BS 34 carburetors

Jan_P

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Your alternator has been charging, but that doesn't mean that the charging system is "fine." One great virtue of the OE breaker point regulator is that it is adjustable. If you don't have a decent manual, go to www.biker.net and download the electrics section of the 1978 factory service manual. Clean points and adjust air gaps first, then try to bring charging into spec range with the output screw. I haven't found an XS650 breaker point regulator yet that didn't respond to service.
Thank you Sir
I might end doing that .I was on that a coupe of years ago .. The stock regulator overcharged warm days on the highway.
Kicking out the Boyer on one cylinder ( as I understood it ) Taking out the mechanical regulator and rectifier .Replacing with new
highway problem disappeared
Had both systems on the bike for a while the mechanical as safety. so I could plug in and out. Hazzle free last years
At this point in time I believe I have had this 11.8 at the start as system Voltage because the regulators lowered it
But have not noticed it.
Plugging in things and starting charging is there .. No reason to measure anything
I like stock .. And don't like to replace things but I could not solve it then I had three of them on the kitchen table a winter
And had a Voltage supply trying ..

I can try to service a mechanical again once I get things running and again have two setups on the bike.
The stumbling can be a intermittent short somewhere else
 

Jan_P

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Moved the carburetor needle one step to the top most position.
Temporary switch for Bypassing the charging circuit I get 0. 5 --0.6 more Volts on the ignition coil in the off position
( Not MIL Spec )
Have an electronic Automotive regulator in the tools compartment and also the stock on its place not connected now but can do it
out on the road should something go wrong.
Tweaked the ignition a little again ,, for one kick start
Test riding this evening ..Se what happens


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Jan_P

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Right side carburetor is overflowing ..Bike runs poorly especially around 2 -3000 rpm stumbling
Leaving it on Pri on the petcock it drops petrol onto the ground.
Is replacement of float valve the way forward. ?
Or is wait and see.
Cleaning ??
Do they have a best before time ??
 

5twins

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The viton tipped needles are usually very long lasting. You may just have some dirt in the seat. If you remove the bowl, put a catch container under the carb, and turn the petcock to "Prime", fuel will flow out and hopefully flush the seat clean.
 

Jim

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Also... the 34's with the Viton tipped needle come with a fine mesh screen that should prevent trash getting to the seat. If it is in fact dirt in the seat, you might want to check and see if the screens are missing.



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Jan_P

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Today upon opening pri it did not overflow
Flushed it all the same

Right plug has been leaner which is surprising because it was the side overflowing
Unless an air leak ..but could not find any major untightened clamp or screw.

tightened the clamp on the intake boot
Changed the plugs and serviced the caps and tightened the wire in the cap
Have tried kick starting standing on the right side with my right leg
Never done that before.
Seems as a working concept.






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5twins

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How old are those plugs? They look pretty worn, lol. These bikes are tough on plugs, wearing them out pretty quickly. I change them by 4K miles, sometimes even 3K. The plugs burn relatively clean and wear pretty evenly, so it's hard to see any wear looking at one by itself. What you need is a brand new plug to compare it to side by side. Then you'll easily see if it's worn. And that wear takes the form of the center electrode getting shorter. This is pretty easy to see when you compare new and old side by side.
 

Jan_P

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Yes Sir they are old
Into the third season not kept a record but around 6 --7000 km making it about 4 K Miles
I have new ones lying around here somewhere that I will put in .Could not find them when I was doing it.
So installed different old ones. That looked better. for testing.
Fired right up but did not have time for a test ride.
 

5twins

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Compare your old ones to your new ones when you find them and I'll bet you will see the wear on the old ones.

I learned this lesson quite a few years ago with one of my BMWs. I was coming home from a rally and the bike seemed to be struggling a bit going 70 down the highway. When I got home, I of course checked the plugs first thing. They looked fine, just like they always did on that bike. Then I checked my maintenance log and saw those plugs had been in there for near 10K miles, lol. I pulled out some new ones and compared them. You could see the center electrode was noticeably shorter on the old plugs, other than that they looked fine. So, new plugs in, a test run down the highway, and all fixed, pulled 70 down the interstate no problem.
 

Jan_P

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Worst running motorcycle I can remember I have had ....
Stumbling as if no electric power .But It is charging
Red Box Boyer
Fuses appears to sit
Battery connection looks tight
Have no kill switch
And have no clue right now
60 miles ride tonight Fine evening otherwise .. not dark even 11:00 pm
Hoping it to be dirt in the carburetor but does not seems so
I have not taken out the plugs or checked anything else.
Did not want to stop out at the roadside ..risking not being able to start it again.

