Subject: Clutch master cylinder repair kit Fri Mar 24, 2023 4:22 am
Hi guys,
Just want to give you some feedback about this repair kit I got from Wemoto. I couldn't find many offers in the internet for these kits, so maybe this information can be useful for some of you.
Even though Wemoto lists this kit for Moto Guzzi, it was interesting to see this is a Yamaha repair kit...I guess it will be much easier to find parts for a Yamaha than for a Guzzi...
About the kit: - The piston is exactly the same that came originally in the bike (11.9 mm) - The piston spring it's a bit shorter, and the spring diameter that contacts the cylinder is a bit smaller. Maybe it could still be used, but I preferred to install the original spring - The dust boot it's a bit longer than the original. The collar has the right diameter, but it is not as thick and stiff as the original. Because it is longer it gets a bit smashed when the clutch lever is fully compressed. Don't know how long it will last...We will see - All the other bits are of no use...even the circlip, that strangely this cylinder doesn't uses.
Anyway, it's case no other options are available, this is a valid solution.[You must be registered and logged in to see this image.]
Yup, all the CARC bikes use the same master cylinders. Remember though that whether it will cure the problem is dependent on the state of the bore of the cylinder.
If you want to replace the Wemoto dust boot with the similar to original one, oem part number is AP8133522.
By the way, this is the most expensive tiny piece of rubber I've ever bought. For the price you will get a nice brembo plastic box and an instruction manual written in probably all existing world languages (dust boot is on the right side of the first photo)
Well done Fruk I bought the wrong 12mm seal and boot set
However in the process I found a more modern 12mm Brembo clutch pump off I (think) 696 Monster. These were widely available new on eBay. That was going to be the cheapest alternative to the radials
fruk Montanarolo
Posts : 16 Join date : 2018-05-24
Subject: Re: Clutch master cylinder repair kit Tue May 09, 2023 8:38 am
Subject: Re: Clutch master cylinder repair kit Mon Jun 19, 2023 6:49 am
Matias wrote:
Hi guys,
Just want to give you some feedback about this repair kit I got from Wemoto. I couldn't find many offers in the internet for these kits, so maybe this information can be useful for some of you.
Even though Wemoto lists this kit for Moto Guzzi, it was interesting to see this is a Yamaha repair kit...I guess it will be much easier to find parts for a Yamaha than for a Guzzi...
About the kit: - The piston is exactly the same that came originally in the bike (11.9 mm) - The piston spring it's a bit shorter, and the spring diameter that contacts the cylinder is a bit smaller. Maybe it could still be used, but I preferred to install the original spring - The dust boot it's a bit longer than the original. The collar has the right diameter, but it is not as thick and stiff as the original. Because it is longer it gets a bit smashed when the clutch lever is fully compressed. Don't know how long it will last...We will see - All the other bits are of no use...even the circlip, that strangely this cylinder doesn't uses.
Anyway, it's case no other options are available, this is a valid solution.[You must be registered and logged in to see this image.]
Thanks for that. I was about to order this revision set, so good to know what to expect from it. I have some questions on this hopefully someone can answer: Do the clutch and front brake cylinders require the same kit? The Wemoto site says some guzzi's use a 13mm piston in the cylinder. Do our GRiSO's all have the 11.9 mm piston size?
Well after getting nowhere with a thorough bleeding (filthy fluid) and my lever reguarly sticking and not returning (dangerous!) i decided to give this wemoto rebuild kit a go.
As other have noted the only parts used from the kit are the piston and the rubber cover (optional).
After a through cleaning the piston bore appeares perfect
While the rubber cover in the kit is the wrong length i found a small amount of glue on the base has held it in place correctly - I guess time will tell how long it lasts. A shame the correct cover is more expensive than the entire rebuild kit!
Bleeding took a lot of fluid but the lever finally feels good - cant say my paint job matches the original patina too well !
Subject: Clutch master cylinder repair kit 
Fri Mar 24, 2023 4:22 am
It's all about sharing John....
Excellent spot! Well done.
