DIY/Modded Stubby H-Pipe

Thanks for the heads up on the material. I put so few miles on this bike, I think I'll just test the material on the road.

So, the shielded coupler was a great fit on the carb . . . but the other end has the exact same ID and OD as my air filters. Just found a 1-1/2" PVC coupler at Home Depot to make a solid connection between the shielded coupler and the air filter. Tomorrow I'll figure out the plumbing, I hope.

Never spent time in the Home Depot plumbing department before . . . new horizons!
 
Great that I found this tread, my bike had air filter fitted directly to the carbs. I am now making my own H pipes out of PVC pluming coupling that i found in my local store. Just needed a small bit of milling and fits perfect. So lets hope it runs a bit better now.
 

Attachments

  • Skärmavbild 2025-04-29 kl. 21.39.12.png
    Skärmavbild 2025-04-29 kl. 21.39.12.png
    446.3 KB · Views: 14
Great that I found this tread, my bike had air filter fitted directly to the carbs. I am now making my own H pipes out of PVC pluming coupling that i found in my local store. Just needed a small bit of milling and fits perfect. So lets hope it runs a bit better now.
Looks like hard plastic?
What will keep the carbs and filter attached to them?

Make sure you mill out that indented stopper in the middle. Don't need turbulence at that point in the intake.
 
Looks like hard plastic?
What will keep the carbs and filter attached to them?

Make sure you mill out that indented stopper in the middle. Don't need turbulence at that point in the intake.
Yepp the stopper in the middle is milled out. I milled out the inner diameter to a tight fit and with a hose clamp around it i cant move them on the carb, so feels like a good fit. And I also milled the out side of the pipe for the pod filters, so they attach on to the pipe, clamp secures them in place.
 

Attachments

  • H pipe.pdf
    83.7 KB · Views: 22
I've found my people! Been doing similar experiments with my own bike--mostly because even a used H-pipe is going to be about 40 years old, I've been trying to find ways to replicate the OEM hose.

Some of the things I've tried are silicone intake hoses (for intercoolers; you can get 55mm-45mm couplers and straight 45-mm hoses in 100mm lengths). Those are my fallback choices.

My other, main idea that seems to be working so far is a 3D-printed one from TPU-95A. This one's taking lots of time because I dimensioned it myself, and modding/tuning my printer is the hard part. More or less a reproduction part. The prototypes I printed seem to work OK, but there's more I can adjust.

https://www.thingiverse.com/thing:6992979
 
Back
Top