A
Anonymous
Guest
I have gotten as little as 40mpg and as much as 55 wwith my 1980 Gs750r...I do not ride easy..I am ON IT alsways :wink:
-
Required reading for all forum users!!!
Welcome!
Register to access the full functionality of the GSResources forum. Until you register and activate your account you will not have full forum access, nor will you be able to post or reply to messages.A note to new registrants...
All new forum registrations must be activated via email before you have full access to the forum.A Special Note about Email accounts!
DO NOT SIGN UP USING hotmail, outlook, gmx, sbcglobal, att, bellsouth or email.com. They delete our forum signup emails.A note to old forum members...
I receive numerous requests from people who can no longer log in because their accounts were deleted. As mentioned in the forum FAQ, user accounts are deleted if you haven't logged in for the past 6 months. If you can't log in, then create a new forum account. If you don't get an error message, then check your email account for an activation message. If you get a message stating that the email address is already in use, then your account still exists so follow the instructions in the forum FAQ for resetting your password.Have you forgotten your password or have a new email address? Then read the forum FAQ for details on how to reset it.
Any email requests for "can't log in anymore" problems or "lost my password" problems will be deleted. Read the forum FAQ and follow the instructions there - that's what we have one for...
-
Returning Visitors
If you are a returning visitor who never received your confirmation email, then odds are your email provider is blockinig emails from our server. The only thing that can be done to get around this is you will have to try creating another forum account using an email address from another domain.
If you are a returning visitor to the forum and can't log in using your old forum name and password but used to be able to then chances are your account is deleted. Purges of the databases are done regularly. You will have to create a new forum account and you should be all set.
A
Anonymous
Guest
thanks dom ill try that but im going to raise the clip 2 notches because i allready had it in the middle.
A
Anonymous
Guest
I took a jewelers screw driver with a bit the right size and cut it to about 1-1/2" inches long and then cut a slot in the top that I could see. The screwdriver was knurled around the shank, so it still grips well to turn. Then to adjust my fuel mixture I loosen the tank bolt and lift it from the rear just enough to slide a 2x2 under. With the 2x2 resting on the upper bike frame the tank is raised about 3 inches, which for me is plenty of room to fit my hand in there and not only turn the screws, but see the notch I cut. I could do 7/8ths of a turn if that's what I needed to do. With this screwdriver I can get to 3 of the 4 carbs without raising the tank, but #2 is impossible with the petcock and clutch cable and vacuum hose all going to that area.
Cheerio,
Roger Moore
Cheerio,
Roger Moore
T
TheNose
Guest
Earl,
I adjusted my carbs like you suggested, 7/8 for fuel, and 1 3/4 for air. Rode about 45 minutes, checked plugs. Number 1, 2, 4 were perfect. Number 3 was just little rich so I opened the air up another 1/8 turn. Is this the right way to correct number 3 being rich? Or should I close the fuel screw? It had just a very little bit of soot on it.
I made the adjustment while the carbs were on the bike. I don't like having to disconnect the control cables. I made a "screwdriver" to make the adjustment. I think I will make one out of a jewelers screwdriver like Roger did.
Terry
I adjusted my carbs like you suggested, 7/8 for fuel, and 1 3/4 for air. Rode about 45 minutes, checked plugs. Number 1, 2, 4 were perfect. Number 3 was just little rich so I opened the air up another 1/8 turn. Is this the right way to correct number 3 being rich? Or should I close the fuel screw? It had just a very little bit of soot on it.
I made the adjustment while the carbs were on the bike. I don't like having to disconnect the control cables. I made a "screwdriver" to make the adjustment. I think I will make one out of a jewelers screwdriver like Roger did.
Terry
A
Anonymous
Guest
milage
milage
Last Wed. I coverd about 180 miles half of which was in 2,3, gear and the rest normal and did about 51 mpg and used about 4 oz of oil.........from 65 to 90 degree temps........
milage
Last Wed. I coverd about 180 miles half of which was in 2,3, gear and the rest normal and did about 51 mpg and used about 4 oz of oil.........from 65 to 90 degree temps........
A
Anonymous
Guest
Perhaps now that I'm not riding along with the BRAKES APPLIED, I may start getting better gas milage myself...
One can only hope
Roger
One can only hope
Roger
I get about 175 km (about 108 miles) before I have to hit reserve on my '78 GS750. It has a Jardine 4 into 1 header and pod filters. I really don't remember where I set the carbs, but whenever I remove a plug, it is light brown. I ride it hard. Redline is no stranger. :twisted:
I dont know that it would make much difference which one you change to make the mixture leaner or richer. I think probably leaving the fuel screws all the same would be best.
So I would tweak the air screw. Besides, the air screw is much easier to get to. Seriously though, my choice would be to tweak the air screw.
Earl
So I would tweak the air screw. Besides, the air screw is much easier to get to.
