Is the use of intake o-rings with rubberbands overkill?

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OckMock
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Is the use of intake o-rings with rubberbands overkill?

#1

Post by OckMock » Sun Nov 22, 2009 3:26 pm

A friend recommended I use both the rubber o-rings and shovel style intake rubber bands with the appropriate aircraft-style intake clamps to fully solve my intake seal.

After pressure testing yesterday, I found a very small intake leak. Im currently using rubber o-rings with the 2 piece clamps. I was always concerned that the 2 piece clamps have a tendency to cut the o-rings in half over time, or squeeze them in such a way that they dont ever properly seal.

As per the recommendation of alot of folks here, I pressure-tested my intake after an extremely difficult cold start condition.

I ordered a set of shovel style rubber bands with the appropriate intake clamps. Before I re-assemble everything, I wanted to get some advice from the gallery here to assess if I should use o-rings AND the rubberbands together?

Or, should I just stick with the o-rings and the 2 piece clamps and get the seal as best as I can?

Any advice?

BTW, I have STD Panheads with Shovel-style intakes.

Thanks.



beets
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Re: Is the use of intake o-rings with rubberbands overkill?

#2

Post by beets » Sun Nov 22, 2009 4:19 pm

I used both on my 56FL with good results. Stock heads and manifold.

Bosheff
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Re: Is the use of intake o-rings with rubberbands overkill?

#3

Post by Bosheff » Sun Nov 22, 2009 6:50 pm

Personally speaking, I have tried just about every set-up known to man on panheads and shovels, and I have come back to the original o-ring, and original H-D clamp set-up on the pans. If your heads and intake have not been damaged at the mateing surfaces there should not be a problem. Make sure your heads have been indexed on the cylinders before torqueing them down so you get a nice even gap on both surfaces. Be sure to run some sort of leveling bracket on the carb/intake set-up to relieve any stress/weight/vibration that will be put upon the o-rings themselves. I have used the plastic inserts that eliminate the o-rings and allow you to go to the rubberband set-up with limited success, but these were a pain in the ass to install with the gas tanks installed. The 2 piece clamps stay tight, but my experience with them has been that they tend to cut into the o-ring where the clamp haves meet. I have wrapped the o-rings with electrical tape to keep the 2 piece clamps from biting the o-ring but I didn't see where that made any difference as the tape merely made a sticky mess on the heads and intake and there was still evidence of pinching even with the tape. I have wrapped teflon tape over the electrical tape to stop the pinching with no luck. I have relieved the contact area on the 2 piece clamps where they come together to get rid of the pinch area, but this still didn't help much. I have to admit that installing o-rings and stock intake clamps by yourself with the tanks on is a test of ones patience, but I have not seen a better set-up as of yet, so I'll stick to what I have learned works....bosheff

NightShift
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Re: Is the use of intake o-rings with rubberbands overkill?

#4

Post by NightShift » Sun Nov 22, 2009 8:28 pm

In my humble opinion, adding bands just adds more places to leak and more rubber to rot from gas.

Respectfully,

RussW
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Re: Is the use of intake o-rings with rubberbands overkill?

#5

Post by RussW » Sun Nov 22, 2009 9:17 pm

Might also want to use a set of the James Viton "O" rings, more gas resistant than the rubber ones that most kits include. I got them here: http://www.itwtrading.com/carb-intake.html

OckMock
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Re: Is the use of intake o-rings with rubberbands overkill?

#6

Post by OckMock » Sun Nov 22, 2009 9:39 pm

I went with the o-ring and 2 piece clamps (as Im still waiting for th rubber bands and a/c clamps in the mail)...added the pressure tester and to be sure the intake valves were closed by fully loosening both intake pushrods...

Sprayed again and actually heard the leak...

Sprayed some soapy water on the intake and watched the bubbles aplenty...I tightened both clamps slowly until there was no more hiss and then no more bubbles...watched it for another 10 mins to be sure....and looks like I solved it....no leaks!

Adjusted everything and went to start the bike...and of course...nothing. Damnit.

Removed the mag, de-glazed the points with Ucles Sam's finest curency...spun the mag on the bench until I lost my finger from the zap and then and re-assembled everything per Morris' spec.

Kicked another 50 times...nothing. So, I added a tad more advance and alot of enrichener...and she finally lit. Ambient temp here is about 53 degrees...

Still dont know what the issue is...this ting should want to start cold with more retard...but it seems as if it wants more advance and alot of gas????

Fuck if I know.

Any advice/ideas???

BTW, motor is fresh...only about 2k miles, if that. This bike was ONE kick in the summer. Only thing changed since was a new set of o-rings and new mag points.

Bosheff
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Re: Is the use of intake o-rings with rubberbands overkill?

#7

Post by Bosheff » Sun Nov 22, 2009 11:42 pm

Check, double check, and recheck again the timing sequence. Sounds like ya could be retarted, initially. It really takes a lota fuel to start a cold hog so I wouldn't be afraid of floodin' the thing unless ya got an S&S Super and ya squeeze it 8 times and then engage the enrichner. If ya try to start it cold with to much advance, it will usually spit back through the carb, or worse yet, it'll try to shove yer leg up yer ass when it fires back. Make sure ya follow all the way through when kickin' it over....bosheff

OckMock
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Re: Is the use of intake o-rings with rubberbands overkill?

