Topic: 1977 400F EXhausts, HAS ANYONE DONE A 4 into 2 set up?

[Laverdaroo]

Evening all, new on here as a new owner of a 1977 one owner from new barn find that was parked up in 1981 under a sheet and left until I came along and managed adeal for it. Ive started to recommission it with carfb overhaul, points, valve check, plugs, caps and leads and just waiting to get the carbs back fro the blasters after he's cleaned the black treacle out of them. They were so bad the slides had to be soaked out in warm methelated spirit and water!
Ive done severalbuilds in my time but NEVER seen a ste of carbs in as bad a state as these were!

Anyway, firmly on with it to get it going and then its some sympathetic upgrades and get her on th eroad for the first year and have a good go at her next winter. I've several others to ride and the Mrs wants this one as it fits her a treat but I have a question that I cant seem to find an answer to anywhere........ Has anybody done a four into two exhaust system on theirs yet?

I'm hoping to fit a pair of reverse cone silencers on the rear of the bike similar to say a Norton/Triumph of the same era, has anybody done this yet? Any picks would be really interesting to look at just to satisfy the mental image in my head that I cant quite grasp yet.

I'm using the standard headers because of the beautiful swoop in front of the barrels but really need a bit of help with the ideas bit of attaching the pipes to the two silencers. Any help gratefully received.
Currently undertaking the front brake up grade as described in the upgrade front brake thread, all going well and glad to be making progress. Wheels re-laced next once I've taught myself to do it but loving the process. Evoked a shed upgrade (approved by her who must be obeyed) WINNING

[ADW]

Try this. For my CB350F. I now have 4 into 4 OEM replicas, but used this for 2 years or so before I got the 4-4. You'll have to hand-make the collector pipes. The mufflers are Dunstall replicas from Emgo I think. Relatively cheap, sounded pretty decent.

[Laverdaroo]

thanks but this is the look I'm going to recreate and the reverse cones would look great and a bit different from the norm. Thankyou for the shots though buddy and a great idea but if i'm going to keep the headers i'll have to make a collector anyway, I was just interested if anybody had done it yet?

[Laverdaroo]

And yes, I know this is a 550

[seanbarney41]

thanks but this is the look I'm going to recreate and the reverse cones would look great and a bit different from the norm. Thankyou for the shots though buddy and a great idea but if i'm going to keep the headers i'll have to make a collector anyway, I was just interested if anybody had done it yet?

how is that a 4 into 2?  Or are you talking about a 4-2-1?  What ADW posted is a 4 into 2.  I cant see any way of building the stock header into a 4 into 2 as it is a 4 into 1.

[Laverdaroo]

I think you may have mis read that seanbarney, I have the original headers as shown and the collector for the 400 OEM
 I want to get the bike looking something like this BUT with the same silencer on both sides. I Know that's a 4 into 1 bud, hence the original question.
Has anybody done a modification to the collector if  at all possible to get a second silencer on the near side also.

I just like the look of this particular bike (albeit a 550) and as the 400/4 is so similar in many ways I was interested to see if anyone had gone that route and indeed is there enough room to fabricate what I want in the room I have and the shape of the headers.

I'm not that into the 'modify it to death' look of the old bikes being brought back to life currently and having just a few changes like the my thoughts on the pipe might be a good project to chase with potentially a great outcome. 4-1-2

I'm talking about modifying/remanufacturing the collector to twin outlet to allow for the second can, there is no other way of doing it. I'm reluctant to use ditch the original headers as they are one of the most endearing bits on the bike and make it the 400/4, I was just interested to see if anybody in a shed somewhere had attempted it before.

[ADW]

Now after re-reading a few times, I understand what you are trying to do (I think). You want to keep the original header that directs everything to the RH side of the bike, but have 2 actual mufflers on either side of the bike that are each connected to two of the exhaust pipes.

If that's the situation you're describing, you're asking for something that you simply are going to have to contemplate, fabricate, and install completely on your own. But it'll be some sort of Franken-collector similar to what I built for the 4 into 2 collectors for my 350F. It's just gonna take time, lots of fiddling, and patience. I doubt anyone can tell you exactly what you'll need to do and measurements and all that.  It's by definition a one-off custom part that will require having the bike and parts right in front of you and figuring it out...that's what I did on my setup. Good luck!