Seriously though, my choice would be to tweak the air screw. Earl
TheNose said:
A
Anonymous
Guest
Gas Milage
Gas Milage
I got my 78 GS750 last week and on my first full tank I hit 168 miles before I had to switch to my reserve tank, that's about 45 mpg. But it needs a tune up, prior owner told me he was getting about 50 mpg when it was properly tuned.
Gas Milage
I got my 78 GS750 last week and on my first full tank I hit 168 miles before I had to switch to my reserve tank, that's about 45 mpg. But it needs a tune up, prior owner told me he was getting about 50 mpg when it was properly tuned.
Re: Gas Milage
Re: Gas Milage
Hmmm, 168 miles sounds about right. To get milage that good, it cant be more than a "hair" out. My opinion is that its better to be getting something in the 45 to 50 range rather than trying to lean it out to get a couple more miles per gallon at the risk of cooking an engine.
Earl
Re: Gas Milage
Hmmm, 168 miles sounds about right. To get milage that good, it cant be more than a "hair" out. My opinion is that its better to be getting something in the 45 to 50 range rather than trying to lean it out to get a couple more miles per gallon at the risk of cooking an engine.
Earl
MilwaukeeDavid said:
A
Anonymous
Guest
Yeah, I seem to remember getting about that much too -- way back when I first got the bike. Maybe I'll get that much now without the brakes dragging, but if I don't... I have no idea how to make it better. The plugs are perfect now and I'm not racing it. The difference of 20 MPG from one bike to the next has to be more than what you'd expect -- unless it's a race bike vs a commuter.
Roger Moore
27 MPG or so on the last tank
Roger Moore
27 MPG or so on the last tank
A
Anonymous
Guest
Earl,
Oh, they "were" dragging. My first trip out after redoing all the brake components was like riding a whole new bike. I never felt the rotors, but just spinning the tires by hand (before and after the rebuild) showed an appreciable change.
Weather's been kind of crappy the past two days, so I've driven to work, but we're looking at about a week of sunny motorcycle weather now, so I should have a good tankful of driving to do to see how much better it'll be.
Roger Moore
Oh, they "were" dragging. My first trip out after redoing all the brake components was like riding a whole new bike. I never felt the rotors, but just spinning the tires by hand (before and after the rebuild) showed an appreciable change.
Weather's been kind of crappy the past two days, so I've driven to work, but we're looking at about a week of sunny motorcycle weather now, so I should have a good tankful of driving to do to see how much better it'll be.
Roger Moore
A
Anonymous
Guest
Maybe not my carburetor settings...
Maybe not my carburetor settings...
OK, so I took Earl's suggestion and set my FUEL screw to 7/8 and my AIR screw to 1 3/4, and I am still getting below 40 mpg. I've got the stock pilot jets in it, the clip is in the second notch from the top on the needle, and the main jets are 100's (one leaner than stock). The plugs look good - ie grayish tan. Also, I know the brakes are not dragging (I recently rebuilt all three calipers). :wink:
The bike starts OK, but it won't idle without the choke in the morning (about 55 degree F air temperature). Even after a fifteen minute ride, including about 5 highway miles, I have to keep my hand on the throttle or it will die. In the afternoons, sometimes it will idle fine (about 1100 rpm) by the time I get home (temperature has been in the 70's in the afternoons). Also, it seems to pop a lot more through the exhaust than it used to, especially when cold. The bike seems to run well around town, on the highway, and it accelerates smoothly.
So I decided to try synchronizing the carburetors. #3 was waaaay out of whack. I brought it back into line with the others, but the best I could do was about 7 inches of vaccuum across the whole rack.
Next, I did a compression test. Cylinder #1 = 115 psi, #2 = 85 psi, #3 = 115 psi, and #4 = 90 psi. I repeated the measurements to make sure I didn't mess anything up, and the results were the same. With a little oil in the sparkplug hole, the compression jumped to 170 on # 1 and #3, and 140 on the other two.
So, I think I know what all this means, but I need someone to confirm my worst nightmares.... Do I need to rebore the cylinders and fit larger pistions? Any chance I'll be able to just hone the walls and replace the rings? Any idea if this will improve fuel economy and make it less cold blooded? The bike has about 30K on it.
Actually, that isn't exactly a nightmare. I love doing stuff like that, I just hate being without
a bike while I do the work. :?
Maybe not my carburetor settings...
OK, so I took Earl's suggestion and set my FUEL screw to 7/8 and my AIR screw to 1 3/4, and I am still getting below 40 mpg. I've got the stock pilot jets in it, the clip is in the second notch from the top on the needle, and the main jets are 100's (one leaner than stock). The plugs look good - ie grayish tan. Also, I know the brakes are not dragging (I recently rebuilt all three calipers). :wink:
The bike starts OK, but it won't idle without the choke in the morning (about 55 degree F air temperature). Even after a fifteen minute ride, including about 5 highway miles, I have to keep my hand on the throttle or it will die. In the afternoons, sometimes it will idle fine (about 1100 rpm) by the time I get home (temperature has been in the 70's in the afternoons). Also, it seems to pop a lot more through the exhaust than it used to, especially when cold. The bike seems to run well around town, on the highway, and it accelerates smoothly.
