Topic: header modifying Q?

[Don R]

 I have a shed find 750 with Jardine 4-2 flare end (trumpet?) pipes, I'm not a fan of the flare but if I could fit reverse cone or a more current appearing end I could live with them. Has anyone made a more appealing pipe out of a set of those or even modded a set of old turnout pipes?
  I'm OK with the look of the 4-2 hooker headers, they sound great too.   
 I saw a wild set of long pipe 4 into 2 into 1 pipes on Yamiya's site. They look crazy, perfect for a performance bike build, not so much for nostalgia though.   
https://www.yamiya750.com/index.php?main_page=product_info&cPath=246_251_142_88&products_id=861&language=en

[Don R]

 Some of the CycleX mufflers look promising. I notice they don't have many headers listed like they used to.

[Alan F.]

My first thought would be to trim the ends off with a pipecutter and fit some billet tips on.

[Terry in Australia]

Yep, if you've got ccess to a lathe Don, you're in business. When I built my K2 "Bitsa", funds were short, so I used what I had. In this case I had a set of those Jardine(?) turnouts that slip on to the OEM headers that I think I bought from another member here, and as cool as they were back in the day, I was looking for something sportier.

Terry's Redneck Exhaust Mod by Terry Prendergast, on Flickr

So (and this was the most difficult part) I carefully measured where I wanted the cones to be mounted, and using two hose clamps with a couple of mm gap, I cut between the lines with my angle grinder with a thin cut off wheel.

Terry's Redneck Exhaust Mod 1 by Terry Prendergast, on Flickr

Terry's Redneck Exhaust Mod 2 by Terry Prendergast, on Flickr

I had some machinable alloy bar that I chucked in the lathe and bored, then turned a taper.

Terry's Redneck Exhaust Mod 5 by Terry Prendergast, on Flickr

Terry's Redneck Exhaust Mod 7 by Terry Prendergast, on Flickr

I drilled and tapped a hole for a 6mm screw and drilled a hole on the insides of each pipe, tapped the cones in with a plastic mallet (they're a very tight fit) and Viola! A stringed instrument!

Redneck Spring Sunday 3 by Terry Prendergast, on Flickr

Terry's Redneck Exhaust Mod 9 by Terry Prendergast, on Flickr

They worked fine, and I ran them until a year ago when I was able to afford a new Delkevic 4 into 1.

Redneck Wednesday air forks 6 fixed by Terry Prendergast, on Flickr

Redneck Wednesday air forks 5 fixed by Terry Prendergast, on Flickr

Redneck Saturday bike fixings 2 by Terry Prendergast, on Flickr

Redneck Saturday bike fixings 3 by Terry Prendergast, on Flickr

The other benefit was that the turn-outs were pretty much unbaffled, so I was able to stuff some stainless steel wool up each pipe to quiten them down somewhat. It was a nice, cheap fix.

[seanbarney41]

Don, are you talking about the trumpet tip ones or the turn outs?  Jardine had both.  I have always liked the trumpet tip ones...the turn outs?  not so much...Ekpent loves them things though.  If you were closer, and you have the trumpets, I would probably trade ya for a cool old 4 into 1.  Probably not worth it to ship.  I have had a couple Jardine 4 into 1's and they sound and run good, as do those 4 into 2's.

[Don R]

Don, are you talking about the trumpet tip ones or the turn outs?  Jardine had both.  I have always liked the trumpet tip ones...the turn outs?  not so much...Ekpent loves them things though.  If you were closer, and you have the trumpets, I would probably trade ya for a cool old 4 into 1.  Probably not worth it to ship.  I have had a couple Jardine 4 into 1's and they sound and run good, as do those 4 into 2's.

 These are the trumpets, I've been up your way a couple times. Drag racing and a trip for race part repair.  Nothing in the near future though. I got some good ideas here, thanks guys. I'm getting tuned up on my stainless steel welding and have a box of 2.5" pipe and fittings to build a car exhaust maybe I'll get creative.

