Just bought an 85 Maxim X

You need to get off the "air pods are the source of all my problems" vibe.
Yes they will cause problems when riding, but for starting and idling they will not. Maybe idle mixture will be off, but usually within adjustable range.
If your engine runs away to 4k it's pulling air and fuel in somewhere past your butterflies, or maybe even before the carbs if there is a rich enough mix to ignite it.
Need to start thinking..

 

Re-check the throttle cable, make sure it is not hung up. If you have pots, take a look to make sure your flies are closed in the idle state. If the bike is running 4k at start, I would guess carbs are not at ""rest" or idle position.

 

What do you mean by flies are closed? What does the rest/idle position look like?

Andy

 

He means throttle butterflies (I hope). Bear in mind it only takes one of the four to push the idle speed up, and that one only needs a tiny bit of opening.
Did you do a bench synch? Using the edge of the butterfly and idle hole?
Are all the throttle spindle free to move?

 

Carbs off I think, unless you have vacuum gauges to do a running synch.

 

Sorry about not giving some visual aids, I always work better with some pics. Here is a rack off a 750 Seca but should be that same principle that we are talking about. When the carbs are at rest of the idle state the butter flies should look like this.
XJ750 carbs by Tim Brown, on Flickr

What sometimes happens is that a cable get hung on the top of the carb as the cable has a little holder that it needs to drop down inside the little cup that has a slit in it. If by chance the cable is hung a little it will look like this and the butterflies will be open enough to give you what high RPM.
XJ750 carbs 1 by Tim Brown, on Flickr
I just mocked them carbs up so you can see what can happen. Not that yours are doing that but could be. Normally if you have a higher then normal RPM at start, you have a hung cable or a air leak. Check all your hoses going to the carbs and make sure that the petcock hose is either on the petcock or plugged or blocked off.

 

Thanks for the visuals. I will double check all hoses and cable routing.

 

OMG what a machine!!!! First ride complete!

I pulled the carbs and checked the butterfly positions 1 & 4 were quite a bit more open than 2 & 3. I adjusted them and reinstalled.
Fired right up, made a minor adjustment and she was idling perfectly.

It took me an embarrassingly long time to realize there is an interlock that wont let you be in gear with the side stand down. I thought the clutch might have a problem.

It kept dying whenever I put it in gear, with the clutch in.

I was just about to pack it in for the day, I sat on it, side stand up, and nonchalantly flicked it into first, to my amazement it did not die.

I went for my maiden ride, what a rush, intake noise, seamless acceleration, first time on an inline four!

Wow, what a machine.

Thanks for all the help getting me to this point.

Andy

 

Now get some vacuum gauges or make a manometer and fine tune all your butterflies.

 

Now you're making me jealous...

 

What a palaver getting the air box in. Heat gun and cursing.

 

Yes but the bike will run so much better and less playing with the CV carbs now that the box is back in the bike. Well done, been there don that....builds character.