Bedding in rings using hard chrome barrels

Moto Rumi technical problems or solutions
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Ren
Posts: 20
Joined: Wed Oct 06, 2010 11:25 am

Bedding in rings using hard chrome barrels

Post by Ren » Tue Jan 14, 2020 1:30 pm

Have decided to start a new thread regarding bedding in rings on hard chromed aluminium barrels .
Any suggestions , has anyone else had this problem ? If so , how did you do it ?
thank you in advance .
Ren

greasy-fingers
Posts: 498
Joined: Thu Jan 07, 2010 11:36 pm

Re: bedding in rings using hard chrome barrels

Post by greasy-fingers » Tue Jan 14, 2020 1:56 pm

My last words on this subject --- you should be aware that cast iron comes in various grades/hardness, are you sure you have rings intended to be used in chrome bores ?

Ren
Posts: 20
Joined: Wed Oct 06, 2010 11:25 am

Re: bedding in rings using hard chrome barrels

Post by Ren » Tue Jan 14, 2020 2:56 pm

I am not a piston and ring manufacturer so don't exactly know what grade cast Iron should be used .
Can you tell me what grade / hardness should be used , Brinell or Rockwell hardness if you please . :?:
regards
Ren

greasy-fingers
Posts: 498
Joined: Thu Jan 07, 2010 11:36 pm

Re: bedding in rings using hard chrome barrels

Post by greasy-fingers » Tue Jan 14, 2020 7:23 pm

Obviously Rumi original spec rings would be best. I have also used pattern hepolite/Hepworth rings in chrome cylinders with success in the past. The running in time I used was about 100 miles at no more than half throttle, and a further 200 or so miles before using full throttle for anything other than short blips, after this I found the listed/standard 78 main jet way too rich with twin 18mm carbs and had to come down to 72, however I found the seat and dropped bars too uncomfortable for long distance use = it was never held on full throttle for long.

Ren
Posts: 20
Joined: Wed Oct 06, 2010 11:25 am

Re: Bedding in rings using hard chrome barrels

Post by Ren » Wed Jan 15, 2020 11:22 am

Thank you , I will re-try with my cast iron rings in a few weeks and see how it goes .
Yes , the drop bars are very unconfortable .
Ren

Ian Skinner
Posts: 535
Joined: Mon Aug 24, 2009 12:36 pm
Location: South Wales UK

Re: Bedding in rings using hard chrome barrels

Post by Ian Skinner » Wed Jan 15, 2020 11:47 am

Hi Guys

Basic rule about chromed bores, is not to fit chrome alloy rings. They will never bed-in, most likely they will rip the chrome lining off the bores!

Ian

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