The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: RichardL on 06.03. 2009 02:32

Title: Exhaust Pipe Problem
Post by: RichardL on 06.03. 2009 02:32
The dilema:
New set of pipes bought some time back (too late to return) has left pipe that hangs too low by 7/8". It looks bad and, I think, will not fit with new stock mufflers I wish to buy.

My proposed solution:
Using a doubled-up length of rope threaded through the pipe I would twist the rope until the pipe gives up a little bit. I already tried this with a manila rope and the rope broke (boys, it was tight!). My idea is to use a stronger synthetic rope which, I am fairly sure, will not break before the pipe bends. I am not that concerned that the chrome might crack.

The question before you:
Will the pipe keep resisting and, then, suddenly kink radically when it finally gives up?

I am fairly certain I recall Groily applying an acetylene torch to correct a bending error. I would opt for the cracked chrome over the black-and-blue look. Anyway, I don't own a welding outfit capable of getting to the needed heat over a wide area. The upshot is, risking the pipe might not be that big a deal, since it is apparently useless for attaching stock mufflers.

Your ideas, guesses, personal experiences and expertise would be appreciated.


Richard L.

Title: Re: Exhaust Pipe Problem
Post by: groily on 06.03. 2009 08:44
Another typically poor set of pipes Richard - it's so boring that so many aren't made correctly.
Yup, I heated and bent mine to make it fit rather than send it back to the UK and get into the usual argument with a not very sympathetic supplier, whose tendency it is to blame the customer. Blued it, but then mine's a scruffy bike compared with yours and it doesn't really notice under the winter muck! A blowlamp will do it. And the Chicago Rope Trickmight too, although I just don't know! Tube is surprisingly strong sometimes. Would it not be possible to amend the mounting bracket at the engine to get the pipe to hang a little higher at the rear, without losing the fit appreciably at the head? A little there translates into quite a lot 18 inches further back? And might be easier?
Title: Re: Exhaust Pipe Problem
Post by: Triton Thrasher on 06.03. 2009 08:46
Ah- the old Spanish windlass- and it snapped! That's why riggers get sacked if they try it.  Could have been worse, if you let go the lever.

You might get 7/8" in a cold bend. Good luck.

How about fitting the silencer and then forcing it higher and fastening it in palce?
Title: Re: Exhaust Pipe Problem
Post by: zitman on 06.03. 2009 11:15
ow about fitting the silencer and then forcing it higher and fastening it in palce?

As TT says.  This was the approach I used on mine.  I ovalled out the hole on the downpipe bracket fixed it all together and "eased" the silencer onto its bracket.  Worked fine.  The Oval hole was invisible under the washer on the mounting bolt (It only need a slight ovalling as a little change at that point is magnified by the time you get to the silencer end of the pipe) and the seal to the head was fine.


Title: Re: Exhaust Pipe Problem
Post by: RichardL on 06.03. 2009 14:25
What you see there is the resultant position when the pipe is fitted fully and straight into the head. I bent the downpipe bracket into position to meet the mounting stud. If I pivot on the stud the pipe pops too far out of the head. I don't think it is possible to tighten-down the bracket enough to tweak the back end of the pipe without, again, pivoting on the stud. The pipe is not a particularly tight fit in the head in any case, so, I think it will be a leakage problem if I compromise the existing fit. I may try to expand the pipe at the head but think a good fit is still the right way to go. Maybe there is some sort of gasket arrangement possible between to finned pipe dressing/cooler and the head. Is this common and is there an available gasket? It seems it would have a hard time staying in place.

Later today or tomorrow I will post a picture of a mock-up I did to see about just lifting the muffler to fit with the pipe where it is. I thought it was a fairly bad angle.

Thanks for your comments. I look forward to more.

Richard L.

P.S. Groily, nothing personal about the blue pipes. I remember the picture and it wasn't that bad. I just don't want to spend $200 on a welding rig to fix a $150 set of pipes. Paying a welding shop is by the hour, and doesn't promise success.
Title: Re: Exhaust Pipe Problem
Post by: beezalex on 06.03. 2009 18:48
Richard, I don't know if you can get MAP gas, but it is fairly cheap here and suffices for bending steel.  It will NOT bend the steel.  It will certainly blue the pipe, but that can be removed with one of the various pipe blue compounds like Blue Job ( or the like.  Heat only the outside of the bend region and heat as large an area as you can.  Put a long iron pipe in the end of the tailpipe, let it good and dark red, then bend it right into place.  Have someone else hold the bike and act quickly after heating, you only have a few seconds to bend the pipe.

