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General Category => General Discussion => Topic started by: Turin on May 26, 2025, 11:43:43 PM

Title: 40mm Bitubo adjustable fork dampers
Post by: Turin on May 26, 2025, 11:43:43 PM: One of the fork dampers on my 1991 cal III is locking up. Contributed to a scare Saturday morning.

I need at least one new damper. Here's the rub, I want to keep the adjustability of the stock dampers (the nifty dials on top , don't want the air valves)

Options? damper kit? NOS parts?
Title: Re: Bitubo adjustable dampers 1991
Post by: Turin on May 27, 2025, 12:11:48 AM: (https://i.ibb.co/zWhXDz7v/fork-tubes.jpg) (https://ibb.co/zWhXDz7v)

(https://i.ibb.co/ymrQMbbm/Le-Mans-bitubo.jpg) (https://ibb.co/ymrQMbbm)

(https://i.ibb.co/9kxYnyJn/damper-bitubo-lemas-cal-3.jpg) (https://ibb.co/9kxYnyJn)
Title: Re: Bitubo adjustable dampers 1991
Post by: PeteS on May 27, 2025, 06:54:21 AM: This happened on my ‘76 Lemans. Almost no fork travel. I drilled the caps for schrader valves to let the trapped air out.
I planned to switch to FAC but still looking for a round tuit.

Pete
Title: Re: Bitubo adjustable dampers 1991
Post by: Antietam Classic Cycle on May 27, 2025, 08:32:24 AM: Quote from: Turin on May 26, 2025, 11:43:43 PM
One of the fork dampers on my 1991 cal III is locking up. Contributed to a scare Saturday morning.

I need at least one new damper. Here's the rub, I want to keep the adjustability of the stock dampers (the nifty dials on top , don't want the air valves)

Options? damper kit? NOS parts?

Same thing happened last year to the dampers on my Cal III FF. I searched for rebuild parts, or complete dampers without success. Ended up installing FAC dampers.
Title: Re: Bitubo adjustable dampers 1991
Post by: Wayne Orwig on May 27, 2025, 08:41:08 AM: Have you tried Harpers?
Title: Re: Bitubo adjustable dampers 1991
Post by: Turin on May 27, 2025, 09:08:24 AM: Curtis is usually my first call. Be trying that shortly.
Title: Re: Bitubo adjustable dampers 1991
Post by: Turin on May 30, 2025, 01:07:04 AM: saw an old thread about rebuilding dampers on the adjustable bitubo forks. ( bitubo rebuild kit #gr0024 )

https://wildguzzi.com/forum/index.php?topic=89277.0 (https://wildguzzi.com/forum/index.php?topic=89277.0)
Title: Re: 40mm Bitubo adjustable fork dampers
Post by: Turin on July 20, 2025, 04:18:11 PM: This is wrapped up. I bought two kits from Harpers. (turns out one kit does both fork tubes) The new pieces have two O-rings on each aluminum insert vs one.
Title: Re: 40mm Bitubo adjustable fork dampers
Post by: blackcat on July 21, 2025, 06:43:33 AM: Hmmm....I should probably contact Curtis and see if he has another kit as I assume it will be impossible to find this in the future.