Suggestions for fixing this vacuum leak

tabaka45

I finally found a vacuum leak that appears to be a bad gasket between the lower part of the intake boot on #1 and the block. I tried to tighten the bolt but that did not stop it. So I guess I need to take the intake boot off and replace the gasket. I've seen writers warn against trying to remove the boots. Haven't removed the carbs yet, but the lower bolt turns. Any suggestions if I have problems with the upper bolt? Also, is there any special consideration if I try to make a gasket?

nickbrit16

I had this same problem man, get some RTV silicone gasket, the high temp stuff and a sheet of gasket (find it at local auto store). Take another gasket from your other boot and stencil it out. Worked for me atleast and was cheaper....

MN-Maxims

The bolts that hold those manifolds on like to snap off. Be careful and only remove the one giving you trouble. For sure buy new bolts.

MN

mlew

After removing the carbs soak them with penatrating oil. Turn them out and in a little at a time to work the oil in. Don't try just turning them out , thats asking for trouble. Most any gasket material at the auto parts store will work.

jeffcoslacker · Red Liner Joined: Jul 22, 2007 Posts: 464 Location: SW MO

I'll agree with all.

New boot gaskets are like $11/each. A roll of FelPro gasket material is $6 and you will have a lifetime supply.

If you can find a thin walled pipe same size as the round opening in the center of the boot, you can place your cut gasket on a wood block and use the pipe and a hammer to punch out the center hole. Sucks trying to cut perfect circles with a razor blade...at least for me.

Mine came equipped with a bolt snapped off in the #1 boot. The others came out with no trouble. I would expect that left outboard is usually the troublemaker for most...that's where all the water runs to when it sits on the sidestand wet...

So far #1 is not sucking air, so I left it alone, replaced the other 3 gaskets. I'll deal with the broken bolt this winter when I pull the motor.

Anyway, I found on my last Maxim that if one starts sucking air through a bad gasket, the others will follow shortly. Saves time to do all while it's apart, long as the bolts aren't an issue.

RickCoMatic · Last edited by RickCoMatic on Sun Aug 12, 2012 2:25 pm; edited 1 time in total

Take a "Cheap" 22mm 12=Point Socket and Sharpen the opening with a Bench Grinder and a Dremel.
Grind the open end to a razor-sharp cutting edge.

Use it as a Cookie Cutter to carve curved openings in Gasket Making Material.

A "Single-Hole Paper Punch" makes small holes easily.
Sight the Hole Punch's I-D on the Bolt Hole Mark.
3 or 4 clips and you have a clean-cut Bolt Hole.

adrian1

Rickomatic, I admire your DIY old school skills!

tabaka45

Used some gasket material I had and made a gasket that fit perfectly. Sync'ed and colortuned today. Ran about 40 miles and it ran perfectly and it appears that my gas mileage has improved drastically. Damn, it feels good when it all comes together. Never could have done it without all the great information and help with carb cleaning, valve information, syncing, colortuning, and finally finding the vacuum leak. thanks to everyone.

bigfitz52

Congrats, man. It feels great; especially when your fuel economy comes up to what it should be. Then you know you've nailed it; just keep an eye on the plugs (every 500~800 miles for now.)

Good job.

tabaka45

bigfitz52 wrote:

Congrats, man. It feels great; especially when your fuel economy comes up to what it should be. Then you know you've nailed it; just keep an eye on the plugs (every 500~800 miles for now.)

Good job.

What should I be looking for with the plugs?

MN-Maxims

Spark plugs should be brown not white or sooty black

RickCoMatic

The "Colorization" of the Plug's Center Electrode Ceramic Insulator.

Black = Too Rich
Dark Brown = Safety Rich

Between Dk. Brown and Brown Paper Bag = Very Good ~ Ideal

Tan = Borderline Lean ~ Performance Tuned ~ Needs Freq. Monitoring
Clean / White = Dangerously Lean ~ Excessively Hot Burn ~ Potentially Extremely Harmful Overheating.

www.ngksparkplugs.com/...aqread.asp

tabaka45

Thanks for the spark plug information. I'll check them after about 100 miles, but after about 20 miles they were dry and beginning to take on the brownest color. These plugs have only about 150 miles on them but they were the ones used when the carbs were running very rich. At that time they were very sooty, so I wanted to see the change after getting the carbs cleaned and adjusted.