FAQ - Exhaust Nut Thread Repair

[BevHevSteve]

Exhaust Nut Thread Repair

From: Russ Whitford <veloce>

Competition Cycle in Milwaukee, WI does these repairs on a regular basis. I have not used them but have talked with a Mach 1 owner who was very happy with their service. They machine out the worn threads and heat shrink an aluminum insert into the head. The insert is welded around the perimeter and the welds machined off for an invisible repair. The Mach 1 has not had any problems. Cost is $75 and the exhaust nut should be sent with the head to make sure it fits. Call Competition Cycle at 414-672-4010.

[manitoufs]

Competition is the dealer that sold my 73 Sport to my now deceased friend, Phil Rozine. I bought an 81 Honda 900F from them. A real old time shop. They sold guns and stuff. I did not think they were still in business.

[jonduc74]

HI Russ I would like to know more if you can tell me about this type of repair as I live in New Zealand and would not like to send my front head overseas for repairs. I have talked to my engineer and he is not sure if there would be enough meat around that area to be able to sleeve the head.

Anyway the idea of heat shrinking an aluminum insert into the head sounds good to me, would I have to remove the values and everything because of the small rubber value seals? Also any more info on this type of repair would be very helpful.
Many Thanks John

[BevHevSteve]

john, russ just sent me the info.... you need to contact the guys that do the repair for info. I send big orders all over the world all the time and am not concerned as I insure them well. You need to strip out everyhign on the head and just send it over WELL insured EXPRESS DELIVERY under no circumstance would you want to send it the cheapest route..... EXPRESS is always under lock and key in the USA.

[baddean]

Hi Steve and Bevel crew,
I offer this update to the contact information for Competition Cycles in Wisconsin.
They moved from their former location about two years ago.
They are indeed alive and well and still repairing exhaust threads and making other aluminum repairs (fins, tabs, etc.)
I spoke with them today and a fine gentleman there indicated that he would appreciate my offering this contact information to all Beveldom.
Since they do not have a web site and are found mostly by word of mouth I now am spreading news.
I will soon be sending them the vertical head from my '73 750GT for said exhaust thread repair.
Dean

Competition Cycle Incorporated
5081 N 124th St
Butler, WI 53007
(262) 373-1122

[sevicke]

whats the big deal we have that sort of technology in nz have milling machines and machinist, ring round your soon find someone who can do this. Try russell thomas if in chch he will weld it up mill it down and retread
no big deal really. If your in chch ill try and remember the machinist who specialised in bevels.

[scrambler]

I had Malcolme at Syds cycle do repair on mine in the process of the rebuiuld. They did a great job.

Scrambler

[Elliot]

There is enough meat to machine out. I machined one out a few years back using a fly cutter on a milling machine. The hardest part is holding the head so that the new exhaust bore is parallel with the original. Just takes a little mucking around during the set up. I made a new insert from phosphor bronze. I then heated the head and shrunk the new insert in. The problem with this is it compresses the ring insert slightly so you should cut the threads a little loose. This insert has worked well for years and the threads are harder than aluminium and less prone to damage.

[ducbock]

hi russ regarding stripped threads= its interesting to note that the swiss army solved that problem by insisting from ducati that the exhaust pipes where flanged & secured with 2x 8 mm studs from new!! what ducati did(presumably thy didnt want to change their moulds) by building up the head fins by welding and tapping 8 mm threads into it. which worked very well.no more exhaust problems!!

[Craig in France]

its interesting to note that the swiss army solved that problem by insisting from ducati that the exhaust pipes where flanged & secured with 2x 8 mm studs from new!! <snip>

Also done on a fair few race bikes of the period - e.g by Bruno Spaggiari (seen it on both his 350 and 450 racers).

I wonder what Ign. Taglioni/Ducati thought was 'wrong' with this fairly conventional way of mounting a exhaust pipe. Anyone know, or care to speculate?

Ciao

Craig

[Chasbmw]

For readers in the UK, Nigel Lacey ( who specialises in Ducati singles) will do this repair on all Ducatis, my 750 had been repaired badly in a previous life and looks good now.

Charles