Hi Folks, I have had the head off my bike for a bit of machining and to do so I removed the valves. The bike has done only about 50 miles since I finished the rebuild. It has new valves, the guides have been done by TL engineering and the barrels were rebored. I fitted new rings, checked the ring gaps and made sure the gaps were set at thirds on the piston.
When I remove the valves as you can see in the photo, they have a healthy coating of soot. The combustion chamber was equally sooty but I cleaned that off with a rag and paraffin. The engine did not appear to be running rich and there was no smoke that I could see.
So my question is - Is this a normal amount of soot after such a short time running or do I have a problem here?
BTW the carbs are new with the recommended jets and settings.
Many thanks in advance.
Cheers Glenn
rings will need time to bed in , then unlike Japanese bikes there are no valve stem seals.
I would be more concerned if it was white and running lean.
Cool, thanks Chaz. Sounds like the reassurance I need! clean 'em up - put 'em back in.
I'm thinking I might give them a light grind with fine paste just to clean the faces perhaps...
Anyway thanks for the reply
Cheers Glenn
Hi Glenn,
The exhaust seat does look a bit sooty for such a low mileage so a clean and light lapping will be a good idea. Make sure that the exhaust valve clearance is right and not too tight otherwise the valve may not close properly when the engine is warm.
Dave.
Also depends on what type of fuel you use , found shell nitro to burn cleaner than some other brands
Quote from: Roy on 11 Dec, 2023, 06:24
Also depends on what type of fuel you use , found shell nitro V power to burn cleaner than some other brands
How does the bike run? Does the engine pull cleanly?
Also what is fuel consumption like?
And does the oil tank smell like it is contaminated with fuel?
Hi,
Looking as bit more closely at this the main consideration is that only about 50 miles have been covered since a rebuild. Whilst the use of a cleaner fuel is beneficial I would expect valve seats with only 50 miles on them to still look pretty much look like they have just been done ditto the seating face on the valve. So the question is why they both look like more miles have been covered.
My comment re valve clearance could go part way to explain but the exhaust valve guide does seem to be a bit oily. Considering that the valves and guides have just been done these symptoms are more an indication of a worn guide.
My advice now would be to take the head back to TL Engineering and get them to check the valve/guide clearance/fit and to touch up the valve seats with correct tool.
Dave.
Good point Roy, I'll track down an Esso garage. I always use premium but I think it's from a BP garage.
Thanks Allan. It feels like it pulls really well though as it is in the early stages of running in, i am not "wringing it's neck" so to speak! And for the same reason I have no idea on consumption, not enough data yet.
Good idea Dave. I think I might send TL the picture actually and see what they say. They are super helpful so hopefully they can advise. I would have thought if it was burning that much oil there would have been some blue smoke but I couldn't see any. Anyway if the valve stems are within tolerance I guess the only things left are rings, valve clearance or rich running. I certainly thought I'd set up the valve clearances correctly but it wouldn't be the first time I was certain of something that turned out not to be the case.
Many thanks all. Cheers Glenn
Well, here's my two penn'orth. I would definitely take the head to an engineering shop. The inlet valve seat insert looks too low and the exhaust looks as if it hasn't been seating at all.
It only looks like a light dusting of soot, which will probably blow off when you are able to get the engine hot enough after a damned good thrashing.
Keep an eye on the plug colour. I assume that also had a dusting of soot?
Don't clean the carbon off, and take it to your engineering shop. Let us know what they say.
Thanks Steve, Yes I'll be talking to TL for sure. However I did do a compression test when I first put the thing back together and It seemed ok. I can't remember the values now but I know I was looking for 130+. Yes the plugs were sooty too.
I look forward to the day I can give it a thrashing but it'll be a while. I'll have to run it in first. and even then it'll be more of a light tickle than a trash being somewhat risk averse in my dotage! ;D
Many Thanks Glenn