650R edelbrock help

7 replies to this topic
  • Fingers

Posted May 18, 2005 - 10:57 PM


Hello all. 2 problems I have that maybe someone can help. I installed my new pumper carb last week. When the bike is warm it starts first or second kick but when cold (after 2 or 3 pumps and 4 or 5 kicks) it rumbles to life for a second or two then stalls. After repeating this 4 or 5 times it will hold an idle (with encouragement) then warm up and run fine after 45 seconds or so. The second problem is the idle. The bike idles high (500-1000rpm above normal) after coming to a stop when warm every time (yes the slide is fully closed and not hanging up and correct free play on throttle cable). After I blip the throttle a couple of times it will suddenly settle and idle normally. I have no backfiring, flat spots or other indications that I am running rich or lean. I am at sea level, uncorked. Any takers on tuning these small problems out?

  • JackAttack

Posted May 18, 2005 - 11:32 PM


The EB pumper reacts well to tuning of the idle screw. That is the dangling arm that comes with the unit. When you first fire up the bike, after a few twists of the throttle, you will need to adjust the idle up a few turns, to keep it running. After it is warmed up you will need to turn the idle down a few turns.

I have now become accustomed to the carb, so I usually give the idle arm screw a few twists before I start the bike. Then after a few miles stop and listen to the bike and turn it down a twist. After a few more miles I stop and listen, and turn it down another twist.

If I am racing, I leave the idle hang a little higher. :)


  • Fingers

Posted May 19, 2005 - 12:42 AM


I tried everything with the idle screw. It did not help the cold start and the hanging idle would return to what the screw was set for after "the hang". IOW the idle speed after the "hang" will be high or low depending on how many turns I have on it. I know the pump is spraying because I have great throttle responce after it starts and if I give it too many twists before kicking it will flood.

  • Old_Man_Time

Posted May 19, 2005 - 04:21 AM


How tight is your throttle cable? I actually cut my bars down 1" on each side. This helped in keeping some slack in the cable after installation. I am not running stock bars which is why this was necassary. Tight cable can effect the way a carb (stock or edelbrock) come off idle.

Also you might try playing with the pump timing screw. Even though it is working it might help to give it a bit more fuel per twist of the throttle.

Keep the air filter clean as that effects the mix.

You may have already checked everyone of these suggestions but it is all I can think might be the problem from experience with my Edelbrock.

Now I pretty much follow the same procedure as JackAttack.

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  • frankstr

Posted May 19, 2005 - 04:46 AM


I turn my idle up a turn or so when cold, 3 quik twists of throttle, Starts first or second kick everytime... :) Then when it warms up I adjust the idle..
Like the other guys are saying check your cables..
Have you adjusted the needle at all, maybe its too rich...adjust the clicker lean till it pops on decel then move it rich 1 click...
Awhile back I played with mine and had it too rich and it had a erratic idle and was harder to start, warm or cold....

  • JackAttack

Posted May 19, 2005 - 09:13 AM


You may want to check that the carb boot/manifold is air-tight where it attaches to the carb and not leaking.

I believe you can spray either carb cleaner or propane around the area while the bike is running to discover any leaks. Someone else may have more info on this.

Also check that the tank(stock) is not hitting the top corner of the carb. This has happened to a few guys, including myself. It will wear a hole in the tank and may be puting pressure on it and letting air into the boot/manifold connection.




  • Desmo

Posted May 19, 2005 - 09:44 AM


I had a similar problem recently after I changed exhaust. I had very similar idle/running conditions.

I had to drastically change the rich/lean settings (knob).

I think you may be lean, as when you "blip" the throttle, it enrichens the mixture, "fixing" the problem. Maybe others, with more experience can give some input.

I ended up at about 13 or 14 clicks and the erratic idle problem vanished.

I'm uncorked, with the stock/HRC tip, airbox not drilled.

hope this helps

  • Fingers

Posted May 19, 2005 - 03:02 PM


Thanks for the help. I will try a few clicks richer and see what happens.

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