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Scooters - 50cc => Agility 50 => Topic started by: nightriderrv on December 22, 2013, 04:25:17 PM
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I upgraded my cylinder to the 50mm and was running the stock head on it the high compression was great but I wanted to have the head on it that was correct for the kit I used. I seen that the valves were looking like they were rusty they were not carbon coated but were very clean just a rusty color just looking for what I would say is a reading on how it was running. Thanks
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I upgraded
In the context of engine longevity, downgraded (http://49ccscoot.proboards.com/thread/7767/39-47-50mm-compairson-video) would probably be a more appropriate term.
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This is a every day rider bike I use it to go every place I need to, I don't have it set up to scream going down the road and rev the motor out. We have a lot of hills and the extra really helps and the fact that I can ride along with traffic so the cars don't take stupid chances trying to go around me. So to me it's a upgrade that was worth it but everyone has there 2 cents to put in...
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This is off topic, but why comment about longevity when the OP comment was not regarding that.
In the OP case it did upgrade the cc's and in upgraded the power in some areas, but agreed it has the potential to reduce the overall longevity, but if properly maintained you probably won't notice for a long time down the street.
If questioning the rust on the valves it means that condensation got in the cylinder at some point. but this could be cold starting and not letting the engine complete warm up before turning it off or cheap gas introducing the condensation which can cause rust if it sets. As far as cylinder head replacement. I unfortunately can't help you since i am not sure myself without more research.
***Edited becuase my post may have came off rude after I re-read it which was not my point.
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I thank you for the input, it could been from riding in the rain I have some small holes drilled in the air box, there behind the body some what but in the rain the whole bike is wet. I do keep the oil changed and use prem gas in it but not to say that it won't have water in it. I have changed the gearing in the rear I'm running the same speed but with the motor turning less when running at full speed so much better as for the longevity.
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questioning the rust on the valves
It's not rust. The valves are near stainless, and also too hot to rust. The brown colour shows the mixture. It looks over-rich to me or there's oil in the gas. The colour will change with the jetting.
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I thank you for the input, it could been from riding in the rain I have some small holes drilled in the air box, there behind the body some what but in the rain the whole bike is wet. I do keep the oil changed and use prem gas in it but not to say that it won't have water in it. I have changed the gearing in the rear I'm running the same speed but with the motor turning less when running at full speed so much better as for the longevity.
Drilling holes in the air box is always a bad idea, since the original air box has very low resistance once you have removed the restriction between the box and the carb and has smoothened out rough edges and transitions.
Anyway, you should check that the valves are air tight. The intake valve can be checked by turning the engine to the start of the compression stroke, when the valve has closed and then pour a little fuel onto the valve. Now turn the engine through the stroke and look for bubbles. If there are any significant bubbles, it means air is escaping here when you compress your air/fuel mixture and that is a waste that lowers the pressure in the engine and therefore loweres power.
With the exhaust valve, you will have to put a finger up into the exhaust channel and touch the valve. Then turn the engine through the strokes and feel for pressures and suctions when the valve should be closed. :)
If they are leaking, you should remove the rust and re-grind them into their seats. If they are not leaking, you should still remove the rust, but re-grinding will hopefully not be needed.
Of course there is also a tool to check leaking valves called a cylinderleak-tester, but those can be costly when you might also need an adapter and a compressor (if you do not own one).