- Joined
- Apr 28, 2015
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- 154
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After a ton of research, trial, error, failure, frustration, and figuring it out I have finally got to the functional prototyping stage of a conversion tube that helps an RH4 head get close to the Narley Ports documented by Jim Schmidt.
I have spent a good amount of time reading and modeling Jim's XR750 to Norton port documentation and communicating with Jim to get this to where it is. The idea is continuation on the idea from Jim Schmidts work on the RH10 Conversion tubes. I elected to get first round of prototypes 3D printed in aluminum and these are now in their second revision and are being run presently in my MK3 Norton. The goal is to increase the velocity into the port, develop a bit more torque down low and carry on up high as well.
With a third revision underway, I am feeling much better about sharing what I have been up to.
Sending files out via email then receiving these in the mail a week later was a trip:
Removal of the old RH10 conversion tubes was simple. A bit of heat from a torch and a tig welding glove had them out in no time. I cleaned the port with acetone, let it dry used Loctite 510 on the new sleeve and installed.
This is all new territory for me and I am still shocked that this actually fit let alone worked as well as it does. Crazy to think how much time and thought goes into something like this. There is a lot to unpack about how it runs after install, idle is quieter and I was able to reduce my idle running a JS2 cam (which like a high idle) down to around 1100 to 1200 rpm from 1400-ish. Starting is easier and time to settle into a running idle is faster. However, when you get on the throttle is when you start to notice things. I immediately noticed a good chunk of low end and midrange and when the cam comes on it is properly fast, it pulls beautifully to 7500 rpm (probably beyond as well). Tons of torque, tons of pull, finding
I am still refining these and plan another revision to get these things to be a closer fit there is still some playing I am doing. A lot of attention has been paid to the cross sectional area and I am working on a slightly more refined fit and dealing with 3D printing specific issues in the next round of prototyping. Curious to hear feedback, this has been a ton of fun to work on and I have already started a couple more Norton projects as well.
I have spent a good amount of time reading and modeling Jim's XR750 to Norton port documentation and communicating with Jim to get this to where it is. The idea is continuation on the idea from Jim Schmidts work on the RH10 Conversion tubes. I elected to get first round of prototypes 3D printed in aluminum and these are now in their second revision and are being run presently in my MK3 Norton. The goal is to increase the velocity into the port, develop a bit more torque down low and carry on up high as well.
With a third revision underway, I am feeling much better about sharing what I have been up to.
![RH4 To Narley Port Conversion Tubes RH4 To Narley Port Conversion Tubes](https://i.imgur.com/3JsAHnk.png)
![RH4 To Narley Port Conversion Tubes RH4 To Narley Port Conversion Tubes](https://i.imgur.com/H10OITo.png)
![RH4 To Narley Port Conversion Tubes RH4 To Narley Port Conversion Tubes](https://i.imgur.com/iwHNoDF.png)
![RH4 To Narley Port Conversion Tubes RH4 To Narley Port Conversion Tubes](https://i.imgur.com/e6wn9C1.png)
Sending files out via email then receiving these in the mail a week later was a trip:
![RH4 To Narley Port Conversion Tubes RH4 To Narley Port Conversion Tubes](https://i.imgur.com/w2OJtvc.jpeg)
![RH4 To Narley Port Conversion Tubes RH4 To Narley Port Conversion Tubes](https://i.imgur.com/CbLHr7v.jpeg)
![RH4 To Narley Port Conversion Tubes RH4 To Narley Port Conversion Tubes](https://i.imgur.com/gQSwpnl.jpeg)
![RH4 To Narley Port Conversion Tubes RH4 To Narley Port Conversion Tubes](https://i.imgur.com/Qjd4XiL.jpeg)
Removal of the old RH10 conversion tubes was simple. A bit of heat from a torch and a tig welding glove had them out in no time. I cleaned the port with acetone, let it dry used Loctite 510 on the new sleeve and installed.
![RH4 To Narley Port Conversion Tubes RH4 To Narley Port Conversion Tubes](https://i.imgur.com/mjCAmL6.jpeg)
This is all new territory for me and I am still shocked that this actually fit let alone worked as well as it does. Crazy to think how much time and thought goes into something like this. There is a lot to unpack about how it runs after install, idle is quieter and I was able to reduce my idle running a JS2 cam (which like a high idle) down to around 1100 to 1200 rpm from 1400-ish. Starting is easier and time to settle into a running idle is faster. However, when you get on the throttle is when you start to notice things. I immediately noticed a good chunk of low end and midrange and when the cam comes on it is properly fast, it pulls beautifully to 7500 rpm (probably beyond as well). Tons of torque, tons of pull, finding
I am still refining these and plan another revision to get these things to be a closer fit there is still some playing I am doing. A lot of attention has been paid to the cross sectional area and I am working on a slightly more refined fit and dealing with 3D printing specific issues in the next round of prototyping. Curious to hear feedback, this has been a ton of fun to work on and I have already started a couple more Norton projects as well.
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