2005Roadstar wrote:
Took it for a ride and was still getting a slight "pop and flutter" type of backfire at slow speeds only (while downshifting) and had a little throttle hesitation off idle.

The 'pop and flutter' may just be the pipes you have. Can't tell over here.

Don't forget you have a CV carb so they do hesitate a bit if you crack the throttle. Once the carb is turned, some of the hesitation off idle can be fixed with the accelerator pump....http://roadstarclinic.com/content/view/63/96/

Doc

Thanks again Doc! Since I started this proccess a few weeks ago I've been reading alot of the Tech Tips and previous posts regarding carbs/jetting/tuning and have seen the accelerator pump mentioned so I'll keep that in mind.
As for the current tuning proccess, it looks like things may be on hold temporarily as we are in a crappy weather pattern and they are calling for rain for the next few days. Will hopefully be able to dial it in soon and bring this to a close so I can get back to riding!!

Thanks again!
In The Wind,
Aaron

Well, we did get a break in the weather yesterday evening so I was able to take the bike out and check things out. Rode non-stop on the interstate for about 1 1/2 hours so I could check my mileage. Kept it between 65-75 mph; still only at 38.7 mpg. Call me crazy, but I'm seriously thinking about putting the carb back to stock settings and see if that doesn't get me back into the low to mid 40 mpg range like before. I've been doing alot of reading in the forum archives and it looks like I'm not the only one who's gas mileage dropped off drastically after rejetting. I know to most this would be taking a step backwards, preformance wise, but with a 4,000 mile trip ahead of me (and the price of gas!!!) I'm more concerned with fuel economy than preformance at this point.
Thanks again to everyone that's tried to help. And even if I do go back to the stock settings, this has been a very valuable learning experience. A month ago I wouldn't have dreamnt of taking a carb apart to rejet, but with everyones help and patience and the Tech Tip articles, I've definitely overcome my "fear" of working on carbs.


In The Wind,
Aaron

2005Roadstar wrote:
PMS to about 3 1/4 turns. So now I'm at washer, clip in 3rd groove, spacer, one washer, DJ175 main and 35 pilot.

If anything, these settings would be viewed as lean so theoretically you should be getting good mileage but to confuse you even more If you lean it out too much your gas mileage will go down.

I suspect that may also be the case for you (you're also getting some popping).

Get yourself a piece of tubing and check the fuel level in the float bowl. If the fuel level is too high, it usually shows up by erratic performance but in your case it may be too high and be masked by your lean settings.

You did do the WOT test and find it OK? If that was OK, then add another silver washer under the spacer.

If you decide to go back to OEM carb settings then you need to run the OEM airbox.

Doc

If you lean it out too much your gas mileage will go down.


I don't know doc... I have to respectfully disagree... I think that lean and your performance will suffer significantly first ... then a drop in your gas millage... I've run mine to lean and she bucks and fights ... but once I got her so that she wasn't bucking my gas millage was great... ~Guido

Thanks guys! Not sure where to start.. but want to comment on some things;

1) Current settings; DJ175 main, 35 pilot, washer-clip on 3rd-spacer-1 washer and PMS at 3 3/8th to 3 1/2, out from 3 1/4. Was able to get rid of most, if not all of the pop on decel. Still have a slight hesitation off idle, but that seems to go away after the motor is hot. Bike seems to be running good with no noticable drop in performance over previous settings. And gas mileage has definitely improved; 32-33 up to 38. So I don't believe I'm to the point yet of being too lean that I'm hurting performance or mpg. But then again, what do I know!?

2) Did both the WOT test and checked the float/fuel level when I replaced the needle valve (to eliminate the fuel pump) and reinstalled the 35 pilot jet. Both checked good. Haven't redone either since adjusting the needle settings. Do I need to? FYI; By simply changing the pilot from the 37 my MPG went up to 35.

3) If I do decide to go back to the stock settings, why would I need to reinstall the stock air box? Before the initial rejetting I was running the Arlen Ness Big Sucker air kit, the RH 65 Special slip-on pipes and stock carb and got my best MPG yet; 42-45 avg.

4) The only difference between then and now is that 1) I've installed an engine guard, which I doubt would cause that kind of a drop in MPG, and 2) I'm running reg. unleaded vs premium, which we've already talked about. Which, by the way, I can't tell any difference in the way the bikes running, good or bad.

