Ariel twin

Bikes or not. Whatever
jj.palmer
Holder of a Nylon Anorak
Holder of a Nylon Anorak
Posts: 255
Joined: Tue Oct 15, 2013 3:07 pm
Location: Denby Village, Derbyshire.
Contact:

Re: Ariel twin

Postby jj.palmer » Fri Aug 30, 2019 7:52 pm

Hi Lee, good to see you are progressing, please keep us informed.
I thought that new larger diameter pistons are normally compensated to retain the same compression ratio. When I rebored my KH to +.040 the height of the new piston from the gudgeon pin to the top of the piston was reduced by .025 when compared to the old one thereby keeping the same ratio.
Check the the height between the old and the new pistons.

John P.

Paul Slootheer
Holder of a Silver Anorak
Holder of a Silver Anorak
Posts: 663
Joined: Mon Jul 30, 2012 5:47 pm
Contact:

Re: Ariel twin

Postby Paul Slootheer » Fri Aug 30, 2019 8:04 pm

Lee, I did buy 6.8 : 1 pistons. Do you want a higher compression?

User avatar
Leejm
Holder of a Golden Anorak
Holder of a Golden Anorak
Posts: 1169
Joined: Thu Feb 05, 2015 1:17 pm
Location: Nuneaton, Warwickshire
Contact:

Re: Ariel twin

Postby Leejm » Fri Aug 30, 2019 8:13 pm

Cheers for john I will have to ask that question.
Paul just thinking out loud with it all. Not made any decsions as yet.
1948 NH, BSA D10 SPORTS. 1953 VHA, 1951 KH rigid project.

jj.palmer
Holder of a Nylon Anorak
Holder of a Nylon Anorak
Posts: 255
Joined: Tue Oct 15, 2013 3:07 pm
Location: Denby Village, Derbyshire.
Contact:

Re: Ariel twin

Postby jj.palmer » Sat Aug 31, 2019 10:17 am

Lee a word of caution from my past mistake, be wary of the weight of new piston assemblies in comparison to the old ones in order to maintain the original balance factor.
The Gandini 6.8:1 comp. ratio piston assemblies that I purchased were 55 grams heavier than the old ones and therefore had to be modified to reduce that weight in order to acheive the original balance factor of 64%.
It may be benificial to check the balance factor before you start.

John P.

Paul Slootheer
Holder of a Silver Anorak
Holder of a Silver Anorak
Posts: 663
Joined: Mon Jul 30, 2012 5:47 pm
Contact:

Re: Ariel twin

Postby Paul Slootheer » Sat Aug 31, 2019 10:41 am

John, what weight in grams did you measure regarding the original pistons?
Regards,
Paul Slootheer

jj.palmer
Holder of a Nylon Anorak
Holder of a Nylon Anorak
Posts: 255
Joined: Tue Oct 15, 2013 3:07 pm
Location: Denby Village, Derbyshire.
Contact:

Re: Ariel twin

Postby jj.palmer » Sat Aug 31, 2019 12:15 pm

Paul, The weight of the original sized piston assembly ie piston, rings and pin, was -
Near side 240.9 grams
Off side 243.1 grams
Average 242 grams
Estimated original weight = 242 grams + 3 grams (wear loss) = 245 grams.

When statically balanced with the above piston assemblies the crank assembly showed a balance factor of 63.3 % say 64 %.
Hope this helps.

John P.

User avatar
Leejm
Holder of a Golden Anorak
Holder of a Golden Anorak
Posts: 1169
Joined: Thu Feb 05, 2015 1:17 pm
Location: Nuneaton, Warwickshire
Contact:

Re: Ariel twin

Postby Leejm » Sat Aug 31, 2019 12:35 pm

Cheers gents for all your input and advice here. Being new to twins it all comes in handy.
1948 NH, BSA D10 SPORTS. 1953 VHA, 1951 KH rigid project.

Paul Slootheer
Holder of a Silver Anorak
Holder of a Silver Anorak
Posts: 663
Joined: Mon Jul 30, 2012 5:47 pm
Contact:

Re: Ariel twin

Postby Paul Slootheer » Sat Aug 31, 2019 12:36 pm

Thank you John.
I measure (on a letter scale) 185 grams for the bare piston, and for the complete (piston, rings, circlips and gudgeon pin), it shows a total of 250 grams... This is a 0.20'' piston from the club, make unknown...
Regards, Paul
Last edited by Paul Slootheer on Mon Sep 02, 2019 8:10 pm, edited 1 time in total.

User avatar
Leejm
Holder of a Golden Anorak
Holder of a Golden Anorak
Posts: 1169
Joined: Thu Feb 05, 2015 1:17 pm
Location: Nuneaton, Warwickshire
Contact:

Re: Ariel twin

Postby Leejm » Sat Aug 31, 2019 12:43 pm

On a good note I now have a BA box!
1948 NH, BSA D10 SPORTS. 1953 VHA, 1951 KH rigid project.

User avatar
Leejm
Holder of a Golden Anorak
Holder of a Golden Anorak
Posts: 1169
Joined: Thu Feb 05, 2015 1:17 pm
Location: Nuneaton, Warwickshire
Contact:

Re: Ariel twin

Postby Leejm » Sun Sep 08, 2019 10:29 am

Bargain of the century! I also have a rear number plate thanks to Alan Morre . Just need to attack that with the angle grinder and welder .
Attachments
600148F7-3A5B-4610-97D6-4D24C3BA12AC.jpeg
1948 NH, BSA D10 SPORTS. 1953 VHA, 1951 KH rigid project.


Return to “Main Chat Forum”

Who is online

Users browsing this forum: No registered users and 10 guests