Good luck
Title: Re: Exhaust Pipe Problem
Post by: RichardL on 06.03. 2009 20:00

Thanks for the thought. I have a MAP/Oxygen rig, but doubt small bottles will last long enough to heat the large extent of the outisde of the bend, especially with the small tip I have (on the torch).  I suppose I could get what we call a come-along winch and do the hot bending with the steel cable in place rather than the rope. I am trying to get the bend to take place over a large portion of the sweeping arc rather than at one spot. All that said, I will think more about your idea. Do you have an opinion on the ability to do the cold bend and whether, or not, I will end up with an insta-kink?

Richard L.
Title: Re: Exhaust Pipe Problem
Post by: beezalex on 06.03. 2009 22:12
Richard, I've tweaked quite a few pipes into place and have yet to kink one, and yours looks like it is PROBABLY tweakable without a kink.  Then again, I never cared what those pipes looked like because the were on race bike, if it was a nice, shiny pipe, I'd probably kink it.  That said, I would install the pipe on the bike, take the MAPP (sorry, I got it wrong the first time, it has two "p's") - careful with the OXY-MAPP since it can get hot enough to melt the pipe - and I would heat about a 3-4" long area of the inside of the bend right where it comes out of the head (I assume you want to lower the right pipe) to cherry red (not orange) and then push down on the back end with a long piece of water pipe stuck in the end.  This should put the chrome cracking in a relatively inconspicuous area and one that already has been bent and probably still has a bit of compressive stress in it.  I think you might be surprised by how easily you can move the tail end of the pipe without any distortion in the heated area.

Good luck.
Title: Re: Exhaust Pipe Problem
Post by: RichardL on 06.03. 2009 23:22
Thanks again. Good food for thought and the main thought I'm digesting is to try the heating on one of my old aftermarket bobber pipes. I won't bend it because it is still worth something but, at least, I can test my MAPP torch. By the way, I'm raising the end, not lowering it, thus the twisty rope in the photo.   

Richard L.
Title: Re: Exhaust Pipe Problem
Post by: BSA_54A10 on 07.03. 2009 12:38
Take the pipe to your local car exhaust shop,
Pay them $ 25.00 to bend it so that it will fit as most now days have a hydraulic pipe bender.
Pull the head off ( which is US and should be replaced) and get the exhaust ports repaired.
You can either just get them machined round again and have the same exhaust shop expand the headder to fit the new slightly larger holes or have a sleeve or spigot fitted or get them built up and remachined back to standard.
No one ever dose the last because while it is the best way to go it is also the most expensive.

You will probably find that 1/2 your problem is the wear in exhaust port.

Bike Beesa
Title: Re: Exhaust Pipe Problem
Post by: RichardL on 07.03. 2009 13:42

Actually, I did take the pipe to the local auto exhaust shop and spoke with the manager who knew something about motorcycles and, I believe, had bent some motorcycle pipes. He told me that rebending on the hydraulic bender would not work. If I recall correctly, it had to do with the material having flowed during the original bend and getting it going again without collapsing would not work (or something like that). That's why I thought I might be able to create a little movement over the overall arc.

I don't know of differences between US heads and English, but I just finished putting the head on and am unlikely to machine the port until the next necessity to take it off again, though the advice is well taken. I will check the port for out-of-round, just to know the truth. The thing I will definately do is to see if the exhaust shop can expand the end. That's a brilliant idea (not that the others are not).

Thanks for your advice. I can't help but think you were thinking of me when you were lambasting cheap pipes. But for a lousy 7/8" I could have pretended they were really expensive.

Maybe the reason A10 owners are a bit tight with the penny has to do with resale value. It seems a museum quality A10 (restored or never restored) has about the same value as a top-line, new, made-by-robots (the machines, not the people, so don't attack me Wisconsinites) Harley Davidson.

Richard L.
Title: Re: Exhaust Pipe Problem
Post by: RichardL on 07.03. 2009 16:09
As promised (threatened?), below are pictures of the silencer mockup I did to explore the fit with the too-low pipe. I suppose some will say, "Why are you bothering us. Just put the silencer on, ease it up and be done with it." Fair enough, because, in the photo where it matches the pillion peg mounting hole it looks like this would be reasonable. In the photo where I've shoved the end in the pipe you can see the distance that the pipe must bend for the silencer hole and mounting hole to meet. OK, maybe I'm obscessing, but if there is a way to do it right, at least I'm looking for it.

Richard L.

