Mc22 1991 trouble starting and idling

1002 Views 13 Replies 5 Participants Last post by dontojames, 4 mo ago

dontojames

Discussion Starter · 5 mo ago

Ok so this is the story so far…
Bought a mc22 1991 and it was running just bit hard to get it started up. So I started with the carbs and had them cleaned and did a basic bench sync. Got a new battery and have a jumper pack, have an auxiliary fuel system on it rn (fuel line and a funnel lol) but I can’t get it to consistently start. Last I got it started it was running fine but idle was at 4k rpm.
i had the dyno sync tool attached to it so I thought it was causing an air leak so Itook em off and I haven’t had any luck getting the bike to idle. Is there any advice cuz I feel like I’ve hit a dead end🥲

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Dannoxyz

· #2 · 5 mo ago

Did you split carbs?
Disassemble to every last nut, bolt and individual component?
Scrub everything with PEA-based fuel-system cleaner?
Including secret hidden secret passages in carb body?
Poke out all bleed holes in jets, emulsion tubes and carb venturi?
Soak everything in ultrasonic cleaner?
Micro soda-blast?
Replace all rubbers when assembling: float valves, float bowl seals, fuel-rail O-rings, pilot-screw O-rings?

That's a lot of work and requires lots of equipment. Easiest to send to customcarbservices.com, Professional motorcycle carb cleaning . Expert workmanship, reasonable fees and fast turnaround.

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dontojames

Discussion Starter · #3 · 5 mo ago

Dannoxyz said:
Did you split carbs?
Disassemble to every last nut, bolt and individual component?
Scrub everything with PEA-based fuel-system cleaner?
Including secret hidden secret passages in carb body?
Poke out all bleed holes in jets, emulsion tubes and carb venturi?
Soak everything in ultrasonic cleaner?
Micro soda-blast?
Replace all rubbers when assembling: float valves, float bowl seals, fuel-rail O-rings, pilot-screw O-rings?

That's a lot of work and requires lots of equipment. Easiest to send to customcarbservices.com, Professional motorcycle carb cleaning . Expert workmanship, reasonable fees and fast turnaround.

Yea I definitely wasn’t that extensive with it. I think I’ll get a professional to clean em incase I messed some part up. I’ll do that after I get the sparks changed.

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Robbiec

· #4 · 5 mo ago

valve clearances next mate.

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dontojames

Discussion Starter · #5 · 5 mo ago

Robbiec said:
valve clearances next mate.

Would that really be the issue? If there are valve clearance issues can the bike still start?

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Dannoxyz

· #6 · 5 mo ago

dontojames said:
Would that really be the issue? If there are valve clearance issues can the bike still start?

Yeah, depends on how far off they are... also if they're too tight or too loose.

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dontojames

Discussion Starter · #7 · 5 mo ago

Ok so update so far. Got it to start and idle for a tad bit, then she dies. I was able to ride for around 5 mins before dying on me. From the exhaust some black smoke was coming out when opening throttle. I’m thinking it’s smth to do with the air fuel mixture and still a possible air leak.
I’ll also check valve clearances since I also need to fix a small oil leak
Any other suggestions pls let me know

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Dannoxyz

· #8 · 5 mo ago

Black smoke is too much petrol. Verify:

float height
all stock jet sizes
all stock needles
all stock slide springs

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thebeefsalad

· #9 · 5 mo ago

Dannoxyz said:
Black smoke is too much petrol. Verify:

float height

all stock jet sizes

all stock needles

all stock slide springs

Bench test the float valve as well! Can't tell you the number of issues I've caught by hooking carbs up to a fuel source off the bike, only to discover shortly later they are pissing fuel. If the float needle(s) are suspect, replace them. IIRC The float seats are not replaceable, but can be cleaned up with a LIGHT polishing (i.e. q-tip and aluminum/mag polish) If they are removeable you'll need new o-rings before reinstall and they will be a lot easier to clean (ultrasonic, FTW!)

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dontojames

Discussion Starter · #10 · 4 mo ago

Ok been a while but I’ve fixed valve clearances (the exhaust ones were WAY out of spec). Got it all reassembled but still won’t start. I’m sure it’s fuel or air but I’m gonna use the old jets as they are stock and the new ones might be too big. Ty for all the responses and suggestions! Will keep updated

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kenneek9

· #11 · 4 mo ago

Where abouts you located?

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dontojames

Discussion Starter · #12 · 4 mo ago

kenneek9 said:
Where abouts you located?

Canberra. I changed the carbs to stock ones and it sounds like it wants to start but nothing so far.

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Dannoxyz

· #13 · 4 mo ago

You mean you swapped carbs for different set? It so, those should be completely overhauled to verify they are factory-fresh clean.

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dontojames

Discussion Starter · #14 · 4 mo ago

Dannoxyz said:
You mean you swapped carbs for different set? It so, those should be completely overhauled to verify they are factory-fresh clean.

Oh I mean the jets I changed them back to stock jets as had originally replaced them for other jets. When changing them I did see the aftermarket ones had a larger idle jet hole so I think putting the stock ones back in is the safe bet (and they were still in good condition).

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