Star Yamahas squeak

Shock probably 

Only the 450 bikes? 

You're not the first to mention it, but I don't think it's been answered. 

From the Glendale thread, benw127 said:

"Anyone notice how squeaky in person all the star Yamaha’s were? Eli’s especially could hear 3 lanes over in person." 

Shims falling out. 

Check valve in the rear shock 

Could be the rear struts

Why would that squeak?

R&D department found out they could make the bike lighter by eliminating grease.

I remember tomacs kawi did the same.

Yup. I remember being at the Tampa race in 2020 and his bike was squeaking the whole way through the whoops leading up to the finish.

Same with the 250s?

This ^^^

Shock, but I think it might be something in the CA on the works KYB shock. Or it’s check valve.

What is the CA on the works KYB shock. Why would it squeak. Why would a check valve squeak. 

Comp adjuster

How does a rebound check valve, sitting in oil audibly squeak loud enough to be heard over a group of 450 engines? That shit doesn't make sense to me. Its closed on compression and opens on rebound, so no fluid going through it 50% of the time and the other 50% it allows flow that is nowhere near the speeds of a compression stroke and its a tiny amount of flow anyways as it sits on the end of your rod/clicker port. Somebody explain what part of the check valve is making noise.

Hydraulic pressure, works on the same principal as a whistle. Fluid moving through a given orifice creates an audible vibration like a wind instrument.

Cavitation in a valve can create noise

It was Will Christian

Not nice.

But really funny.

I believe it was Eddie Larret (sp?) on one of Keefer’s shows who said when he was an SX mechanic they would go super light on linkage grease in SX to create a stiffer chassis movement, pack it full for outdoors. 

So...technically it's a queefe and NOT a squeak ?

Must be what caused the leak in Daytona that smoked when hitting the exhaust

I could hear it too last night. And yeah only the Star bikes 

my bikes have squeaked just rolling them across the garage when i put like 80 hrs on them. LOL

As long as there's some grease in the bearing, it will preform the same whether it's just a tiny amount or packed full. Makes no difference otherwise. I bet most people wouldn't be able to tell the difference between no grease at all and packed full (up until when it seizes at least).

That wasn't sqeaking you heard, it was Tomac, Cooper Webb and Justing Cooper complaining under their helmets about how fast Jett Lawrence's Honda is compared to their Yamaha's

Related story…when I got back into riding in ‘18 after a long time away, I decided to buy a basket case 02 CR250 and fix it up. While checking it over, I assumed the shock shaft was bent or the shock was empty/galled as it would stick in place at whatever point you compressed the rear suspension. Didn’t mind as it was going to be a frame-up build, but was definitely something I hadn’t seen before. Turned out the linkage was completely rusted solid. Shock was fine. I was amazed that the linkage could be so rusted that it could overcome the shock spring.