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Discussion Starter · #1 ·
Ok, so I have no hair left.
Got a cb250k4
Worked well in summer
Points changed
Condenser changed
Points Gapped
Static timing done
Carbs cleaned 3 times
Jets checked
Coil checked
Battery charged
Plugs gapped and changed
Valves done and set
Cam chain reset
Float height set
Air screws set
Carbs balanced
Bike is a joy to ride!
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Winter starts
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Bike starts then coughs and stutters
Right hand carb pops
Plugs go black with carbon
Clean and check
Check gap and timings
Runs super well for 5 minutes then dies
Bike running super rich plugs keep getting black with carbon
Recharge battery, go through steps again then bike still not working well.

Am I thinking I should check compression now or am I doing something wrong?
Settings all as per mannual or workshop book.

Grrrr
 

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Did you leave the same gas in it over the winter?

It might simply be bad fuel.Without some type of stabilizer modern fules go weak in 2-3 months MAX.

Drain it and the float bowls. dump it in your car tank wehre it will be dulited to where the car won't care.

Refill with fresh fuel.
 

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Discussion Starter · #4 ·
Points were from common motor
I may be doing something wrong.

I set the the points gap as per manual for the left and right when both points are the widest then gap.

Rotor the flywheel to the LF mark on compression stroke with my light. It’s bang on

Do I then do the same for the left or do I turn the plate? Then do the right on the F Mark?

Grrr
 

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Discussion Starter · #7 ·
Ok looks like I had to redo cam tensioner
Redo valves and then redo points and then did some dynamic timing. She’s very sensitive in winter!
 

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Discussion Starter · #9 ·
Thinking a few things.
1. Points from common motor (not sure how good they are)
2. Setting points gap with feeler gauge
3. Rotating points cover to set left LF point
4. Dynamic timing using strobe for fine tune
5. Carb synchronisation
6. Valve adjust
7. Float height

Not in right order, but this did the trick. Like all of you I got severe and light popping on the right carb. A lot of this was because of timing and air screw
 

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Discussion Starter · #10 ·
Ok,
So all was running well and then back to not starting.
Replaced points and condenser with NOS from David silver.

Replaced both coils as had bit of a leak from one.. think past their used by date. Then set everything back up and changed oil again.
 
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