[carnivorous chicken]

Why not use headers from a 350F? That would avoid all four pipes being swept to the RHS and then trying to reroute two to the LHS. 350F headers are the exact same size. Using the 400F header and trying to make a 4-1-2 (?!) seems like looks over function.

[Nurse Julie]

You could always buy a set of 4 into 4 pipes for a 400/4 from Yamiya and have a play 😁😁😁😁

[Alaxy Galaxy]

Ok, so I think OP wants a 4-1-2 system. Kinda like if you have a V8 mustang that all collects into one catalytic converter, but then splits up to two exhaust tips. Is that it?

[Laverdaroo]

I'm not sure why this is so difficult to understand!

I was simply asking if anybody had used the original headers (because they are the best looking bit of the bike), and making them a twin exit system.
SO,  I wont be using CB350 header pipes, I wont be using Deeptone's  just the CB400F ones and making a bespoke, one off (custom) collector that will accept all four headers and pass the gasses through into two exit pipes..........not rocket science surely?

I wasn't after measurements, I was only asking if anyone had done anything like this before and had any tips on what worked and any heads up on not to do. I figure its been a bit of a brain fart for the majority  to understand, I thought it a fairly straightforward and a  reasonable request/topic but it appears not!
Never mind people, I'll just stick to what I always do and simply get on with it, the pipes are off the bike and the steel is coming this afternoon, the hammers are out and the kettle is on, this could be a long day!


Thanks anyway !

[carnivorous chicken]

I'm not sure why this is so difficult to understand!

 I figure its been a bit of a brain fart for the majority  to understand,

Or, perhaps, a brain fart to conceive of in the first place. You can lead a horse to water... But hey, it's your bike, don't let anyone talk you out of a bad idea. Do post pics when you've got it done though.

[Laverdaroo]

 

[Laverdaroo]

Ok, so I think OP wants a 4-1-2 system. Kinda like if you have a V8 mustang that all collects into one catalytic converter, but then splits up to two exhaust tips. Is that it?

Exactly that Alaxy Galaxy, you get the jist. Except no catalytic converter, I don't need one of those.
Its exactly form over function that's what customising is all about when the engine is fine as it is and you just want to make your bike stand out a bit for the beautiful thing it is (stock headers). The 550 picture I posted earlier looks fantastic and is really tastefully done, I don't need to play with the motor just do a few tweaks to suit the pipes when done.

I thought that 550 would look smart and just a bit different to the norm if it had 'twinnies' on the back like the Norton's did hence the question. It seems Carnivorous chicken seems to think otherwise, bless him

I'm a little surprised nobody has attempted it before as it seems a great optical upgrade

Onwards

[newday777]

I was simply asking if anybody had used the original headers (because they are the best looking bit of the bike), and making them a twin exit system.
just the CB400F ones and making a bespoke, one off (custom) collector that will accept all four headers and pass the gasses through into two exit pipes.

I wasn't after measurements, I was only asking if anyone had done anything like this before and had any tips on what worked and any heads up on not to do the pipes are off the bike and the steel is coming this afternoon, the hammers are out and the kettle is on, this could be a long day!


Thanks anyway !

It has been said the English language can be taken 6 different ways.......

A picture always helps.....

The problem I see in my mind and what I've read over the years, of performance exhaust, the flow is balanced and engineered(I could be wrong and have forgotten lots! there is a lot to learn of tuning exhaust to get the best performance).

You are trying to use looks(your statement reflects that) and not properly engineered flow and back pressure so you will loose performance. The 400/4 stock exhaust is not designed for optimal performance but more for sexy design and noise emissions requirements. Adding in a second outlet to the 4/1 collector if the stock exhaust design as your are proposing and the resulting pipe to the left side added muffler for the look you want will be a seriously unbalanced system. The collector is too far to the rear to add in your secondary added outlet pipe to the left side to get a good flow. If your header is in very good condition, save it, get another to hack up.
It's your bike to do as you want, but there will be a cost. Cutting up a good stock system that can not be gotten again new to restore the bike back to original will be a big factor. Many are wanting only the stock bikes, not hacked up jobs. You won't be able to restore the exhaust header once cut up.



