Start problem XS650 1981

[MR16]

Hi
Need some help
My XS want start at all.
Data:
Boyer ignition,
Mikuni vm34 carbs cleaned several times
New spark plugs
Charged battery
Ignition set right (used YouTube )

It seems like the motor isn't getting any petrol from the carbs...at the moment its not fireing (have sparks) . Before this stage, it started but would only run with full choke. Any idea..
Thank's for any reply.
Regards MortenR /Arendal /Norway

 

[gggGary]

Will it start, run for a bit, on a couple shots of carb cleaner in the carbs?
open float drains, put a catch pan under, open petcock, get a good steady flow of gas?
Pictures! get us a couple of pictures?
The detective squad loves evidence!
Compression tested?
Valves, cam chain tension set?

 

[Jan_P]

Assuming no changes and the bike was running last year .
Petcock open ( pri )
perhaps plugs out turn it over smelling for gas / petrol
Perhaps a little gas in via the spark plug hole.
Maybe consider start gas.
Something should happen if spark
I can be normal spring getting it starting problems.

 

[MR16]

Hi again.
Thank`s for tips on how to solv this problem.
I have tried out spraying with carburator cleaner , drained the float house, taken out the plugs and smelling for gas, nothing, cleaned the carburators (again) , adjusted the ignition , checked the valve clearence .. Well at the moment my XS starts after a few kicks, goes very porly , and stops when the choke is turned of... I`m starting to think that there could be something with the ignition system.. bad connection ?? Thank`s for any reply, Regards Morten

 

[Raymond]

Hi Morten, if you think it might be the ignition system then its definitely the carbs! Ha! I have found that starting problems in the Spring or after a long lay-up are often due to modern fuel turning gummy. This can block the carb jets. If it runs with choke but stops when choke turned off, that seems to confirm not enough petrol getting through? If the bike can start with carb cleaner sprayed in the carbs, then once the fuel starts to flow that can clear the problem, melt the gummy build up. Otherwise, might mean cleaning the carbs again. Oh, you just did that . . .

How long since you had the bike running?

 

[Jan_P]

All right this is something I have done
The Boyer in different versions ..
It may well be an ignition problem .. I have had lots of those and none with carburetors
It would be strange both stopped working over the winter.

Battery must be up to standard Boyer is sensitive to wrong Voltage.
I would take out the plugs and put them against the engine block .Kicking the bike to see if there is spark
Do this carefully it can as I hear lead to damage if the ground is lost.
Boyer Fault finding procedures are on line --->
Something like that
http://vintagebikemagazine.com/technical-articles/boyer-trouble-shooting/

When I looked for faults in my Boyer I drew wires for a short time from battery + and - .It cant be left so because the ignition wont stand the power on
But I left the extra ground wire all the way to the battery from those spots that needs ground

I would guess it is poor Ground ( as with a handful other bikes last 6 months )
If you go for a quick test ..draw the ground wires needed with extra wires to minus on battery

 

[MR16]

Hi Morten, if you think it might be the ignition system then its definitely the carbs! Ha! I have found that starting problems in the Spring or after a long lay-up are often due to modern fuel turning gummy. This can block the carb jets. If it runs with choke but stops when choke turned off, that seems to confirm not enough petrol getting through? If the bike can start with carb cleaner sprayed in the carbs, then once the fuel starts to flow that can clear the problem, melt the gummy build up. Otherwise, might mean cleaning the carbs again. Oh, you just did that . . .

How long since you had the bike running?

Thk`s Raymond.
I started the bike yesterday, but again it only runs (bad) on full choke. I will drain the carburators, and use fresh petrol today. Maybe this will solve the problem..
New update follows

 

[MR16]

All right this is something I have done
The Boyer in different versions ..
It may well be an ignition problem .. I have had lots of those and none with carburetors
It would be strange both stopped working over the winter.

