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Re:Poor MPG I'm stumpped
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TOPIC: Re:Poor MPG I'm stumpped
#1004881
bencadenbach (User)
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Poor MPG I'm stumpped 3 Months, 1 Week ago  
Ok so I have an 03 and I'm only able to get about 29 MPG. Cant figure what up.

MY set up

V&H longshots
K&N Cone airfliter
Ported Manifold
pilot Mikuni 37.5
main 167.5 Mikuni
Clip 4th groove
PMS 2.5 turns out from seated
Float 5mm above seam
New needle and seat

What the hell could there possibly be left to mess with. Any ideas would be much appreciated. Thanks
 
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#1004901
Edge51 (User)
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Re:Poor MPG I'm stumpped 3 Months, 1 Week ago  
I'm no expert but 29 does seem pretty low...I thought I was low at 35. I"m sure some of the very knowledgeable guys will chime in here soon...

This mighty help..... http://www.fuelly.com/motorcycle/yamaha/roadstar.
 
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Last Edit: 2017/03/19 22:58 By Edge51.
 
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#1004902
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Re:Poor MPG I'm stumpped 3 Months, 1 Week ago  
They are only supposed to get 32 mpg
 
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#1004906
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Re:Poor MPG I'm stumpped 3 Months, 1 Week ago  
A stuck enrichener will ruin your fuel economy.
 
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#1004919
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Re:Poor MPG I'm stumpped 3 Months, 1 Week ago  
maybe 5mm above the seam is a bit much try about 3mm , the needle could be stuck and not sitting right down in the slide, is there a washer on both sides of the clip, the top one for the spring to sit on, just a guess
 
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#1004922
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Re:Poor MPG I'm stumpped 3 Months, 1 Week ago  
29mpg in what kind of riding situation??? If that is in town light to light and you are having fun with the throttle that is about right. If it is HWY mileage cruising at 70-mph it is bad it should be in the low 40's. if it is hwy mpg cruising at 80+ it is about right. If it is a combination hwy and city it may be a little low but again depends on your riding style and how much fun you are having.

If you are riding easy on the throttle then here are a couple things to try before digging to far into the carb.

Turn the PMS "IN" 1/4 turn. If that don't give you the results you are looking for
Remove the washer from under the spacer on the needle. That will put your needle adjustment on groove 3 1/2 and lean it out a bit.

Check these things before changing the float level.

Just my guess but I think just like most people with correct jetting and low MPG you are just having fun with the twist of the throttle and are expecting too much afterwards. Can't have it both ways.
 
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#1004925
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Re:Poor MPG I'm stumpped 3 Months, 1 Week ago  
How are your cold starts? Do you need the enricher?
Is the idle adjusted to 900rpms when the motor is hot after a ride?
How many cold starts on each tank? More then a few cold starts and being aggressive on the throttle as Dave mentioned, will destroy your fuel mileage
How long do you leave the enricher on? As JD mentioned, is it possible the enricher is hanging up? Is it possible the l;ittle brass end on the enricher, that has a rubber seal in it needs replacing? There is an oring around the outside, and a flat seal/seat right in the end. If either one of thos are damaged. missing, they will let fuel past.
Double check the float height. Make sure it's no higher then 5mm above the bowl to carb mating surface on the intake manifold side of the carb.

New needle and seat this year? Last year? Have you run Seafoam, MMO, or Techron in your fuel lately?

Is it possible something is blocking the needle and seat from closing properly? You can open the bowl drain turn the petcock on and turn the key to on and let the pump(if you have it still) push fuel through the needle and seat to flush it out. About 10 secs will be plenty. Do that when you recheck your float level, and you'll still have the tube on the bowl drain to catch the fuel in something.
 
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#1004926
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Re:Poor MPG I'm stumpped 3 Months, 1 Week ago  
The enrichener is still working properly and I have it trimmed down to make sure it is completely seated. So I'm not thinking that's the culprit.
 
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#1004929
bencadenbach (User)
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Re:Poor MPG I'm stumpped 3 Months, 1 Week ago  
Last two test tanks were all highway riding about 75 with two cold starts first tank was 29 MPG second tank a few days later was 28. Not sure how to check the RPM's. I leave the enricher on for maybe 1 min I close it when I'm ready to pull out I don't run with it on. I have not run any seafoam through it in a while. Needle and Seat replaced this year less than 300mi ago. I just recently adjusted the float level it was almost 6mm below and adjusted to 5mm above with no real change in MPG.

OK so I'm going to flush the needle out
Check the enricher
run a little seafoam
turn in the PMS .25
and go for a long cruse with the wife so I am sure to behave myself and make sure its not my right wrist that need adjustment.

Thanks for the suggestions I'll see what I come up with.
 
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