The basics of exhaust theory...

https://burnsstainless.com/blogs/articles-1/exhaust-header-theory

A bit more indepth study (this is an automotive perspective writing)

https://www.enginelabs.com/engine-tech/exhaust/performance-exhaust-system-design-and-theory/

[newday777]

Ok, so I think OP wants a 4-1-2 system. Kinda like if you have a V8 mustang that all collects into one catalytic converter, but then splits up to two exhaust tips. Is that it?

Exactly that Alaxy Galaxy, you get the jist. Except no catalytic converter, I don't need one of those.
Its exactly form over function that's what customising is all about when the engine is fine as it is and you just want to make your bike stand out a bit for the beautiful thing it is (stock headers). The 550 picture I posted earlier looks fantastic and is really tastefully done, I don't need to play with the motor just do a few tweaks to suit the pipes when done.

I thought that 550 would look smart and just a bit different to the norm if it had 'twinnies' on the back like the Norton's did hence the question. It seems Carnivorous chicken seems to think otherwise, bless him

I'm a little surprised nobody has attempted it before as it seems a great optical upgrade

Onwards

You will need to move the collector forward closer to the points/clutch area to do as you want to be able to flow out the left side pipe.

[Laverdaroo]

Yeah, so I gather after preliminary measurements today in the shed.
 I have 4 collectors that have been damaged and repaired/patched on the left underside which I've been slowly gathering up on Ebay,  so I'm not short on bits to play with. Especially as the left hand sides are damaged anyway which is the main surgery area, I knew it wouldn't be easy so started hunting for them late last year, I've only paid around £12 for the most expensive one so its cost efficient and they're virtually scrap anyway because of the damage but ideal for what I want.
I had a really good chat with a guy from a long established bike restoration company this afternoon, found his number in one of the classic bike comics I had who said he'd done one 'back in the day' and that it  is  possible, he said he may still have the drawings still as he did it when he was an apprentice at engineering school but essentially you cut up one collector and with a bit of jiggery pokery and heaps of experience graft it onto the left side of the collector.    We're on lockdown here but as soon as I can get to him I'm going to take the rolling chassis with the engine in it up to him and he's going to fab one up for me for around £180.....Result!

I'll have to set it up on the dyno, that's a given, it may involve some different carbs but that's all part of the process. I've made exhausts for all my bikes over the years including my 800VYEC, 853 Ducati, CBR400, 600, blade and several LC's so well up on my flow dynamics and engine requirements but cheers for all the bumf you sent over, interesting read and well put. A lot of the explanations can be a bit full on, those put it quite simply and you never know it all,  a good read is always welcome. I'll pass that on.

On a different note; I managed to score a really tidy set of forks today from Ebay,  old stock  from a closing down sale at a breakers....£100 delivered, result as my stantions are past repair from being left for so long. I've stripped them today and the bottom sections are  being sent off with the carbs to the vapour blasters tomorrow to get a tidy up before they go back together, so things are moving on and  I should be able to have a test fire after the weekend once the carbs are back together, I'm currently sitting looking at 4 plastic tubs of carb bits all to refit so chomping at the bit to start the rebuild.

I'm only doing this to see if she's worth pursuing, if its a non starter then she's a long term project and I'll have the motor apart but as there's only 9K on the clock I was hoping to not have to strip it. I was hoping to get this one sorted fairly quickly being so straight forward and easy to work on. Although it's blathered in muck and grease from being laid up in a tractor shed since 1981, underneath is a really nice little bike that's aching to be sorted.  All the electrics have been tested and all the recommission work has been done so its just the carbs and a gob full of fuel and a crossed set of fingers!
 f
I'll keep you posted.

No need to worry,.........."No OEM headers will be injured during the process"

[newday777]

Love it. Good job finding the old restoration guy.
I was thinking the other day as I looked at the collector picture the best approach might be cutting up two of them for using the right side halves w/ a fabbed block off plate of the hacked off hole. Then fab up connector pipes to each muffler.
I hope it works out well for you.

[Alan F.]

No need to worry,.........."No OEM headers will be injured during the process"

If you'd led with this, you would have received different responses.