#8

Post by OckMock » Mon Nov 23, 2009 1:35 am

Bosheff:

Checked and double-checked....

Once I got it running I hit it with the timing light. When mag was fully advanced, the 35deg BTDC mark was not in window. So, I adjusted the mag base screws to allow for more advance. Once I did that, timing mark was right in the middle of the window.

At this point timing is spot-on.

Im running a Super B...and I guess I should close the butterfly all the way when prime kicking with enrichener on...and add a few more primes when temps drop below 50 or so...hoping that should do it.

Ever heard of mag points getting glazed after sitting for a week or so??? My mag points keep fighting me for some reason. Learned a new trick to use a dollar bill to de-glaze them.

Cotten
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Re: Is the use of intake o-rings with rubberbands overkill?

#9

Post by Cotten » Mon Nov 23, 2009 3:40 am

OckMock!

Take those two-piece clamps and toss them in your scrap bin.

Use original style clamps with screws, not nuts on a stud. If you buy stainless, make certain that they are no more than .750" wide.

Find the sweet spot where the manifold seals best by bubbletesting while your tighten the clamps, and then massage your support bracket to mate the carb without stress or bind.

Good luck,

....Cotten

OckMock
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Re: Is the use of intake o-rings with rubberbands overkill?

#10

Post by OckMock » Mon Nov 23, 2009 5:18 am

Cotten:

Thats exactly what I did with the 2 piece clamps...tightened until bubbling stopped. Its funny, until I read this forum, I was way too lazy to appropriately check the intake for leaks other than the eyeball or WD40 test. Your tech tip even forced me to make my own pressure tester plate...so thanks for that!

But, I hear ya, I should use the appropriate clamps...I was in a bit of a hurry to get this ting running today.

By chance would you have a pic of the clamp you mean?? Im assuming Tedd's carries it?

The only other clamps I ever used had the single stud with the nylock nut...and I always found them to "slip" off the o-ring to one side...thus my switch to the 2 piece clamps.

Cotten
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Re: Is the use of intake o-rings with rubberbands overkill?

#11

Post by Cotten » Mon Nov 23, 2009 3:08 pm

OckMock!

Tedd's offers zinc (ugh!) or cadmium reproduction clamps (35-0439) as well as stainless clamps with #10 screws like OEM (35-9177).

But it is the stainless clamps that are .030" too wide, and must be ground.

And forming a flat OEM-style strap to make a nice "bow" takes patience.

For a Chubblehead manifold, I would choose to grind the stainless.

Shamefully, Tedd doesn't offer James Gaskets true Viton o-rings at this time, so please support your local independent shop and ask them to stock some direct from James for everyone.

....Cotten

Bosheff
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Re: Is the use of intake o-rings with rubberbands overkill?

#12

Post by Bosheff » Tue Nov 24, 2009 12:52 am

I ain't got a clue bout yer points glazin in yer mag. Went round the block with a mag in the early 70's and decided life was to short to depend on one of them things. I do know a mag will lose it's charge just from sittin' and ya got to have the coil revitalized or its no go. I've seen one fill up with motor oil, but never glaze the contacts over. It would seem to me the glazing must be occuring when the thing is runnin, which leads me to believe the mag is not functioning properly which may be all or part of yer hard start condition. It has been my experience that magnetos is like bein pregnant. Either you is or you isn't....bosheff

Cotten
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Re: Is the use of intake o-rings with rubberbands overkill?

#13

Post by Cotten » Tue Nov 24, 2009 3:48 pm

Mags are miraculous when they work!

The rest of the time they don't.

....Cotten

OckMock
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Re: Is the use of intake o-rings with rubberbands overkill?

#14

Post by OckMock » Tue Nov 24, 2009 4:46 pm

I dont think its corrosion...

When the bike sits, sometimes overnight or up to 3-4 days, I get a very weak spark from the mag. This mag, btw, was freshly rebuilt and remagnetized last year by Morris.

I replaced 2 sets of points and condensors within about 6 months of each other. I probably didnt have to replace the points, but I did anyway.

What Ive been doing now is the dollar bill trick to go back and forth across the points faces. When I do this it brings the strong spark back as evidence of the bike starting pretty easily thereafter.

So Im using the term"glazing" here, but I may be talking out my ass. Im not re-dressing the points each time, but simply "cleaning' them.

Any ideas for me?

duoglide58
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Re: Is the use of intake o-rings with rubberbands overkill?

#15

Post by duoglide58 » Sun Dec 06, 2009 3:46 am

I wish the 2 pc clamps were contructed like Victaulic Clamps. Rather than the 2 haves just putting up to each other the Victaulics have tabs and recesses machined in each half so that the pressure it more uniform and you do not have that pinch point.
Doug

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