Honda Twins banner

1 - 15 of 15 Posts

·
Premium Member
Joined
·
2,915 Posts
Discussion Starter #1
Does anyone think that this is a viable option, or better yet, already done this ?

Using one of those '12 ton' hydraulic pipe benders from Ebay, Machine Mart, Harbour Freight et al ?

Mild steel tube, packed with sand to reduce creasing.
 

·
Registered
Joined
·
2,941 Posts
There are tons of videos about pipe benders vs tubing benders, tubing rollers are another option. My thoughts gravitate toward the Japanese fabricators that bend free hand with just a torch and a radius gauge.

I recommend the videos as research before deciding on your method of bending. Your material of choice will also help dictate your method, as not all methods will produce the same results with the same materials.

Someday I'll give this a shot myself, subscribed!
 

·
Premium Member
Joined
·
2,915 Posts
Discussion Starter #3
Ah, that was my fevered imagination working last night. In the cold light of day, I think some pre bent mandrel bends will be my best bet, stick them together with the mig welder. Cluttering up my shed with a pipe bender that might get used a couple of times only doesn't seem such a good idea on reflection.

I've just managed to find a rusty set of down pipes on Ebay, like hens teeth for some reason, that'll sort out the difficult top part of the pipe work.

And a can of PJ1 black exhaust paint …..
 

·
Registered
Joined
·
710 Posts
Go to a good muffler shop and they will be able to bend it to any specs, they should be able to do header pipes as well.
 

·
Registered
Joined
·
2,941 Posts
I think one hurdle is finding the right material to begin with, Shops may not have suitably narrow tubing for smaller displacement motorcycles. I remember I did a search a year or two back and my most local and inexpensive choice was zinc plated steel fencepost tubing with a 1.15" ID for my 250 Nighthawks (if memory serves)
The zinc plating can be removed easily with a soak in plain white vinegar, then I could bend the tubing with whatever means I wanted to experiment with.
Or I could leave the zinc on just to experiment with bending without wasting lots of money on materials.

I'm not certain how well it would bend but for less than a dollar a foot retail it seemed worth experimenting on.

I remember watching one video where the presenter was bending pipe or tubing (can't remember) with a hydraulic bender, he showed the huge difference that a slightly undersized bending die (smaller die than tubing) can make in the quality of bend produced. It was amazing and really stands out in my memory.
I'll have to look for this video later when I have more time available.
 

·
Registered
Joined
·
121 Posts
I had a company called J&D Tube Benders in Schofield, WI (J & D Tube Benders | Manufacturers of Hydraulic Tube Lines and Bending) mandrel bend some header pipes for me a couple of years ago for a CB450 cafe project I was working on with my brother. I just send them a drawing (PDF file in my case) with all the measurements and angles and once I had approved the quote they shipped them out a week or so later. Pics below. I tried using a bunch of pre-made mandrel bends from Columbia River but in the end the stuff from J&D was more cost effective and much cleaner because there weren't' a bunch of weld seems to contend with.

If you're looking to replicate the stock profile I'm not sure this is an option as Honda tended to have quite a large radius curve on their header pipes.




 

·
Premium Member
Joined
·
2,915 Posts
Discussion Starter #7
Thanks for the interesting replies.

This is what I hope to achieve. I still have to sort out some suitable mufflers to go on the end of the pipes. Apologies for the accidental selfie. :-?

20190904_142147.jpg

The double skinned original down pipes ( headers ) have a 35mm OD, as do the pattern ones in my photo. This means that 38mm tube, with a 1.5mm wall thickness, is a nice sliding fit, and could either be clamped or welded. There will in fact only be the one join in the pipes, and that will be tucked away down behind the footpegs.

Interesting comment about Hondas large radius curves, it is quite noticeable that the pattern part shown here has much more acute bends. I wish to preserve these chrome pipes, so I've got some tatty rusty originals on the way, along with a pair of 45 degree mandrel bends in mild steel, rather then the stainless in my photo. Plan is to then paint these parts black, as SL175 pipes. I've requested that the new bends have longer lower legs than the short one shown here, to give me a bit more flexibility in final position.
 

·
Registered
Joined
·
3,478 Posts
Back when I was building the 450 I considered building my exhaust. Someone on this forum cited Cone Engineering as a source of very high quality exhaust components. f you like to weld, it would be a fun project. https://www.coneeng.com/motorcycle_components.html
 

·
Registered
Joined
·
757 Posts
Cool idea Richard. Having experimented with welding pipes earlier this year (the experiment is not over yet!) I'd highly recommend some serious practice welding on like material before tackling your only pipes. Decent welds can be had with your mig welder but practice and get the settings right before giving in to temptation and going after the pipes you intend to use. I found that wire speed was critical to getting a good weld, which can be a bit tricky as you go around the pipe. If you can clamp it so the joint is pointing up, enabling you to stay level (think of the equator) as you go around the pipe instead of trying to weld with the pipes horizontal, where you're upside down half the time, you'll do a lot better... if that description makes any sense at all. :-?
 

·
Registered
Joined
·
710 Posts
A good muffler shop or parts supply should be able to get any type of pipe needed. Personally, I would take the bike to the shop and have the pipe bent, fit and marked for alignment.
 

·
Registered
Joined
·
2,941 Posts
True, except for smaller bikes below 350 CCs, at that point optimal tubing dimensions are out of scope for most muffler shops, even the best ones.
 

·
Registered
Joined
·
710 Posts
True, except for smaller bikes below 350 CCs, at that point optimal tubing dimensions are out of scope for most muffler shops, even the best ones.
Out of scope? Not sure what you mean by that but I can have it bent at our small town shop.
 

·
Registered
Joined
·
2,941 Posts
Out of scope = not within normal capability.

Here in the States small diameter exhaust tubing is not why most muffler and custom exhaust shops exist. Most customers want larger than stock diameter tubing for more performance or a more aggressive sound.
 

·
Premium Member
Joined
·
2,915 Posts
Discussion Starter #15 (Edited)
I went with a specialist pipe bender, through Ebay, and got these bends made up, delivered today. Completely kink free mandrel bends. I'm sure he'd have been able to bend the complete header pipe all in one piece, but I'd have to get the flanges made as well, also until I find some suitable mufflers I don't know the exact length of the bottom pipe run. This way, I can trombone ( is that a word ? ) the sliding section to get a good fit, before welding or clamping the join. It only cost 30 UKP for the pair of pipes, delivery included.

20191018_170614.jpg

38mm OD mild steel, 35mm ID.
 
1 - 15 of 15 Posts
Top