Author Topic: Exhausted by an exhaust pipe!  (Read 698 times)

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Offline isettaman

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Exhausted by an exhaust pipe!
« on: 10 Jul 2020 at 15:36 »
Hi All
Have been trying to assemble the exhaust system to my 80 Plus, with brand new pipes supplied with the bike, only to find that the pipes don't lie at the correct angle, parallel to the frame. With the front ends snug in the exhaust ports, both pipes follow an alarming downward path. Having researched this, I believe I may have Dragonfly pipes instead of Plus ones. Am I correct in this? Also, presuming the Mark and Plus pipes are the same, they don't have the sealing ring that the Dragonfly ones have so how does one get an effective gas seal at the exhaust ports?
Finally, if what I think is true, does anyone want a pair of Dragonfly pipes??
Cheers
Dave








Image orientation fixed - Dave (admin), 11 July 2020
« Last Edit: 10 Jul 2020 at 21:06 by Dave »

Offline eddie

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Re: Exhausted by an exhaust pipe!
« Reply #1 on: 10 Jul 2020 at 17:01 »
H Dave,
             I think you just have a set of pipes that haven't quite been bent the full 180 degrees. They are definately not Dragonfly pipes as those are much shorter. If they were my pipes, i would attempt to tweak them so that they lay level with the frame bottom tube. Get a length of 1 1/4" dia bar to fit in the front of the pipe and remove the sharp edge from the end of the bar (so that it doesn't mark the pipe). Then fit a sleeve over the pipe where it normally goes into the cylinder head (so that you don't stretch the pipe). You should now be able to pull the tail of the pipe up to the bar (either manually or by using a spanish windlass) until the pipe lays naturally in the frame clip.

  Hope this helps,
                            Regards,
                                            Eddie.

Offline giz.neal

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Re: Exhausted by an exhaust pipe!
« Reply #2 on: 10 Jul 2020 at 17:21 »
Dave,

Strangely enough I encountered a similar problem last year with a set of pipes from a well known on-line supplier. The off-side pipe with the shorter bend didn't appear to be correct. However, I swapped pipes between my 90+ (for which the new pipes were purchased) and the family 80+ and lo and behold they fit each other fine. How this happens I have no idea, but it is typically Douglas! Sorry, No help I know.

Steve

Offline isettaman

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Re: Exhausted by an exhaust pipe!
« Reply #3 on: 10 Jul 2020 at 21:57 »
Thanks for your advice, Eddie
I can't quite visualise your suggested method of adjusting the bend in the pipe.
Are you saying that the tail and the head of the pipe should effectively be parallel to each other?
So the 11/4" bar needs to be long enough to reach to the end of the tail?
Should the tail piece also have some support inside it?
Am I on the right track?
Dave

Offline isettaman

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Re: Exhausted by an exhaust pipe!
« Reply #4 on: 10 Jul 2020 at 22:27 »
Hi Eddie
On inspection, I have found that the pipe is slightly short of the 180deg but look at how the collar has been welded onto the pipe!
That's the major problem which will require a major fettle!
Dave







Image orientation fixed - Dave (admin), 11 July 2020
« Last Edit: 11 Jul 2020 at 09:38 by Dave »

Offline Vitesse

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Re: Exhausted by an exhaust pipe!
« Reply #5 on: 10 Jul 2020 at 22:39 »
At the risk of insulting your intelligence - have you tried swapping sides? Stranger things have worked . . .

Offline graeme

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Re: Exhausted by an exhaust pipe!
« Reply #6 on: 11 Jul 2020 at 06:46 »
The pipes weren't supplied by a well known company in Bournemouth by any chance? They normally send their rubbish off to us in the colonies, knowing it would be too expensive to bother posting them back for a refund  :x

Offline EW-Ron

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Re: Exhausted by an exhaust pipe!
« Reply #7 on: 11 Jul 2020 at 06:55 »
And checked they are not for the trials model ...

https://www.shannons.com.au/library/images/news/Y294DFE745PERK6D/PDavey5.jpg

Sorry !

Offline eddie

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Re: Exhausted by an exhaust pipe!
« Reply #8 on: 11 Jul 2020 at 07:50 »
Hi Dave,
               The idea of the 1 1/4" bar up the stub end of the pipe and an outer sleeve to support it, was to enable more leverage to be applied to the stub that goes into the exhaust port (without distorting it). You are probably only looking for another degree or two of bend - it wouldn't matter if it was just the stub that was tweaked in order to get the pipe laying at the correct angle.
   With regard to the 'collar' on your pipe - that will be totally useless on a 'Plus' - it needs to be square to the pipe on both edges - 1. so that the pipe pulls back square in the port, and 2. so that the exhaust clamp ring sits evenly on the other edge. Obviously, whoever made the pipes, were more interested in the profit margin than the quality of their product, and if you are certain of their origin, a demand for a 'fit for purpose' replacement would be in order.

 Ron,
         The only postwar Douglas pipes that had the collars were the 'Plus' pipes that had the retaining ring, and the Dragonfly pipes where the collar just kept the copper/asbestos washer in place. All other models just had plain pipes pushed into the exhaust ports - the finned cooling rings seen on some bikes were just that - they did nothing to help secure the pipes.

