Piston problems Model C
Piston problems Model C
Rebuilt bike a couple of years ago, set of this morning on a run 18 miles in piston nipped up! Been running great, plenty of oil?
-
- Holder of a Golden Anorak
- Posts: 2391
- Joined: Sat Jul 07, 2018 5:39 pm
- Contact:
Re: Piston problems Model C
is it Runing to rich and washing the oil off the boor or is the timeing out
- brenton.roy
- Holder of a Golden Anorak
- Posts: 2056
- Joined: Sun Feb 27, 2011 1:13 pm
- Location: Adelaide, South Australia
- Contact:
Re: Piston problems Model C
The pitting on the crown suggests it was burning really hot. Lean?
It's not easy to jet the mains as we tend not to ride at big throttle openings.
It's not easy to jet the mains as we tend not to ride at big throttle openings.
'51,'56 Squares, '48 VH, '27 Model C, R67/2, Mk IV Le Mans, '06 Super Duke and Ariel projects.
-
- Holder of a Platinum Anorak
- Posts: 5054
- Joined: Tue May 10, 2011 9:42 am
- Location: Victoria.. Australia.
- Contact:
Re: Piston problems Model C
Insufficient clearance It looks like. Perhaps the day was a bit warmer or your riding a bit more enthusiastic than normal. It takes thousands of miles to wear a bit of extra clearance on the piston and sometimes a piston will "grow " slightly. Don't file off the "heavily"dragged areas, they will already be undersize most likely. It's also a good idea to relieve under the lower ring and drill a few holes at an angle through the skirt. (NOT in the ring groove). A bit of two stroke in the fuel, doesn't hurt either. An egg cup to a tank of fuel is enough. Nev
-
- Holder of a Golden Anorak
- Posts: 1837
- Joined: Sun May 22, 2011 2:10 pm
- Location: Brisbane QLD
- Contact:
Re: Piston problems Model C
Insufficient,or deficient cam relief,if you ask me .....in fact it looks like the piston is just plain round ,with no taper,and no cam.....there was similar one pictured a few weeks ago,and I thought the same thing then........if you are going to use a round piston,give it plenty of clearance...like .006-.008........are both sides the same?.....the rod may be bossing in the piston and forcing it over.....ie crank not centred.
Re: Piston problems Model C
Thanks for your suggestions, but its none of the above, with the exception of perhaps being a little too enthusiastic!
Barrel being lightly honed then its back together for another go.
Barrel being lightly honed then its back together for another go.
- Karol Burger
- Holder of a Silver Anorak
- Posts: 790
- Joined: Mon Jul 30, 2018 7:08 am
- Location: Rudinka/ Slovensko
- Contact:
Re: Piston problems Model C
it also happened to me with my original piston. I couldn't find the cause. I sanded the damaged area, and the error did not happen again I think I adjusted the mixture in the carburetor a bit
Ariel 500 E - 1927 /Ariel SF-1931 ,Ariel SB - 1932 / Ariel 4F6 - 1932, 1934 / AOMCC Slovakia Branch Secretary
https://www.arielklub.sk/
https://www.facebook.com/groups/322716757874756
https://www.facebook.com/ArielKlub.sk
https://www.arielklub.sk/
https://www.facebook.com/groups/322716757874756
https://www.facebook.com/ArielKlub.sk
-
- Holder of a Waxed Cotton Anorak
- Posts: 535
- Joined: Thu Mar 10, 2011 6:19 pm
- Location: Swindon, UK
- Contact:
Re: Piston problems Model C
A wise man once told me that original Black Ariel pistons had a habit of expanding, but not contracting. His advice if it nipped up was to clean up the high spots on the piston (file not emery) and try again.
KOBI
Swindon Branch Combined Operations (Chairman and Secretary)
Ariels - 1913 TT Model, 20 Roadster, 28 Model D, 30 Model B, 38 VH, 52 VH
Velocette MAC, KSS Mk1
Swindon Branch Combined Operations (Chairman and Secretary)
Ariels - 1913 TT Model, 20 Roadster, 28 Model D, 30 Model B, 38 VH, 52 VH
Velocette MAC, KSS Mk1
-
- Holder of a Platinum Anorak
- Posts: 5054
- Joined: Tue May 10, 2011 9:42 am
- Location: Victoria.. Australia.
- Contact:
Re: Piston problems Model C
What looks like high spots has become low spots due seizing and shrinking the metal. Check with bearing blue or a micrometer. Most just hone a bit out and try again. It makes the ring gap wider though.. Filing a piston skirt all over takes skill and time. It was more common with two strokes that have NO ovality or crankcase compression disappears . Nev
-
- Posts: 13
- Joined: Wed May 25, 2022 8:47 pm
- Location: Crawley
- Contact:
Re: Piston problems Model C
OK so I not had much experience with ariels but from my experience rebuild other engines that's got hot very hot even the grudgion pin kissing been the bore through expansion. Most likely you were running a bit lean.
Proud owner of a Mk1 Square four
Who is online
Users browsing this forum: No registered users and 0 guests