So I decided to try synchronizing the carburetors. #3 was waaaay out of whack. I brought it back into line with the others, but the best I could do was about 7 inches of vaccuum across the whole rack.
Next, I did a compression test. Cylinder #1 = 115 psi, #2 = 85 psi, #3 = 115 psi, and #4 = 90 psi. I repeated the measurements to make sure I didn't mess anything up, and the results were the same. With a little oil in the sparkplug hole, the compression jumped to 170 on # 1 and #3, and 140 on the other two.
So, I think I know what all this means, but I need someone to confirm my worst nightmares.... Do I need to rebore the cylinders and fit larger pistions? Any chance I'll be able to just hone the walls and replace the rings? Any idea if this will improve fuel economy and make it less cold blooded? The bike has about 30K on it.
Actually, that isn't exactly a nightmare. I love doing stuff like that, I just hate being without
a bike while I do the work. :?
A
Anonymous
Guest
Probably just worn rings.
A
Anonymous
Guest
I'm riding a 82' GS1100E and getting around 20MPG. I have only recently begun trying to track down the problem. I just wanted to thank everyone that posted here because it's given me some good ideas and a number of things to check. I'll let you all know what I find.
Thanks all..
Thanks all..
Re: Maybe not my carburetor settings...
Re: Maybe not my carburetor settings...
Brian
It seems to me that its likely all you need are new rings.
Seven inches difference in vacum between the carbs is way out of sync. They should be within an inch or two.
I thinks its doubtful you will be able to tune the engine precisely with the compression readings that far apart. Your gas milage is related to the compression, so I expect that when your compression is evened out to what it should be, your milage will also improve.
Earl
Re: Maybe not my carburetor settings...
Brian
It seems to me that its likely all you need are new rings.
Seven inches difference in vacum between the carbs is way out of sync. They should be within an inch or two.
I thinks its doubtful you will be able to tune the engine precisely with the compression readings that far apart. Your gas milage is related to the compression, so I expect that when your compression is evened out to what it should be, your milage will also improve.
Earl
A
Anonymous
Guest
Yep... Sounds like rings to me too. You may have "stuck rings" though, not necessarily bad rings. If the bike only has 30,000 miles on it, it's hard to imagine rings being that far gone (and has it sat for some period?). My bike has about the same milage, and its compression is not that low.
You might want to start off by pulling the spark plugs and pouring a half a cup of carb cleaner (something like Berryman's B-100 chemtool) into each cylinder and letting it sit there for a half hour and then turn it over a few times with the plugs re-installed, but the kill switch in the OFF position. Then do it again. Make sure the cylinder bore are as perpendicular to the ground as possible. If the rings are "glued" to the pistons, this should help free them up. Rings should be floating in their grooves, and they may not be.
You'll need to change the oil after doing this, or shortly thereafter. A little Berryman's in the crankcase shouldn't hurt, since you use the same chemical to flush an engine anyway -- but wet clutches are my only concern. Shouldn't really hurt, but change the oil -- since diluted oil isn't a good thing.
Whether you can just re-ring (assuming the above doesn't help) depends on the actual wear in the cylinder bore. This will have to be mic'd to see what it the wear actually is. If it's within tolerances, then a good hone and re-ring should make it good to go.
Good luck!
Roger Moore
You might want to start off by pulling the spark plugs and pouring a half a cup of carb cleaner (something like Berryman's B-100 chemtool) into each cylinder and letting it sit there for a half hour and then turn it over a few times with the plugs re-installed, but the kill switch in the OFF position. Then do it again. Make sure the cylinder bore are as perpendicular to the ground as possible. If the rings are "glued" to the pistons, this should help free them up. Rings should be floating in their grooves, and they may not be.
You'll need to change the oil after doing this, or shortly thereafter. A little Berryman's in the crankcase shouldn't hurt, since you use the same chemical to flush an engine anyway -- but wet clutches are my only concern. Shouldn't really hurt, but change the oil -- since diluted oil isn't a good thing.
Whether you can just re-ring (assuming the above doesn't help) depends on the actual wear in the cylinder bore. This will have to be mic'd to see what it the wear actually is. If it's within tolerances, then a good hone and re-ring should make it good to go.
Good luck!
Roger Moore
A
Anonymous
Guest
Earl, my compression is about 150 across the board, and this fill-up I got only 30 MPG. This seems very low to me for a bike that really runs well now, and has no sign of sooty plugs and is not been "got on" much at all. I'm a pretty laid back cruizer on the bike. Most of my riding is "in town" commuting, and have yet been able to (find the time to) get it on the freeway for a tankful. Hopefully soon I will. Maybe I got spiders still living in the cylinders? Haven't synched the carbs yet, but plan to. They can't be too far off for how well it runs -- I' think. But hey, a motorcycle mechanic I don't claim to be, but it's really only the carbs on the bike that I'm foggy on.
Roger Moore
