Gotta stop looking at ads BMW F650

Mailman said:
I always really enjoy these bring ‘em back to life threads Gary! 😃
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Glad to see you're easily entertained.😉
Carbs off, one side clean. I'm done for today. Not picking on you Kevin cuz I have done chem cleans. But these were way past that.
Airbox would not come out of frame but I got it cocked enough to remove the carbs.
KIMG3837.JPG
Gunky gas from float bowls
KIMG3840_01_BURST1003840_COVER.JPG
Main, and needle, and needle jet
KIMG3848.JPGKIMG3849~2.JPG
Took a while with single strand of copper but worked down through about 1/4" of hard crud to clear the pilot.
KIMG3854~2.JPG

KIMG3846.JPG
Bought kits but don't think I'll need any parts from them.
Tomorrow reassemble this one, do side two and mebby get r back together. Glad I'm not pay'n BMW labor rates!
 
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gggGary said:
Glad to see you're easily entertained..😉
Carbs off one side clean. I'm done for today. Not picking on you Kevin cuz I have done chem cleans. But these were way past that.
Airbox would not come out of frame but I got it cocked enough to remove the carbs.
View attachment 244683
View attachment 244682
Gunky gas from float bowls
View attachment 244682
Main, and needle, and needle jet
View attachment 244680View attachment 244678
Took a while with single strand of copper but worked down through about 1/4" of hard crud to clear the pilot.
View attachment 244679

View attachment 244681
Tomorrow reassemble do side two and mebby get r back together. Glad I'm not pay'n BMW labor rates!
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I’ve often wondered about the reasoning for two carburetors for one cylinder? Are they jetted differently?
 
Mailman said:
I’ve often wondered about the reasoning for two carburetors for one cylinder? Are they jetted differently?
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I'll know tomorrow but don't think so, they are an identical pair, one for each intake valve. Other than being spaced a bit close together I'm 95% certain they'd be plug and play as jetted onto an XS650...

If you've been in a CV mikuni there's no mysteries here. Think pilots and mains might be the same part# as late model BS38
seems it has 132.5 mains, 42.5 pilots
 

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Mailman said:
I’ve often wondered about the reasoning for two carburetors for one cylinder? Are they jetted differently?
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It's a 4 valve head Bob. Running 1 carb to 1 valve means you can run smaller carbs. That keeps airflow through the carbs in it's sweet spot.
1 giant carb would be a real pain to dial in from idle to redline.
Kinda the same reason we had 2 barrel and 4 barrel carbs. Think of it as a 2 barrel carb is actually 2 separate carbs that share the same float bowl. The key point is multiple smaller venturi's give better performance than one big one.
 
Random thoughts firing ahead... Danger...

With 2 carbs and 2 plugs, you could add a second ignition system (I assume there's just one for both plugs) and short of a catastrophic engine failure, you'd have a bike that's almost guaranteed to get you home. Limping maybe... but it'll make the barn.
 
Mailman said:
Are they jetted differently?
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There is a difference, only one side has an enricher circuit, otherwise identical.
Second side is dirtier inside. It was kinda funny when I opened the float bowl drains one side came out greenish with some water blobs, the other came out clear but with chunks of red (whatever)
just some of how they are built and crap inside.
The "jungle gym" is kind of neat, but the oring that seals the idle fuel supply pickup tube was toast on both sides.
KIMG3859.JPGKIMG3861.JPG
nice main jet
main.jpg
almost missed this screen.
KIMG3860.JPG
pushed inside the fuel tee.
 

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Mailman said:
I’ve often wondered about the reasoning for two carburetors for one cylinder? Are they jetted differently?
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Honda did it with their RFVCC singles in the 80's, with later models they returned to single carb.
As almost everyone made and still makes 4 valve singles with single carbs I see it as unnecessary complication that increases cost with little real benefit.
The Honda carbs were jetted identically though they did change jetting over the years I assume to lean them out for emissions.
Of course I sometimes think Honda changes things only to keep engineers busy
 
RC4MAN said:
Honda did it with their RFVCC singles in the 80's, with later models they returned to single carb.
As almost everyone made and still makes 4 valve singles with single carbs I see it as unnecessary complication that increases cost with little real benefit.
The Honda carbs were jetted identically though they did change jetting over the years I assume to lean them out for emissions.
Of course I sometimes think Honda changes things only to keep engineers busy
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Is one configuration better for ham fisted throttle i.e. whack it open.
 