[Laverdaroo]

I'll keep you posted, I'm in no rush, not with this lockdown!
At least i know hat path I'm on with the thought process. The carbatooterss are coming back Friday all vapour blasted  so its gonna be a good session in the shed with the radio, building those with a view to trying to breath some life back into her and seeing if she'll cough and fart into life on Sunday. I'm quite confident but it'll be interesting to see how it goes.


AlanF, I lead with a question, which was a simple request  and got sneered at by those who  didn't read the question. All water under the bridge,yadda yadda,  I've a bike to concentrate on..

[carnivorous chicken]

AlanF, I lead with a question, which was a simple request  and got sneered at by those who  didn't read the question.

I'm using the standard headers because of the beautiful swoop in front of the barrels but really need a bit of help with the ideas bit of attaching the pipes to the two silencers. Any help gratefully received.

I'm talking about modifying/remanufacturing the collector to twin outlet to allow for the second can, there is no other way of doing it.

I'm a little surprised nobody has attempted it before as it seems a great optical upgrade

No need to worry,.........."No OEM headers will be injured during the process"

I'm still not convinced this isn't some kind of sophisticated trolling, but there you go.

Like everyone keeps saying, it's your bike. Me and the others are making suggestions based only based on what you've said, which, as you can see, changes with each post.

I personally think you should make it 4-1-2-4 for something even more out of the ordinary, but that's just me.

[Alan F.]

Yup, we sure have seen out share of new members recently that will open with a question, then 119 replies later the op still is resisting long accepted solutions by those well in the know.

I don't think that's what we have here, the plan here is to create something new and cool out of something cool that's damaged beyond its intended use. Cut, flip, file, fit, file some more until fit is perfect, then mock up on the bike. Perhaps hold your new collector together with safety wire for mock up.

Understanding is the key to acceptance. I can't wait to see it now that I'm clear on where you're headed.

I've a bike to concentrate on..

Jeez, you sure do. I dig the ratcheting screwdriver though, those are great. Sold under the Snap-On name in the States, didn't know they were common in the UK.
CHEERS.

[Laverdaroo]

Yeah, Alan, they're really good, I've the long handled T shaped one and a cranked handle one as well. They're from the snap on bloke who comes to my pals garage with a van full of of 'shiney stuff' every month. Its a regular thing over here for them to have a sales patch and these guys franchise a business off of snap on and travel from garage to garage selling the tools. You must have something similar across the pond? It's uncanny how many times he's turned up when I've just popped by for a cup of tea in my lunch break

Well, carnivorous chicken..............really don't know what to say except you couldn't be further from the truth. I was under the impression that what's forums are for, for new members to come on and ask questions relevant to the subject to those who've already had a go, learnt from experience or through expertise.

I'm not sure which of those you think you are in but if you take the time to read the post you've just put up to try to prove your point, you'll notice that the questions are completely relevant, honest and to the point. The only time any of this has gone off thread is when you read things wrongly, get the wrong idea through not reading English and forming a biased opinion through ignorance and a misunderstanding of what was asked in the first place.
 All the information was there, all you had to do was get off your 'expert cloud' of 'thinking you know everything' and read it. Sadly you've not done that and now claiming the post is a troll and fake. You're one of those aren't you? Trolling? Conspiracy, fake news, stolen this n that? You voted for him didn't you?

I think you need to stop reading these things if it gets you this twisted and  suspicious about things you've read wrongly. Everyone's been really cool and understood the question except you, so please don't comment if you cant be pleasant, this is supposed to be fun and about the motorbikes, not whether or not you can understand a clear question and then accuse somebody of lying, who's genuine and simply after a heads up and a bit of info, its very boring and if I'm honest, kinda shows you up mate .............irrespective of how many posts you've put up and how long you've been on here and how many bikes you say you've had/have!


AlanF, I'll get some piccies up of the weekend shenanigans as it goes on, cheers for the comment buddy, bit of a state isnt she? She'll go, I'm sure of it .

[Laverdaroo]

Alan, how she was when I found her......

