Bonneville America Forums Forums Technical Forums General Tech rich, lean, wrong jets???

Hello all,

I have a 2005 BA with the Triumph OR longs on and it seams that it runs rough...that is at first crack of the throtle it bogs, spits, and clunks before you roll thru the rough spot. With the engin cold it is as smooth as can be in the same spot (provided the choke is on) the bike still has the stock setup with the exception of the pipes...when I asked my dealer for the stock pipes and jets he said that "according to the manufacturer" those pipes could use the stock jets as they offer the same back preasure and that the bike would smooth out once I had some time in the seat (it only has 88 miles on it....come on spring!) also it back fires, just a little tiny "whoomp" when I shut her down...my first thought was (due to the back fireing and the spitting at down shift) that she was to rich....but with the marked improvement while choked maybe too lean.....the last bonnie I had was a 1979 750 with dunstills and a rejet (and no electric start)and the damm thing never ran right, but its been years since I wrenched on a bike, please don't tell me I'm back where I was with the 79...I thought these new trumpets were "bullet proof"
I love the new BA but don't want to spend my time wrenching it I want to RIDE it and leave the wrenching to the cold winter months dreaming about a shopping spree with Brent and adding all that new shiny stuff!

Rob

You don't absolutely need jets with TORs.

Your best start is to do the following (or get it done at the dealer):

- Check you carb vacuum ports for leaks (do you have the AI removed?)
- Adjust your air screws
- Balance the carbs

This will give you a good starting point to further troubleshoot any remaining issues. If you decide to change anything, do one thing at a time and see if everything is OK after that. Nothing worse that trying to track down a problem after a half dozen mods...

Rob, I'm sure you'll hear from others on this site that the factory Triumphs are set up VERY lean (ie: too lean). Even though Triumph may say that you "could" use the stock carb set up, it almost certainly would not be the best. I had my bike for less than 2 weeks before changing pipes and jets. The headers were already blueing from running lean. After the new pipes and main jets, I had to change the pilots due to excessive popping on decel. I ended up with exactly what came with my exhausts and what they recommended. It has run incredibly well ever since and there has been NO blueing for 2000 miles. I owned a Bonnie in '71 and I can't believe how reliable they are now. Once you get it set up right, you shouldn't have any problems or spend time "wrenching" (other than chain adjustments, etc.).

The AI is not removed (yet) I'm still tring to convince the dealer that it won't void the warantee (but I'm sure we can work that out) so every thing is still set dead stock (except the TOR's)...the odd thing is when I took the bike out with the stock pipes on it seemed fine (it was much warmer then also) I hope to get some more 50 plus days up here soon but for now I think were back to a good old fashion New England winter and even riding it to the dealer is deadly. I NEED to get the repair manual so I can re-aquiant myself with the carbs (I had the 79 apart so often I could do it in my sleep...I even think I did once or twice) But that was 15 plus years ago and now I'm not even sure where the mix screws are any more....I guess I need to take a look on a day where I can spend more than five min admirring it in the shed with out turning blue! I'm sure (as you have stated and I have read here that its a simple adjustment) I have been lurking here for months prior to the purchase (two weeks ago today...happy aneversary to us) just a little discorraging way to start.

Well you are going about it the right way Rob (getting a manual).

Dinqua's site has lots of info on the carbs and is a good place to start. You probably have the D air mixture screws and they are in the same place as the old ones. Dinqua's pics show the locations. Get a small mirror so you can see the bottoms of the carbs...

Refer to the pic below for the following AI removal steps (btw, www.newspeedmaster.com has a removal kit for $25):
(The AI removal is very easy and you do not have to remove the tank unless you want to remove the AI reed valve assembly)
The two parts labeled 10 hanging down in the pic are those tubes into the crankcase in front of the sparkplugs. Remove them and seal the holes with bolts and copper crush washers.
Remove the end of the rubber pipe (#11) from the airbox and plug the airbox hole.
Remove the hose (#8) that connects to the intake manifold (or is it on the carb?) and plug that port.

You have removed your AI. You can dress the hanging parts up out of the way or remove the tank and unbolt the AI reed assembly from the frame and throw the whole mess in a box. Frankly, I tossed mine in the trash.

The AI components:

Rob,
It sounds like your dealer is a bit of a jerk.... But he could get in trouble by removing your AI system. It should not void the warranty if you do it, but if he won't back you up you could have a problem.
Anyway, after you buy the kit from Brent and remove the stupid thing, save the little plastic hose and connect it between the 2 ports on your intake manifold. It helps smooth out the idle.



I had the Long TOR's on my bike for awhile and it ran fine with the stock jetting, but my pilot screws were set way too lean from the factory. If I remember correctly, the right side was nearly closed.

Here's another site with carb info. These are a little bigger than ours but the same design.

CVK40

If the (whoomp) you refer to is just after you turn the engine off your idle speed may be a little too slow, adjust your idle speed up a fraction and see if the (whoomp)goes away ,my bet it does.

Thanks for all the info!! As I have witnessed all these months of lurking on this site...your insite is priceless...the AI will go away...and the adjustments will comence (just as soon as the warmer weather settles in) Also I see here a few "neighbors" and I'm sure I will pick there brain (may be over some beer and tips on the BBQ) to bring me back up to speed.

It's been a while, but I think the Whoomp went away when I removed my AI. I never thought anything was wrong with it, but I remember every time I shut it off, I'd hear whoomp from one side, then the other.