ESR head o-rings

[destey]

I've got a 265 pv from ESR and the orings are bad on it. I see they have a kit for $30 but it only comes with an inner and outer orings. I figure I can buy 10-20 o-rings for $30.

What do I do, measure the grooves and buy them from mcmaster? One is black and the other is orange. Not sure what material they are.

[Langbolt]

The Black one is VITON & the Orange one is SILICONE

YOU CAN'T USE PLUMBING O-RINGS

Look up '91 YZ250 Cylinder head O-rings....they might be the right size.....they are for the 310 kits

:devil:

[CanuckR]

Measure the inside diamaeter of the O ring glands, and the width of the gland as well. Look up an O ring sizing chart on the internet, there are lots of them. They are usually on O ring manufactureres websites. Odds are it will be a standard sized O ring. The O ring size will have a number (like 041) order a small bag of each size in the appropriate material.
I ordered a bag of 10 o rings for the inside and outside of my cool head. cost me like 30$ with shipping.
I used Viton o rings for the inside and plain silicone for the outside. Hope that helps
Derek

[destey]

I'll give it a try, thanks!

[destey]

I measured my cylinder (twice) and got 3.012"ID / 3.208"OD for the inner

and

4.359 / 4.524 for the outer oring. And 0.070" thickness for both.

But going through mcmaster's website neither measurement I got matches up with a DASH number.

For the inner they have (silicon)
041 (2.989" 3.129")
042 (3.239" 3.379")

For the outer they have (viton)
046 (4.239" 4.379")
047 (4.489" 4.629")

Which ones should I choose? They don't seem to match up with the measurements I took. Could they be non-standard orings? thanks

[Grande Huevos]

i had this prob with my ct 310 and i called every o ring place in the phone book and couldnt find asnybody who made them in the right material to handle the heat. Ended up buying the yz 250 o rings and they fit perfect and saved a few bucks. I wouldnt try and go cheap on your motor it will just end up costing you in the long run

[destey]

I guess I will bite the bullet and pay $30 from ESR for 2 orings. Just kills me I can pay $15 and get 20 orings from mcmaster

[mx91a]

The -041 is the inner o-ring size and the -046 is the outer o-ring size. The glands may have been machined a little large to stretch the o-ring slightly to keep in in place so it doesn't fall out during assembly, especially if the o-rings are installed in the head and not the cylinder.

[destey]

Originally posted by mx91a
The -041 is the inner o-ring size and the -046 is the outer o-ring size. The glands may have been machined a little large to stretch the o-ring slightly to keep in in place so it doesn't fall out during assembly, especially if the o-rings are installed in the head and not the cylinder.

Oh, cool! Thanks!

[Motofool250r]

yea always gotta stretch them a little bit to get them to fit back in the holes..

and if they are stretched too much put em in the freezer for a few mins then try again.

[destey]

Anyone know the thickness of the oring?

The ones I ordered are too thin. Which also probably explains why the 041 measurements didn't match my cylinder.

[Langbolt]

2mm

The one's I use are METRIC O-Rings

:D

[mx91a]

I just measured the o-rings for my LRD cylinder and they are about 0.068" wide. What size o-rings did you get?

[265 sleeper]

I had some that I had got a while back . They measured the same as the one for my esr cylinder . Im using them now and they fit perfect. They measure .041. For the inner oring . The outer one I reused .

[destey]

The ones I got are 1/16" Fractional (0.070" Actual).

I'm guessing I should have gotten the 3/32 or 1/8.

Another possibility is the old orings expanded and that's why they look thicker. But I'm thinking its more likely I bought the wrong size.

[265 sleeper]

They should only stick a fraction of an inch

[jon370r]

Buy the YZ 250 o-rings for $15 from anyone near you that can get parts, no problem.

[destey]

Tried the YZ250 orings, both are too small.

ESR won't return my emails about if I can buy just the orings instead of the $30 kit that has a bunch of parts that I already have too many of.

I'd rather not deal with ESR if possible. I bought a cr250 adapter plate from them and a month after I paid via credit card over the phone, they lost my order (after calling a week prior where they said it already shipped).

Anyone know if I can splice in a section and melt it together?

[destey]

Bump, hoping to get some more help on this. The yz250 orings were quite a bit too small, the 041's were as well. Not sure what thickness they're supposed to be. Mcmaster sells 1/16 (.070) and 3/32 (.103).

The 041 looks like it should work but its too small and I end up stretching it quite a bit and it won't stay in the groove at all. Looks too thin too. But maybe not.

041 oring w/ 0.070 width= 2.989" ID and 3.129" OD I just measured the cylinder cutout at 3.015" ID which is pretty close to the measurements I got a few months ago.

151 oring w/0.103 width= 2.987"ID and 3.193 OD. Could be this one, what do you guys think?

These two are silicon.

[mx91a]

What is the width of the o-ring gland in the cylinder? The o-ring should stretch pretty easily from 2.989 to 3.015"

[Langbolt]

Destey,

Look up some o-ring suppliers in your area.

Most Industrial supply places have accounts with them and can order you in what you need.

