more fuel than the motor can burn and the excess ends up in the exhaust (and you may have an air leak in your exhaust).

MikeL
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Re: Throttle Response

#7

Post by MikeL » Tue Oct 23, 2012 5:53 pm

DuoGlide: I have a new condensor that I will try.

Cotten, I do have solid replacement pushrods, I will double check tonight but just wanting to confirm that the correct adjustment for the pushrods is the ability to turn freely with finger when valve is closed but no play up and down.
Also I did bubble test the cover screws above the intake and everything was good.

Steve, I have closed off the accelerator pump and opened it 1/4 turn at a time and have found the setting that works the best but does not eliminate the build up of gas and backfire.
When I gradually roll on the throttle it does run fairly smoothly. But I find even when I roll on it smoothly, open the throttle (almost open) and shift gears the bike will back fire when I let off and pull the clutch to shift.

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Re: Throttle Response

#8

Post by Huck » Tue Oct 23, 2012 5:59 pm

Manual timer?

Cotten
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Re: Throttle Response

#9

Post by Cotten » Tue Oct 23, 2012 6:28 pm

MikeL!

If your pushrods are aluminum, you want them quite stiff, but still turn-able.
The Knowledge Base or the search function should show many previous discussions on solid tappet adjustment.

...Cotten

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Re: Throttle Response

#10

Post by Bigincher » Wed Oct 24, 2012 12:48 am

The stock jets as the carb is boxed and shipped, are too large for a stock 74" motor. Try a smaller intermediate, maybe .0295. No larger than a 72 or 74 on the main.

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Re: Throttle Response

#11

Post by panbagger » Wed Oct 24, 2012 12:58 am

If i can remember right my super E has a .0295 intermediate and either 68 or a 70 main jet... and that seems to work well. Scott

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Re: Throttle Response

#12

Post by 58flh » Wed Oct 24, 2012 4:40 am

Check your ex. pipes to look for soot building up around the entire clamp!,& have a look at the auto adv. if running singlepoint ig.!--I run a S&S E on a stock74 with a main of .072 & have no issues with it!--Runs fine thru the whole RPM range!--Craked or rolled wide open.--just something to check while in there!----Richie

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Re: Throttle Response

#13

Post by 1962FLH » Wed Oct 24, 2012 2:34 pm

I did a total restoration on my 62 FLH and after 450 miles mine acted the same way. It happened to me just after a fill up on fuel so I suspected P4 gas . I drained the tanks of the P4 gas and put it in my 52 Chevy Truck as it will run on just about anything. I cleaned out the carb and tanks with filled with new P4 gas from different station and same problem. What I found was a bad condenser; it was new (450 miles) but caused this problem anyway. I have had this problem before and do carry extra points and condenser in tool role. This just took place yesterday and wanted to share my experience with you as it may help. Remember a bad condenser will exhibit a different symptom each time it goes out so it should be first suspect when things are not right. I have to remind myself of this from time to time.
Good luck with your bike.
John

MikeL
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Re: Throttle Response

#14

Post by MikeL » Mon Oct 29, 2012 12:46 am

Cotten was correct, I adjusted the pushrods (Aluminum) and everything seems to be working good after my test ride in the snow today.

Thanks

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