Ian Comerford Posted September 21, 2021 Share Posted September 21, 2021 My engine is now around 4000 miles on from its rebuild and over the last month or so I thought I noticed a slight difference in colour of the exhaust outlets. After doing ca 1450 miles over the weekend on a run to a French classic event, mostly at decent speed I noticed the difference is more distinct as per the picture. Behind the pipes is a single chamber, so gasses from both banks go into it and then exit via the pipes, but I think it sensible to assume that one bank, the left, is running better than the other. I would welcome thoughts on what might cause this, could it just be a single plug or injector underperforming, or something more complex? Link to comment Share on other sites More sharing options...
Roy M Posted September 21, 2021 Share Posted September 21, 2021 Could you have a partial blockage in the right hand pipe which is reducing gas velocity and causing soot to form? If it's this there would probably be a temperature difference between the pipes which would be most noticeable at cold start as the temperatures would even out due to conduction later. Link to comment Share on other sites More sharing options...
Jonny Hart Posted September 22, 2021 Share Posted September 22, 2021 Surely the gases from L and R get mixed together in the silencer? If so, then it has to be something to do with the air flow out of the exhaust and wouldn't be anything to do with L and R cylinder banks. Link to comment Share on other sites More sharing options...
Chris T Posted September 22, 2021 Share Posted September 22, 2021 Same problem here, right exhaust noticeably rustier than left.... 2 Link to comment Share on other sites More sharing options...
Wingnonut Posted September 22, 2021 Share Posted September 22, 2021 (edited) Gotta be what Jonny says. Edited September 22, 2021 by Wingnonut Link to comment Share on other sites More sharing options...
Lesworth Posted September 22, 2021 Share Posted September 22, 2021 Will be interesting to see if you get the same difference when you have the new exhaust fitted Ian. Link to comment Share on other sites More sharing options...
Nige Posted September 22, 2021 Share Posted September 22, 2021 (edited) You on SSIs Ian? If so I reckon that right hand bank could causing some of the soot. Even though it merges together in the muffler gases from either side will exist the nearest point/tail pipe. If not SSIs then it's a funny one. Have you compared the plugs from either side? Edited September 22, 2021 by Nige Link to comment Share on other sites More sharing options...
Ian Comerford Posted September 24, 2021 Author Share Posted September 24, 2021 Thanks all for your responses, it’s appreciated. The engine has SSIs and the centre of the silencer has a single chamber taking gasses from both sides before they exit via the two pipes. This could mean you can’t really tell what is happening and can’t say that the black pipe relates to the right side of the engine. I’m going to take the plugs out as a starter and see what they tell me. I will report back and look forward to more useful input. Ian Link to comment Share on other sites More sharing options...
Nige Posted September 24, 2021 Share Posted September 24, 2021 (edited) I still reckon there is soot from one side. The gases aren't going to mix that thoroughly and evenly before they exit, most likely bounce off each other and exit through the nearest hole. Explain how else is it going to happen? Have you compared the plugs yet? Edited September 24, 2021 by Nige Link to comment Share on other sites More sharing options...
Ian Comerford Posted September 24, 2021 Author Share Posted September 24, 2021 Not yet Nige, some time on Sunday probably. I agree with you but don’t understand how it can happen. I probably wouldn’t have noticed this if the exhaust had a single outlet as the two colours would have merged and may not have looked strange Link to comment Share on other sites More sharing options...
World Citizen Posted September 24, 2021 Share Posted September 24, 2021 Are you taking too many LH corners too fast from a cold start 🤔 Ian you are The Spark Plug Whisperer 😉 Link to comment Share on other sites More sharing options...
Ian Comerford Posted September 25, 2021 Author Share Posted September 25, 2021 8 hours ago, World Citizen said: Are you taking too many LH corners too fast from a cold start 🤔 Ian you are The Spark Plug Whisperer 😉 Late night Stephen….? Link to comment Share on other sites More sharing options...
Beaky Posted September 25, 2021 Share Posted September 25, 2021 Ian, why not ask the engine builder? They if anyone maybe able to direct you to the cause Link to comment Share on other sites More sharing options...
World Citizen Posted September 25, 2021 Share Posted September 25, 2021 Sorry Ian, I'm not helping am I 🤐 Link to comment Share on other sites More sharing options...
Ian Comerford Posted September 27, 2021 Author Share Posted September 27, 2021 Plugs out today and they look pretty similar apart from the middle one on the right hand bank which is slightly sooty. I’m going to clean then and put that one on the opposing side and see what they look like after a few hundred miles. Nothing to worry about here though 1 Link to comment Share on other sites More sharing options...
Beaky Posted October 13, 2021 Share Posted October 13, 2021 Any news of the Funny One! Link to comment Share on other sites More sharing options...
Ian Comerford Posted October 13, 2021 Author Share Posted October 13, 2021 No, I need to do some more miles with the plug in the new position to determine whether it is faulty or there’s some other issue Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now