Carb Rebuilt, dies after warm idling

T

Tin Soldier

Daily Driver
I just got a rebuilt carb (32 DATR) from MWB. I installed it my 75 X (1300 with some wear and tear, but ran) in place of an existing carb (32 DATR) that had hiccups, backfiring, non-smooth idle, but didn't die.

With the new carb, I get the engine running, it has a much smoother idle, as it should, but after it warms, the exhaust gets acrid, bluish, and then the thing starts to sound like it's getting too rich and if I turn up the rpm, the thing dies. Then hard start, but after waiting for awhile it will start.

This seems like it ought to be a pretty simple fix, but I'm not comfortable yet adjusting anything on the carb other than the idle mixture adjustment. MWB wasn't quite sure what was going on but did recommend the idle mixture only.

Does this seem like a simple fix, or am I wondering into a few weekends of assessing timing, chasing down a hoses to be sure they're in the right place, checking compression,...with all of that I'd probably just start rebuilding the other 1300 I have.

Thanks
 
Tin Soldier said:
I just got a rebuilt carb (32 DATR) from MWB. I installed it my 75 X (1300 with some wear and tear, but ran) in place of an existing carb (32 DATR) that had hiccups, backfiring, non-smooth idle, but didn't die.

With the new carb, I get the engine running, it has a much smoother idle, as it should, but after it warms, the exhaust gets acrid, bluish, and then the thing starts to sound like it's getting too rich and if I turn up the rpm, the thing dies. Then hard start, but after waiting for awhile it will start.

This seems like it ought to be a pretty simple fix, but I'm not comfortable yet adjusting anything on the carb other than the idle mixture adjustment. MWB wasn't quite sure what was going on but did recommend the idle mixture only.

Does this seem like a simple fix, or am I wondering into a few weekends of assessing timing, chasing down a hoses to be sure they're in the right place, checking compression,...with all of that I'd probably just start rebuilding the other 1300 I have.

Thanks
Click to expand...
Is the choke opening?
 
any progress? I had the usual problems with mine, stalling/bucking after warm up, idle mixture screw had no effect, rough idle, black smoke, hesitation etc but was ok in higher revs. the carb had warped between the top and bottom parts of the carb mating surface, and wasn't sealing the gasket which caused a vaccum leak and raw fuel to be sucked in at idle when theres higher vaccum, I had to sand the bottom half flat using a glass plate however the top part of the carb is difficult as there are things in the way, you can remove the auto choke with three screws behind the fast idle cam whick makes it slightly easier. I used a long strip of glass about an inch wide with sand paper tightly wrapped around it and a lot of trial and error got it flat enough and now it runs fine. If u need info from workshop manuals email me i can send u the downloaded copy as they have the specific setup for the carbs
 
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