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Old 06-10-2014, 04:27 AM   #301
dvblue_2000
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Quote:
Originally Posted by Beater View Post
OK. Has anyone broken the 40mpg mark? Not this weekend, but the next I was going to do some serious maitenance on the bikes. At this point I will be able to tell you what I'm running.
I'm glad it's not just me getting under 40 MPG. My R60/7's running great so I'm not going to tamper with the Mikunis anymore. I'm running mid to upper 30s and an occasional 40.
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Old 06-10-2014, 04:30 AM   #302
dvblue_2000
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Originally Posted by christophebp View Post
Hey all,
I have a r75/5 with mikunis from rocky point, installed with default settings.
The bike runs well but the left carb is spitting all over my boots. What should i look for to debug that?
Mine leaked when parked so I monkeyed with the floats, but I think the real problem with mine was the choke/enrichener plunger not going all the way down. I now push them down with my finger instead of lifting the lever.
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Old 06-11-2014, 11:25 PM   #303
christophebp
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Thanks Fred and dvblue. I'll check it out this weekend.
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Old 07-10-2014, 08:15 AM   #304
bmwblake
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Maybe i missed it somewhere in the thread but is there anyone running an r75/5 that can let me know what they're running?

I don't have my numbers on hand but they certainly aren't working anywhere except idle. I think I'm lean on the mains for sure.
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Old 07-10-2014, 10:11 AM   #305
supershaft
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Quote:
Originally Posted by dvblue_2000 View Post
I'm glad it's not just me getting under 40 MPG. My R60/7's running great so I'm not going to tamper with the Mikunis anymore. I'm running mid to upper 30s and an occasional 40.
Upper 30's and an occasional 40 is excellent mileage in the real world. That's what they got brand new and setup about perfectly. Most all of our customers reported mid to upper 30's and their bikes were almost brand new and in excellent condition. Mikuni's can and should get a little better mileage than Bings. Some of it is just jetting leaner since the factory shipped their Bings rich on top and some of it is the carbs.
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Old 07-10-2014, 11:22 AM   #306
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I've recently put 160 mains in mine ... Getting about 35mpg (25 pilot, R100, Double plugged, VM32's). I haven't played with the needle position ... but that's next. I'd like to get 40 ... but we'll see where we end up.

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Originally Posted by supershaft View Post
Upper 30's and an occasional 40 is excellent mileage in the real world. That's what they got brand new and setup about perfectly. Most all of our customers reported mid to upper 30's and their bikes were almost brand new and in excellent condition. Mikuni's can and should get a little better mileage than Bings. Some of it is just jetting leaner since the factory shipped their Bings rich on top and some of it is the carbs.
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'85 R80RT G/Sified <|> '91 R100GS Bumblebee (103K miles and climbing) <|> '73 R75/5 LWB
Airhead Zen: Ride - Repair - Ride - Maintain - Ride - Repeat
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Old 07-10-2014, 12:54 PM   #307
supershaft
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Originally Posted by Beater View Post
I've recently put 160 mains in mine ... Getting about 35mpg (25 pilot, R100, Double plugged, VM32's). I haven't played with the needle position ... but that's next. I'd like to get 40 ... but we'll see where we end up.
The biggest variables in jetting rarely gets mentioned here on the net. Dual plugged? Displacement? Exhaust? To a large degree even carb size doesn't make that much of a difference. The airbox and intake setup? HUGE difference. No one seems to mention port size either. Big or small port heads? It matters more than a lot of things. 32mm Mikuni's on a R100? It needs much bigger. Small port heads? 38's. Low rpm power? 38mm Mikuni's give you much more low end grunt and top end than 32mm Bings. Have your cake and eat it too! Big port heads? I might go no larger than 36mm Mikuni's. The big port heads are much easier to tune to a stand still so to speak.

supershaft screwed with this post 07-10-2014 at 12:59 PM
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Old 07-10-2014, 02:37 PM   #308
Beater
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The Dobber has 32's as well ... single plug, small port, 160 mains and 20 pilot. Stock intake and airbox.

It's far and away the fastest and quickest Airhead I've ever owned, but it probably has something to do with the fact that it also weighs about 50 pounds lighter than the stock version of the same bike. The Dobber gets around 37mpg consistenly, and BB the '91 GS gets around 35. I still think she needs to be leaned out some more ...

Quote:
Originally Posted by supershaft View Post
The biggest variables in jetting rarely gets mentioned here on the net. Dual plugged? Displacement? Exhaust? To a large degree even carb size doesn't make that much of a difference. The airbox and intake setup? HUGE difference. No one seems to mention port size either. Big or small port heads? It matters more than a lot of things. 32mm Mikuni's on a R100? It needs much bigger. Small port heads? 38's. Low rpm power? 38mm Mikuni's give you much more low end grunt and top end than 32mm Bings. Have your cake and eat it too! Big port heads? I might go no larger than 36mm Mikuni's. The big port heads are much easier to tune to a stand still so to speak.
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'85 R80RT G/Sified <|> '91 R100GS Bumblebee (103K miles and climbing) <|> '73 R75/5 LWB
Airhead Zen: Ride - Repair - Ride - Maintain - Ride - Repeat
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Old 12-16-2014, 03:13 PM   #309
Beater
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OK - Put VM32's on to the 73 R75/5. After some finagling, It's running really nice ... idle and acceleration to 6.5K rpm.

30 pilots
175 mains
Stock airbox set-up and thinner (0.25mm) metal cylinder gasket (in between cylinder and block).

I have no idea what mpg I'll be getting, but if it is any experience, mid-to-high 30's.
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'85 R80RT G/Sified <|> '91 R100GS Bumblebee (103K miles and climbing) <|> '73 R75/5 LWB
Airhead Zen: Ride - Repair - Ride - Maintain - Ride - Repeat
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