Battery must be up to standard Boyer is sensitive to wrong Voltage.
I would take out the plugs and put them against the engine block .Kicking the bike to see if there is spark
Do this carefully it can as I hear lead to damage if the ground is lost.
Boyer Fault finding procedures are on line --->
Something like that
http://vintagebikemagazine.com/technical-articles/boyer-trouble-shooting/

When I looked for faults in my Boyer I drew wires for a short time from battery + and - .It cant be left so because the ignition wont stand the power on
But I left the extra ground wire all the way to the battery from those spots that needs ground

I would guess it is poor Ground ( as with a handful other bikes last 6 months )
If you go for a quick test ..draw the ground wires needed with extra wires to minus on battery

Takker for svar, Jan
I know that I had som battery issues before, so I will check the voltage. Ground connection next ..

 

[RustiePyles]

If it runs with the choke on, its not the ignition. It's a fuel issue. Lets assume that if it's running with the choke on the bowls are filling up and its not the needles and seats. You are left with 2 (but not limited to) options. You have plugged idle jets or air passages, or you have vacuum leaks. Check the sync port(s) on the intakes, check the carb boot clamps, check the slide diaphragms for leaks. If no leaks are found, pull the carbs and clean them. Simply spraying them out with carb cleaner will not dislodge blocked ports/jets. Have you changed the air filters recently, some brands of pod filters are known to block air bleed ports at the mouth of the carbs.

 

[Jan_P]

This is also something I know -- No disrespect to mr R Pyles
Who knows these things.
I don't know these Carburetors
But I have been riding home with no charging and battery going down.
Surprisingly many times. Even depressing many times
If the battery is to low the bike stops .
If you turn the lights off and are " Soft on The Throttle " you can run a bit longer
But if you give gas it stalls. ,It seems as if a richer mixture don't ignites
BS34 -s
So in those cases the bike runs and gets me home but it is not a carburetor fault.
If it stalls eventually it usually recovers after a short period so much that bike can be started again and a little more riding can be done
So the stalling and riding in those cases never was a Carburetor problem. Even if it was mixture dependent
it was a charging problem affecting he spark.
I never touched the carburetors in those cases . Besides a quick inspection
After battery charging it ran again .And then repair the charging circuit.
Point being that it can run with some mixtures the perfectly or not perfectly operating carburetor delivers
But not with all if the ignition is weak.

Since I never had any Carburetor problems ..and I find it unlikely both carburetors clog up in the same climate I have
I with this information still think it makes sense do a Quick check of the ignition Boyer and voltage.
It is simple to look if the spark looks right and measure voltage.
First before tearing down carburetors again.

 

[xjwmx]

it seems like every bike on here that wont even start has an exotic ignition or carb. Then the advice for fixing it will be somebody's history back to the mayflower

 

[Jan_P]

it seems like every bike on here that wont even start has an exotic ignition or carb. Then the advice for fixing it will be somebody's history back to the mayflower

Jaeehh a philosophical question .. Why would anyone bolt on something not the factory designer has put on there .
And not expecting getting into problems. Which I also at times have wondered about...
And then again when problems arise .. Why not try on line
After standing in the long line queue under the sign " Gentlemen applying for the patent on the Wheel again "
One recall the proverbial " Life is to short to make every mistake someone else already have done "
Which again leads to a Philosophical question why are there people doing it
Or rather a Psychological problem

 

[RustiePyles]

Jaeehh a philosophical question .. Why would anyone bolt on something not the factory designer has put on there .
And not expecting getting into problems. Which I also at times have wondered about...
And then again when problems arise .. Why not try on line
After standing in the long line queue under the sign " Gentlemen applying for the patent on the Wheel again "
One recall the proverbial " Life is to short to make every mistake someone else already have done "
Which again leads to a Philosophical question why are there people doing it
Or rather a Psychological problem

There is no one easy answer to this question. It's a result of many factors not the least of which is that some of the parts to repair these OEM systems are getting hard to find, very expensive, or just plain unavailable. 2nd there is a flood of shade tree "mechanics" on FB espousing the virtues "simpler" systems based on a lack of understanding and knowledge of the OEM systems. 3rd there is some validity to more modern or performance parts offering better performance. Many systems that were not designed by the factory for these bikes will just fine but with the caveat that it requires some amount of knowledge of aforementioned systems to properly tune and tweak them. Having said that nobody is born with said knowledge, the only way to acquire it is through experience and/or training.