Tech Corner
Technical Q and A for classic motorcycle maintenance and repair.

Pitted Master Cylinder Fixes

Motorcycle Classics tech expert Keith Fellenstein

Editor's note: If you're having trouble with that old Suzuki, BSA or BMW, Keith Fellenstein is your guy. From motorcycle tuning tips to detailed motorcycle engine repair, he can draw from a wealth of experience to help guide you to success. Send questions to: Keith's Garage, Motorcycle Classics, 1503 SW 42nd St., Topeka, KS 66609, or send an e-mail with "Keith's Garage" as the subject.

Q: A couple of issues ago, I fielded a question about a pitted master cylinder on a Honda, where the part in question wasn't available as a replacement. I mentioned that I didn't know of any places that offered sleeves for Hondas, though I knew of plenty for British bikes. Several readers wrote back with places they knew of that offered that service. Proof, if any were needed, that motorcycle gearheads are the best people. Here's a sampling. Thanks to everyone who wrote in with solutions to the problem. — Keith Fellenstein

A: I had a similar situation on my 1980 Suzuki GS1000 even though it is used regularly. The infamous pitted bore, and since the bike is pretty much made out of unobtainium I had it sleeved. In my case I used White Post Restorations. They installed a brass sleeve of the original bore size and now it's better than new with no more corrosion issues. — Floyd Webb/via email

A: In your response regarding the CBX master cylinder, you said you didn't know of any companies that provide sleeving service for Hondas or any other brand master cylinders. I have run into this issue on several of the vintage metric bikes I work on. There is a company in Minneapolis, Minnesota, that can sleeve pretty much any metric master cylinder as long as it's within the dimensions of the special European stainless steel tubing they stock. They bore out the cylinder, press in the stainless sleeve and then hone out the inner diameter to match the original inner diameter so OEM or aftermarket stock cylinder components will fit right in. Contact Brake & Equipment Warehouse. — Earl Johnson/via email

Triumph Tiger Gauge Vibration

Motorcycle Classics tech expert Keith Fellenstein

Editor's note: If you're having trouble with that old Suzuki, BSA or BMW, Keith Fellenstein is your guy. From motorcycle tuning tips to detailed motorcycle engine repair, he can draw from a wealth of experience to help guide you to success. Send questions to: Keith's Garage, Motorcycle Classics,1503 SW 42nd St., Topeka, KS 66609, or send an e-mail with "Keith's Garage" as the subject.

Q: I have a 1977 Triumph Tiger. I have a recurring problem with both the tachometer and speedometer. At higher speeds (50mph-plus) that generate greater vibration, the entire gauge begins to rotate within the black rubber housing that holds the gauge. As it rotates, the lighting fixture/bulb comes loose and then falls out of the gauge. I then have to remove the gauge and rubber housing from the chrome bracket that holds them, remove the gauge from the rubber housing and then re-seat the gauge so that the opening for the bulb lines up with its matched opening on the rubber housing. You may very well have heard of this before. Any ideas how I can prevent this from happening (besides keeping my speeds under 50mph)? Thanks for your help and for your terrific columns in Motorcycle Classics. — Ron/via email

Blaster logo

A: In addition to the vibration, you have the torque reaction of the instrument against the rotation of the cable, too. A number of fixes come to mind, but probably the easiest one would be some double-sided tape or foam installed between each of the instruments and the cup. It wouldn't require much to hold it still against the vibration.