Gas Milage

motorshag · Mar 24, 2013

Would syncing the carbs help a 77 650 get better gas mileage? I'm getting about 70 miles before I have to switch to reserve. (I know, not good) I synced the carbs the other day, and was hoping that may help a little. (They were way out of synce) I rebuilt the top end of the motor last spring. But have not rebuilt the carbs yet. To be honest, I'm a little scared to tackle this, because it been tried by me in a past project. It didn't go as planned

thanks in advance for any help!

2poler · Mar 24, 2013

What Gas Tank Do You Have?

Posted via Mobile

motorshag · Mar 24, 2013

The 3.9 Gallon one.

motorshag · Mar 24, 2013

The 3.9 Gallon one.

scabber · Mar 24, 2013

Time to look at those carbs I would say. Dumping that much gas can ruin your new top end.

motorshag · Mar 25, 2013

Yes. I guess you are right. I've got the rebuild kit on order from Mikes XS. Wish me luck.

XSLeo · Mar 26, 2013

You don't need rebuild kits. Most of them come with generic brass parts. These brass parts very seldom work in our carbs.
If you read www.amckayltd.com/carbguide.pdf it will tell you how to tear down, clean, inspect your carbs. Often the only parts you need to replace are gaskets, and then they can be reused more often than not.
Read the guide. As you inspect the parts you can then decide what parts you need. Buying just what you need is cheaper than buying kits with little you can use.
Leo

motorshag · Mar 26, 2013

Thank XSLeo. I printed that out a few weeks ago. Was going to start reading it. I'll post my issues or progress here. Thanks for the advice.

retiredgentleman · Mar 26, 2013

motorshag said:
Thank XSLeo. I printed that out a few weeks ago. Was going to start reading it. I'll post my issues or progress here. Thanks for the advice.

You don't need luck, you need knowledge. If you had read all of the Carb Guide, Leo mentioned, before ordering the carb kit from Mikesxs, you would know that the kit you ordered has the wrong jets for a 1977. Mikesxs sells a lot of parts that are wrong or of poor quality.

There is lots of info on this site, but you have to do the reading to gain the benefit.

alfredo · Mar 26, 2013

I get about 60/70 mpg on my motor. I tend to have a heavy wrist as well.

motorshag · Mar 26, 2013

retiredgentleman said:
You don't need luck, you need knowledge. If you had read all of the Carb Guide, Leo mentioned, before ordering the carb kit from Mikesxs, you would know that the kit you ordered has the wrong jets for a 1977. Mikesxs sells a lot of parts that are wrong or of poor quality.

There is lots of info on this site, but you have to do the reading to gain the benefit.

Yes, I unfortunately just read that part about the rebuild kit this morning. Ugh. Well at at a minimum I will go through them, and see how they look. :banghead:

weekendrider · Mar 26, 2013

What size jets are in the carbs?

motorshag · Mar 26, 2013

weekendrider said:
What size jets are in the carbs?

I have a XS650 D. So I purchase the rebuild kit for the XS650C/D 1976-77. I've not takin the carbs off to really clean them yet. I've had them off to change the boots and i've dropped the bowels, to check them. However I don't know what size the jets are yet. I know they are the BS38 carbs. That's all I know as of yet.

motorshag · Apr 1, 2013

So...carb sync, needle re-positioning (leaner set at #2 Slot), new air filters, new manifold boot clamps, and air box clamps, hole in muffler welded, has giving me another 50 miles a tank full. 120 miles on a tank so far, and still haven't flipped over to reserve yet. That makes it 40 MPG thus far. I'm not as of yet getting 60/70 like Alfredo, but I'll take 40 MPG over the 25 I was getting, till I can completely go through the carbs this weekend. So...there's that update. Happy Monday!

alfredo · Apr 1, 2013

motorshag said:
So...carb sync, needle re-positioning (leaner set at #2 Slot), new air filters, new manifold boot clamps, and air box clamps, hole in muffler welded, has giving me another 50 miles a tank full. 120 miles on a tank so far, and still haven't flipped over to reserve yet. That makes it 40 MPG thus far. I'm not as of yet getting 60/70 like Alfredo, but I'll take 40 MPG over the 25 I was getting, till I can completely go through the carbs this weekend. So...there's that update. Happy Monday!

Yeah. I took the bike to a guy that changed up some internal bits on the 34s that I'm running. He said that basically he leaned it out. Mine takes 5-15 kicks with the idle turned up to get it started and when the temperature is in the 30s it breaks up a little. Once it's warm and running it always starts right up. So that might explain my seriously good MPG.

I plan on waiting until it gets warmer and seeing if the startup is better. If not, may rejet.

:cheers:

motorshag · Apr 1, 2013

alfredo said:
Yeah. I took the bike to a guy that changed up some internal bits on the 34s that I'm running. He said that basically he leaned it out. Mine takes 5-15 kicks with the idle turned up to get it started and when the temperature is in the 30s it breaks up a little. Once it's warm and running it always starts right up. So that might explain my seriously good MPG.

I plan on waiting until it gets warmer and seeing if the startup is better. If not, may rejet.

Wow. That many kicks is a considered a workout in my book. HA!

motorshag · Apr 5, 2013

So. I am now getting 34 miles a gallon, about 116 miles in a tank before I switch to reserve. Not sure if that is real bad, or kind of normal. Its better than the 25 miles I was getting before I did a lot of tweaking. I will note, that is all city riding. I am taking this bike on the EDR in late May. My goal before the trip was to make sure I could at least get 100.00 Miles before fueling up. Accomplished that...

alfredo · Apr 5, 2013

motorshag said:
So. I am now getting 34 miles a gallon, about 116 miles in a tank before I switch to reserve. Not sure if that is real bad, or kind of normal. Its better than the 25 miles I was getting before I did a lot of tweaking. I will note, that is all city riding. I am taking this bike on the EDR in late May. My goal before the trip was to make sure I could at least get 100.00 Miles before fueling up. Accomplished that...

Pictures absolutely required on the EDR run man. Instagram or otherwise.

:cheers:

deadchef · Apr 5, 2013

alfredo said:
I get about 60/70 mpg on my motor. I tend to have a heavy wrist as well.

i'm not doubting your findings but 60-70 seems extraordinary. how do your plugs look running that lean? any concerns?

gggGary · Apr 5, 2013

I tend to get high 40's to low fifty's on about 5 or 6 XS650's that I have ridden and checked. 60 if I'm putting around at 45MPH but "it hurts my motor to go so slow"

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