Rebuilding Carbs

So Im selling my maxim to my roommate who needs it more than I do. However he wants me to get it running again first. While ive been away its been sitting outside and went to hell. The carbs and petcock leak very baddly, I was planning on doing a full rebuild of the carbs.... however I hate that its a PITA to pull and replace the carb rack with the stock airbox... Thought I'd just go to pods at the same time. However I also dont want to deal with buying 32 god damn jets just to tune it in right.

Suggestions?


Pods or just buck up and deal with the damn carb boots and airbox. My personal preference is the pods...

Suggestions on where to start on jetsize?

 

And its a what I believe an 85 maxim midnight... may be just a plain maxim though. xj700, I have mikunis not keihens

From what I understand I should go with a 43 idle jet and a 120 main jet. The carbs dont have mixture screws so i just have to get it right the first time... as I dont want to be constantly changing jets for the first month.

 

I don't think pulling the carbs are so bad on my bike. What I do is remove the clamps on both sides (air and engine manifolds). Then I just pull the air manifolds off completely. Then the carbs come out rather easily (pull off left side first, then the right side).

When you put it back on, mount the carbs to the engine manifolds then take your air manifolds and fold them back on the carb side (the fold should stay for you). Then insert them into the airbox. Once you have all four inserted into the air box just unfold the manifolds and they flip right onto the carbs. Now you just have to put the clamps back on (somewhat a pain for #2 and #3), but all and all its not that bad if you can fold over the air manifolds.

Hope this helps.

 

Ive done it many many times... technique is not so much the problem as is the fact that hte boots dont have much of their elastisity as they used to. Little bit dry rot. So I figure instead of buying new boots ill go for hte extra bling and go pods.

 

I have read too many times on this forum that converting to PODS is more of a hiderance than a benefit. Personally I would steer clear of them to prevent added headache. The benefit is very minimal anyhow. My .02 worth. :wink:

 

I can hardly see that the gain be minimal when considering the rubber boot in the air box limits the flow not only because its Under the seat, but because the entire pathway MIGHT be as big as 2 carb bodies.... Maybe... Im working on mikuni carbs all day long on jetskis and tuning is not a big issue... I just hate buying 40 jets to start dialing in with.

 

Have a close look at one ~> Airbox -to- Carb Rubber Boot <~

Notice that it's Design is intended for it to function as a Velocity Stack.

Theoretically, ... The -- Under-the-seat -- Airbox opening is the initial Main AIR Jet.
That Rubber opening serves to "Limit" the Maximum Cubic Feet per Minute of Air allowed to the Carbs.
That volume is Filtered and becomes the Common source of Intake Air Supplied to the 4 Carbs.
That Max CFM pulled - divided by 4 is the CFM Needed to maintain the Air~Fuel Mixture of ONE Carb.

Eliminating the Airbox and Installing a Pod Air Filter:
Upsets the Air~Fuel Ratio that many try to correct with only larger FUEL Jetting and Ignore Main AIR Jetting requirement.

The Pods are connected to the Carb eliminating the effect of Pre-carb Velocity needed to pass-over the Emulsion Tube opening and draw-up FUEL from the MAIN Fuel Jet.

The consequence is turbulence created where velocity is needed.
The AIR Quotient of the Air-Fuel Ratio multiplied many time over the correct AIR requirement.

Adding PODS just for looks is going to be frustrating.

Adding PODS for Performance is going to require bringing the Air-Fuel Mixture close to Design requirements.
Kits.
Trial and error.
Patient experimentation and finding the right sized Jetting.

There is LESS Velocity across the Top of the Emulsion Tube.
Tougher for the Fuel to Rise-up without opening-up some more Air around the Emulsion Tube.

I gave-up trying to guess.
I suppose if I had an instrument that could calculate the CFM at the Airbox Opening with a well tuned-up bike running flat-out on a Dyno ... you'd have Data to begin crunching the numbers.

But, something tells me that the Jet Kit People probably did that; already.

So, there's a few guy's who did all the tinkering and got their bikes "Smokin'"

Far too many others wound-up with: "No Cigar's"

 

Ah... you know I deal with air velocities all the time on the jetskis however I never thought about that on the bike. Didnt think of the carb design and having a low jet signal......

 

I have tried the pod filters before, Here's my 2 cents.
Leave the stock airbox, leave the stock air box, do I need to say it again.
Just replace the stock air filter with a high flow one like K&N, you will get better preformance without the headache from the pods. You might need to increase the jet size by one if you do that.
Remember to leave the stock airbox.

 

I concurr with that advice... keep it as stock as you can and you'll avoid a lot od problems... I have the K&N filter on my Maxim and it works very well. Also nice to know you can clean and reuse it for a long long time.

I have a K&N on my airplane and get 1/2" more manifold pressure at altitude (9000 + feet) over the stock filter.