Moto Guzzino Exhaust Insert

[Duccout]

Has anyone here used one of Moto Guzzino's exhaust thread repair inserts? It looks like the simplest answer to the problem.

[double diamond]

The insert repair is deriguer but definitely not simple. The existing threads must be machined out to to a press fit for the insert, then the insert welded in place. So you’ll have to send the head out for installation (unless you’re equipped to do it yourself). There’s a place in Wisconsin? Minnesota? that offers the service. It was $75 last time I looked it up.

Matt

[Duccout]

I'm in the UK, but I have a guy who can fit it for me. I'm currently wondering if it would be feasible to get an oversized ring nut made instead.

[amartina75]

i made a couple oversized exhaust nuts for myself. If your threads are not really bad I think that’s the best option by far.
I also suspect the original nuts may have been underside or at least at the bottom of the thread spec although I have never measured one. I’ve seen threads that really don’t look too worn yet are very loose.
If you make a test piece out of aluminum make sure you use anti seize on the threads or there’s a good chance you’ll get it stuck (guess how I know that)

[Jordan]

Good tip.

[CanuckDuc]

The options highlighted in other posts on this topic, while worthy of attempting in some cases, it should be noted that the insert repair can result in a permanent fix especially with regards to seriously damaged threads, etc. In case one is attempting this task, I thought could share my experiences regarding the Moto Guzzino insert.

I have installed a number of these inserts with good results. Because the insert incorporates an integral base of the threaded segment it works more effectively than would a simple straight-through type insert that is sometimes done. You can build from bar stock something similar but for many the supplied insert can simplify the machining tasks required. Because the insert material is from an extrusion and not a casting process, the repair in some respects can be superior to the original. I'm sure there are many equally or better techniques carried out by others as well. The following repair methods have worked for me and may prove useful to others doing this job.

The insert is supplied with a somewhat larger OD than is hopefully ever needed to create a new, clean hole caused from damaged or missing threads. A compromise between the head casting integrity vs the insert integrity should be considered. I make the insert OD of 2.050" using a .0025-.003" shrink fit into the head socket. New OEM & all the replacement new exhaust rings I have tried have still threaded freely into the insert after cooling at this shrink fit, any much tighter fit this could be an issue.

Process is as follows: Fixture head to mill table. I try to level off the original gasket surface where possible & make a best choice of the old thread/outer c/bore for the hole centerline. Then I bore out to whatever size provides a clean hole (just dusting the gasket base flat) preferably to a 2.050"-ish. ID, then put a generous chamfer on the top face, this is also a good time to skim the head spigot face flat. I like to have the insert ready in the lathe at this time to turn the OD down to the 2.5-thou larger than head socket hole size. Also I make a radius on the inner face edge to assist the installing into the head socket task easier & a generous chamfer on the outer face as well. The length of the insert should be fine as is supplied, no other rework to the inset should be necessary.
I chill the insert along with ring in a freezer overnight (or here in Canada at this time of year, a couple minutes outdoors). I Heat head in oven at 250F for min. of 1 hr. Using the previously installed & chilled ex. ring helps as does a way of preventing the hot head from rolling about during the fitting step. A quick/smooth motion works with a seated confirming hammer tap on the ring afterwards. The two chamfered edges at the face can be filled with a tight TIG weld to finish.

The insert base ID is about 1.325", you may need to match this step to the port. In most cases I have found very little rework there needed. I do have pics regarding these procedures but currently been unsuccessful in attaching them to this post.
Hope this can help out.

[LaceyDucati]

Hi all,

If anyone needs the inserts in the UK, we can supply them, they're ours.

Regards Nigel

[Duccout]

Thanks Nigel, that's some postage saved!