Author Topic: Rd125/200 downpipes (headers)  (Read 290 times)

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Offline adydeere

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Rd125/200 downpipes (headers)
« on: September 29, 2020, 10:08:54 AM »
Hi all,
I have a set of microns for an RD200 but would like to fit them on an RD125 I have offered them up but the downpipes are too short does anyone know if the RD200 downpipes will fit as it looks like they are longer but not sure if the exhaust port is higher on the 200?
I can get a sleeve made that will do the job but would be nice to have a single downpipe.
Regards
Ady

Online Astute Greaser

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Re: Rd125/200 downpipes (headers)
« Reply #1 on: September 29, 2020, 10:51:43 AM »
Can't answer your question but for others to help, you need to state the full model numbers of both bikes ie A/B, 1E7, 1E8 etc as downpipes are different each model

Offline adydeere

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Re: Rd125/200 downpipes (headers)
« Reply #2 on: September 29, 2020, 12:39:55 PM »
Thank you astute for the reply although I wanted to keep it simple so here goes it is actually an AS3 and stamped AS3 on the frame and engine although it is an almost identical engine to a 1E7 with the same heads and barrels with read valve intakes so I hope that helps. The microns had RD200 on the box and I think they were made for the 1E8.
« Last Edit: September 29, 2020, 05:51:31 PM by adydeere »

Online Alistair64

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Re: Rd125/200 downpipes (headers)
« Reply #3 on: September 29, 2020, 08:39:59 PM »
Interesting and this takes me back 35 years!
In the mid-80's I had an RD125DX fitted with Microns.
My Dad had an RD200DX and I remember we swapped them over to his bike to try it out.
I don't remember any fitting issues and that they bolted straight on.
In fact they worked just as well on the 200 as they did on the 125 - I say 'well', but bottom end was lost on both bikes with a slight gain at the top end, but boy, did they sound good  ;D
I wouldn't mind betting that the Microns sold for the 125 and 200 were the same pipes.
Strange that you say the 125 downpipes seem too short, because although they are shorter, they definitely didn't give me a problem back then.

Footnote: Although I can't remember what I had for dinner 2 nights ago, certain things that happened all those years ago just stick in the mind  :D
1982 Candy red RD200DX
1983 Yellow/black RD200DX (resprayed and previously owned by another forum member)
1986 White/red RD350F1 YPVS - owned since 1987...yes, honestly!!

Offline adydeere

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Re: Rd125/200 downpipes (headers)
« Reply #4 on: September 30, 2020, 04:52:25 PM »
Hi Alistair,
The mounting points marry up but its just that the downpipes are too short.
Thanks
Ady

Online Alistair64

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Re: Rd125/200 downpipes (headers)
« Reply #5 on: September 30, 2020, 08:28:13 PM »
Understood, but I seem to recall that the pipes just slid further up the longer downpipes on the 200.
They still fitted the 125.

Just had a thought that maybe the Microns for the 125 and 200 are different lengths after all.
So the 125 pipes will fit the 200, but not vice versa.
1982 Candy red RD200DX
1983 Yellow/black RD200DX (resprayed and previously owned by another forum member)
1986 White/red RD350F1 YPVS - owned since 1987...yes, honestly!!

Offline adydeere

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Re: Rd125/200 downpipes (headers)
« Reply #6 on: October 02, 2020, 09:50:34 AM »
That would make sense so its just whether or not a 200 exhaust port is a lot higher as there will be some wiggle room if its only a few millimeters it shouldn't be problem.

Online Astute Greaser

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Re: Rd125/200 downpipes (headers)
« Reply #7 on: October 02, 2020, 10:52:00 AM »
Hopefully this will help.
Find flatbed scan (photocopy) pdf of a RD200A (round tank) 397 RH downpipe.
If you print this off 1:1 you can lay your AS3 RD125 downpipe on top to compare.
Cheers
-Mike
If you can't download this properly pm me your email and I'll send direct

Offline adydeere

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Re: Rd125/200 downpipes (headers)
« Reply #8 on: October 02, 2020, 01:51:32 PM »
Thanks Mike that is excellent I will be in the workshop next week and let you know.
Regards
Ady

Online Alistair64

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Re: Rd125/200 downpipes (headers)
« Reply #9 on: October 02, 2020, 07:39:46 PM »
That would make sense so its just whether or not a 200 exhaust port is a lot higher as there will be some wiggle room if its only a few millimeters it shouldn't be problem.

Ady, I think you can assume that there is very little difference between where the exhaust ports sit due to the very small difference in stroke lengths.
I'm sure it won't cause an issue.
1982 Candy red RD200DX
1983 Yellow/black RD200DX (resprayed and previously owned by another forum member)
1986 White/red RD350F1 YPVS - owned since 1987...yes, honestly!!

Offline adydeere

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Re: Rd125/200 downpipes (headers)
« Reply #10 on: October 13, 2020, 01:34:51 PM »
Hi, just to confirm that the RD200 downpipes fit perfectly so the project carries on.
Thanks
Ady

Online Astute Greaser

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Re: Rd125/200 downpipes (headers)
« Reply #11 on: October 13, 2020, 05:25:53 PM »
So Ady
How much longer is the RD200A pipe to your AS3/RD125A pipe  ???
-Mike