Has anyone used JBM replacement carb diaphragms ?

aSTerix · Feb 18, 2020

I am looking at just buying replacement rubber diaphragms and glueing them to the existing piston slides, the procedure to cut the diaphragm mounting rings off , is shown here :

JBM Diaphragm for Honda VFR400R , VFR400RR, NC-30, VTR250, PC800

Purchase the JBM Industries replacement vintage motorcycle diaphragm or membrane on Honda VFR400R, VFR400RR, NC-30, VTR250, PC800 with plastic slides in Keihin carburetors. How the central rubber tire works and installed on plastic or metal slides.

www.jbmindustries.com

Was wondering if anyone has been down this path before ?

Thankyou to @oude geit for the steer towards JBM

aSTerix · Apr 4, 2020

I just got the price from Honda for new piston slides with diaphragms, $250 for a set of 4 !!

Using JBM would cost $80

heffly · Apr 4, 2020

I used them on my VTX about 40000 miles ago. I learned of them on the VTX forum.

aSTerix · Apr 4, 2020

heffly said:
I used them on my VTX about 40000 miles ago. I learned of them on the VTX forum.

Did you need to cut off the old Diaphragms and glue the new ones onto the slide ?

ST1100Y · Apr 5, 2020

Asterysk said:
I just got the price from Honda for new piston slides with diaphragms, $250 for a set of 4

Check which ST model, hence which carbs you have; IIRC are EC spec carbs equipped with aluminum cast sliders, whilst the US spec have the shown plastic ones

aSTerix · Apr 5, 2020

ST1100Y said:
Check which ST model, hence which carbs you have; IIRC are EC spec carbs equipped with aluminum cast sliders, whilst the US spec have the shown plastic ones

Aha, I hadn't picked up on that. Wonder if the cutting technique will work on the aluminium, also I better double check the ID measurements.

ST1100Y · Apr 5, 2020

Asterysk said:
Aha, I hadn't picked up on that. Wonder if the cutting technique will work on the aluminium, also I better double check the ID measurements.

Did a CB750 with an NRP kit a while back, aluminum sliders with plastic twist-locks, pretty easy...

heffly · Apr 5, 2020

Asterysk said:
Did you need to cut off the old Diaphragms and glue the new ones onto the slide ?

I did have to remove the old one.

aSTerix · Apr 22, 2020

heffly said:
I did have to remove the old one.

Can you recall if you removed both rings or just the top one ? I have been looking at the video and instructions and both seem to be valid options !

aSTerix · Apr 22, 2020

From my research and measurements it looks like the K-72-S will fit my ST1100 metal slides. I have just ordered one to try it out and will report back with some photos if it works.