This is definitely a case of hindsight being 20-20. The only reason I had the bike rejetted in the first place was because thats what I'd always been told; If you change pipes or air intake you need to rejet. Hell, I've even preached that to newer riders. I rode the bike a full season (March-Nov. and almost 10,000 miles) before deciding to rejet, and the only reason was because I had some backfiring on decel. And if I'd known then what I know now, (didn't have a computer so I hadn't discovered RSC!) that might have been eliminated by removing the AIS and/or adjusting the PMS. Yes, I did gain some on the performance, but not enough to warrant losing 10-12 MPG! That's why I'm thinking of going back to the stock settings; just to see what happens. It can't hurt!!!

Thanks again for all the help!!

In The Wind,
Aaron

davehrn wrote:
I don't know doc... I have to respectfully disagree... I think that lean and your performance will suffer significantly first ... then a drop in your gas millage... I've run mine to lean and she bucks and fights ... but once I got her so that she wasn't bucking my gas millage was great... ~Guido

I believe the opposite .... a reduction in gas mileage before performance degradation is sufficient to notice.

How lean is too lean before your performance suffers? I believe that there are points on each side of the optimum setting where the bike will run poorly but between the optimum and that point is where your gas mileage will be affected.

The optimum setting is close to the stoichiometric air/fuel ratio of 14.7:1. An A/F ratio less that means that you have more fuel than required, thus your gas mileage will go down. We are all aware the the R* can run with low A/F ratios before performance degradation is noticed and the impact it can have.

The converse also occurs. As the A/F ratio increases, you enter the lean zone (no beer there ). Although you are using less fuel, you're also less efficient and your gas mileage will decrease. There will also be a point where it's so lean that begin you notice the performance degradation.

Remember that its' not black and white but a transition on either side of the optimium setting.

Thats my perspective.

Doc

2005Roadstar wrote:

1) Current settings; DJ175 main, 35 pilot, washer-clip on 3rd-spacer-1 washer and PMS at 3 3/8th to 3 1/2, out from 3 1/4. Was able to get rid of most, if not all of the pop on decel. Still have a slight hesitation off idle, but that seems to go away after the motor is hot.

The hesitation off idle when cold but not when warm usually means you are slightly lean. Try 2 silver washers under the white spacer.

2) Did both the WOT test and checked the float/fuel level when I replaced the needle valve (to eliminate the fuel pump) and reinstalled the 35 pilot jet. Both checked good. Haven't redone either since adjusting the needle settings. Do I need to? FYI; By simply changing the pilot from the 37 my MPG went up to 35.

No need to check the float level unless you think you bumped the floats while changing the jet out. You don't need to redo the WOT test either.


3) If I do decide to go back to the stock settings, why would I need to reinstall the stock air box? Before the initial rejetting I was running the Arlen Ness Big Sucker air kit, the RH 65 Special slip-on pipes and stock carb and got my best MPG yet; 42-45 avg.

I may be misinterpreting what you mean but the stock settings are for the stock airbox.

Remind me again - why did you rejet if you were getting 42-45 mpg and the bike was running fine? Were you running stock settings with the Big Sucker and wanted better mileage?

Doc

Doc,
By "stock" I mean factory settings. When I bought the bike it was completely stock, with the exception of Iridium plugs the previous owner had put in at the dealer. Within a month I added the air kit and pipes without touching the carb. So I have no reason to believe the carb had anything but factory settings. Since I didn't do the original rejetting, I can't say for sure though.

As for why I had it rejetted in the first place, it backfired on decel all the time. So I figured if it were rejetted that would take care of it, and it did. But had I known then about the AIS causing backfire problems I would've removed it first, before having it rejetted. Live and learn!!!

Thanks,
In The Wind,
Aaron

I think this bike, more than any I've ridden, gets a wider variety of mpg's according to wind, speed and the way I ride it. I have recorded mpg of 48 on calm days, running below 70 in flat country. I can drop that 3 or 4 mpg just by pushing it a little and getting on the throttle a bit harder leaving towns.
Yesterday I ran 164 miles into a pretty stiff wind at generally 72 mph or a bit more, and passed several trucks slowed by the wind. I got only 39 mpg on that tank.
Mine is stock other than a drilled airbox, stage one exhaust and AIS removed. Love the way it runs and sounds, even the flutter and spitting on deceleration and it has more power and speed than I'll ever use.