gas mileage on a /7?

[BoxerTwin]

Howdy,

I went for a ride this week after having a bunch of minor things worked on.
The bike sounds great, feels great and is all in all fine.

I'm getting about 26mpg on it.
That seems kind of low. I am a big guy 6'3" 280 so that might be it but even then it seems low when I hear rumors of 42 - 46 mpg.

this is my mileage for hwy riding 3.5K - 4K RPMs

thoughts?

[Ken in Oklahoma]

Well, I'm bigger than you and I get in the mid 30's on my '77 R100/7 and '77 R100S. I don't pay close attention to my mileage and am always astonished at reports of over 40mpg--and there are many.

In any event it seems to me that you should be betting better than 26 mpg, unless you have some very unique riding circumstances.

How about some more information? What kind of riding do you do? Is your /7 running just fine aside from the mileage. Has the mileage ever been good on your bike? How about a thumbnail sketch of what has been done to your bike. Anything recent.

Do you do your own mechanical work or farm it out?

I think you get the idea. Now that you "know" that your bike probably should do better, we're going to want something to get our teeth in to other than telling you that you need a thorough tune up on your bike.



Ken

[BoxerTwin]

Well, I'm bigger than you and I get in the mid 30's on my '77 R100/7 and '77 R100S. I don't pay close attention to my mileage and am always astonished at reports of over 40mpg--and there are many.

In any event it seems to me that you should be betting better than 26 mpg, unless you have some very unique riding circumstances.

How about some more information? What kind of riding do you do? Is your /7 running just fine aside from the mileage. Has the mileage ever been good on your bike? How about a thumbnail sketch of what has been done to your bike. Anything recent.

Do you do your own mechanical work or farm it out?

I think you get the idea. Now that you "know" that your bike probably should do better, we're going to want something to get our teeth in to other than telling you that you need a thorough tune up on your bike.



Ken

Nice to see there are a collection of us 'average sized' guys who ride these.

So the work...this gets hard.
The PO tore it apart and did a crap job of rebuilding it.

I have fix the heads, the he put the wrong valve in the wrong end. Heads have been rebuilt with the intake valve in the intake and the exhaust valve in the exhaust.

Fix numerous electric issues, he thought proper electrical work meant you strip a section of wire, twist it to the other end and wrap it in e-tape. I repaired most of his electrical the right way (I was an electronic repair tech so this is the one area I can actually do really well).

rebuilt the carbs two or three years ago.
just cleaned them and readjusted them. Might be the issue here but the plugs look nice after about 200 miles.
not rich looking that I would expect for getting poor gas mileage.

the bike runs really well right now. Probably best that it has run in the 4 years I have owned it. Smooth at all RPM's.
my only complaint would be lacking gas mileage.

The best mileage I ever had on it was about 33MPG.

I farm out some of the work that is too hard for me, most that requires tools I don't have (like rebuilding a head and valves). I do most other work that I can figure out via Haynes, Duane's web pages and this forum.

thanks,

Glen

[SteveD]

How old are the needles and needle jets? They wear, and mileage falls accordingly.

[Duane Ausherman]

Our 750 cc road racer would get in the high 20s. You are right, you have a problem.

[Major Softie]

SteveD's suggestion is the most common cause with these bikes, so it's the first thing to check. BUT, since this idiot PO rebuilt the carbs, it's hard to believe that he did everything right. It's also possible that he made a large increase in the jet size. I'd definitely check to see if it still has stock jetting.

[BoxerTwin]

SteveD's suggestion is the most common cause with these bikes, so it's the first thing to check. BUT, since this idiot PO rebuilt the carbs, it's hard to believe that he did everything right. It's also possible that he made a large increase in the jet size. I'd definitely check to see if it still has stock jetting.

I'll take a look at this. This would make a lot of sense.