why does my black jack mileage suck? 37.7 on fuelly

unsavory · Post by **unsavory** » Fri Sep 26, 2014 4:02 am

Hi Folks,
I did some searching here
Mine backfires on deceleration, also read about too rich fuel/oil jetting, bad exhaust gasket
It has 2k miles
Just had it serviced at san francisco scooter center, no reported probs
Also mentioned the backfiring to Diego (works there) and he said it's the exhaust and they all do that (it has the prima exhaust, i dont know who installed it)
I bought it on cl for good price recently
I have to fill this thing up every 30miles
I'm 220 lbs and ride it kinda hard
I recently had a 2009 125 and got 66mpg doing the same riding
Someone else on feully had gotten 83
Here's mine
http://www.fuelly.com/motorcycle/genuin ... ory/317285
and overall
http://www.fuelly.com/motorcycle/genuin ... ck_pp/2009

What are other people getting and what, if anything should I bring it back to the shop for

Thanks in advance

G

skipper20 · Post by **skipper20** » Fri Sep 26, 2014 4:37 pm

unsavory wrote:Hi Folks,
I did some searching here
Mine backfires on deceleration, also read about too rich fuel/oil jetting, bad exhaust gasket
It has 2k miles
Just had it serviced at san francisco scooter center, no reported probs
Also mentioned the backfiring to Diego (works there) and he said it's the exhaust and they all do that (it has the prima exhaust, i dont know who installed it)
I bought it on cl for good price recently
I have to fill this thing up every 30miles
I'm 220 lbs and ride it kinda hard
I recently had a 2009 125 and got 66mpg doing the same riding
Someone else on feully had gotten 83
Here's mine
http://www.fuelly.com/motorcycle/genuin ... ory/317285
and overall
http://www.fuelly.com/motorcycle/genuin ... ck_pp/2009

What are other people getting and what, if anything should I bring it back to the shop for

Thanks in advance

G

Despite what Diego tells you, it should NOT backfire. While my tech skills are limited to oil and filter changes, my inner sense tells me that you've got some carb and/or valve adjustment issues. I would take it to another shop and get a 2nd opinion. I don't keep accurate track of the fuel mileage on my Blackjack but just mentally noting the mileage between fill-ups (it's hard to squeeze in more than 1 gallon) I'm getting 60 - 70 mpg. I'm about 50 lbs. lighter than you and I ride mine fairly conservatively but notwithstanding, you should be doing better than 37.7 mpg. Get a 2nd opinion and stop listening to a so-called mechanic who claims backfiring is normal. It's not.

Bill in Seattle
'09 150 Blackjack
'12 170i Italia
'08 250i Aprilia 250i Sport City

unsavory · Post by **unsavory** » Fri Sep 26, 2014 5:15 pm

thank you
I guess I should bring back there though as carb adjustment was part of their $200 service I just had done

Also
It runs fast on startup, then idles and low revs once warm, which is normal
It didn't backfire last night, more happens when WOT then releasing twister
I'll call them

unsavory · Post by **unsavory** » Fri Sep 26, 2014 7:57 pm

I stopped by shop
They are going to try and swap out for a regular exhaust and I'll drive for a bit and see what happens

ed85379 · Post by **ed85379** » Fri Sep 26, 2014 8:05 pm

unsavory wrote:I stopped by shop
They are going to try and swap out for a regular exhaust and I'll drive for a bit and see what happens

There is no way the problem is the exhaust, unless that pipe is literally broken in some way. Sounds like the guys at your shop don't know what they're doing.

My blackjack, with the prima exhaust, at ~7K miles now, still gets from 65-70mpg. I'm about 145, but regularly ride with another passenger for another 105 pounds, and I ride it HARD. WOT, on the highway daily.

Oh, and I only get the occasional pop when I first start riding, before it has had time to warm up. The one time I was getting backfires while riding, it was caused by bad fuel, which then gunked everything up and killed my sparkplug.

charlie55 · Post by **charlie55** » Fri Sep 26, 2014 9:43 pm

I can't speak to your fuel economy problems, but I thought I'd throw a couple of things out there, based upon my Honda, and let the Buddy experts chime in.

It is common for our carburetors to have an air-cutoff valve assembly somewhere on their carburetors. I believe that its purpose is to "rich-up" your pilot circuit during deceleration so as to reduce lean-condition popping and backfiring. The main cause of failure is a damaged or an incorrectly-installed rubber diaphragm. Failure of this component can cause the backfiring you're experiencing. If the Buddy's carb is so-equipped, then it should be inspected since it's an easy task for a mechanic.

As Ed mentioned in his post, in order for your exhaust system to be causing a backfire, it would have to be compromised in some way that allows outside air into the pipe/muffler. Cracks, rust-through, holes from object impacts, and even loose connections can all result in anything ranging from "baby-fart" popping to Manhattan Project detonations. This is pretty easy to check, even if you're not mechanically-inclined. The Helix, thanks to Honda's exhaust gasketing system, is a notorious popper.

