SF Exhaust system

[breganzane]

Hello all, I have an early 750 SF. The exhaust has the balance pipes between the downpipes. Is the system in two or three peices?
The balance pipe pulled out of the LH side but is seriously stuck int the RH pipe
I want to have them re-chromed but I don't want to damage them trying to dismantle something that shouldn't be taken apart

Hi @Fitz ,
I fixed up a local fella's early SF with that type of exhaust. I found that the link pipe was stuck hard in both sides. The geometry is such that you can't remove the exhaust with it all in one piece, since the ports poke outwards. The link was requiring rechroming anyway, and is just a straight piece of tube so I cut the link pipe in half (hint, cut it in the middle if you have to, it gives more options for extraction of the stubs.

The pipes were actually in pretty good original nik (1-owner bike) and came up fine with a polish. Replicas are always a bit of a crapshoot (usually wrong shape or don't quite fit) so stick with original if at all possible. And if not, then I'll have your originals!

I tried lots of soaking in various oils etc, tried heat (though didn't want to wreck the chrome on the headers) and even turned up a bung and welded it into the cut tube, welded a bar onto that to use as a lever etc. All to no avail the link pipe ends were rusted hard in.
In the end I cut it just past the header socket and used a die grinder to scallop the inside of the link tube till I could collapse it inwards with some carefully directed violence.

The socket then cleaned out with a small flap wheel on the die grinder and a new link tube made up. Didn't take all that long once I'd decided I had to destroy the link pipe, and saved the original headers for direct re-use.

Ha! You can!! That pic is the build phase. Finished product has everything black ceramicked except the parallel stainless muffler section. Yes, Cam, removable reverse cone and baffles for repacking or trying different baffle profiles. This is what it looks like finished.

Hey @piranha-bro2 - you've taken 'lightened bottom end' a bit far there mate!

 

[Paul Marx]

The no air filters worry me - couldn't tour in Oz on unmade roads with none - did that on my SF1 with an air box but no filter - bores were a mess when i arrived in Perth from Darwin and beyond at 62,000 miles (100,000km) - would have been time for a rebore anyway but the rings were in pieces and the bores so worn I had to go to 2nd OS.

I wouldn't tour Oz on unmade roads without air filters. Or go beach racing.

Paul

 

[piranha-bro2]

Hey piranha-bro2 - you've taken 'lightened bottom end' a bit far there mate!

Lighter than air, Steve!

 

[CLEMTOG]

I wouldnt go beach racing, my son Tom, did Mablethorpe one time and got third place due to a cheat who cut a corner to beat him home, fisrt place was (as usual) George Pickering one of Toms flat track pals, the post race washing was done within 30 minutes at Georges farm on a purpose built concrete base, with central drain, first their was loads of plain water, then pressure washer, then steam, six months later he was still finding stuff like frozen axles (well greased before assembly) knackered chain, and small bots that just snap, like lever pinch clamps, he has vowed never again, unless its someone elses bike, eg messers Kawasaki, Indian etc,

weirdly he has also done Weston beach race, and did very well there as well, but it wasn't so bad, but as I type he tells me that in the week after,the whole bike was bare frame stripped for re-powder coating and lots of new and replacement parts, and an engine gearbox rebuild, apparently still not nice though

CLEM

 

[ColinL]

Anyone tried to fit a Supertrapp exhaust? They seem to be common on track bikes making <102db.
Big enough flow capacity for Harleys so should be good on an SF twin. And tuneable plates for optimisation on a Dyno.

 

[Tippie]

A few people have them in classic racing here on single cylinder bikes and seem happy enough, but by far the majority on all bikes is a cylindrical canister with a straight through perforated pipe packed with fibreglass wool or such.

 

[Haggis]

Anyone tried to fit a Supertrapp exhaust? They seem to be common on track bikes making <102db.
Big enough flow capacity for Harleys so should be good on an SF twin. And tuneable plates for optimisation on a Dyno.

Hi Colin. I had supertrapp on an old FJ11000 and also messed with them on dirt bikes back in the 80s. The process was to adjust the number of supertrapp plates - basically to get the noise level you want - then set the carb jetting to suit the flow.

 

[Laverda SF]

Hell yes a 70 750 SFO - Went from that DMG Balance tube to a Slater Brothers 2 into 1 Pipes weighing less then 1/2 the weight but I had to change the main Jets on my Dellortto 30A VHBs from 25's to 32's and had to go open mouth on the carbs - No Velocity stacks or air filters what so ever - should have put Mukuni 34's on her but them open mouth Delortto 30A's worked ;o)

I got stories about them 2 in 1 Slater Breganzie Pipes you would not believe - Try keeping the Baffle in and not bouncing it off your neighbors Vintage Chrysler 300 - LOL

Big free flowing lite exhaust system with a little porting in the exhaust chamber.
You would not believe the racket she made without the Baffle.

Doubt you can find them pipes today but the buyer of my ride probably has them as he restored my bike to original except for the head lamp my innovation for night riding the Shield in crap weather ;o(

He's a city and prairie Guy and has no concept of riding the Cambrian Shield.

He should also have my one of a kind rear sets and if sold the money comes to me - Condition of the sale.

Talk to "Crete" in this Forum if your interested in my parts.