Had my rear shock serviced.

There should be 10 bar of gas, mine had 6. And the oil was in bad shape. Seems that Yamaha saved some money here also. 

 

Pretty different shock now. I advise that you have your rear shock serviced for the right amount of gas and decent oil, before doing anything else. Like changing the spring. 

Excellent advise! This seems to be an area often overlooked by many. Forks seem easy to do, the shock not so easy. How many miles/Km did you have on the bike at this service? 

 

I have to send out my track bike shock to get refreshed. I’m wondering if I should include the T7’s too. Mine has about 4K miles. 

About 23.000 km's and two years. By bike had rust inside the front forks. Yamaha replaced the inner parts to the forks and at the same time they serviced the rear shock. I changed a stiffer spring (90 Nm) before the service. Now when the shock is much better, maybe a 85 Nm spring would suite me better.

Similar issue here, bike has only 3500km on it.

I wanted to get the shock revalved and took it out to a new suspension guy I decided to try.

We spoke about what issues I was having and what changes should be made.

 

I had removed the spring at home and I passed him  the shock.  He compressed it one time and said something was wrong with the pressure.

He checked the pressure before disassembly and it was at 80psi(5.5bar).  He usually uses 180psi(12.5bar) in KYB motocross shocks so this is where mine was set after service.

He didn't mention anything else was unusual, but low miles on the shock so I didn't expect the oil to be terrible yet.

 

All shocks I used when  I was club racing were serviced every year.

Street shocks always get done every 2nd year at the longest no matter the mileage.

 

So if you are having issues with the rear wallowing, there is a possibility it could be as simple as a low charge in the reservoir.

Just because your bike is a year old, consider when the shock might have been made.  Who knows the lead time from KYB to Yamaha to assembly and then the standard 6 months stuck on a ship outside Long Beach for the American customers. 🙂

From where do you check the shock pressure? Is it the allen bolt near the reservoir? There's nothing about it even on the workshop manual.

58 minutes ago, andy74rc said:

From where do you check the shock pressure? Is it the allen bolt near the reservoir? There's nothing about it even on the workshop manual.

You can't check it at home with out special tools.

On the end of the reservoir you will see a small hole.  Our shocks use a needle type fitting inserted into this hole to recharge/pressurize the bladder after service.

Some shocks use a normal schrader valve which would make it easy, but unfortunately ours is setup differently.

 

You would need a suspension shop to reset the pressure if you want to have it checked.  If you have a good one nearby take the shock over and ask them to check/set the pressure to the proper pressure.  Better yet get a normal service done if you haven't had this done yet.

 

 

 

 

Thank you! I just changed spring. The bike is still at 0 km, pressing the shaft without spring everything seems in order although is of course impossible to be sure. So for now I'll put it back as it is.

(On a side note, as I'm going through the bike for a fair number of upgrades and mods, I have to say I found everything done properly. Even the swingarm shaft was with a proper coating of grease from the factory).

Very interesting topic!

I’d like to install the K-Tech shock absorber piston.

Does anybody know the exact amount of oil needed?

OEM shock pressure should be 10 bar and looking for that needle type to charge the bladder. Any specs?

Thank you to everyone who will help me 😊

 

 

 

On 1/16/2022 at 11:53 PM, Totti said:

Had my rear shock serviced.

There should be 10 bar of gas, mine had 6. And the oil was in bad shape. Seems that Yamaha saved some money here also. 

 

Pretty different shock now. I advise that you have your rear shock serviced for the right amount of gas and decent oil, before doing anything else. Like changing the spring. 

Same with mine. Had it serviced at 20k km at it was also at 6 bar. 

21 hours ago, Aburamla said:

Very interesting topic!

I’d like to install the K-Tech shock absorber piston.

Does anybody know the exact amount of oil needed?

OEM shock pressure should be 10 bar and looking for that needle type to charge the bladder. Any specs?

Thank you to everyone who will help me 😊

 

 

 

You will not find listed anywhere an  exact amount of oil. 

You need to fill and bleed it so there is no air remaining in the shock.  It takes however much it needs, but you could measure the shock body and calculate the approx volume.  My quick guess would be between 200--300ml, but you will waste/spill  some so you will need more.  A single 500 ml or 1 litre bottle of the proper weight oil will be more than enough.

 

I think most suspension shops these days are using a vacuum pump to fill and service their shocks these days.  It could certainly be done manually if you wish to do so, as I am sure some on here are servicing their shocks at home without a vacuum pump.

 

There are some very good service videos on YouTube showing the basic steps to service a shock, but there are also some very bad ones as well.

So look around and be sure you know the steps before you dive in.

Personally I have local suspension guy do mine.  He has a professional Vacuum pump setup that does a perfect job of getting all the air out.  Air left in the shock will allow cavitation and it is imperative to have it all removed.

 

If I was going to do mine at home I would change out the bladder cap from the needle style to a schrader valve type for easier servicing.

Search around for more info but the aftermarket sells replacement  bladder caps with schrader valves for the yz80 and most of the Japanese 80 mx bikes.  These are a direct fit for our shocks as well.

 

 

 

 

Edited March 24, 20232 yr by williestreet

Totti, how much do you weigh in full combat gear ? I weigh 101 ready to go.
 

i just service my shock today and found that it only had 75 psi in it before i tore it apart, i have both a 85 and a 90 spring here at home to put on.

 

i actually just recently got the 90 since the 85 seemed kinda weak, but now i just think most of the weak feeling came from to low pressure.

Mine rear had a soft/wallowing feeling before I had it serviced.  It also only had around 75psi of charge, so I would say the low pressure is a large part of the weak feeling you are experiencing.  

Mine was revalved and set to 175psi.  Soft wallowing feeling disappeared. 

100kg without gear, using a 90N spring.

 

On 11/20/2024 at 10:13 PM, Prestone said:

Totti, how much do you weigh in full combat gear ? I weigh 101 ready to go.
 

i just service my shock today and found that it only had 75 psi in it before i tore it apart, i have both a 85 and a 90 spring here at home to put on.

 

i actually just recently got the 90 since the 85 seemed kinda weak, but now i just think most of the weak feeling came from to low pressure.

My weight is about 100 kg in swimsuit. So with gear it's probably 110 - 115 kg? The bike has a 90 Nm spring and the sag is perfect without any adjustments to the spring. 

@Prestone or anyone else servicing your own shocks, are you replacing the seals each time? I see a part number above for a schrader style bladder, any part numbers for seals/seal kits?  

Edited December 24, 2024Dec 24 by Samm

1 hour ago, Samm said:

@Prestone or anyone else servicing your own shocks, are you replacing the seals each time? I see a part number above for a schrader style bladder, any part numbers for seals/seal kits?  

Didnt change the seals this time but have a set of them just in case.

 

you can buy a schrader cap for the bladder housing, its the same as used on yz85 like this one

 

KYB 40 x 20 KYB Shock Absorber Reservoir End Cap

---

KYB 40 x 20 KYB Shock Absorber Reservoir End Cap

 

Thanks @Prestone, how about the seals? Same part # as what’s in the YZ85 shock? 

9 minutes ago, Samm said:

Thanks @Prestone, how about the seals? Same part # as what’s in the YZ85 shock? 

Havent got a clue actually, i got mine from offtheroad.de.

but since its a K-tech kit they should be avalible at any shop who sells K-tech.

 

https://www.off-the-road.de/en/tenere-700/suspension-wheels/wear-parts/141264/k-tech-shock-absorber-seal-head-service-kit-kyb-40/14-yamaha-tenere-700?c=379