Cx500 - firing on one cylinder

[Jay2903]

I’ll try and keep it short.
I’m trying to get an 81 cx500 running has been sat up a good while. Got to the point where it fires up but fires only on the left cylinder. (Right pipe cold). Carbs are clean, fuel in the bowl. When I spray some cleaner though the inlet it fires.
I took the manifolds off, the attached videos show what’s going on ?

[WD Forte]

Not unusual for on old neglected CX

When it's running stick your hand over the non running inlet and remove it a few times to see if it fires on that cylinder at all

If it does, remove the crabs and clean em proper
You might want do that anyway they look a bit mingy

Use an inline fuel filter too, that tank has probably got 40 year iof crap ready to flow in the carbs the tank strainer wont stop
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bikers smell of wee

[Jay2903]

[Nobby the Bastard]

Have you swap the carbs over to see if the issue follows it?
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trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Sprint ST 1050

[WD Forte]

CX carbs are handed and held together as a unit
L,R swapping isn't really an option

Is this going to be on of them cool cafe racers?
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bikers smell of wee

[Nobby the Bastard]

[blurredman]

Mine (and all) cx's are buggers to start if left for more than a few weeks.
____________________
CBT: 12/06/10, Theory: 22/09/10, Module 1: 09/11/10, Module 2: 19/01/11
Past: 1991 Honda CG125BR-J, 1992 (1980) Honda XL125S, 1996 Kawasaki GPZ500S.
Current: 1973 MZ ES250/2 - 17k. , 1979 Suzuki TS185ER - 9k, 1981 Honda CX500B - 91k, 1987 MZ ETZ250 (295cc) - 38k, 1989 MZ ETZ251 - 49k

[Easy-X]

I couldn't download those vids but have you checked the spark plug for that side?
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Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[kgm]

[WD Forte]

[blurredman]

[Jay2903]

Can anyone see the clips ? Was hoping that would shed some light. I haven’t really got any experience with cv carbs. When I wind the throttle open the left one moves a little and the right one sort of flutters. Shouldn’t they moving up and down more and evenly ?

[WD Forte]

All mine would start fine if used regularly but leave the feckers
a fortnight or so and they'd do the one cylinder trick and you have to
wait bit for no2 to kick in

Never bothered me enough to start fiddling with drain screws
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bikers smell of wee

[Jay2903]

[bikenut]

Your videos took Thier time !

Anyways just watched them...

Can't remember if the valves are inclined or not, will go to CMSNL for a look-see next.
From memory valve clearance adjustment is via screw abnd lock nut ?

You say bike been standing idle for some time...

Valves ( and clutches, brakes, cables etc. ) Can and do stick, open usually.

By its nature, left standing, a valve or too can be left open, humidity can end up in cylinder and valve seats/faces etc. And cause poor sealing...

Plugs are deeply recessed, are/where the "water drain holes" clear...?

Compression test after valve clearance check.

Where any valve clearances rather wide, particularly on the "fluttering dash pot piston" side, the piston that flutters ?

Off to CMSNL for a look-see...
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nuts about bikes

[bikenut]

1980 ( A) and 81 ( B) for UK, exploded view suggests valves are inclined...

Check valve working clearance.

Tight, then adjust.

Slack, by how much...

Was that valve sticky/stuck and now bent, or lots of crud between seat in head and valve face ??

Compression test then report back.

Better safe then sorry...

Bikes that have been resting for some time need a very gentle sympathetic and cautious " reawakening". I stuck valve can wreck an engine in one turn...very quickly !!!

Some people think one turn of an engine is enough, it AINT !!!!!!!
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nuts about bikes

[bikenut]

Hi jay, how you getting on with the cx ?

You got your shed ?

You know of CMSNL so know the valve clearance adjustment method now ?

Much more basic and simple compared to the dohc bike you had eh !
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nuts about bikes

[Jay2903]

[blurredman]

You can get the same symptoms of high speed coil breakdown with spark plug cap issues, indeed.




What did your stator readings come to?
____________________
CBT: 12/06/10, Theory: 22/09/10, Module 1: 09/11/10, Module 2: 19/01/11
Past: 1991 Honda CG125BR-J, 1992 (1980) Honda XL125S, 1996 Kawasaki GPZ500S.
Current: 1973 MZ ES250/2 - 17k. , 1979 Suzuki TS185ER - 9k, 1981 Honda CX500B - 91k, 1987 MZ ETZ250 (295cc) - 38k, 1989 MZ ETZ251 - 49k

[bikenut]

This is were those red neon plug caps come in so handy...

A stator resistance check both cold and hot, an AC voltage checks when cold and hot.

Increased revs means increased "rate of change" meaning Increased activity bolts output, but you will see falling AC voltage, down to about 28 volts, then misfire...

If you have access to a mega tester, test the coil insulation breakdown, even heat related make and break contact...
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nuts about bikes

[blurredman]

They post this on the CX forum all the time, but it's a handy image...

I have a few markings myself though which are barely just about within margin, and one or two are a little out but the whole system working fine for me still at the minute. 90k miles on my original stator here...


https://www.cx500forum.com/attachments/correctedstatorchart_zps6ab4572d-jpg.20258/
____________________
CBT: 12/06/10, Theory: 22/09/10, Module 1: 09/11/10, Module 2: 19/01/11
Past: 1991 Honda CG125BR-J, 1992 (1980) Honda XL125S, 1996 Kawasaki GPZ500S.
Current: 1973 MZ ES250/2 - 17k. , 1979 Suzuki TS185ER - 9k, 1981 Honda CX500B - 91k, 1987 MZ ETZ250 (295cc) - 38k, 1989 MZ ETZ251 - 49k

[Jay2903]

[blurredman]

Oh dear.


Until the stator is rewound (or replaced) you'll be limited to slow speed..
____________________
CBT: 12/06/10, Theory: 22/09/10, Module 1: 09/11/10, Module 2: 19/01/11
Past: 1991 Honda CG125BR-J, 1992 (1980) Honda XL125S, 1996 Kawasaki GPZ500S.
Current: 1973 MZ ES250/2 - 17k. , 1979 Suzuki TS185ER - 9k, 1981 Honda CX500B - 91k, 1987 MZ ETZ250 (295cc) - 38k, 1989 MZ ETZ251 - 49k

[WD Forte]

I dumped all that AC CDI bollox for the later TI systems on my CXs
If I had an AC CDI CX now I'd just get an Ignitech DCCDIP2 for it.

OK Its £150 plus postage but its Plug and play so no dropping the lump whipping the back off with all the associated faffery and cost
so its actually of cheaper and easier
Also, if you do replace the stator, the CDI boxes can fail suddenly with no warning leaving you up shit creek cos they is like well NLA innit
Also 2:
The advance coils at the back of the case can quietly fail
This won't stop the bike but will rob it of some of its 'get up and go'

Ignitechs work on DC so independently of all these elderly systems bar the pulsers.

Linky
https://www.ignitech.cz/en/vyrobky/dccdip2/dccdip2.htm
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bikers smell of wee

[Jay2903]

Stator readings hot
1 - 5 = 126
2 - 5 = 103
3 -5 = 348
4-5 = 124
6-5 = 108
7-5 = 237
9-5 = 364
9-8 = 99