Mmm ...... another 550J puzzle, any ideas ?

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Hix2061
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Mmm ...... another 550J puzzle, any ideas ?

Post by Hix2061 »

morning all
Finally got to the point of being able to fire up the bike yesterday, and appear to have a couple of issues.

1. RH cylinder not firing despite a good spark, spot on timing and fuel .... confused

2. Engine runs on two of the cylinders on choke, but if it open the throttle it just stalls.

Guess I’ll sort problem one then worry about two ! Tempted to try changing the coil as I think I’ve pretty much checked everything else.

Ideas welcome before I start head butting the garage wall !!!
1976 Suzuki GT550A
1973 Suzuki GT550J
Bultaco Sherpa350
Ducati multistrada
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Hix2061
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Re: Mmm ...... another 550J puzzle, any ideas ?

Post by Hix2061 »

Ok, so a bit more checking this afternoon. Primary and secondary resistance figures for all coils as they should be . Compression figures for all cylinders between 130 and 140, so also fine. Timing rechecked with a strobe light, new plugs fitted...... still the same issue on the rh cylinder.

Very confused now :tw
1976 Suzuki GT550A
1973 Suzuki GT550J
Bultaco Sherpa350
Ducati multistrada
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itsnotateapot
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Re: Mmm ...... another 550J puzzle, any ideas ?

Post by itsnotateapot »

Have you got a good fully charged battery on it.
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canaletto5
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Re: Mmm ...... another 550J puzzle, any ideas ?

Post by canaletto5 »

Hix2061 wrote:Ok, so a bit more checking this afternoon. Primary and secondary resistance figures for all coils as they should be . Compression figures for all cylinders between 130 and 140, so also fine. Timing rechecked with a strobe light, new plugs fitted...... still the same issue on the rh cylinder.

Very confused now :tw
Have you checked the exhaust pipe is clear of carbon build up ?
Kettletimes3
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Re: Mmm ...... another 550J puzzle, any ideas ?

Post by Kettletimes3 »

Have you cleaned the carbs.Pilot jets.
barney01
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Re: Mmm ...... another 550J puzzle, any ideas ?

Post by barney01 »

+1 pilot jets blocked or pilot and pilot bypass circuit blocked. Although non firing cylinder gets fuel, is the choke opening okay? It needs enrichment to fire.
Incorrect float level? Either too high or more likely too low.
Sticking diaphragm in petrol tap, remember petrol for choke is drawn from bottom of the bowl. Try starting with tap on prime.
NO SMOKE .......NO POKE
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Hix2061
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Re: Mmm ...... another 550J puzzle, any ideas ?

Post by Hix2061 »

itsnotateapot wrote:Have you got a good fully charged battery on it.
Yep, it’s a new battery, but have just checked and it’s not charging, so that may be part of the problem. I have a spare, so will swop it over today and see what happens. Thanks for your help. Cheers
1976 Suzuki GT550A
1973 Suzuki GT550J
Bultaco Sherpa350
Ducati multistrada
User avatar
Hix2061
Posts: 84
Joined: Tue Aug 16, 2016 9:01 am

Re: Mmm ...... another 550J puzzle, any ideas ?

Post by Hix2061 »

barney01 wrote:+1 pilot jets blocked or pilot and pilot bypass circuit blocked. Although non firing cylinder gets fuel, is the choke opening okay? It needs enrichment to fire.
Incorrect float level? Either too high or more likely too low.
Sticking diaphragm in petrol tap, remember petrol for choke is drawn from bottom of the bowl. Try starting with tap on prime.
Have ultrsonically cleaned all carbs, and checked the jets are clear with an airline, so these should be ok. Fuel is getting to the carbs on prime, but not on reserve, so maybe I need to check the diaphragm too. The bike will only just tick over with full choke. Choke system appears to be operating ok, and moves freely. Have also reset the float heights to 25.8mm

Will have a look at the diaphragm.

Thanks for your help
Cheers
1976 Suzuki GT550A
1973 Suzuki GT550J
Bultaco Sherpa350
Ducati multistrada
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Hix2061
Posts: 84
Joined: Tue Aug 16, 2016 9:01 am

Re: Mmm ...... another 550J puzzle, any ideas ?

Post by Hix2061 »

canaletto5 wrote:
Hix2061 wrote:Ok, so a bit more checking this afternoon. Primary and secondary resistance figures for all coils as they should be . Compression figures for all cylinders between 130 and 140, so also fine. Timing rechecked with a strobe light, new plugs fitted...... still the same issue on the rh cylinder.

Very confused now :tw
Have you checked the exhaust pipe is clear of carbon build up ?
Yep, three of the four have been rechecked and I’ve had them running on my other 550, so should be ok.
1976 Suzuki GT550A
1973 Suzuki GT550J
Bultaco Sherpa350
Ducati multistrada
barney01
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Joined: Wed Sep 26, 2012 7:33 pm
Location: Prestatyn.Wales

Re: Mmm ...... another 550J puzzle, any ideas ?

Post by barney01 »

Just sayin' took me two or three attempts in the ultrasonic cleaner to finally get them clear.
How rusty is your fuel tank inside. Are you using in line filters? Jets soon block up again if you don't
NO SMOKE .......NO POKE
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