Kevin Werner said:
Is one configuration better for ham fisted throttle i.e. whack it open.
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That's perhaps a more theoretical question rather than practical as Honda and most others have returned to and stay with single carbs.
I'm sure Honda has state of the art fluid dynamic software and flow benches to optimize those characteristics through the range of throttle positions.
Additionally diaphragm carbs of the type used on our 650 were used as one means to negate that, accelerator pumps have been another on Delortto or Mikuni Pumper carbs
 
It lives. Sounds smooth, quiet, accelerates good, idles, just a trip round the driveways on a test tank. Gotta cycle the coolant temperature a couple times make sure the system is topped up before the gas tank and all the tupperware goes back on.
Think I found a smoking gun; carb vacuum line that went nowhere from an evap canister delete gone wrong."
More breathless updates later.
 
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So got everything back on, BMW Zere ist only VONE VAY to assemble the tupperware get anything out of order take it ALL off and start over. :doh:
put some gas in the tank brum brum, around the driveways, up the hill and back, all good. Geared up and headed to town, filled the tank and off I went running great, 30 miles later stopped for pics.
f650 left.jpg KIMG3867.JPG
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And while waiting for Allison to come get me with the trailer, I shot this stream I was near.
Very peaceful............
KIMG3870.JPG
:doh:
 
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gggGary said:
And while waiting for Allison to come get me with the trailer, I shot this stream I was near.
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I was about to post the heart eyes emoji until I got to the last. You're lucky; Mildred won't drive the trailer. I have to have her come get me, drive back and hook-up the trailer, and...........

Awaiting the "rest of the story"..........;)

(and I thought you'd be in Iowa today:lmao:)
 
She always has the horse trailer hooked up and ready to roll.
Was there in 20 minutes.
It was running perfect shut it off to take pics got ready to leave, key on, dash lights fine, everything electric working, no start, not even a hint of the starter motor spinning, no relay click, nada. No joy push starting on the gravel road either, even though I pushed it up a decent hill...
Got it home and out of the trailer, it bump started rolling it down to the garage. Tried the e-start and broom broom. So now I gotta fix a bike that works "fine". :shrug:
Prolly just tool up so I can troubleshoot and head out again.
And was running so great, never had any issues in garage either, where I must of spun the motor over 30 times.
 
Working fine, rode another 20 miles assembled some tools and jumpers did several kill starts no issues, shrug. Rumours of side stand switch issues on that forum. Finally found a bike this tailbag fits nicely. Think bike looks good windshield on or off, 4 bolts bingo Bango.
It's got working heated grips front n rear crash saddle bag rack bars. Too bad I've already been TOLD it's not mine to keep. 🙄
KIMG3876.JPG


Paint's not quite as nice as the pics make it look, it was used for some light off roading. The PLASTIC "bash plate" is still in good shape....
The front wheel can really be turned hard. suspension is "OK" Doesn't really want to pull til 3K after 4K it gets going, redline is 7500 I've had it to 75MPH. Pretty happy on the highway about 3800 at an indicated 60MPH. After 3K it's smooth for a single. Might benefit from bumping the pilots up a size.
No drips or leaks, gas, oil, or coolant. Very quiet, even for the old man's ears.
 
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gggGary said:
She always has the horse trailer hooked up and ready to roll.
Was there in 20 minutes.
It was running perfect shut it off to take pics got ready to leave, key on, dash lights fine, everything electric working, no start, not even a hint of the starter motor spinning, no relay click, nada. No joy push starting on the gravel road either, even though I pushed it up a decent hill...
Got it home and out of the trailer, it bump started rolling it down to the garage. Tried the e-start and broom broom. So now I gotta fix a bike that works "fine". :shrug:
Prolly just tool up so I can troubleshoot and head out again.
And was running so great, never had any issues in garage either, where I must of spun the motor over 30 times.
Click to expand...
Sounds like you caught what Raymond has, or at least a variant.
 

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