Starts fine and idles fine.

Can it stumble if the pilot jet is to large ?
Going stock perhaps ??

Needle is in the topmost position

have
Main 135
Pilot 42.5
Air 130
About the same as stock exhausts little more open
Stock air filter

I remember Mailmans " Does it ever end ? "
 

Jan_P

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Took out the spark plugs
the replaced set looks the same as

# Post 67

Right side running leaner and hotter .
I don't have different jetting or needle setup on left and right
I have a Boyer Bransden ignition so ---Is it not so that the spark is there and the same on both sides ??
or no spark at all
Had overflowing right carburetor last time.
Even if black left plug I have never had any stumbling because of that before

Is this adding up to a Dirty Pilot jet or two ??
Does Bowls down and cleaning Both Sides Sound as a reasonable step ?
 

Jan_P

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Cleaned the Right side Jets .No change
Weak spark noticed it with plugs on cylinder head kicking
Cleaned the inside of the caps got better spark sounded better test-ride 500 yards one way --- stalled -- pushing it home.
Going to jump the Boyer system Se if any change .Suspecting the ignition lock after all.
Since there appears to be a weak design that Mr 5 T never have seen. #41 # 42
Testing some with a light bulb and Voltmeter

For the Gonzo Ignition boys there can be aspects

http://vintagebikemagazine.com/technical-articles/boyer-trouble-shooting/

>>>>

  • Radio frequency emitted from alternator wires and spark plugs can interfere with the Boyer ignition box. The MKIII and MKIV (black boxes) are the least sensitive to RF interference. The Micro-Digital (red box) and Micro-Power (blue box) are both very sensitive to RF interference. It is strongly advised that RF canceling resistor spark plug covers (5000 ohm) be used with these units.
  • Alternator wires should never be located near, or run parallel to, the timing plate wires, or battery ground or feed wires. For example: T160 wiring harness carries the alternator wires in the same wiring sub-harness with the wires coming from the timing plate. This will cause the bike not to start or run poorly.
 

Team Junk

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Thank You Jan. Very good troubleshooting guide that also is very useful for trouble shooting the Gonzo . I will post the link in the Gonzo thread.

The guide depicts having 2 ignition coils.

Are you using 2 coils or a single dual output coil ? If separate coils than there can be a large difference in spark on the 2 sides.

I would hook up a timing light and compare the 2 sides. Most timing lights these days are polarity sensitive so you may have to flip the timing light pickup when you change sides.

From this distance I would bet on carb issues.
 

Jan_P

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Thank You Jan. Very good troubleshooting guide that also is very useful for trouble shooting the Gonzo . I will post the link in the Gonzo thread.

The guide depicts having 2 ignition coils.

Are you using 2 coils or a single dual output coil ? If separate coils than there can be a large difference in spark on the 2 sides.

I would hook up a timing light and compare the 2 sides. Most timing lights these days are polarity sensitive so you may have to flip the timing light pickup when you change sides.

From this distance I would bet on carb issues.

Thank you Sir

I have 1 Boyer dual output coil Micro Digital. Ignition
Cant use a timing light because the last rewind moved the marks.
Found a difference on suppressor cap resistance one has dropped to 4.82 k the other 5.08 k ( cold )
Getting new ones ASAP.
Have good power on Boyer Coil and Box ( Cold )
Im on it not gone through all . If everything checks out ill bypass

Something like that

On a negative ground system run a jumper from the battery negative terminal to the white wire coming out of the EI box. Run another jumper from the battery positive terminal to coil where the red wire from the box is attached to the positive terminal of the coil. See wiring diagram for your bike downloadable below.

In both cases be sure to run a ground wire directly from the battery to the engine!


And plugging in a stock regulator

It feels as ignition problem .. I have not had any carburetor problems to speak off over the years.
Feels as if it is both sides and not just one. Would run on one cylinder.
I am on it.
 

Jan_P

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Have Made a major mistake
Lacking a ground wire
From the ignition box there goes a white wire to ground --> via the coil base
I have that straight to ground without passing the coil mount point ...Dumb ...***
See what happens with all the wires there lol

I now remember having one there sometime but it is not there Now
 

Jan_P

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Coil does not need to be grounded . Coil mount is just a convenient ground.

OK but it is drawn like that in the instructions
White goes to the coil base and then to Earth
Perhaps not any difference. .But as the saying goes " Follow the manual it is surprisingly often correct "
When I get new plug caps ill test it.



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Team Junk

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Maybe a belts and suspender thing ( I hope that doesn't translate into nonsense for you) . Maybe just trying to reduce RF from the coil to prevent induced noise onto the pickup wiring.
 
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