seeing red!!!

Barrie2777 · Post by **Barrie2777** » Thu Jun 10, 2010 11:19 am

I received my "pop off" tester and checked the 502, 503 and my 400. Neither Diablo would hold any pressure. One popped off at 8psi. The other couldn't even be pumped up. This leads me to believe there may be dirt on the seat. The 400 popped off at 10-11 psi and held at 4psi.

fap67 · Post by **fap67** » Thu Jun 10, 2010 5:19 pm

Hey Barrie,did you know the needle and seat need to be wet to get them to test properly? You can use either gas/oil mix or some type of spray product such as WD40. Don't forget about the copper gasket under the seat, I've had them leak a few times. Good luck!

Barrie2777 · Post by **Barrie2777** » Sat Jun 12, 2010 8:48 pm

If there was an Olympics for removing, dismantling, assembling and remounting a carb on a Diablo I believe I would take gold , hands down. I managed to set the pop off at near 10-1/2 psi. The engine will start and run but only at high rpm. When it goes down to idle speed, the gas shoots out of the carb like ol faithful, even with the high speed screwed all the way in. This tells me it is drawing gas from somewhere else besides the high speed port. I even changed the welsh plug beneath the high speed port. It could be drawing gas from the base of the seat for the needle but I don't have one to change today . Is there any other possible place for all this gas to come from? I think I'll order a set next week when I'm in buying the "For Sale" sign.

Barrie2777 · Post by **Barrie2777** » Sun Jun 13, 2010 8:01 pm

I took a deep breath today and tore apart the carb on the 502. I squirted carb cleaner in every oriface, checked every part, blew air through every hole, gave the welsh plug a tap for good luck then adjusted the lever arm to apply more pressure to the needle. All together again, not record time because I dropped one of the body screws in the debris on the floor, and this time a pop off test "a la benchtop". The pop off tester read under 10 psi. All apart again this time to bend the lever slightly below the body of the carb. This is contrary to the Tillotson instructions but what the ....!!! nothing else works. This time the pop off test was a 10.5 psi. By the way I am doing this bench top testing with WD40 in the needle passage as Frank suggested. Carb back on the engine, gas down the throat to get everything going and halleluah!!!! fire in the hole ( not an actual fire like I had on the 503) the engine caught and continued to run. I have started and stopped it several times today with long intervals between starts. The gas is not seeping back as it was last week. Tomorrow is another day..............

Barrie2777 · Post by **Barrie2777** » Sun Jun 20, 2010 11:39 am

Yesterday I decided it was time to complete the second 502. This carb is a HR 7A and did not have the correct lever arm for a Diablo. I found a correct choke rod on a Sach engine and removed it. This rod was bent at 30 degrees so...no problem...just heat and straighten. Well...it broke during that exercise. Today I soldered it back together and it should perform royally until it breaks again. I rolled the 502 to the door and cranked it several time without the gas being pulled up to the carb. Back to the work area for a carb tear down and if you recall from my 503, I'm getting rather proficient at this task. Just before I loosened all the body bolts I noticed that the vacuum tube was not there. I'm a HUS-SKI guy and that part is not needed!!! Back to the door and start it did!!!! Some adjustment with the idle and I drove it onto the lawn for its inaugural showing. I thought it would be good to park the two 502's side by side so back I went for the 502 that had the "pop off" problem. Starting reliably until now!!! It wouldn't start. Out with the plug, back on with the plug wire...where is the end to put on the plug. It fell off obviously due to the numerous "off" and "on's" in the last week. On with the contact end and start it did!!!!

Go Go Diablo · Post by **Go Go Diablo** » Sun Jun 20, 2010 12:16 pm

Two Restored Diablos side by side and no picture to share?

Barrie2777 · Post by **Barrie2777** » Sun Jun 20, 2010 12:38 pm

I had edited my post before reading yours. Seaters to come later.

Barrie2777 · Post by **Barrie2777** » Thu Jun 24, 2010 8:35 pm

Too bad all my fine woodworking will be covered with the pleated seat covers from Bruce. These seats are screwed and glued together at the back joint. I will remove the screws and shape the bottom corner with an electric hand planer at a later date. I measured my seat back to seat angle at 12 dregrees and made all the seat frames at this angle. Sometimes it is bewildering how to get a 102 degree block but by angling the saw blade 39 degrees and taking a cut from either side, Bob's your uncle...102 degrees.

Barrie2777 · Post by **Barrie2777** » Tue Jun 29, 2010 8:34 pm

This is an original seat from my 502. It s' cover is perfect but the padding was compressed and made the seat look loose. I removed the staples from one side and the end, then pushed the new foam in and restapled it together. A little vinyl reconditioner will finisih the job.