Bonneville America Forums Forums Technical Forums General Tech smoothness at idle

I run in traffic a lot being down here in Havana north and I was always having to burp the throttle to keep it from either idling up or stalling while sitting at lights. Awhile ago, someone here mentioned connecting the vacuum ports to smooth out the idle.

While getting ready for GA, I came across some thick walled small diameter rubber fuel line. I took a piece about 8" long and connected it between the carb vacuum ports. I used the cylinder ports and I don't think it would make a difference which pair is used.

I am here to tell you that this DOES make a difference. I do not have to muck with the throttle while idling anymore. It is much smoother sitting there. For les than a dollar, try it out!!

You know who you are that tried this first and THANK YOU!!

Phil,

I connected mine at the carb side and yes, it seems to make a big difference at idle.

Tried connecting the intake side as well without any change so I plugged them back up.

will give it a try, although I've got some flexible plastic vacuum tubing which should be even better than rubber hose....

For those with the CA emissions setup, go to an autoparts store and get a nylon T fitting intended for windshield washer or vacuum control systems and insert it into the hose connected to the right manifold. Then run a length of hose from the fitting to the left manifold.

I've been thinking about trying this as well, but I can't find any type of hose that's chrome....

or some of that cool Bentley-Harris aluminized 1/4" ID Flexible convoluted tubing...

I suggested this recently to someone and wish I could claim fame for this mod but not the case. I read it on the old forum some time long long ago. I does seem to work. Recently I put the black plugs back on trying to sort out another problem and the wandering has returned. Mine was cutting out at speed. Thought it was to do with the rev limiter for a while. Im running or was running the freak set up with 160 mains, one shim,epco's,pingel pet, in line fuel filter with t juction filter removed. It only seemed to do this in 3rd gear or higher at about 7000 rpm's. So not being one to try one thing at a time I removed the vacuum connection line, lowered jetting to 155's and off I went. The bike shut down at 7k at about 80 something mph and didnt refire until it droped to about 20 mph. Was just about to pull off the road and search for a phone. Anyway it refired so back home I go and ponder what to do. Too lazy to rejet again and nothing bigger than 160 in my box anyway I tryed restricting the air intake. This seems to have solved the stalling so I assume I was to lean even with the 160's. Plugs indicated this as well but I didnt believe them. I sometimes wonder why I have taken a perfectly fine running machine and screwed with it. Too much free time on my hands I guess.

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I run in traffic a lot being down here in Havana north and I was always having to burp the throttle to keep it from either idling up or stalling while sitting at lights. Awhile ago, someone here mentioned connecting the vacuum ports to smooth out the idle.

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Wow, that is almost word for word my description to the dealer on the prob I am having with my bike. Thanks Phil, I will mention that solution to the dealer or try myself. I'm taking the bike in today for a couple of probs, (brake issue and a chrome one). I had the carbs rejetted when I fit the drag pipes and have been having the idling prob ever since. Tried messing with the air screws but didn't help.
The sitting in traffic thing sucks bigtime! It gets worse every year. I live exactly 6 miles from where I work, a dream come true right? In my car that takes anywhere from 45 mins to an hour. On the bike I can shave about 15 off that. I am seriously contemplating wrapping my header pipes, not that I like that look so much as the fact my calves are turning into something akin to beef jerkey.
Have to take a deep breath here and hit the enter button as I feel a "traffic rant" coming on, don't get me started...lol


Steve

Trash...don't know if you've tried the TBS needles, but I've got pretty much the same setup as you and the TBS needles made a world of difference in the throttle response and acceleration...no shims. I also cut one turn off the springs which gives it a more crisp turn on the throttle as well. I'm going to try your vacuum connection now since my bike has surged like that since I bought it.

I think I might do the vacuum thing too. Sounds like a cheap experiment! Yesterday it felt like my bike would hesitate right when I would get on it down low on the rev range... wonder if that would help...

Hey good to know. I still have all that AI stuff sitting around somewhere.