Motoseal on reed gasket?

Related:
Create New Tag

10/18/2018 11:52 AM

Bought a new reed gasket for my yz250 and was told by some others users of another forum to use a thin coat of “motoseal” on both sides of the gasket when reassembling. Local auto parts store has it but for $10 a tube its kinda pricey for only needing just a tiny bit when thenrest will sit in the tool box forever... is it actually necassary to use it or any type of “sealant” on this gasket?

|

10/18/2018 12:52 PM

Needs to be sealant that won't be eaten by the fuel and up to a certain temp as it's right off the cylinder. Any rtv should be good I used threebond on mine

|

10/18/2018 1:20 PM

grimsypro wrote:

Needs to be sealant that won't be eaten by the fuel and up to a certain temp as it's right off the cylinder. Any rtv should be ...more

Would it hurt not to use any? I really dont feel like spending $10 on a giant tube of sealant and using half a fingernails worth. Kinda tight on funds as im doing other things to my bike...

|

10/18/2018 3:47 PM

On my 2001 yz250, i didnt put anything on the gasket. Had no issues. If you want, you can put belray waterproof grease on it if youre worried about air leak or something. I really dont think a coating is required anyways. Just make sure your surfaces are clean and you tighten it correctly

|

10/18/2018 3:57 PM

You’re fine putting it on dry. I’ve used yamabond to salvage a torn gasket, but other than that there’s no need

|

RPM Performance
CT
783

10/18/2018 4:43 PM

Sealing is what gaskets do. As long as your manifold junctions are flat and straight, you don't need any sealant.

|

Braaapin' aint easy.

10/18/2018 4:46 PM

Thanks for the opinions guys. Currently going through an air leak battle with the bike and working on fixing it so i wasnt sure if just cleaning the surface and using the gasket dry was ok...

|

10/18/2018 7:51 PM

kb228 wrote:

On my 2001 yz250, i didnt put anything on the gasket. Had no issues. If you want, you can put belray waterproof grease on it ...more

Years ago I'd use sealant on all paper gaskets. I was paranoid about leaks.

Then when I worked at the Maico (and Acerbis , UFO, MSR and other products) distributors, working on my 320, trying different things, that required a fair amount of 'on' and 'offing' of gasket jointed parts, the owner put me onto using grease on gaskets. Not so much for a seal (which it does enhance) , but to avoid sticking and tearing of gaskets and laborious joint clean up .

I certainly don't do it with everything (nor recommend it) , but, for example, with my current experimenting with reed block / carb spacers (one of which is a pick up / exit point for 2 Vacuum lines for an automatic de-comp and a Mikuni fuel pump for my 500s 'drop' Tank) , I use sealant on the one side that will be the semi permanent side, and a light coat of grease on the 'removal' side. Works well and I've never had a problem over several decades.

It also has kept the original, big, thick HM / E Line Lighting kit gasket healthy over 15 years, and, hopefully, now the same type of gasket on the dodgy Electric start kit I use from time to time. The mongrels who made that should have used an Oring, and positive stop, male to female 'engagement' fitting of the sidecover, to the engine cases.

|

10/18/2018 8:14 PM

Motoseal does work very good on the reed block but any gas-resistant sealant will do. I think Motoseal might actually be Permatex Ultra-Grey just relabled to appeal to the motorcycle crowd,

|

Powerband in every gear !

10/19/2018 7:56 AM

You install it dry and then leak down test it. If it leaks then you use sealant.

|

10/19/2018 8:43 AM

Hondas4Life3 wrote:

You install it dry and then leak down test it. If it leaks then you use sealant.

I did a leak down test and my bike looses air due to the powervalve seal. Even using a new seal.

|

10/19/2018 8:54 AM

Hondas4Life3 wrote:

You install it dry and then leak down test it. If it leaks then you use sealant.

Alec138 wrote:

I did a leak down test and my bike looses air due to the powervalve seal. Even using a new seal.

Did you make sure all your surfaces are flat? If the bike ever overheated you could have warped gasket surfaces that wont seal.

|

10/21/2018 6:23 AM

I had a very slight leak from my power valve cover. Was barely bubbling up after 10 minutes. Smeared a bit of grease both sides of the gasket and it went away. Is yours on the inside where the rod goes through?

|

10/21/2018 6:52 AM

grimsypro wrote:

I had a very slight leak from my power valve cover. Was barely bubbling up after 10 minutes. Smeared a bit of grease both ...more

Yeah its a very common issue on yz250s. The bore where the rod rides inside the seal gets warped or whatever and it will never seal right unless you buy a new cylinder or do this mod where you press a metal bushing into the hole. I did pull the gasket off and add a bit of grease a while back as well.

|

10/21/2018 6:52 AM

Hondas4Life3 wrote:

You install it dry and then leak down test it. If it leaks then you use sealant.

Alec138 wrote:

I did a leak down test and my bike looses air due to the powervalve seal. Even using a new seal.

kb228 wrote:

Did you make sure all your surfaces are flat? If the bike ever overheated you could have warped gasket surfaces that wont ...more

Read my last reply below. I explained why it wont seal.

|

10/21/2018 11:44 AM

I did read up in it when mine was leaking. Sounds like a pain in the ass! Did you get it sorted?

|

10/21/2018 12:35 PM

grimsypro wrote:

I did read up in it when mine was leaking. Sounds like a pain in the ass! Did you get it sorted?

Not going to worry about it because it causes no issues besides making a stain which simple green and a scruber will get rid of

|

10/22/2018 2:33 AM

Ye pretty sure it shouldn't cause a leak as the power valve is under positive pressure.

|