Alba Posted September 1, 2015 Share Posted September 1, 2015 I adjusted the values tonight, note to self never do with fairing on and son 'helping' BEER ..... It got me thinking what is the consequence of setting them too tight or too slack or not at TDC or too much of a difference between sides? Is there a significant impact on performance, MPG responsiveness etc ...... Link to comment
SANTA Posted September 1, 2015 Share Posted September 1, 2015 I adjusted the values tonight, note to self never do with fairing on and son 'helping' BEER ..... It got me thinking what is the consequence of setting them too tight or too slack or not at TDC or too much of a difference between sides? Is there a significant impact on performance, MPG responsiveness etc ...... not sure how you adjust values...we usually adjust valves. beer is a good lubricant to much during the process will impair the results... your best riding and mileage and smooth operation are obtian if you do the adjustment at the appropriate TDC and match the intakes and exhaust as close as humanly possible;; BMW (german) engineers have sometimes been accused of not being human hence the difficulty in acheiving the wanted results... Link to comment
dirtrider Posted September 1, 2015 Share Posted September 1, 2015 Evening Alba It depends on HOW tight or HOW loose they are. The BMW setting spec assumes they will migrate a little before next re-setting so a thousandth too tight or a thousandth too loose is not going to damage anything unless they tighten more during usage. A little error on the loose side is no big deal & about all you get with that is a little valve clatter. On the other hand a little tight (especially exhaust valves) & you can easily burn a valve. A little difference between sides & you will never notice. A lot of difference between sides means ONE SIDE is way off & possible valve burning. My suggestion is: If you think your valve's were not re-set correctly it might be your best interest to go back in & verify the settings. For what it's worth I (personally) use the police-bike policy of setting the exhaust valves slightly on the loose side as I run my bikes pretty darn hard. Link to comment
Stan Walker Posted September 1, 2015 Share Posted September 1, 2015 Too tight can lead to burned valves. You wouldn't like that. Too loose within reason is usually just noisy. Not at TDC. Depends on how far off from TDC you were. Close, no effect. Way off could prevent engine from running as the valves won't open as far as they should. Side to side difference within reason will probably just effect how smoothly the engine runs. Frankly, if you doubt what you have done, do it over. If your not sure on how to do it, get help that knows. edit: darn your fast dirtrider...... Stan Link to comment
Alba Posted September 2, 2015 Author Share Posted September 2, 2015 Many thanks guys. Must sort out my values when adjusting my valves lol ...... I'll go back in and see how tight the exhaust side is interesting to know about the impact of them being too tight. I used the rod in the cylinder method (first time) confirming with the arrow on the cam chain pulley. A nice method rather than taking off the plastic to get to the 'peep' hole. Thanks again Link to comment
Stan Walker Posted September 2, 2015 Share Posted September 2, 2015 interesting to know about the impact of them being too tight Exhaust valves get extremely hot when open and exposed to just burned combustion gases. They rely on contact with the valve seat to remove this heat. A little tight reduces this time. A lot tight may leave them open all the time. Stan Link to comment
dirtrider Posted September 2, 2015 Share Posted September 2, 2015 I'll go back in and see how tight the exhaust side is interesting to know about the impact of them being too tight. Morning Alba The exhaust valves (well pass the hot exhaust gasses) so they run a lot hotter than the intake valves that pass cooler intake air/fuel. That also means the exhaust valve stems get a LOT hotter than the intake valve stems so the exhaust valve stems expand more (get longer) & the valve heads expand slightly getting larger. SO the parts expanding do CLOSE the working gap more than the intakes. You see this in most engine valve adjustment settings with the exhaust valve setting gaps being specified larger than the intake setting gaps. Link to comment
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