Intake O-Rings Question

[Guest]

Ok. I had to take my starter off and replace the brushes. I decided to take a peak at my intake boots that I had a guy replace about 2 years or so ago.

I know I need to replace the orings. Just wondering if the ones on there are messed up or if this is what they should look like. If he used the wrong ones or not. Anybody that has an opinion I would really appreciate it.

[BassCliff]

Hi,

I've never seen those O-rings do that before. Those must've the wrong size or been made from the wrong kind of rubber. They are cheap enough, just get some new ones. Robert Barr at cycleorings.com has them as does Z1 or any OEM vendor.


Thank you for your indulgence,

BassCliff

[081dbx64]

GR8!...this same guy rebuilt my carbs.

Now I have a decision to make.

[tom203]

The boot o-rings need to be made from Viton to withstand head temperatures; ordinary o-rings at hardware stores are Buna rubber which doesn't last long at 300 degrees plus.

[BassCliff]

Hi

If those O-rings are made of the right rubber but are just a little too thick for the channel, there's been no harm done if they are not leaking.

My old O-rings looked like this:



As you can see they just dried out and got flat. They did not spread outside the channel.

The Viton rubber O-rings are needed for high heat applications such as this. The Nitrile (Buna-N) O-rings are used in the carbs.

Thank you for your indulgence,

BassCliff

[sedelen]

Well, they look like at least they provided a good seal, they're awful thick, but definitely the wrong O rings.

The sad part is the right ones are $1.14 each @ Boulevard Suzuki for a GS1000E, don't know what bike you got, but it's got to make you wonder what did he use in the carbs?

O-rings,
Robert Barr

http://www.cycleorings.com/

[SqDancerLynn1]

To me it looks like they put a small amount of silicon on the O rings-- the squeeze over. ANY time you remove the intake boots Replace the O rings

[mustangflyr]

This is a good time to true those surfaces on the intake boots on the cylinder head side considering they will warp. Use a flat file, had a better seal on the o-rings that way.

[bwringer]

The o-rings in the OP's picture were fine.

What happened was that the person who installed the boots used slightly thicker "American" sized Viton o-rings. They commonly squeeze out a bit like this, but it has no effect on sealing. If they had used a non heat-tolerant o-ring, it would be crumbling, dry, and cracked within a few hours.

Until very recently, Viton o-rings in the correct metric size were not easily available, so many of us used "American" size o-rings. You have cleverly chosen to not reveal which bike you're working on , but for example, the intake o-rings on a GS850 can be replaced with a #128 Viton o-ring -- a bag of 25 is about $12 at McMaster-Carr. They're a wee bit thicker than the OEM o-ring, so they look like this when removed. I've had a set on my bike for several years with no issues -- the squeeze-out is harmless.

Anyway, yes, these o-rings must be replaced whenever the intake boots are removed.