2002 Works Honda HRC RC125 with a twist

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6/30/2020 10:57 PM

Subed !!! I'm in SJ as well & need to come by to see this stuff in person ! tongue

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Speak softly and carry a big stick.

7/1/2020 4:04 AM

The biggest interest for me is the internal parts of the engine, how they are improved, what is changed so that everything works best. Great work and I look forward to continuing these amazing projectsw00t w00t

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7/1/2020 8:47 AM

matt.3150 wrote:

Here’s 1994 HRC RC125 engine, the picture shows one engine case, but I have both, and there are factory sandcast engine cases, so pretty rare stuff.


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Amazing collection! Have you compared the geometry of the cases and the porting of cylinder with stock parts?

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7/1/2020 12:01 PM

matt.3150 wrote:

Here’s 1994 HRC RC125 engine, the picture shows one engine case, but I have both, and there are factory sandcast engine cases, so pretty rare stuff.


Photo

Banana_oil wrote:

Amazing collection! Have you compared the geometry of the cases and the porting of cylinder with stock parts?

The cases have some differences nothing really really major, the cylinder has some differences also but more major.

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7/1/2020 12:45 PM

dawidslaby767 wrote:

The biggest interest for me is the internal parts of the engine, how they are improved, what is changed so that everything works best. Great work and I look forward to continuing these amazing projectsw00t w00t

Well on the case there is a ton of epoxy work done to them, they actually made molds so they could replicate the shape in the reef valve area! The cylinder has made to use orings on the head, also ported and added epoxy at the bottom of the ports to change how the fuel mixture flows into the cylinder. The entire exhaust was plugs with aluminum and they remachined in with the opposite shaped D hole. The power valves were brazed up and reshaped fir a much tighter seal to increase psi , much less blow by.

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7/1/2020 12:47 PM


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7/1/2020 6:15 PM
Edited Date/Time: 7/1/2020 6:26 PM

Hard to see with the 2D of a photo, but the reed box seems quite intrusive to the flow into transfers. I wonder why such little expoxy in the corners, to reinforce/patch bolt holes? Interested in epoxy placement in the transfer.
With the raised floor ex duct floor how is the manifold interface?
Where these US Honda developed cylinders?
Thanks for the time and effort of posting. Keen to see dyno runs when back together.

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7/1/2020 6:51 PM

Wow I'm a sucker for hrc goodies but this is overload. I keep going over the pics. Just wow. Girlfriend keeps nagging me cause i havent paid her attention since I've opened the thread a hour ago lol Each bike u named and showed so far are all damn awesome bikes. Keep the pics coming and when u get a chance make individual builds for each !!

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7/1/2020 8:52 PM

Chris99Flannery wrote:

Hard to see with the 2D of a photo, but the reed box seems quite intrusive to the flow into transfers. I wonder why such little expoxy in the corners, to reinforce/patch bolt holes? Interested in epoxy placement in the transfer.
With the raised floor ex duct floor how is the manifold interface?
Where these US Honda developed cylinders?
Thanks for the time and effort of posting. Keen to see dyno runs when back together.

Yes it was developed by AHM with some help from Japan, one of my closest friend is one of the guys that did the majority of R&D work. So as far as the reed valve area goes, From my understand the important part is the shape of that area not flow rates, opening things up so the air fuel mixture would flow better was not the best for power, or ridable power. Also the amount of bottom end compression is important there’s a give and a take with allot of this stuff, and the amount of volume in that area make a different as also. Everything that they came up with was check on the dyno to make sure thing were moving in the right direction.

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7/1/2020 9:34 PM

Very interesting! How about exhaust port shape and timing? How wide is it and is the duration different?

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7/1/2020 10:00 PM

Banana_oil wrote:

Very interesting! How about exhaust port shape and timing? How wide is it and is the duration different?

Well since it’s a long rod and a spacer plate goes under neith the cylinder, I could not really tell you, But I can’t give you too much!

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7/2/2020 2:27 AM

Chris99Flannery wrote:

Hard to see with the 2D of a photo, but the reed box seems quite intrusive to the flow into transfers. I wonder why such little expoxy in the corners, to reinforce/patch bolt holes? Interested in epoxy placement in the transfer.
With the raised floor ex duct floor how is the manifold interface?
Where these US Honda developed cylinders?
Thanks for the time and effort of posting. Keen to see dyno runs when back together.

matt.3150 wrote:

Yes it was developed by AHM with some help from Japan, one of my closest friend is one of the guys that did the majority of R&D work. So as far as the reed valve area goes, From my understand the important part is the shape of that area not flow rates, opening things up so the air fuel mixture would flow better was not the best for power, or ridable power. Also the amount of bottom end compression is important there’s a give and a take with allot of this stuff, and the amount of volume in that area make a different as also. Everything that they came up with was check on the dyno to make sure thing were moving in the right direction.

Ive expoxied my 99 reed cavity and ground more angle up towards the transfers. Using a rad valve with custom thin reeds. Also i welded my exhaust manifold to match and suit my exhaust duct, among another list of things.
Totally agree, changing one thing requires careful consideration of parts of the engine cycle. Either way i’m gaining with my CR.
Cant wait to see more and maybe some dyno time if you do.

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7/2/2020 4:48 AM

Nice bike!! There's some expert level bike builders on here

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7/2/2020 6:03 AM

Incredible build, can’t wait to see the finished product!

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7/2/2020 4:23 PM

Here’s a bit if a mock up, not the engine that will be in the final build, also have a different frame. But It’s just a visual mock up Photo

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7/2/2020 11:22 PM

So here’s some HRC 2003-2004 engine kit. Photo

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7/2/2020 11:23 PM

Oh yea forgot about the HRC works crank for the RC250 Photo

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7/3/2020 7:36 PM

matt.3150 wrote:

So here’s some HRC 2003-2004 engine kit. Photo

WOW ! Very interested in the entire set up if you're willing to sell it..

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Speak softly and carry a big stick.

7/4/2020 1:17 PM

matt.3150 wrote:

So here’s some HRC 2003-2004 engine kit. Photo

H4L wrote:

WOW ! Very interested in the entire set up if you're willing to sell it..

Sorry I been collecting parts for years, so at this point I don’t want to sell anything, I finally am ready to start building bikes

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7/4/2020 1:18 PM

Back to the 125 a bit updated picture Photo

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7/4/2020 1:19 PM

Once I get the cases back from the welder, I can start my engine build!

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7/4/2020 1:42 PM

matt.3150 wrote:

Once I get the cases back from the welder, I can start my engine build!

Can’t wait to see this build get going bud, going to be amazing smile

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