Kagama Occasional screeching noise

[Nelson.81]

What is it with Corally and their part numbers, and/or dimensions - always being wrong?

Personally, I set my shocks for little to zero rebound.

Wait for the bubbles to rise up out of the oil. It helps when shock caps have bleed screws, but when they don't, the cap can be loosened as the shaft is pressed up into the shock body and then tightened back up before releasing the shaft. It's one of those jobs where it feels like you could use a third hand!

Getting each pair of shocks the same is more important than zero rebound IMO.

View attachment 11042
View attachment 11044
View attachment 11045
According to AI, slightly pull the shaft up before tightening the cap to create a slight vacuum that compensates for compression. This ensures zero rebound.

As for o-rings, obviously, unless they are exactly the right size, stiction will alter the feel of the shocks and essentially change the damping.

My understanding is that silicone o-rings are known to be the lowest friction option. Use of green slime helps ensure longevity and reduce leakage.

My Baja's IRC shocks have umbrella seals, which are known to be extremely tough and leak proof, but they're not as smooth.

Stop teasing me with those sworkz shocks too nice , they high on my wish list you can even get upgraded orings for them I think lol. I will own a set someday. I needed to rebuild my shocks before & cost of the shock shafts, orings, inserts for like an extra £10 I was able to get a complete set shocks with extra springs from a breakers was a no brainier.

 

[Atomic Skull]

What is it with Corally and their part numbers, and/or dimensions - always being wrong?

Personally, I set my shocks for little to zero rebound.

Wait for the bubbles to rise up out of the oil. It helps when shock caps have bleed screws, but when they don't, the cap can be loosened as the shaft is pressed up into the shock body and then tightened back up before releasing the shaft. It's one of those jobs where it feels like you could use a third hand!

Getting each pair of shocks the same is more important than zero rebound IMO.

View attachment 11042
View attachment 11044
View attachment 11045
According to AI, slightly pull the shaft up before tightening the cap to create a slight vacuum that compensates for compression. This ensures zero rebound.

As for o-rings, obviously, unless they are exactly the right size, stiction will alter the feel of the shocks and essentially change the damping.

My understanding is that silicone o-rings are known to be the lowest friction option. Use of green slime helps ensure longevity and reduce leakage.

My Baja's IRC shocks have umbrella seals, which are known to be extremely tough and leak proof, but they're not as smooth.

Viton is the elastomer cousin of teflon, it is a fluoropolymer and has lower friction that silicone while also be a lot more durable, chemical and heat resistant.

I think I actually like the feel of the shocks with the higher compression seals, it may make it less bouncy over rough terrain I'll see later when I test it out.

EDIT: Ugh no, it's great for jumping and nothing else. Ordered some proper 4mm I.D. x 1.5mm C.S. viton o-rings from O-rings and more.


It *is* great for jumping though.

 

[Horatio]

Viton is the elastomer cousin of teflon, it is a fluoropolymer and has lower friction that silicone while also be a lot more durable, chemical and heat resistant.

I think I actually like the feel of the shocks with the higher compression seals, it may make it less bouncy over rough terrain I'll see later when I test it out.

EDIT: Ugh no, it's great for jumping and nothing else. Ordered some proper 4mm I.D. x 1.5mm C.S. viton o-rings from O-rings and more.


It *is* great for jumping though.

Perhaps the main reason why RC companies still use silicone o-rings is purely down to unit cost?

One would think the difference would be minimal though in exchange for better chemical resistance and longevity.

Often, the marketing with modern shock packages tout 'low friction seals'.

 

[Horatio]

Stop teasing me with those sworkz shocks too nice , they high on my wish list you can even get upgraded orings for them I think lol. I will own a set someday. I needed to rebuild my shocks before & cost of the shock shafts, orings, inserts for like an extra £10 I was able to get a complete set shocks with extra springs from a breakers was a no brainier.

They are super nice.

I've also heard that Tekno shocks are top tier.

I'm happy to try different o-rings where existing ones have failed. In my case, that's only my XTR's centre diff and the orange output o-rings, which can tear.

I'm wondering if that is down to chemical degradation and if Atomic Skull"s viton o-rings would be better to replace these in the diffs:

And can those stated o-ring dimensions be trusted, or do I have to don my specs and attempt to measure them with my calipers - without snipping them!

 

[Atomic Skull]

They are super nice.

I've also heard that Tekno shocks are top tier.

I'm happy to try different o-rings where existing ones have failed. In my case, that's only my XTR's centre diff and the orange output o-rings, which can tear.

I'm wondering if that is down to chemical degradation and if Atomic Skull"s viton o-rings would be better to replace these in the diffs:

View attachment 11049
And can those stated o-ring dimensions be trusted, or do I have to don my specs and attempt to measure them with my calipers - without snipping them!

The dimensions cannot be trusted, the manual is wrong about the size of the differential o-rings as well they are not 5x8 they are more like 5.5x8.5. However the 5x8 Viton O-ring when installed over the 5.85mm diff cup shaft is stretched to fit the O-ring seat exactly, the OD of the seat is 8.28 and the outside diameter of the o-ring when installed over the shaft is 8.28. The height of the O-ring is also slightly higher than the seat which provides a bit of longitudinal compression on the seal, The firmer o-ring seal also seems to help keep the outdrive cups from wobbling as much and greatly reduced runout in the dogbones. There seems to be no difference between the sillicone and viton o-ring's resistance to shaft rotation.

EDIT: These 5.5 x 8.5mm might work better but the 5x8 seem to work fine so far. I'm going to give them a try later though.

https://oringsandmore.com/fkm-o-ring-5-5-x-1-5mm-jis-s6-minimum-15-pcs/

 

[danl]

Look forward to hear results after a little time. Just opened my front and rear diffs and orings seemed fine for now, albeit both diffs were low on fluid from factory. Only appox 13 packs thru it. The center diff orings totally smoked and replaced already with oem's

@Atomic Skull and @slomoe

Results are in. I could not find viton ones so I went with Nitrile (buna N) o rings and they are holding up great after months of use. By comparison the stock corally silicone ones would need to be replaced at a diff service. This holds true for the rear and center diffs in my Spark. I'll be moving away from silicone o-rings for applications in contact with silicone fluid.