  Regards,
                 Eddie.

Offline isettaman

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Re: Exhausted by an exhaust pipe!
« Reply #9 on: 11 Jul 2020 at 09:27 »
Thanks, Eddie
I now have a clear picture regarding getting the correct bend on the pipes and canít see it being too difficult to achieve. The collars are a different matter. Iím not an expert, but fettling would involve cutting the old ones off, welding new ones in and then re-chroming. A process which would probably cost more than a pair of new pipes.
Iíll phone Ralph who sold me the project to find out where he got them from and if he has any paperwork. Bearing in mind that he could have bought them 40 years ago!

Offline isettaman

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Re: Exhausted by an exhaust pipe!
« Reply #10 on: 11 Jul 2020 at 17:52 »
Hi Eddie
Just spoken to Ralph, he confirmed that he bought them in the 70's from the Club spares. He has no paperwork and it is a long time ago and I'm sure the Club spares don't stock them any more, anyway. They were all wrapped up in that crinkly brown paper and he never thought to examine them at the time. They are actually stainless so I will cast around for a good stainless welder to see if a repair is viable.
Dave

Offline Roys rider

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Re: Exhausted by an exhaust pipe!
« Reply #11 on: 11 Jul 2020 at 21:19 »
Hi
This conversation identifies the problem I am having with the 'new' fly, in that the left 1970s pipe is an inch low and the silencer wont screw up without a big push, which will distort the exhaust port fit.. A neighbour tells me that there is an specials exhaust company in Congleton, Cheshire. I haven't been yet due to inertia and lockdown but I understand he is quite helpful. I will see what I can find out. Mind you Eddie's technique is cheaper if only on petrol.
Peter

Offline isettaman

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Re: Exhausted by an exhaust pipe!
« Reply #12 on: 11 Jul 2020 at 22:03 »
I'm back
I've found a stainless steel motorcycle exhaust specialist here in Wakefield so I'll be off to see him on Monday.
Dave

Offline EW-Ron

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Re: Exhausted by an exhaust pipe!
« Reply #13 on: 11 Jul 2020 at 22:36 »
They are actually stainless so I will cast around for a good stainless welder to see if a repair is viable.

If they are stainless, they could also be heated and tweaked to increase the bend without the fear of the chrome cracking.
And then be polished again.

My suggestion they might be trials pipes was mostly in jest.
I have now been edumacated !!

Offline eddie

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Re: Exhausted by an exhaust pipe!
« Reply #14 on: 12 Jul 2020 at 07:30 »
Dave,
          This may not please the purists, but if the pipes are stainless, use the sleeve (as suggested for tweaking the end of the pipe) to check how far out of square the collar is - and trim the collar back carefully until it is square. Then trim back the other side of the collar until it is the same width most of the way round. The pipe should now fit in the port, and the clamp ring secure it in place - if not, you may need to fit a thin spacer in the clamp ring to make up for the material removed from the collar. You may also need to trim the end of the pipe if it is now too long for the port. If the trimming cuts through the weld in a couple of places, I wouldn't worry about it, as it will still be plenty strong enough to secure the pipe in place, and the cosmetics won't matter as the clamp ring will cover it.

   Regards,
                  Eddie.

Offline isettaman

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Re: Exhausted by an exhaust pipe!
« Reply #15 on: 13 Jul 2020 at 08:18 »
Hi Eddie
I had considered trimming the collar to get it square, unfortunately, with the split in it there would be a portion with no collar at all. I suppose I could put a spacer either side of the collar after trimming it but I feel visit to the specialist is on the cards. The other pipe, I think, just requires a tweek to get it to the required 180deg.
Dave

Offline Vitesse

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Re: Exhausted by an exhaust pipe!
« Reply #16 on: 13 Jul 2020 at 09:09 »
Would having an area without a section of collar matter?  Unless I'm wrong (quite possible as I haven't had to strip my bike at all yet) it has no sealing function, merely is a bearing surface for the exhaust nut to bear on. I've had split collets on many bikes performing the same fuction.

Offline isettaman

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Re: Exhausted by an exhaust pipe!
« Reply #17 on: 13 Jul 2020 at 09:34 »
Hmmm
I've a pair of copper asbestos seals which came with the bike, presumably these are to seal the ports?
Dave

Offline eddie

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Re: Exhausted by an exhaust pipe!
« Reply #18 on: 13 Jul 2020 at 10:58 »
I have never seen a parts book for the 'Plus' series, so don't know whether seals were listed for the exhaust pipes. The Dragonflies had copper/asbestos seals but they were not a particularly good fit on the pipes, so probably didn't seal very well. I have always assembled my Dragonfly exhausts with a smear of Holts Firegum in the ports and the seals omitted - the pipes have never moved or leaked.

  Regards,
                  Eddie.

Offline isettaman

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Re: Exhausted by an exhaust pipe!
« Reply #19 on: 14 Jul 2020 at 08:44 »
The exhaust specialist isn't taking on any further work until September so I'm going with your suggestions, Eddie, with trimming the deformed collar and adjusting the bends with a suitable bar etc.
I will report back my progress.
Dave

 

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