P.S. Graphics by copying a photo from a dealer site, printing a PDF, clipping to AutoCad, scaling 1:1; printing in three pages, gluing to cardboard and cutting out.
Title: Re: Exhaust Pipe Problem
Post by: RichardL on 07.03. 2009 18:43
OK. I went out this morning and checked out a different exhaust shop that had the right diameter bender. He too warned me against trying to rebend the pipe but said he would do it, but no promises. I'm thinking: "Not that much to lose." I ask: "How much?" He says: "Nothing." I say: "Go for it." The picture below is the result. It's a cross between looks OK and just looks functional. I think it's good enough that I don't have to buy new mufflers and new pipes in the same year. Following the common belief, I am way too cheap for that.

I think the next photos will be when the new mufflers are on, for those still awake.

Richard L.
Title: Re: Exhaust Pipe Problem
Post by: BSA_54A10 on 08.03. 2009 00:27
I was not trying to be offensive, it was just a coiencidence that the two threads came up together.
What I am conscerned about is the suggestion that we "out" the suppliers of what we think is shoddy goods.
As in the previous post just about every retailer I know keeps several different quality parts.
As I know may of them quite well I do know that most would rather not stock crap as in the long run then end up with the problem of trying to tell the customer that it's their fault that the bits don't fit and that is why cheap parts are cheap parts.
Much easier to only sell the good bits that won't come back in the hands of an irate customer but the commercial reality is that if they don't carry the rubbish that they would rather not, no one comes through the door and all of the sales go to the nameless faceless web based companies, some of whome are good guys but a lot are shameless junk merchants.
So if we start slandering the retailers ( who was only doing his job of supplying the poor quality parts that we want to buy ) they wll end up with an undeserved reputation which could easliy cause them to go out back wards.
OTOH if you want to tell us that a "Bill Smith " exhaust did not fit & they told you to get nicked when you complained then that is a slightly different story . However you still must publish the full story.
Overlander had all sorts of troubles with a person who I directed there. The headders simply did not fit, however what was omitted that the owner had upgraded his A10 with a set of thick flange barrels so naturally the correct pipes for his year model would not fit & he needed a custom bend. 

Now as for Ritchie who seem to think that parts prices should reflect the end value of the bike that are attatched to.
A couple of points.
You will do better to think of the price of parts in $ / mile terms rather than as  % of resale value.
When I got my WM20 I forked out $ 750 to have the magneto & dynamo fully reconditioned.
Now I am not flash with cash but those two units were original so had been there for nearly 60 years.
I now have a set of electrics that work perfectly ( if I maintain them) so the cost in $ / mile to date is about 15¢ .
Furthermore when we went to an All British Rally where it rained so hard that the bonfire floated away the M20 started to play up so I took it back to Scotty who found that the bearings were cactus ( think I know where the water came from) so he replaced them and the seals as well for free even though it was over 2 years since I had them done.
Others complain that they spent $ 250 with him & the units broke down & he the charged another $ 275 to fix them again where as if they had not been so cheap in the first place & got a full recondition rather than the cheapest patch up job then Scotty would have been happy to look at or even redoo the job and they would not have had the reoccuring problems. But as they had whinged & bitched about the exhorbenent price of the repair he gave them the appropriate after sales service.

The other problem is that replacement parts are by virtue of the age & use of the bikes a very low volume. In many cases the volume is so low that the only economic way to make them is by hand and that is expensive.
Class 1 machinists in OZ get $ 40 / hr in wages and that is with out considering the running cost of the equipment used to make them then the high cost of maintaining a low volume inventory.
Setting up a spring winder for instance to make AA return springs takes about 1 & 1/2 hours and will make up to 2000 units an hour.
In the days when the volume turn around was 2,000,000 a year it was economic to make them in 10 different spring rates sort, package & store them till despatch.
Now days the world wide consumption would be closer to 200 pair a year so the labour cost in setting  up the machine is around $ 5.00 each.
Bikie Beesa
Title: Re: Exhaust Pipe Problem
Post by: RichardL on 08.03. 2009 01:10

No offense taken at any point. I knew the pipes were not of the highest manufacture when I bought them from British Only on a deep sale just before they sold most of their BSA stock to Domiracer. Yes, the cheapness was a feature. On the other hand, at the time I bought them, the bike was quite a way from complete. Given the condition of the bike when I started and my limited experience in building motorcycles, there was, in the back of my head, until the bike started about a year later, the slight doubt that the thing would even work. By the time the pipes were on the bike and I noticed the problem, it was over a year later and they were used. I ultimately called British Only about it just to see if they could sell me a left pipe, only. They could not, but said they would have taken them back had I discovered it earlier and if they were not used. Hence, it is hard to ascribe too much recalcitrance to the vender, in this case.

Now that you've seen the "fix," will you think me riding around on a bodged-up mess? I have a hunch that I will be looking for the nicest pipes I can find, next year.

