Valve clearance

[DukeMaster]

Hello,

I would appreciate some input from more experienced members here. I had check the valve clearances and I found that all four valves are out of specs and pretty tight. Both intake valves were only 0.04mm and both exhaust valves were 0.08mm.

Now since the dealer has shims that are 0.05mm apart in size from each other I had decided to set them on the loose side. One exhaust is 0.17mm and the other is 0.16mm which is good enough for me. On the intake side one valve is 0.12mm which is good but the other is 0.14mm and if I use one size bigger shim than that valve will be 0.09mm. I have seen from the manual of the new ktm 17/18 that valve specs have changed. Exhaust 0.15 - 0.20mm and intake 0.10 - 0.15mm and this is applicable on older generation of our bikes. So now my question is, is it better to leave it at 0.14mm or should I shim it at 0.09mm?

I forgot to mention that my bike is 2015.

Thanks

 

[ReidMcT]

I would go with 0.14

 

[John390]

if its low mileage and on its first or even second adjustment, I'd go with the bigger clearance, because it may still continue to tighten up.

However, if its higher mileage and had a few adjustments, on the intake I may go with the tighter clearance. Tighter clearance on valves will give more net lift to the valve, thereby increasing performance at higher rpm. Exhaust valves can burn if too tight, but its pretty rare on intakes so its a bit safer to go with tighter clearances. I'd want em more even, so if you could get the other one closer to .09 that would be more optimal.

of course 0.14 will be safer, and it you can get them both the same thats great too.

 

[DukeMaster]

if its low mileage and on its first or even second adjustment, I'd go with the bigger clearance, because it may still continue to tighten up.

However, if its higher mileage and had a few adjustments, on the intake I may go with the tighter clearance. Tighter clearance on valves will give more net lift to the valve, thereby increasing performance at higher rpm. Exhaust valves can burn if too tight, but its pretty rare on intakes so its a bit safer to go with tighter clearances. I'd want em more even, so if you could get the other one closer to .09 that would be more optimal.

of course 0.14 will be safer, and it you can get them both the same thats great too.

It has 16k km on the odo. The valves were newer ajdusted before, i dont think that they were checked even I explicitly told the service center to check them at 1000km service. If I go the shim one size bigger I get 0.07mm and 0.09mm which is too tigh. Ill just set them at 0.14 and 0.12 and call it a day.

Thanks for the replies my friends.

 

[ReidMcT]

This thread reminded me that I'm coming up on my initial (1000 km) service interval; so I ordered a shim kit from Hot Cams (HCSHIM31). [FONT=Verdana,Arial,Tahoma,Calibri,Geneva,sans-serif]https://www.amazon.com/gp/product/B007KBKT6C

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[SWdragon]

This thread reminded me that I'm coming up on my initial (1000 km) service interval; so I ordered a shim kit from Hot Cams (HCSHIM31). https://www.amazon.com/gp/product/B007KBKT6C

Just FYI on valve adjustment issues, if you haven't read it already.

https://www.rc390-forum.com/forum/e...ightmare-ideas.html?highlight=valve+clearance

 

[ReidMcT]

Just FYI on valve adjustment issues, if you haven't read it already.

https://www.rc390-forum.com/forum/e...ightmare-ideas.html?highlight=valve+clearance

Yes, I did see it; but such pointers are always appreciated, thanks. What I took from that thread was to inspect the keepers and retainers carefully to be sure they will continue to hold the valves as designed. I imagine this is a concern more on older engines; but who knows. Awareness is always better than ignorance.

 

[DukeMaster]

Yes, I did see it; but such pointers are always appreciated, thanks. What I took from that thread was to inspect the keepers and retainers carefully to be sure they will continue to hold the valves as designed. I imagine this is a concern more on older engines; but who knows. Awareness is always better than ignorance.

Just look at the valve stems and make sure that the top of the valve stem is about 1 mm above the retainers.