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Author Topic: Cylinder condition after replate also piston wash  (Read 7377 times)

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Offline Mike-Evans

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Cylinder condition after replate also piston wash
« on: July 05, 2016, 05:54:32 PM »
Whats your thoughts on these cylinder marks after a full rebuild and 5 hours running. Theres no depth to any of the marks.
Bike is always warmed before riding.
Always cleaned and oiled filter

Also, thought on head colour and piston wash?





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Offline Mike-Evans

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Re: Cylinder condition after replate also piston wash
« Reply #1 on: July 06, 2016, 07:34:32 PM »
Bump - help me out guys  :-D

I've been told that marks on the intake side is due to lack of lubrication - not mixed correctly, or the 2t oil separated in the tank, or water in fuel.....

I use Putoline 2t and 125ml to 5l of fuel which is 40:1, although the manual says to use 32:1, should I up the oil?

The new piston I fitted had a coating around the fron, sides and rear, and apparently is there to help the break in procedure and wears off after use.... this coating is still in place and there is no scratchs/marks on the piston....

Help/advise appreciated  8-)
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Offline BFT-Mechanic

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Re: Cylinder condition after replate also piston wash
« Reply #2 on: July 11, 2016, 06:56:39 AM »
In my opinion you are riding to slow or to rich on the main jetting if it looks like this after a 5 hour running.
The piston and cilinder head is completely black, there is no sign of any flow from the transfer ports over the piston head.

What is the color of the spark plug, and what is the heat rating of the plug?

The marks in the cilinder looks to me like it is from the piston coating, the place of the mark is above the bridge form the inlet of the cilinder.
At this point there is more pressure on the piston and coating.
No need to worry i would say, just keep an eye on the temperature that it is not to cold before hitting the throttle
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Offline Mike-Evans

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Re: Cylinder condition after replate also piston wash
« Reply #3 on: July 20, 2016, 08:27:07 AM »
This is the colour of the plug after the last outing:


I have increased the main jet by 1 after the break in, this was the colour of the plug before I upped the main jet:


I did drop the clip on the needle by 1 to make it richer on the last outing but after 1 lap of the track the bike was spluttering and crackeling terrible, so I put the clip back to the previous position (number 3 - middle) and it run much better so I think the needle is where it needs to be

Plug is NGK BR9EG although the manual say B10EG

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