 Those are awesome Terry, I have a friend with a lathe but he's got a broken leg after he leaned a ladder against it and got bucked off.

[seanbarney41]

Ok don!  Hit me up anytime you are in the area and want to hang.

[Don R]

 Terry, those look a little like the 4-2 hooker headers.  I had a set on a stock engine and rode it to visit a friend, when I got home he called to say how awesome that engine sounded. He's an old hot rodder, pro mechanic so knows engines. Since then I moved them to a bike with an older rebuild big bore engine (not sure what kit was used) and they sound totally different, louder and less like a F1 engine.  I suspect I've blown out the packing or baffles themselves.

[seanbarney41]

I have definitely noticed "more compression" has sound all it's own

[Terry in Australia]

Terry, those look a little like the 4-2 hooker headers.  I had a set on a stock engine and rode it to visit a friend, when I got home he called to say how awesome that engine sounded. He's an old hot rodder, pro mechanic so knows engines. Since then I moved them to a bike with an older rebuild big bore engine (not sure what kit was used) and they sound totally different, louder and less like a F1 engine.  I suspect I've blown out the packing or baffles themselves.

Yep, no idea what brand mine were Don, I do know though, that the bike ran way better with the new Delkevic 4 into 1, well, until the gearbox locked up and tried to spit me down the road. Sean's comment about high comp engines sounding different rings true, I have Delkevics on all 3 of my running CB750's, but the K0 with the high comp CB77 pistons actually sounds louder with a real "cackle" that the other two don't.

K0 engine build 7 Nov 2020 3 by Terry Prendergast, on Flickr

[Don R]

 I have a set of 812 pistons that look like those Terry, except the fool PO put them in backwards and then notched the dome for valve clearance.  He was also the guy that wrapped the fiberglass packing over the end of the baffle and ran it until it ran no more.  His brother told me "ran when parked" when I bought it.  I just wanted the mags and didn't know I'd just bought a 14,1xx diecast for $650.  I left bike of the month pics at the bike shop near his house for him to see.

[Terry in Australia]

Thanks Don, maybe the guy who built your engine was the same turkey who built the engine I bought for my K2 "Bitsa" with one of the selectors put in backwards (so only 3 gears) the end smashed off the clutch basket shaft, left out the clutch thrust washer entirely and used what looks like a Kawasaki sprocket nut to replace the missing Honda clutch nut? I fixed all those things, only to hear a definite "Knock" when I fire it up, so it's coming back out for another rebuild. I've said it before and I'll say it again, some folks shouldn't be allowed to own tools...........

[Don R]

 I remember commenting back then that this guy should turn in his tools or suffer broken fingers.  What's odd was this bike was built as a clone of one he couldn't buy. My sandcast, the one he wanted and couldn't buy and the one he built were the first three 750's sold at our local shop.  5511- 9,0xx - 14100
  My 14,100 was just a few frame numbers from the French bikes with sandcast engines that have been found as the exceptions to the 7414 sandcast cut off.   
 Useless but interesting trivia.

[Terry in Australia]

I remember commenting back then that this guy should turn in his tools or suffer broken fingers.  What's odd was this bike was built as a clone of one he couldn't buy. My sandcast, the one he wanted and couldn't buy and the one he built were the first three 750's sold at our local shop.  5511- 9,0xx - 14100
  My 14,100 was just a few frame numbers from the French bikes with sandcast engines that have been found as the exceptions to the 7414 sandcast cut off.   
 Useless but interesting trivia.

Well maybe not useless Don, I'd never heard of that. There was a particularly snooty sandcast owner here many years ago who thought he was somehow worthy of extra credit for owning a sandcast K0, so I suggested that I might take a spare set of SteveK0's engine cases to China (back when we were friendly with China, pre-virus) and have a few dozen sets of sandcast cases cast, and he just about had a heart attack! Would have been funny if a heap of sandcasts suddenly turned up on Ebay, going cheap........