Exhaust header pipe nut tool (MG# 14927700)

Special tool made by Lee Davis

Lee Davis designed and made this tool out of hardened steel with the intent that a hammer can be used to pound on stubby handle. I gave it a try and I found his tool to be extremely durable. I really like that his tool engages each recess in the lockring.

Lee no longer makes this too, but I will leave this photo and credit here to inspire others.

Special tools nearly identical to the original Moto Guzzi tool

I extracted this recommendation from Ralf Brinkmann off of the old Yahoo! Loopframe_Guzzi news group (which has now moved to Groups.io). In Ralf's own words:

I use DIN 1810 A wrenches - very common and low priced in Germany.

To get the appropriate wrench size just measure the outer diameter of the nuts in millimeters - and look into a tool table (DIN 1810 A). The two numbers punched into the wrench are telling you the range for use in millimeters. Outer diameter of the nuts may differ from bike to bike. Searching a little bit I found some different pairs and measured the outer diameters of each pair:

• Very antique chrome plated brass pairs with worn out slots: 55 mm
• Zinc plated steel sets with nut and counter nut: 56 mm - 57 mm
• Aftermarket stainless steel set with nut and counter nut: 58 mm - 64 mm

Thanks to Jason for sending me this information via e-mail. Jason's original description of the problem/question:

Bottom line is I need a hook wrench to pull it off and have a look. I found the links on your website, but I measure the nuts at around 56 mm - 57 mm, which falls outside of the size ranges available from those venders. Should the wrench be slightly undersized, or slightly oversized?

Gregory Bender's reply:

I think I would lean toward a slightly undersized wrench, though I'm not completely certain. Sorry I don't have a better answer. Please do let me know what you learn, as I'd love to add the information to my website.

Jason's findings:

Just wanted to get back to you as promised. I ended up ordering an adjustable wrench from Amazon that ultimately didn't fit. The tooth was too large, so I immediately went in and ordered a 52 mm - 55 mm fixed version from the folks that you provide a link for on your site. They were very helpful, and shipped their wrench out to me right away. Unfortunately, I am impatient, and went at the first adjustable version with a file while I was waiting for the second to arrive, and got it to work after sliding my giant, 3 ft long cheater pipe over the end! Bottom line is the 52 mm - 55 mm version, though smaller than the outer diameter of the nut, is correct, and would have worked fine. I found this out when my second wrench arived in the mail. The adjustable version, once filed to fit, worked also, but seems to have a considerable amount of play which could allow the tooth to slip, which it did, damaging the nut. If I had it to do over again, I'd go slightly smaller as you suggested. Adventures in wrenching! Thanks for your help, and your awesome website!

Here are a few places where you can purchase the special hook wrench that will permit you to easily tighten and loosen the exhaust header pipe securing nuts. You'll need one wrench.

• McMaster-Carr part number 6975A18 or McMaster-Carr part number 6975A19
• MG Cycle part number MG# 14927700
• Newman Tools Inc
• Andreas Maier Fellbach (US site)
• Andreas Maier Fellbach (Switzerland site)