Your current shop/mechanic is talking out of his ass. Find another one and have them check whichever of these items is applicable. (In addition to whatever else they do).

unsavory · Post by **unsavory** » Fri Sep 26, 2014 9:50 pm

thanks, all this info help diagnose
Shop is the the Genuine dealer for SF
http://sfscootercentre.com/
I also pinged the craigslist seller if he did any mods on in such as carbs, jets, etc, which he didnt do
It doesnt backfire that much actually

k1dude · Post by **k1dude** » Sat Sep 27, 2014 3:41 am

37.7 is simply wrong. There's something WRONG with the scooter. It isn't the exhaust. Is there gas puddling under the scooter while it's parked?

I haven't had much luck with SF Scooter Center. IMHO, they didn't know what they were doing and they charge out the wazzoo. So I do all my wrenching myself. Try another dealer.

ScooterDave · Post by **ScooterDave** » Sat Oct 11, 2014 7:47 pm

unsavory wrote: Just had it serviced at san francisco scooter center, no reported probs
Also mentioned the backfiring to Diego (works there) and he said it's the exhaust and they all do that (it has the prima exhaust, i dont know who installed it)

I love it. Any dealer that told me that it is normal for a scooter to backfire or to say that it is common for the exhaust to do that is talking out their ass! It would be the last time I would EVER darken their doorstep.

Scooters are designed to run with a certain air fuel mixture and that needs to be adjusted to work with the exhaust. When you change the exhaust, you need to adjust the air fuel mixture. This is usually done by rejetting the carb.

If the scooter is backfiring, you do not have to correct amout of air & fuel in your carb.

jrsjr · Post by **jrsjr** » Sun Oct 12, 2014 12:20 am

ScooterDave wrote:
unsavory wrote: Just had it serviced at san francisco scooter center, no reported probs
Also mentioned the backfiring to Diego (works there) and he said it's the exhaust and they all do that (it has the prima exhaust, i dont know who installed it)
I love it. Any dealer that told me that it is normal for a scooter to backfire or to say that it is common for the exhaust to do that is talking out their ass! It would be the last time I would EVER darken their doorstep.

Scooters are designed to run with a certain air fuel mixture and that needs to be adjusted to work with the exhaust. When you change the exhaust, you need to adjust the air fuel mixture. This is usually done by rejetting the carb.

If the scooter is backfiring, you do not have to correct amout of air & fuel in your carb.

Holy Carp! We've been touched by the fabled Scooter Dave!

Wow. How are you, Dave? Minding your heart health, I hope. Welcome back. Please take it a little easy on the newbies.

KrispyKreme · Post by **KrispyKreme** » Sun Oct 12, 2014 1:41 am

ScooterDave wrote:
unsavory wrote: Just had it serviced at san francisco scooter center, no reported probs
Also mentioned the backfiring to Diego (works there) and he said it's the exhaust and they all do that (it has the prima exhaust, i dont know who installed it)
I love it. Any dealer that told me that it is normal for a scooter to backfire or to say that it is common for the exhaust to do that is talking out their ass! It would be the last time I would EVER darken their doorstep.

Scooters are designed to run with a certain air fuel mixture and that needs to be adjusted to work with the exhaust. When you change the exhaust, you need to adjust the air fuel mixture. This is usually done by rejetting the carb.

If the scooter is backfiring, you do not have to correct amout of air & fuel in your carb.

That is very accurate. A very good wrencher speaking his mind.

ScooterDave · Post by **ScooterDave** » Sun Oct 12, 2014 4:51 am

jrsjr wrote:Holy Carp! We've been touched by the fabled Scooter Dave! Wow. How are you, Dave? Minding your heart health, I hope. Welcome back. Please take it a little easy on the newbies.

That's right. The man the myth the legend because chicks dig me and guys want to be me.

I am up to 4 heart attacks, 1 stroke and 6 stints keeping the achohol infused blood pumping through my veins. At the local bike night here, the motorcyclists have a pool going as to how long I am going to live.

Thank you for the welcome back. Work & my health have kept me off many websites for quite a while and I am just starting to come back to many of the 2 wheeled forums again. My girlfriend has me doing all this new age crap and yoga (I agreed to yoga because of 1. they serve alchohol and 2. girls in yoga shorts and 3. girls in yoga shorts and lastly 4. girls in yoga shorts) to keep me toned down so, you might see a new and improved Dave that is now palying well with others.

Syd · Post by **Syd** » Sun Oct 12, 2014 5:18 am

jrsjr wrote:
ScooterDave wrote:
unsavory wrote: Just had it serviced at san francisco scooter center, no reported probs
Also mentioned the backfiring to Diego (works there) and he said it's the exhaust and they all do that (it has the prima exhaust, i dont know who installed it)
I love it. Any dealer that told me that it is normal for a scooter to backfire or to say that it is common for the exhaust to do that is talking out their ass! It would be the last time I would EVER darken their doorstep.

Scooters are designed to run with a certain air fuel mixture and that needs to be adjusted to work with the exhaust. When you change the exhaust, you need to adjust the air fuel mixture. This is usually done by rejetting the carb.

If the scooter is backfiring, you do not have to correct amout of air & fuel in your carb.
Holy Carp! We've been touched by the fabled Scooter Dave! Wow. How are you, Dave? Minding your heart health, I hope. Welcome back. Please take it a little easy on the newbies.

