Different cylinder temperature

WojtekPoland · 15 September, 2024, 18:35:34

Welcome everyone. I am a new member from Poland. Today started engine after renovation. One cylinder is colder than second, exhausting pipe has also different colour. Any idea what can be wrong? I found unknown pipe also on the oil tank next to the breathing pipe, oil goes outside, where to connect it?
Thanks for any help

DAVE BRADY · 15 September, 2024, 21:05:33

Hi Wojtek,

Welcome to the BSAOC Forum.
What bike do you have? Are both cylinders firing properly? The one that gets hot is probably OK but the other may not be sparking. This will also account for the different exhaust colour.

Dave

WojtekPoland · 16 September, 2024, 08:44:03

Thank You for Your message Dave. Both sparks are same, nice blue thunder

. Today I want to check. valves and try replace carburators, and ask friend of mine to plug stroboscope

DAVE BRADY · 16 September, 2024, 09:05:02

Hi,

What bike do you have?

Dave.

WojtekPoland · 16 September, 2024, 14:38:16

BSA A 56 Lightning 1968

DAVE BRADY · 16 September, 2024, 15:03:33

Hi,

As you have two carbs. the chances are that one has a blockage. The giving the one that is not running properly a good clean with carb. cleaner and an airline.

Dave.

cornishbob · 16 September, 2024, 18:02:22

with a good spark theres not much that could be wrong so the fuel has to be the obvious suspect to start

WojtekPoland · 16 September, 2024, 18:27:34

Thank You Dave for tips, tomorrow I will start checking carburators, will let know what was wrong.
Wojtek

WojtekPoland · 17 September, 2024, 11:10:23

Good afternoon Dave. I could not believe, but after 10 minutes beand new one spark just broke down...that was the reason.
Best regards Wojtek

DAVE BRADY · 17 September, 2024, 11:47:38

Hi,

It is not unknown for a new plug to be faulty. So, problem solved. Good luck with the bike and enjoy riding it.

Dave.

chaz · 17 September, 2024, 20:19:40

one thing to check with spark plugs is , to get them from a reputable dealer.
NGK (Niterra USA) are being copied now from the East, China area. The quality of some of these is not as good as original. mainly iridium.

I know there is the odd genuine failure, being porcelain if the box is dropped or courier handled roughly, it can be damaged.
An old game we used to play was a pencil line down the porcelain from top to hexagon body, on a mates bike would stop it sparking.

https://www.ngkntk.com/newsroom/blog/emea/fake-or-not/

cornishbob · 18 September, 2024, 08:06:34

maybe the forum could start a 'list' of dealers that do and more importantly DON'T sell the real ones

Mike Farmer · 19 September, 2024, 11:24:57

I dont know if its the same now but I understand one of the manufacturers only Batch tested about one in a 10000. that meant there could be a 100 bad ones out to market before a problem was picked up

Mike

WojtekPoland · 19 October, 2024, 19:58:57

Unfortunately problem is back. There is some issue arround right cylinder. I demounted air filters during engine running , from right carburetor part of fuel fog is going outside not inside. What can be wrong, valves timing? I think I setted timing wheels up correct with marks.

DAVE BRADY · 19 October, 2024, 21:06:10

Hi,

If the valve timing was out it would be on both cylinders. Have you checked the valve clearances? If the inlet valve is not closing properly it could allow the fuel to be blown out of the carb.
Make sure that the left valve is fully open to set the right hand one to 8 thou.
Check the other valve clearances at the same time.

Dave.