XJ 1100 carbs (Video)

one slide not dropping!

http://www.youtube.com/watch?v=vkSGj2vFfio

 

All you need to do is scrub and polish the Diaphragm Piston Bores.

Use ScotchBrite Bad, Medium (Gray) and Scrub the Bores.
Read the Forum Post: "Clunk Test"

Clunk Test: xjbikes.com/Forums/vie...clunk.html

Refinishing the Bores is easy.
I used to do Wet-sanding the article suggests; but find it easier and quicker to BUFF with ScotchBrite Scrubbing.
Followed by Performance POLISHING.

I use a DREMEL Tool with a Buffing Wheel.
Jewelers Rouge's #5 & #6
Put a Mirror Finish on the Bore.

Those Pistons will rise and fall better than Brand New.

a) ScotchBrite - - - - b) DREMEL Polish - - - - c) Polished Bore


Performance Polished Bore:

 

there is a mirror like finish on all the bores. I made sure of that. no nicks or scuffs on the slide or the bore. all the others are dropping nicely.

idk wtf the problem is.

 

Make sure there is nothing gunked up in the hole next to the needle on the diaphragm bore.

See what happens when you swap 3 + 4. If you put in a different diaphragm and if it still goes down slow, I would suspect the bore needs more manhandling.

 

Try re-arranging the Diaphragm Assy's.

 

i should have mentioned that i have two racks of carbs and I tried like three different slides. all doing the same thing. the hole next to the needle is clear and air can pass thru. the spring is installed correctly and the rubber surround is seated correctly

 

So it's something about that bore or carb. Could it be the emulsion tube that that needle goes into? Although that whhooomp groaning noise makes me think otherwise.

 

The Piston does NOT fall rapidly when the Spring and Cover are installed.
It reacts to Vacuum Pressure once fully assembled.

If the Piston does not drag in the other 3 Bores, ... the offending Bore needs further refinishing.

Wet-sand the I.D. with strips of 600, 800, 1000, 1200 and Up, ... with WD-40 as the wetting agent.

When the strip "Loads-up" with material from the Bore, ... discard it and start anew.
Test as you go.

The idea is to renew the surface without removal of too much material or having it become out-of-round.

 

Quite so -- that kinda gives me the impression that there's something wrong with the other three, vs the one that doesn't want to drop as quickly.

I'm probably wrong, but I'd be inclined to say that if the offending piston passes the clunk test without the cover and spring installed... the problem isn't in the bore.

 

So, if the rest of them are dropping like rocks, is there something wrong with them?

 

I'm inclined to agree. I'm rebuilding my '83 1100 Maxim and noticed the spark plug from #2 was wet and black with deposits. Noticed that the coil end of the plug wire was green and loose, but the surprise was upon inspection of the carbs and #2 piston fell rather quick with a "snap" at the bottom. The other 3 carb pistons fell smoothly, evenly and at the same rate relative to each other. I had to re-position the rubber diaphragm with a very small amount of gasket sealer around the edge. Worked like a charm... all 4 carb pistons slide nice and smooth.

 

Reasons that Diaphragm Pistons CLUNK -- With -- Springs and Tops in place:

a) Extra or Over-sized Vent Holes drilled at the bottom of the Diaphragm Piston as related to installing Jet Kits or altering Pistons to alleviate Lean condition.

b) Pin Holes, Holes, Cracks or chaffing on the Diaphragm Rubber.

c) Diaphragm Locating Edges not seated in channel when Top is replaced on Carb.