A couple years ago I went so far as to try and find your obituary! Haha! Glad to see you back, Dave.

ScooterDave · Post by **ScooterDave** » Sun Oct 12, 2014 6:14 am

Syd wrote:A couple years ago I went so far as to try and find your obituary! Haha! Glad to see you back, Dave.

Thanks Syd. You are not the only one that has done a search for my obituary.

If anything were to happen to me because of my health, and there is a pretty good chance that I do not live to a ripe old age, there is money set aside with my attorney for one hell of a huge party. Everyone is invited and if my instructions are followed, it will be an event you will not remember.

jrsjr · Post by **jrsjr** » Sun Oct 12, 2014 5:24 pm

ScooterDave wrote:
Syd wrote:A couple years ago I went so far as to try and find your obituary! Haha! Glad to see you back, Dave.
Thanks Syd. You are not the only one that has done a search for my obituary.

If anything were to happen to me because of my health, and there is a pretty good chance that I do not live to a ripe old age, there is money set aside with my attorney for one hell of a huge party. Everyone is invited and if my instructions are followed, it will be an event you will not remember.

I'm almost afraid to ask about the disposition of the ashes. Blow them from a cannon, perhaps?

k1dude · Post by **k1dude** » Thu Oct 16, 2014 5:23 pm

Welcome back ScooterDave. Your input has been sorely missed. Although I'm not thrilled about you playing well with others.

tiii · Post by **tiii** » Mon Apr 27, 2015 9:28 pm

What grade of fuel are you buying? For the non-CA posters here, our fuel has a lot of nonsense in it that makes us get poor mileage compared to the free states.

My Blackjack get's in the 60mpg range if limited to just in town (yeah we have crazy hills) I can see it dropping to 50mpg. I'm 195lbs and go everywhere with the throttle WFO.

KrispyKreme · Post by **KrispyKreme** » Tue Apr 28, 2015 4:05 pm

tiii wrote:
My Blackjack get's in the 60mpg range if limited to just in town (yeah we have crazy hills) I can see it dropping to 50mpg. I'm 195lbs and go everywhere with the throttle WFO.

Fuel grade won't make a difference, just use the recommended. I've run 87 in my 150 w/no problems for years now. You being close to 2 bills and going WFO all the time is your answer. Lose a few pounds and stop being ham-fisted and I promise you you're mileage will improve. Otherwise don't worry about it. Whether you buy your gas in Cali or a "free" state it won't make much difference.

PeteH · Post by **PeteH** » Tue Apr 28, 2015 4:09 pm

I have a 150cc, Prima pipe, weigh in at a portly 240 with gear, and get high 70s, low 80s MPG. My mileage actually went up a little after the Prima install.

KrispyKreme · Post by **KrispyKreme** » Tue Apr 28, 2015 4:47 pm

PeteH wrote:I have a 150cc, Prima pipe, weigh in at a portly 240 with gear, and get high 70s, low 80s MPG. My mileage actually went up a little after the Prima install.

I have a stock 150 and weigh about 175 and get around 65mpg. That seems to be inline with most I've seen. Maybe the engine break-in makes a difference.

That's all I have.

I am out of ideas.

Edit- I lied. Try a shot of Seafoam.

skully93 · Post by **skully93** » Tue Apr 28, 2015 7:00 pm

KrispyKreme wrote:
Edit- I lied. Try a shot of Seafoam.

Make sure said shot goes in the tank of the scoot. I'm more of a bourbon or whiskey man.

tiii · Post by **tiii** » Sun May 03, 2015 12:37 am

KrispyKreme wrote:
tiii wrote:
My Blackjack get's in the 60mpg range if limited to just in town (yeah we have crazy hills) I can see it dropping to 50mpg. I'm 195lbs and go everywhere with the throttle WFO.
Fuel grade won't make a difference, just use the recommended. I've run 87 in my 150 w/no problems for years now. You being close to 2 bills and going WFO all the time is your answer. Lose a few pounds and stop being ham-fisted and I promise you you're mileage will improve. Otherwise don't worry about it. Whether you buy your gas in Cali or a "free" state it won't make much difference.

Not complaining about my 60mpg, just pointing out that CA fuel has amounts of methanol and other nonsense (kinda like winterized formula all year around). My car gets better by 10 mpg on Nevada and Arizona gasoline.

Won't grade of fuel get you worse mpg, like if you run 89-91 in a vehicle tuned for 87?

Modern Buddy

why does my black jack mileage suck? 37.7 on fuelly

why does my black jack mileage suck? 37.7 on fuelly

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Re: why does my black jack mileage suck? 37.7 on fuelly

Re: why does my black jack mileage suck? 37.7 on fuelly

Re: why does my black jack mileage suck? 37.7 on fuelly

Re: why does my black jack mileage suck? 37.7 on fuelly

Re: why does my black jack mileage suck? 37.7 on fuelly

Re: why does my black jack mileage suck? 37.7 on fuelly

Re: why does my black jack mileage suck? 37.7 on fuelly