Gremlins...

[Czekus21]

I my XSpieriences with carb syncing, I found that if your going to use gauges, You NEED all four to set them up right. You may set up one carb to one spec but as soon as you turn the screw on the next carb, the one you just did will be off agian. That equals out to ALOT of moveing the guage. Unless you want to take forever and a weekend to get your carbs set up, I'd be looking at a 4 gauge set.

[John]

Vacuum Gauges

I just bought a set of gauges from JC Whitney for $63. They arrived a few days ago, and I just finished sync'n my carbs about an hour ago. I had the carbs out a few weeks ago to replace the brass floats (one had a hole in it, and I didn't want to go through what I did on the 79 SF that I recently finished) with some plastic ones from a set of 81 SH carbs. It took a few tries, but I finally got the float level tweaked in at 24 mm. I did the twist tie sync just for s#its n' giggles, and it wasn't as good as before I messed with it (yeah, I know. If it ain't broke...)I tried to 'earball' it as best I could. That's when I ordered the gauges. Well, anyway, the idle is real smooth now, not erratic like an h-d any more. They balanced out at around 13 inches of vacuum. I set the ide at 1200 rpm, as per the bikes' tach, it accelerates quickly and decelerates back to base idle just fine.
Anyway, if you can afford it, I would suggest getting a set. They are great, and you can be the envy of all the kids in your block.

[trbig]

I don't remember where I saw a tool like this... if it was on here, or somewhere else, but what I used was a piece of 3" PVC with some caps... drilled a couple holes for some brass nipples to attach the lines to. this keeps the needle from jumping.


Then I bought a brass gang-valve for a fish tank online for $2.50. I attached 4 lines to it, and to the carbs on the other end. I can then open each screw on the gang-valve to single out the carb I want, and close the others. this way, there's no moving of gauges... but yeah.. I have noticed that moving one.. say... between carbs 2 and 3, if I check 4 again, it has changed. Once I get close, it's just a matter of small adjustments.



Tod

[trbig]

OK.. absolutely screwed up the carb synch. Went to go buy some longer fuel lines to help with tank placement... by the time I got back, the bike cooled down and wouldn't even fire up!!
So... back off with the carbs. Got a bread tie, but was advised by TC that it is easier to just adjust the top of the butterflies to the small hole in the top of the throat of the carbs. Make them all match the #3 butterfly. Then close the butterflies with the main idle adjust screw, re-install the carbs (Even with the tech tips for this... still a major pain the the arse) and fire it up... adjust idle after warm up. I re-checked the vacuum on the carbs, and they were all within 1/2 a pound... good enough for me! I was afraid to start turning things and screw it up again. Someday soon I will get the K&N style filters, and I won't be afraid of having to pull the carbs again, so i will adjust again. Thanks TC.

Tod

[webbcraft2150]

Dennis Kirk and Chapperal sell mercury "carbsticks" for about $35. Best tool investment I have made in years. Using the tech tips from here had em all dialed in in about 30 minutes. Bike ran better than it ever has. I do it now about once a month just cause I can, never very far off. Sidenote, I put a big box fan in front of the engine when I do this to keep things cooled off, and DO NOT blip the throttle with carbstick hooked up.

[trbig]

Anybody ever heard of anyone's bike actually ingesting the mercury? Just wondering if it sits in there beating on the pistons, or if it burns off? Kind of off the subject... but curious mind(s) wanna know!! C'mon Prometheus.... surely you know "Someone else" who could have done such a thing!
Tod

[webbcraft2150]

Who wants to try and see what happens?

[TopCatGr58]

The mercury is liquid, but when it gets sucked into the combustion chamber, it gets vaporized, and the resultant fumes are very dangerous, heavy metal poisoning is no fun!!! The vapors can be inhaled, and can make you very ill!!!

The pistons are moving way too fast, so there's not much chance for hydralocking the cylinders with that little volume of mercury.

Was thinking about this, wonder about putting an air filter INLINE with the lines, so that IF the throttle got blipped, that the mercury would be stopped by the filter, but it would still allow air to flow so that accurate measurements would still be possible!
T.C.

[Ken Talbot]

If you install the plastic restrictors in the hose just out of the glass tubes, you should not have a problem with mercury getting sucked into the engine. If you do not have restrictors, you really should install them immediately. They are a simple piece of plastic with a very fine hole drilled through them. These also help to dampen the fluctuations when you are doing a tune-up.

[trbig]

Ahhh... now the discussion begins.. lol. Mercury above -40 degrees is in a liquid state... but doesn't begin to boil until 675 degrees.... but it IS a metal. It is extremely dense... do you not think it would beat up the top of a piston? Have you ever seen what common water does to the top of a Diesel piston? It has a much lower "Vaporization" point, and far less dense. I'm not talking about hydro-locking it... just hangin around a bit and beatin the thing up.
C'mon... someone out there... sacrifice your baby for us in the name of science!! lol.

Tod

[TopCatGr58]

Well Tod,

I was talking more about the Venturi effect of vaporization as the mercury was being sucked into the manifold, and then it would get atomized as it entered the combustion chamber. And, I'm pretty sure the temps inside the combustion chamber are a bit more that 675 degrees! So, in that small quantity and density, I really don't think it would cause any damage, would be pushed back out the exhaust in vapor form. Heck, LEAD is much harder than mercury, and when it was in gas, it didn't cause any damage!

I'm not familiar with diesel engines, or any alleged damage that occurs to their pistons by having water in the fuel!? I do know that they work by compressing the air/fuel mixture at very high compression ratios, and this extreme pressure along with the friction of the pistons in the cylinder walls causes the mixture to spontaneously ignite. I would imagine that the water contamination would raise the flash point, effectively cooling the chamber to the point of inhibiting combustion!?!? Now whether the water is impacting the pistons, or more likely it's breaking down some carbon buildup which could appear as pitting!!?

All conjecture on my part, awaiting a Diesel Mech to clarify!
T.C.

[trbig]

Not sure either... just like to argu... ahem... Discuss things. I have seen some damage to pistons that looked like a nut or bolt had been beating around in the cylinder.. and was told that it was from water.... actual small dents in the piston head and combustion chamber of the head. Who knows... been lied to before!!

Tod

[mro]

breaking down some carbon buildup

old enginemen "trick" to remove carbon in the combustion chamber.

rev engine up, slowly pour a coke bottle of water thru carb/intake while keeping rpm up. water turns to steam in chamber and blows out carbon top of pistons/valves etc...



mro

[trbig]

I think I'll stick to Marvel Mystery Oil in the gas... lol. Something about red hot pistons getting doused with water... doesn't sound good for the longevity of a motor.

Tod

[Pat Kelly]

My cat's name it Gremlin (looking at title of this thread). She's 16 years old. She hates our 1 year old kitten.