So, if I've got this right, you believe in paying for good quality parts rather than buying cheap crap. Correct, or did I miss something? *smile* ;)

Richard L.

Title: Re: Exhaust Pipe Problem
Post by: BSA_54A10 on 11.03. 2009 21:58
Yep, Got it in one.
If you can not afford quality, then go for the cheap bits in the knowledge that they probably will not fit and require some degree of "fitting" as you have done with your pipes.
When you find some one with good quality parts that fit correctly, TELL THE WHOLE WORLD.
If you bought cheap & they were dissapointing then grin & bear it.
Things work much better if you heap praise on the "good guys" and damm by ommission the bad guys, Sort of like ebay.
Some parts I use are top drawer while others are from slightly lower down the chest but when I get bad bits I just work on them till I am happy with them rather than carrying on like a mad tart because my own cheapness had brought me undone.

If I had the cash at the time & could find what I wanted when I needed it then I would always put the best quality parts on as I prefer to be riding rather than wrenching.
If possible I also fit correct parts , but if it is a case of wrong bits & on the road or correct bits on back order then I tend towards the road.
You can always find the right bits latter on but you can never go on the run that you missed and we all have a finite riding life.
I have a hide thicker than an elephant so all the nay sayers rubbishing me for having wrong parts on the bike get ignored.
Then there is the fact that it is MY BIKE so I have the right to fit whatever parts that I like so the next item for the WM20 will be a fishtale exhaust. Totally incorrect, but I like the look ( and sound) of the fishtale and it will give a bit more clearence between the incorrect kick start lever and the correct round muffler.

If I had a $ for every one I have come across over the years who spent years & years doing a catalogue perfect restoration then never got to ride his handiwork due to , heat attack, stroke , muscular distrophy, etc, etc, etc then I would have a garage full of gold stars and a very fat bank account.

Bike beesa
Title: Re: Exhaust Pipe Problem
Post by: groily on 11.03. 2009 22:23
Now you're talking Trevor . . . working and running beats waiting and worrying about the 'right' bits any day. Doesn't really matter what is 'right' to those of us who make no claims; and even for those who try to get it dead right, such claims often turn out to be debatable. I'd have to know more than the pea-brain can handle to be able to assemble something that might be, maybe, 'correct' - and while doing it, I'd have missed thousands of miles of amusement (and no doubt a fair bit of 'wrenching' as well).
So a fishtail which isn't fouled by the incorrect kick-start lever wouldn't bother me a bit, any more than the fact that my A's meant to be a Super Rocket so where's the alloy head and what cam has it got?
I reckon all the scary ways of dying you list are more likely to be ventured upon the person who's worried about whether his advance/retard lever should have the hex-head screw or the counter-bored round one than on the guy who just hooks it up and goes for a ride . . . . . . But hey, ours is a broad church - there might even be a Harley owner somewhere around!
Title: Re: Exhaust Pipe Problem
Post by: BSA_54A10 on 11.03. 2009 22:26
And good to hear that you are on the road.
Ride it with pride, knowing what you have done to get it mobile.
Enjoy your bike, that is what they were made for.
A little line that I have used for many years when some one points out the pipes ( or any other wrong, missing or bodged bit ).
"Yes I know, but I did not have the correct bit at the time , have you got one ? "
Usually they will pull there head in and slunk off to the hole that they came from.
And if you are really lucky they will pipe up with "yes I got an old one at home"
And if you are really, really lucky, they will follow up with " I don't need it any more you can have it for a pint" .
It dose pay to be nice, even when trying to put nit pickers in their place.
Bike Beesa
Title: Re: Exhaust Pipe Problem
Post by: RichardL on 11.03. 2009 23:35
Hey All,

New mufflers arrived today from British Cycle in Nova Scotia and they (the mufflers) are beatiful and, as far as I can tell, made in England. I am gassed (not drunk). Anyway, a quick question. At each end of the baffle chamber there is a hole drilled from the chamber into the pipe portion, like some kind of bypass. There is a burr on the coupling end that prevents full insertion of the exhaust pipe into the muffler. No problem, I can remove the burr. The question is, is there supposed to be exhaust gas flow through these holes which are only about 1/4" diameter?

Thanks for any help.

Richard L.
Title: Re: Exhaust Pipe Problem
Post by: RichardL on 12.03. 2009 04:43
Below is a drawing of the muffler showing where the holes in question are located. I have a theory. The holes are drilled in the pipe so that the person who is welding the body of the muffler to the internal pipe knows where to position the pipe, as in, "Mr. McArcker, please be sure you place the pipe in the body so that the holes cannot be seen after it is welded." How does that sound for a rationale?

Richard L.