gs450 - still not running right

[KiwiAlfa156]

The orientation convention is LH RH as if you are sitting on the bike. The other naming convention is Cylinder number 1 is the left most one, sitting on the bike facing forward. In the case of a twin, the RH cylinder is number 2.

So to be clear.

LH (cylinder 1) plug going brown, header is ~350°F
RH (cylinder 2) plug no colour, header is ~250°F

From that I'd say your LH is your good one, you RH is way too cold. It's just above boiling point of water.



I'm picking a clogged pilot jet in the RH carb (or pilot outlet/screw) possibly by-pass orifices.

[bren]

Yes, i'm using the same left = cyl 1 terminology.

now, just to be clear, before I took the carbs apart and dipped them, the left cylinder was cold, and the right one was hot. initially, the cold cylinder had the darker plug and the hot one had no color. i switched some part when i put the carbs back together, and now, the right cylinder is cold. I'm in the process of elimination to find out what part is making the difference. I'm also converging on the pilot jet.

I'm not sure if the cold cylinder is too rich, or if the hot cylinder is too lean. On that video, The bike was still slightly warm, but not like "warm" warm, just above room temperature type of warm - just warm enough to start without choke. and it only ran for about a minute or two at idle, so it wouldn't have time to get fully hot. My feeling is that the hot cylinder is getting too hot too fast, but I am really not sure. The ambient temp today is right around 70F.

[KiwiAlfa156]

Did you remove the jets when you cleaned or just dipped the carbs with the jets in situ?

Exhaust gas is about 350°F so that tallies with you hot pipe.

[bren]

i completely disassembled everything, with the exception of one main jet which i didn't want to disturb because it's a little stripped. I didn't take apart the slides either. apart from that, every jet came out. that list i wrote earlier in the thread is every component that could have gotten switched over upon reassembly.

edit: i'll add that the last time i let it warm up for a little longer, the cold header got up to 350 and the hot one got up to 450 and beyond. i only cut it during the video because it ran away when i flicked the throttle

[Rob S.]

...it ran away when i flicked the throttle

Doesn't that usually indicate an intake air leak?

[bren]

Doesn't that usually indicate an intake air leak?

yes, that's my understanding, or it could indicate a severe imbalance between carbs. but also a leak would lead to a lean condition. the fact that the lean condition switched cylinders leads me to want to rule out any air leaks

[dgates1]

Well first mistake I see from the video is the Morgan Carbtune is designed to work when it is hanging straight. You have it hanging straight but it is upside down. Should be hanging from the top side where the hoses connect. That could skew your balance reading.

Second thought after watching is, do the throttle plates stick at all, or perhaps your throttle cable is sticking?

[oldGSfan]

I find the water-based Berryman's dip less effective than the original. Now I dunk the carb and parts in the Berryman's basket and put the bucket in my large ultrasonic for 10 minutes. They come out amazing. I have had nothing but carb rebuilding success since I started doing this, and a lot of troubles previously.

Of course, an ultrasonic that's big enough to fit the carb would work, it's just more convenient. I just used it to unstick a slide on a Keihin that was completely gunked up with years-old varnish. It took 20 mins, and fell right out.