[Troy Jollimore]

How’s the seal on your airbox, or is there any mods done to it? Since you can rev high at all, the ignition or electronics aren’t at fault, unless it’s some weird speed limiter. Which is unlikely. It sounds like giving your entire fuel system a good once-over is in order, but if airflow is messed up at that particular speed, that’ll kill engine power as well.

 

[Troy Jollimore]

Just looking at something that affected a couple of riders on the Shadow forum I‘m on. At 75mph, airflow was disrupted to their intakes and their bikes hit a wall. Once their air filter and/or intake were adjusted (returned to stock in one case), their engines could breathe at speed again.

 

[Troy Jollimore]

The only thing you can really do is set up an independent fuel feed. Gravity should do fine. If both cylinders run, you know where to look for the problem, if they don’t, you can only directly put fuel down the throat of the ‘not firing’ carburetor and see if it fires. If it does, then you know where to look for the problem.

Otherwise, you’ll be taking that cylinder’s head off and checking/reassembling to factory spec as per the manual.

 

[Troy Jollimore]

As for the oil light, that's another issue entirely. And there are a lot smarter members here that I on SVR who can provide some input. Good luck.

I’m more thinking the oil light came on only because the engine had cut out momentarily, so there was no oil pressure.

 

[Troy Jollimore]

Too bad you didn’t ask about it being inside of the bowl, or sent a pic first. Adjustments like that are always on the outside. PM @mad8vskillz and see what he can offer you for a replacement carb.

 

[Troy Jollimore]

This one was 3.25 turns from seated, so I naturally had two questions, how many turns "should" it be for stock? (I saw catmanpoops archived site say 2.5 but I've learned my lesson on not checking) and, when reinstalling it, it should be o-ring, washer,spring, screw in that order? the manual doesn't really specify and I want to check to be 100% certain.

When the manual isn’t specific, take a look at a parts diagram. It shows your order as being correct. And most carbs will be 2 to 2.5 turns out, ideally. When you get around 4 turns it usually means it’s time to change jets, you’re at altitude, or something else may be wrong.

 

[Troy Jollimore]

Good idea! It’s possible that these carbs were on a bike with modifications, that the previous owner set them this high. I’ve also heard it said that in rare cases over time the screws can “back” themselves out. Nevertheless, I buttoned up everything yesterday but haven’t been able to get the bike to start just yet. (It’s always a little finnicky getting that initial fuel to the carbs).

You’re familiar with the setting procedure for the A/F screws? You’re supposed to have a service tach, and watch for a ~50rpm drop when you hit the ‘sweet spot’, but most of us go by ear. Especially when doing multiple carbs. Adjusting them tends to be more of an art than a science…

The initial run shouldn’t be finicky, though. Fuel pump or gravity gets fuel to the bowl, the floats rise as the bowl fills to the proper level that the jets are well-submerged. The floats then close the fuel inlet valves. Air coming in from an outside tube supplies atmospheric pressure to help ‘push down’ on the fuel level to go along with the vacuum sucking fuel through the jets… If everything is done right, it should fire almost right away.

 

[Troy Jollimore]

You also have to crank the engine for a bit just to get the pump working, compared to electric.

Yeah, 2.5 turns is a good starting point. And it’s more fine tuning, so it won’t affect things too much.