If this is to gain acceptance as an alternative part, we need to know the full details of what is involved in the modification.
Dimensions of the oem and Yamaha parts, part number, spacer and perhaps a diagram of how the replacement part is assembled - an exploded diagram maybe - would all be useful. With this information I can document it on my website for all to see and assess.

 

 

Hello, I did not understand exactly what needs to be modified...I have a problem with my TRE K 1130, I bought everything except the part mentioned above. Ilija, if he can clarify here or +385918821730 Siniša, Thank you

 

Hello Sinisa, I send you message on the Viber app.

 

Ilija, don't keep it a secret. Let us all know what you did.

 

It is not a secret,I am too busy with work shop an store.
I will post everything in my first free time.

 

I bought a Yamaha sprag clutch outer race and bearing, as discussed here, to consider adaption to the Benelli 899/1130. Besides the bolt hole difference, the Yamaha ring is 2mm thinner and the step in the bore is 2mm shallower than in the Benelli outer race. The diagram attached shows the purpose of a spacer that I think is required to adapt the Yamaha outer race. The spacer would be a total of 4mm thick, with a 2mm recess to locate the Yamaha race concentrically on the Benelli sprag clutch flange. I have ordered a BMW sprag clutch to compare, in the hope it has a 3mm counter bore, to locate on a flange boss the same way as the Benelli, avoiding the need for a spacer ring.

 

That is correct,your drawing is good.I did it just like that.

If you find better solution for outer ring that doesnt need spacer,please share here.

My company is in proces of manufacturing high quality Z25 and starter gears with starter gear ring.Unlimited amount,manufactured from steel 4321 and 4835.In a few days I will collect first amount of Z25 shafts tested on 55HRC.
Soon I will share here with new topic,please wait,more details soon.