Edelbrock ????????????

[jws]

I was out at Rasor Road last weekend and I noticed that my bike was not dropping back to idle real fast when I would wack the throttle - it kinda hangs at a high idle then slowly drops back to idle???

I talked to Chris at edelbrock today and did all the things he said to try - but it still hangs at high idle then slowly drops back down.

anyone have any ideas before i send it in for Chris to look at???

Thanks for any help

Jeff

[qadsan]

Jeff, those symptoms would lead me to look into an air leak between the carb intake and the cylinder (i.e. rubber intake boot).

When the engine is at WOT, the air/fuel mixture is easily sucked through the intake manifold because that is the path with the least restriction (low vacuum). When the throttle is chopped, the throttle slide blocks / restricts the air flow and the intake manifold vacuum greatly increases.

This high manifold vacuum puts more stress on the ruber boot and if it’s able to suck any air past or through the rubber boot, then the mixture will lean out, thus causing the idle speed to increase. When you're back on the throttle, the vacuum quickly decreases and won't stress the boot as much (air will take the path of the least resistance which is through the Venturi). If the leak is small enough, it can be hard to detect. I would suggest trying to twist your carb in the boot and see if it twists. If it does, then your intake clamps need to be tightened. If not, I’d still remove the boot and give it a good visual and then replace it if necessary. I hope it turns out to be something simple and inexpensive.

[jws]

Thanks for the quick reply qadsan

I just went out and pulled the carb off again and checked the intake - it looks like new I took the card appart today found lots of fine dirt in the upper part and slide area - cleaned it out real good with brake clean then wd 40ed it. Took the plunger appart also and cleaned it up. The bowl looked good it was pretty clean. Put it all back together and it was still hangin??

I have had this carb for almost 2 years and its worked awesome without any adjusting since the first week I was dialing it in. I haven't even taken it off the bike before today.

I will play with it again tomorrow when i get home from work - I will try spraying around the intake boot while its idling and see if it shoots up any - The cables are fine I disconnected them and tried whacking the cable wheel a few times and its the same thing. I will try new gas tomorrow also.

thanks, Jeff

[qadsan]

You could try fuming the intake are with propane if you happen to have a portable propane torch. The idle should change significantly if propane gets sucked in.

Does it only happen at your riding location (i.e. upper desert) or at your house too?

I wonder if the slide isn't closing all the way all the time??? Maybe the throttle return spring is getting weaker or perhaps the dirt in the slide area created a burr that prevents the slide from working as smooth as it should, thus preventing it from closing all the way at times? Maybe the anti-friction coating is wearing thin on the slide? You can try increasing your throttle return spring tension on the carb's throttle cam. If that does the trick and the thottle tension is acceptable to you, then you're set. If it does the trick but the throttle tension is too much, then something is up with the slide.

[4Takt]

My Edelbrock started doing the exact same thing last week. I haven't figured it out yet, but my intake manifold is fine.

4Takt

[jws]

Ok - bikes back to running like it should

Here is what I did...............

cleaned carb inside and out with brake clean then WD 40

reset the valves - intake were on the tight side, exhaust were fine

drained gas and put in fresh

new plug

Fired right up first kick and it seemed to fix the problem

I was so happy that she was running good again I went ahead and changed the oil, blead the brakes, greased the steering stem and pulled out the chain adjuster bolts and greased them too.

I am off to Dove Springs for the weekend.........................