Archived Posts

[Admin]

Hey Fred....I posted a solution to enlarge your rubber stopper gas cap on the VJMC, but seemed to have stirred up the hornets a bit. Brake fluid will work, but will not last, and who wants brake fluid residue in the gas?

One inch of gas in a coffee can, set the cap in, note that the gas is not contacting the chrome, cover with lid, and wait two days. Try the fit! As long as you have gas in tank, and the cap receives a slouch of gas once in a while, you will have no problems, and it will retain its' size. Everyone seemed concerned with the gas touching the rubber plunger...DUH?????

If gas doesn't work........I'll buy ya' some Enzite...Just ask BOB!!!!

[Admin]

Yes... the hornets are really buzzing over at VJMC. I had one of my old gas caps soaking in brake fluid for 48hrs, did not do much to it, but some of the guys are saying it takes a LONG time to work. I threw this cap into a can with gas, a tuna can actually, the cap just barely slid into the can, now I need a screwdriver to pry it out. This is just after 48hrs in the gas. My other cap, the one that will go on the bike and is in good shape is now soaking in brake fluid. I have a feeling the gas will win on this one too. The other thing that just occurred to me, if I soak the cap in brake fluid for a long time, what is going to happen to my expensive freshly painted gas tank when I put a gas cap on top that has been soaked in brake fluid. I think I know the answer to that one!

Fred

[Admin]

Hi all,
I'm in the process of cleaning the engine up while I have it out of the frame and I was looking at replacing/replating the cylinder head nuts. Here's some questions:
I remember somewhere that these can be a bear (sorry Gordon) to get out, or was that only for the early models?
The most correct way to do this it to take the head off, but can I remove and replace these nuts singularly in head torque down sequence, or do I need to bite the bullet and take the whole head off?
I was looking at the fiche on mrcycle.com and they have 2 current part numbers for the head gasket that supercedes 3 previous part numbers. Which one would be correct for the 1975 gt750?
Should I just dress it up and fugetaboutit?
Any other pitfalls?
Also, was the head and cylinder clear coated aluminum and the rest of the case painted? I couldnt tell when I looked at it earlier.

Thanks guys.
Pete

[Admin]

Pete, I have an extra copper head gasket that I bought from Dave -- do you want it for your project?

[Admin]

Hold that thought! I may take you up on that Gordon if it turns out
I have to dig in.

[Admin]

I've replaced them one at a time before. The truth is that you could take them all out without disturbing the head most of the time. The gasket is usually pretty stuck.


Lane

[Admin]

Hi all,
.... the cylinder head nuts......I remember somewhere that these can be a bear (sorry Gordon) to get out, or was that only for the early models?.....

The heads and nuts usually pop right off (usually).

Its the cylinders that are glued on like stink (usually).

I'd pop the head off and clean out the carbon on the piston as long as I was at it; but you certainly wouldn't have to.

Good luck!

[Admin]

Update on the gas caps: The old one soaking in gasoline out in the garage has softened and gone very supple, it has also " enlarged" itself to the point where it now gives a snug fit in the tank. Previously, it had about 1/8 gap when sitting in the tank opening. The cap soaking in the brake fluid has done nothing, still the same, but it has been just a week. I have also purchased a bottle of Rubber Renue which I will now put on the old cap. The old cap was actually one step from being tossed, but now may become very usable.
I don't have a lot of confidence that the brake fluid will do anything, I don't have the patience to let it sit around for 2 months. The Rubber Renue takes 12-24 hrs, will see how that works.

Fred

[Admin]

i dont see how brake fluid could affect the rubber, since steel braided rubber likes are used full of fluid all the time. they dont swell until they are worn through. and then need to be replaced.

[Admin]

Well, Vince, there's rubber and then there are elastomers. Something that looks like rubber may not necessarily BE "rubber", but rather an elastomer.
Elastomers are typically manmade substances that may look and feel like NATURAL rubber....but aren't.
Various manmade elastomers and natural rubber each have certain characteristics that make them desirable for certain functions.
Brake lines are lined inside with natural rubber which is NOT affected by brake fluid. The outside casing is a manmade elastomer because of the requirement to keep the rubber liner protected from sunlight, ozone, gasoline, etc etc and to add strength to the whole assembly because of the high pressures involved. The natural rubber liner does NOT stand up well to ANY of those conditions/substances, especially gasoline or any petroleum based substances.
Manmade elastomers, whether buna-N or some other manmade substance, typically do NOT react well to brake fluid, so can't be used as a liner in brake hoses.
Aren't you sorry you mentioned this ???

But now you know what's what with brake lines......

[Admin]

elastomers

I think I saw some girls use those in a movie once!!

[Admin]

thanks for the info rick, ive changed a lot of brake lines and now i will look at them a different way.

[Admin]

I own a '72 T500 and just obtained an airbox from a '74. The box seems to fit generally but the front mount on top of the box is about 1" to 2" longer than where the mount is located on the frame - is this the only difference? Anybody know?

[Admin]

The problem is mainly due to the fact when they changed the carb intakes from the integral rubber flange to the aluminum spigot and intake side tube type.
This change caused the carbs to move back slightly from the cylinders but the airbox boot remained the same design.
Therefore the mounting brackets and design on the later airboxes were altered from the earlier types.

[Admin]

Thanks Allan. I'll make it fit. Or is there someone who wants to swap a '74 for a '72 version.