[carnivorous chicken]

Yeah, Alan, they're really good, I've the long handled T shaped one and a cranked handle one as well. They're from the snap on bloke who comes to my pals garage with a van full of of 'shiney stuff' every month. Its a regular thing over here for them to have a sales patch and these guys franchise a business off of snap on and travel from garage to garage selling the tools. You must have something similar across the pond? It's uncanny how many times he's turned up when I've just popped by for a cup of tea in my lunch break

Well, carnivorous chicken..............really don't know what to say except you couldn't be further from the truth. I was under the impression that what's forums are for, for new members to come on and ask questions relevant to the subject to those who've already had a go, learnt from experience or through expertise.

I'm not sure which of those you think you are in but if you take the time to read the post you've just put up to try to prove your point, you'll notice that the questions are completely relevant, honest and to the point. The only time any of this has gone off thread is when you read things wrongly, get the wrong idea through not reading English and forming a biased opinion through ignorance and a misunderstanding of what was asked in the first place.
 All the information was there, all you had to do was get off your 'expert cloud' of 'thinking you know everything' and read it. Sadly you've not done that and now claiming the post is a troll and fake. You're one of those aren't you? Trolling? Conspiracy, fake news, stolen this n that? You voted for him didn't you?

I think you need to stop reading these things if it gets you this twisted and  suspicious about things you've read wrongly. Everyone's been really cool and understood the question except you, so please don't comment if you cant be pleasant, this is supposed to be fun and about the motorbikes, not whether or not you can understand a clear question and then accuse somebody of lying, who's genuine and simply after a heads up and a bit of info, its very boring and if I'm honest, kinda shows you up mate .............irrespective of how many posts you've put up and how long you've been on here and how many bikes you say you've had/have!


AlanF, I'll get some piccies up of the weekend shenanigans as it goes on, cheers for the comment buddy, bit of a state isnt she? She'll go, I'm sure of it .

My sincerest apologies. Your earlier posts made it seem kind of preposterous, and I wan't the only person who thought so. As Alan F pointed out, there are quite a few people who come on here, propose something dumb, ask for advice, get it, and then ignore it and start s4it. As you pointed out, you're more after looks than performance. I've also been joking, and that of course goes over some people's heads when its online. My English comprehension is pretty decent, and I wasn't the only one who didn't get it. I don't mind the insults -- as I said, some of what I said was in humor and I generally assume the same about others. Best of luck. Post photos. And welcome to the forum.

[Alan F.]

I'd just carefully worded a reply but checked back before posting and found crisis averted!

Please don't talk about politics though, it's against forum guidelines for all of us.

Snap-On works just like that in the States too, small world.

Your 'before pic' is better than some, worse than others. It's a project alright. Clean what's dirty, fix only what's broken and ride before modifying anything. That's the general advise.

It'll run and ride, getting past your MOT seems like the hard part. Once that's done I'd bolt on your modded pipes. That's how it mostly works here in the States.

[Laverdaroo]

reciprocated apologies man,
that's the problem with texting, there's too many dynamics missing from the conversation to aid in the understanding. Sorry about the 'one of those' comments, bit sly, sorry.

I'm just on here to learn, give a bit back, have a little fun and chat to like minded shed dwellers and fiddlers about bikes and other cobweb related stuff.
I genuinely thought it was a fair question and was genuinely surprised it hadn't already been done, I even 'sense checked' the post with a few mates and they kinda sided with me and thought it fair.

Anyway, yadda yadda, can we all be mates and start again?
I'm Laverdaroo, Live in Bristol in the uk, absolutely besotted with all things motorcycle since the age of 15 and love the restoration side of things after fiddling for years and  finishing a trick 748 a couple of years ago which I bought in boxes (which sadly had to go last year to pay for the lock down the lock down)!

This year I'm having a go at this little thing for my girlfriend to ride,  it's what she wants and that's what's being built. The earlier shot of the 500 is the thing she wants but as she's only 5'4" she cant get her feet down safely on the 500/550 and doesn't want to alter it with short shocks etc. The 400 has a lower height , lighter and fits her a treat. BUT, she wants twin exits and a better front brake or twin disc set up on the front sometime in the future.
Its a cool little project and should be fairly easy but the pipes will take time and I just wanted to start my homework early. There's plenty of jobs to do first, like get her running!


bestest of regards from accross the pond