Again, the '87 Brat. I yarded out all the normal emissions stuff. Piddled around with it, fired it up to check for vacuum leaks. Today, took it for a drive and going out of the idle circuit into the primary it hardly runs.....unless you pin it and it will eventually wind out once it gets clear through the first 3/4 of the primary circuit.

If I back off and let it run off the idle circuit, its great. Again, into the primary it hardly will run. Stutters and stammers.

 

While spraying out the carb could I have dislodged something and now have a blockage? I cant think of anything else it might be. No vacuum leaks. I have the advance going directly into manifold vacuum, fwiw.

 

What am I missing?

What exactly have you "yarded" out?

 

Emissions systems account for only a small percentage of all that stuff.

 

You really need to understand the operation of the Hitachi before you start removing stuff.

 

GD

I only 'yarded' out what I have yarded out on other Hitatchis.

 

Actually, in the meanwhile I found a pictorial that you [GD] did regarding doing the same. Thats all that I took out. Either way, it left me with a box full of parts and vacuum hose.

Well - have you removed the top of the carb and inspected the top cover gasket and blown out the passages?

 

You very well may need to replace the top cover gasket and you may as well rebuild the carb in the process as I haven't found a source for the gasket outside of an entire kit.

 

GD

I havent yet, that is inline though. Kinda short on time at the moment, so I am going for a quick fix right now. I figure I dislodged some carbon or gunk and caused a blockage.

 

I'll get a carb number and order a kit at least.

Found the culprit. One of the ported fittings above the incoming fuel line was leaking vacuum.

Found the culprit. One of the ported fittings above the incoming fuel line was leaking vacuum.

 

Yeah - the metering ports make things REALLY weird when there's leaks there. You can cap them off if you like - they don't do much.

 

GD

I actually had a hose going from it to the one in front of it...thinking it would act as a plug. Seems the other must be a vent or something.

I actually had a hose going from it to the one in front of it...thinking it would act as a plug. Seems the other must be a vent or something.

 

Both are metering ports for different puposes, but yeah - you can't T them together or connect them to each other. They will cause all sorts of weird (undriveable) behavior.

 

GD