A couple carb rebuild questions

Hi guys

I started cleaning my carbs tonite and I have a few questions.

1) I found one hole in a diaphram. Most have about 4 marks on them that look like rub wear marks. Not sure what it is rubbing against. What is the best way to repair diaphrams? I read here some use black silicone. Is this a good method? Any prep required? Where should it be applied top side or bottom? Does it make sense to put some on the wear marks too? Or will this impede performance of the slides?

2) How much bugging up can there be on the jets. It looks like someone was in these carbs before me. Some of the slots are buggered up. With this affect draw? This is on the pilots.

3) All the jets look clear there are no obstructions. How clean should they be?

4) Does it make sense to amorall or spray silicon on the diapharms after they are repaired. How about the tips on the float valves.

Thanks in advance!

 

Firstly, what type of carbs are they and how big are the holes? Pics will help.

Holes in the diaphragm will definitely affect performance, so they must be repaired or replaced. Hold the diaphragm to a bright light to see the pinholes. RTV gasket silicone is not gasolene resistant and will swell and fall off (I tried it).

A recent post recommended using a vinyl (?) paint, the stuff used to dip tool handles in but I have not tried this method. A friend repaired his XS1100 Mikuni boots using a latex rubber glue and fine gauze cotton cloth. It worked but was only on for a couple of months before he converted the whole shebang to a single carb setup so I'm not sure about durability.

I had mine replaced using NRP carbs in the UK. Depending on the size and brand of your carbs you may be able to use the ones offered by JBM which are much cheaper than NRP ...

http://www.jbmindustries.com./index.html

I'm not sure about the wear marks, you'll need to post a pic. My old ones had regular marks around them that were fold lines from the wrinkles in the rubber. Chacal at XJ4ever mentions a product to condition the rubbers before re-assembly. I'm guessing a rubber preservative like amour-all or rubber grease will do pretty much the same job if used sparingly. I re-assembled mine dry because I'm expecting to have them apart again very soon. Any other part that has direct fuel contact will soon be washed clean so using it anywhere else will just cause other problems if goo starts rolling about in the fuel passages.

If you haven't already you need to read this post ...

http://www.xjbikes.com/Forums/viewtopic/t=14692.html

to get an idea of what "clean" really means. Think of a hospital surgery room, then a bit cleaner again. A fanatical, almost religious devotion to the cleaning task is required to achieve this. A calm methodical state of mind and clean well lit work area is a must. Soft soothing music also helps (I'm not joking) <end of rant!>

Regarding the jets, if they are deformed that badly I'd be replacing them, they are not an expensive item in the scheme of things.

 

For the price of the NEW Rubber Diaphragms offered by JBM, ... you can't go wrong.

If they just need a little TLC ...
Try this:

Diaphragm Rubber Repair:

Thoroughly clean the whole Rubber with Isopropyl alcohol.
Apply MASKING TAPE to the OPPOSITE SIDE of the Repair.
(Holding the tear together > Perfectly!)

Cut a Small Funnel to act as a Form.
Make the Hole in the Funnel a tight fit.
Slip the Piston into the Funnel and smooth it out.

Tape the Rubber to the Form.
Make sure Rubber is not buckled or wrinkled.

Salvage some "Repair Material"
(I used a small section of Material cut from a Nylon Windbreaker)
Thin Dacron Polyester.

Cut-out a PATCH of Repair Material to COVER the SCUFF, PIN HOLE or TEAR.
Coat the Rubber over the TEAR with a thin coat of LIQUID Electrical Tape.
Use an Artist Brush.

Note:
Open the Can
Cut-off the Dabber and discard.
Use a Carb Cleaner Red-Tube to Dip into the Can and use just a few drops at a time.

>> Quickly apply the Patch with TWEEZERS and "Iron-Out" any Air Bubble or wrinkle with a BIC Ball Point Pen (Cover and Blunt End)
Smooth-out Patch.
You don't get much time to do this.

Once Dry:
Apply 2nd Coat of Liquid Electrical Tape.
When 1st side is dry ... repeat process on other side of Rubber ...
BUT
Don't Stick Tape on the Repair ... Just Smooth the Diaphragm Rubber Out.

November 23, 2009
"The RickCoMatic Patch"

 

Thanks guys. The hole is pretty much a pin hole. I'll give the liquid tape a try.

iandmac, they are HSC32s. Thanks for the info

Rick I was surprised you are online after the win. Figured you would still be partying. Wow you have seen a couple world series wins and a stanley cup.


Pat