Order METRIC O-rings

76mm x 2.0mm in Viton for the Inner

110mm x 2.0mm in Silicone for the Outer

These are Standard sizes that are available

:devil:

[destey]

I was thinking it could be metric but mcmaster didn't have anything in that size. But I'll give it a try, thanks!

I found this too, could help someone in the future.



oring gland size design - metric (http://www.allorings.com/gland_metric.htm)

[mikev3704]

I just went through this on my ESR 310 kit. I have a good website to purchase o-rings. Pm me and I will send u the link. The oring for the combustion to the head is an oring size of 1" id 1 3/16 od and 3/32 oring thickness. The oring number is #120.

Mike

[destey]

I measured again, got

Inside oring
--
76.57mm ID
2.59mm gland width
81.8mm OD


Outside
--
110.69mm
2.77mm gland width
116.11mm OD


I've tried the 041 and 046 orings and they're too small. The 041 has to stretch to even fit over the studs, not even close to fitting in the groove, even if I stretch it huge like a rubber band. Definitely not those two orings.

As far as metric, I checked mcmaster, granger, mscdirect, oringsusa, oringwarehouse, and a couple other sites and no one has the right metric in the right materials. Anyone know a good supplier?

[mx91a]

Why are you trying to stretch the -041 over the studs it is for the inside gland to seal combustion gasses. A -041 o-ring is 3" ID (76.2mm) I can not believe it doesn't fit in a 76.57mm ID gland as you have measured. A -046 o-ring is 4.25" ID (107.95mm) it should be able to stretch 3mm to fit inside the outer gland you measured at 110.69mm ID. Are you sure you have the right size o-rings? ESR is an American company I don't think they would use metric o-rings. There isn't even a 2mmX110mm o-ring here is the metric chart:

http://www.gbsa.com/downloads/Metric%20O-Rings.pdf

Maybe 2.5mmX110mm will work since your gland width is 2.6- 2.7mm? Or a -151 and -156 since they are thicker 3/32 cross section...

[mx91a]

Originally posted by mikev3704
I just went through this on my ESR 310 kit. I have a good website to purchase o-rings. Pm me and I will send u the link. The oring for the combustion to the head is an oring size of 1" id 1 3/16 od and 3/32 oring thickness. The oring number is #120.

Mike

These are the o-rings between the dome and shell? Surely not between the head and cylinder...

[Langbolt]

Look in here:

You'll find a few for a 110 ID size....2mm, 2.25mm, 3mm

Page 52

Or maybe it's the 110.30 ID x 2.4 ???

http://www.globalrubber.com/pdf/catalogue/Pt09_Metric_Sizes_and_Dimensions.pdf

:devil:

[mx91a]

Put the o-rings on the top of the jug, started on one side in the gland and lay them around keeping their shape circular and take a picture. Notice how my outer o-ring is a few mms smaller than the gland but goes in no problem.

[mikev3704]

Yes #120 goes between the head and shell..

Mike

[latheboy]

Lang, do you think I can use buna-n material for the outer? I can get that a whole lot quicker.
I found a a supplier for the 76mm X 2mm Viton.

Maybe I will go with the english sizes as discussed in this thread.



Originally posted by Langbolt
Destey,

Look up some o-ring suppliers in your area.

Most Industrial supply places have accounts with them and can order you in what you need.

Order METRIC O-rings

76mm x 2.0mm in Viton for the Inner

110mm x 2.0mm in Silicone for the Outer

These are Standard sizes that are available

:devil:

[Langbolt]

Latheboy,

I wouldn't recommend buna-n (or NITRILE) for cylinder head o-rings.

The Heat range for Nitrile is -40 to +250f

That's why we use Silicone (+450f) for the Inner & Viton (+400) for the outer.

Unless you run your motor really cool (140f) I wouldn't chance it for a $6 O-ring

:devil:

[destey]

Well I bit the bullet and finally just ordered them straight from ESR. $19 a set :(

He did spill the beans and said the 265pv is really a 310 pro-x cylinder. So it uses those orings.

[destey]

I just see they charged me $36. So must be $17 shipping to ship 2 o rings.

****ing ESR. Now I remember why I tried just about everything to not deal with them.

[Langbolt]

When you get the NEW ones....Measure them....then order a bunch from a O-Ring Supplier....it'll all work out in the end.

:D

[wes350x]

Originally posted by destey
I just see they charged me $36. So must be $17 shipping to ship 2 o rings.

****ing ESR. Now I remember why I tried just about everything to not deal with them.

I know, I ordered a small reed plate for 35$ and they hit me with the 17$ shipping too. I hate to make a small order from them for this reason. Seems like they can help you out for small items but nope, same price for all.

[Pinned250R]

I ordered an air box elim kit, prefilter, and the exhaust clamp/rear resi mount. said itd be here that friday(it was monday), i never got it, following tuesday i call, they hadnt shipped if because they didnt have the filter in stock. so i told them to ship out everything they have and ship the filter next, all for 1 shipping charge. they did, and it was here 4 days later. I called them monday to see if my air filter had been shipped yet, he said no, but they got them in now. then i asked if they sell O-rings for their silencer, he said yeah but shipping will be more than the cost of them. So i told him to just put them in with the filter. He didnt charge me for the o-rings. i guess you just need to bully em around a little bit?!? I love their prices, and their product, they just need another guy or 2...