Akrapovich pop-rivet help request

I'm taking apart my Akra silencers so I can have a look at the packing and change the titanium sleeves over for carbon ones.

They are fabricated with pop rivets which are easy to drill out and replace. But there are three fasteners, one on the rear band and two on the front, which are different - see photo. I think they are used sometimes to attach the heat shields. They are turned steel plugs with an internal thread.

Does anyone know how to get them out without damaging them? Or how they are fixed in? I've tried unscrewing them by putting in a bolt but it just reaches the bottom and the whole thing turns - it's neither a left or right handed thread.

I can drill them out but will have to find another way to put the cans back together - the hole is much bigger than a pop rivet shaft.

Thanks.

I drilled them out. Turns out that is the only way, not sure how they are factory fitted but I will have to find another way when putting the cans back together. I'll probably epoxy a washer to the inside of the end-caps so that the same size pop rivet can be used, the rivet head is bigger than the hole so it will be OK on the outside.

Here's a picture of the internals in case anyone wants to see what the Akra baffle system looks like. It's pretty much a straight through perforated tube surrounded by packing. Nothing fancy or clever.

That's interesting. How do you do it? Do you put a nut onto the bolt and then screw the bolt into the nutsert and then wind down the nut so that it pulls up and deforms at the weak point?

Considering this, not made my mind up yet! I have to cut the carbon sleeve anyway because it comes oversize but I don't want to mess with what might be a very finely tuned exhaust system. Akra must spend a lot of time getting the best compromise between silencing and performance optimisation, (at least I bloody hope they do given the price they charge!)

Shorter, stubby silencers would definitely look better but they would be louder and I don't want any flat spots in power. But I'm also getting a custom map done next month so maybe map can be optimised to suit any exhaust length.

Does anyone know about this?

Kuerbis, thanks for your offer. I will let you know how I get on, I think I can probably sort out fitting the nutserts from what you've told me.

Somebody on here has had thier Akros cut down but dont no if it made any diffrence running wise, wouldnt have a clue what to search for tho mate - but it has been done B4!!! (i was looking to have mine done but when i sam the pics it put me off as IMO the arse end just didnt look right?!)

With all the diffrent systems being fitted including single can systems etc i cant see whay a pc3 shouldnr be able to work the fueling around any combination!

Myself along with Mrbubblehead cut ours down, he has round Akras.

as far as performance I'm not sure it's really measurable but the sound I believe is a bit louder and IMO it looks better.

http://www.superduke.net/forum/album_pic.php?pic_id=990

Nice bike superDUKE220, how much did you cut off the Evos? 100mm?

You have a lot of Rizoma kit like me. How do the indicators stand up the the exhaust heat?

So I rang Rivetnut Technology Systems Ltd and found out that this other fixing is called a Rivetnut and the specific part number is RFCA-05030-G. It is aluminium with an M5 thread and a 7mm diameter shaft.

Unit 5 Bridgegate Business Park
Gatehouse Way
Aylesbury
Buckinghamshire
HP19 8XN

http://www.rivetnut.co.uk/contact.htm

They sold me 100 for about a fiver and I bought a hand tool for fixing them in for £28. I thought that it was something worth having - now I can go around my house drilling holes through stuff and mounting M5 fixing points everywhere.

Big Ash, if you want to repack your cans I could post you the tool and some rivets if you want.

Update on the CF sleeves is that I talked to PJ Engineering who are now sending me two lengths of 115.75mm internal diameter tube which is apparently what the Akras require. I've got them to cut the tubes to length because it's not easy to do neatly without a band saw and the ends of the samples I have are a bastard for injecting micro shards of carbon into your hands and fingers. Decided to shorten the silencers by 35mm so they don't stick out so much at the back but probably not increase the sound much.

Here's what arrived today. A hundred rivetnuts, same spec as Akrapovich, together with the hand tool for inserting them to the correct force. Now I just need the correct diameter CF sleeves and I'm ready to roll.