(Special) Alloy of intake boot screws?

[roeme]

When taking of the carburetors from one of my bikes, I ruined the heads of some of the screws which attach the intake boots to the engines body (At least I got them out without stripped threads!).

When discussing with a buddy why the hell they deformed apparently way too easy, the idea came up that these are not steel screws, but some other, softer, alloy must be used. Reasoning being that the engine's body is cast aluminium, and when heat comes in to play, the screws must expand/contract by the same factor, or else they'd break under the resulting tension.

Are we right or wrong?

Are regular, over-the-counter screws safe to be used?

[uk gs nut]

Use stainless screws with anti seize grease or copper grease. The standard Suzuki screws are soft and chew up easy.

[roeme]

Use stainless screws with anti seize grease or copper grease. The standard Suzuki screws are soft and chew up easy.

So the aforementioned heat expansion coefficient difference to the engine's body isn't a problem?

[SVSooke]

There must be hundreds if not thousands of GS's bikes running just fine with SS boot screws in them.A lot of the problems with the OEM screws is using a regular Philips driver on a JIS screw head.Even with a JIS driver the alloy most of the case screws all the Japanese makers used was very poor.I'm sure because the bean counters (accountants) got involved ,pretty sure it had nothing to do with expansion rates.

[Steve]

The commonly-accepted theory here is that those screws are made of aged Cheddar cheese.

Yes, stainless steel screws (with anti-sieze) are a common replacement.

You can get those screws easily (and inexpensively) from cycleorings.com, along with the o-rings to rebuild your carbs.

.

[Nessism]

Suzuki used steel screws. Your concern about differential expansion between the aluminum and steel is unfounded.

[roeme]

Thanks a lot guys!

I will then go the SS (or nickel plated, whatever is available here) route with liberal amounts of anti-seize.

The commonly-accepted theory here is that those screws are made of aged Cheddar cheese.

Bwahaha! That really nails it

You can get those screws easily (and inexpensively) from cycleorings.com, along with the o-rings to rebuild your carbs.

Unfortunately completely missed that when I ordered the intake o-rings. But I might've got a second set of carbs to do down the road anyway, so.

Your concern about differential expansion between the aluminum and steel is unfounded.

Well, they do expand differently: https://en.wikipedia.org/wiki/Therma...ious_materials

It just wasn't sure whether it's a problem or not, which this forum (once again!) has cleared up.

[Nessism]

There are something like 50,000,000 vehicles sold each year with aluminum engines held together with steel fasteners.

[greg78gs750]

they are a "special" alloy, all right....heh.

[60ratrod]

being that this is a ground bound 2 wheeled mode of transportation and not a trans-atmospheric exploration vehicle or high performance race automobile, expansion rates are really a non-issue. the important bits are the rubber to make a good seal.

[GregT]

The commonly-accepted theory here is that those screws are made of aged Cheddar cheese.

.

I can report that late model suzukis have boot retaining screws made from a slightly harder cheese...But most now are a countersunk head so are harder to move anyway....

[roeme]

Just stumbled across this old thread, just have to note that humor of you lot is glorious.

The screws have been replaced by SS screws, called 'Inox' around here.

[Johnny]

I just changed the intake boots about a week ago. Learned a couple of things. First, the airbox does come out (on a 250), I got it out and later put it back on from the left side of the bike (while myself operating on the right side), to achieve that I had to remove both side plates and the battery box, carburetors, and also that smaller engine cover retaining the clutch cable. Secondly, after the bike had sat through the night drowned in penetrating oil, followed by hours of violence with an impact driver, only one screw of four came loose. I did all kinds of witch dance to get the other three, but no go. Finally it struck me that I need to get the washers off. One was a lock washer which I could knock off with a really small screwdriver and a hammer, the screw got loose immediately, but the remaining two washers where either ordinary closed type or I just didn't see the opening in them, so I sawed them through with a hacksaw blade. Finally success. Really, it were the washers holding those screws stucked. For replacement I used stainless steel allen head bolts with copper paste on them (and new washers too).