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'74 CR125 - It start but for 5 second and stop
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Author:  stou [ Fri Jul 12, 2013 6:05 pm ]
Post subject:  '74 CR125 - It start but for 5 second and stop
I almost completed my '74 CR125M restauration, but I have problems to make it running fine.

When I try to start it, I put the choke on and it start after only 2 kicks. But it run only for 5 second and die. I kick it again 2 or 3 times, and it does the same thing all the time.

I did a complete engine rebuild. New bearings, new seals, new oversized piston and rings.

The carburator was completely clogged. I did a soda blast and a complete cleaning.

I didn't found the basic setup for the carb. How many turn the fuel screw (slow jet)? For the air screw, they said to start at 1 1/2 turn, I did the same with the fuel screw, 1 1/2. The jet needle, it was at the second groove. I tried at the third also.

The rubber boots are hard, It look ok but I wonder if it can suck air? But I can't try to spray some cleaner to see if it affect the running since it doesn't run for more than 5 seconds every time.

I looked at the spark plug and it look a little bit wet.

Any idea of what can cause this kind of problem?
Author:  rayivers [ Sat Jul 13, 2013 4:41 am ]
Post subject:  Re: '74 CR125 - It start but for 5 second and stop
You put the choke on, start the bike, then immediately turn the choke off and it runs for 5 seconds? Or is the choke on for 5 seconds (too long)? Does this bike have the original carb, with '005A' stamped on the body behind the choke?

Can you start the bike without the choke, maybe by push-starting it?

Try running the air screw at 2 or 2.5 turns out for now. The idle speed screw (large one on left side) is adjusted to get the idle speed you want - there's no fuel screw on this carb. 1.5 turns on the speed screw isn't even close; I believe mine's turned in over 6 turns. Try backing out the speed screw completely, then turn it in 5.5 turns and start the bike, and if it still only runs for a short time, turn the speed screw in another 1/2 turn and try again.

Jetting for the original '74 carb is 125 main, 60 pilot, 200 air, and 3.5 throttle valve.

Ray
Author:  stou [ Sat Jul 13, 2013 11:34 am ]
Post subject:  Re: '74 CR125 - It start but for 5 second and stop
Rayivers, you're the man!!!

Yes, this is the original carb, 005A. And also yes, when I tried to start it, I let the choke on. I didn't remember that from 40 years ago! :lol:

So I did the adjustment you wrote, put the choke on, start it, put the choke off and gived a little bit of throttle, and it worked!!!

I will now have to adjust the idle once warm and it will be very good I think!

Thanks a lot Rayivers!
Author:  rayivers [ Sat Jul 13, 2013 1:55 pm ]
Post subject:  Re: '74 CR125 - It start but for 5 second and stop
No problem - I'm glad it worked!

Ray
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