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coils

Started by Scottie1, February 08, 2019, 09:58:39 AM

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Scottie1

My bike is having a extremely hard time starting from cold. I have had carbs rebuild tuned up etc. I got a OHM meter and stuck both ends into the pig tail on the coils. One displayed 2.8 and one 3.2. I then took one lead from the pig tail and stuck it into the spark plug cap and nothing registered. Would this be an indication that my coils are bad and would the relay trick i have read about work or shall i get new coils.
1986 FJ1200
1982 XJ750 R Seca

Troyskie

Have you done the check of using a spare (good) plug in the cap and cranking with the spare plug earthed against the engine to view the spark? The difference between a weak spark and strong spark is pretty noticeable.

You can do that on all the plug caps with the spare, but just 1 & 2 will check both coils for spark. Doing them all will check the leads.

It could also be fouled plugs. Give them all a good inspection, clean and gap check (apologies if you've already done it)

Troyskie
1984 FJ1100 Ms Effie brand new :)
1984 FJ1100 Pearlie, stock as.
1985 FJ1100 Mr Effie 647,000K and still running hard.
1985 FJ1200 'Yummy' takes a licking & keeps on ticking
After all is said and done, more is said than done :)
2013 Trumpy Tiger 800, let's do a lap of Oz

FJ_Hooligan

Cold starting is the only issue?

Does it run good when warmed up?  If so, then you most likely have a carb problem.  Clogged choke fuel orifices maybe?
DavidR.

Scottie1

Quote from: FJ_Hooligan on February 08, 2019, 04:10:02 PM
Cold starting is the only issue?

Does it run good when warmed up?  If so, then you most likely have a carb problem.  Clogged choke fuel orifices maybe?
I've just had the carbs cleaned and new jets put in. Maybe I should get it looked at again as it use to start first time until I had the work done.
1986 FJ1200
1982 XJ750 R Seca

Scottie1

And yes only cold start after it's warm it runs good
1986 FJ1200
1982 XJ750 R Seca

Scottie1

Quote from: Scottie1 on February 08, 2019, 06:30:07 PM
And yes only cold start after it's warm it runs
When I had new choke jets put in I was told to get size 45 Robert at RPM called and asked if this was correct. Maybe the jets are to big
1986 FJ1200
1982 XJ750 R Seca

ribbert

While a carby issue is the obvious choice for a cold only hard starting problem, it's not the only one.

A battery that is getting tired will drop below the voltage needed to fire the coils when the starter motor is engaged, sort of like a load test. Even if the starter sounds to be spinning over healthily, the voltage can drop right down, a relay will not fix this. It is more about the battery losing power in time the bike takes to get cold (like overnight) than it is about actually being cold.

Easiest way to check this is to see if it fires up with a jump start from the car.

Noel
"Tell a wise man something he doesn't know and he'll thank you, tell a fool something he doesn't know and he'll abuse you"

Troyskie

Nice one Noel!

Mate, if you have a multimeter check the voltage on crank. If it is below say 9 volts on crank you have a batflattery issue.
Then try Noels' method.

Troyskie
1984 FJ1100 Ms Effie brand new :)
1984 FJ1100 Pearlie, stock as.
1985 FJ1100 Mr Effie 647,000K and still running hard.
1985 FJ1200 'Yummy' takes a licking & keeps on ticking
After all is said and done, more is said than done :)
2013 Trumpy Tiger 800, let's do a lap of Oz

Scottie1

I got a brand new AGM battery and it still has the same problems. So I'm sure it maybe the carbs then even with choke on it won't start and once it does it misses and pops.
1986 FJ1200
1982 XJ750 R Seca

ribbert

Quote from: Scottie1 on February 09, 2019, 06:38:31 AM
I got a brand new AGM battery and it still has the same problems. So I'm sure it maybe the carbs then even with choke on it won't start and once it does it misses and pops.

Yep, sounds like carbs then.

Noel
"Tell a wise man something he doesn't know and he'll thank you, tell a fool something he doesn't know and he'll abuse you"

FJ_Hooligan

Quote from: Scottie1 on February 08, 2019, 06:34:01 PM
And yes only cold start after it's warm it runs
When I had new choke jets put in I was told to get size 45 Robert at RPM called and asked if this was correct. Maybe the jets are to big

Those #45 jets are Idle Jets.  The choke circuit does not have a replaceable jet.

However, the choke circuit does pull fuel from the float bowl through a tiny orifice that is easily clogged by debris or gunk in the fuel.  When this happens the choke doesn't work well and, in fact, can make cold starting worse because it's letting even more air (and little to no fuel) into the intake which only makes the mixture more lean.

Who cleaned the carbs?  Checking this circuit for obstruction is not commonly known.  And, since you didn't have this problem before the carb work, then something else may be messed up
DavidR.

FJ_Hooligan

Quote from: Scottie1 on February 09, 2019, 06:38:31 AM
I got a brand new AGM battery and it still has the same problems. So I'm sure it maybe the carbs then even with choke on it won't start and once it does it misses and pops.

DEFINITELY something screwed up with the carbs.  Undo the previous work or find the fault.
DavidR.

Old Rider

What is inside the holes where the red arrows pointing and how do they come out?

Pat Conlon

Old Rider, did you mean to post your question here?
If not, no worries I can move over to your thread, just let me know....

To answer your question, courtesy of our Carb Guru, DavidR:

That's the Main Air Bleed.  It provides a passage for bleed air that gets mixed with fuel in the needle jet, or emulsion tube.  

If it gets clogged, the mixture drawn into the carb throat will be overly rich.

It's a fixed orafice that performs essentially the same function as the removeable Air Pilot (Idle) Jet on the opposite side of the intake.  The Air Pilot Jet controls the amount of bleed air that gets mixed with fuel from the Idle Jet.  The resulting mixture then travels to the Idle Mixture ports.


1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3

Scottie1

Quote from: FJ_Hooligan on February 09, 2019, 07:27:50 PM
Quote from: Scottie1 on February 09, 2019, 06:38:31 AM
I got a brand new AGM battery and it still has the same problems. So I'm sure it maybe the carbs then even with choke on it won't start and once it does it misses and pops.

DEFINITELY something screwed up with the carbs.  Undo the previous work or find the fault.

I am taking the bike back to the shop who done the work. He previously worked on my XJ carbs and done a great job. I'm sure he will get it figured out for the $455 i paid to have them done. If i knew RPM did this i would of sent them to them instead.
1986 FJ1200
1982 XJ750 R Seca