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yamha ybr spark plug (hot/high speed engine)


conor95
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hi

im a bit confused with what spak plug to put in my bike it has in it now cr6hsa which we think has been in their since new and it need's replacing. i was told that their are a number of spark plugs avalible for the ybr for example the one i have in it now is apparently meant for slow inner city driving (or its better at it), but i was told their is another spark plug that is better for higher speeds e.g. A roads. from what i could find on the internet it pointed to the NGK C7HSA for this so i went and brought it but now it comes to putting it in the bike and i am worried that it will cause it damage. if annyone could clear this up it would be greatly appreciated.

thanks conor

(sorry for spelling mistakes its not my strong point)

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  • Moderator

Its just the temperature range of the plug. Heat causes resistance that causes heat etc. The resistance reduces the spark energy.

The 6 plug will run fine but will be ideal at the city stuff and give easier starting.

The 7 may cause a little harder starting but should give a cleaner burn on higher speed stuff.

Thats the theory. To be honest, i doubt you will notice. Certainly wont harm the bike.

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Nah. Go from a 6 to a 9 and it will get more of a problem. But still only how it starts and throttle response etc.

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I have a YBR and i had the same thaugh as you, so i stuck a cr7 in set witht he correct gap (according to the manual) and the bike didnt agree in the slightest. would take me 10 minuites to start it, then i wasnt able to acheave over 6000 RPM. as soon as i put the 6 back in it went back to how it was before. it may just me my bike bieng tempremental, but i just thaught id share.

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So harder to start. And ultimately different spark characteristics at higher speeds.

With such a dramatic effect of such a subtle change you might want to give the bike a once over. Check filters and valve clearances etc. 1 step up should not really affect it that much.

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I found that too, put a CR7HIX in and it made the engine knock, so I've gone back to the normal CR6HSA and its a lot smoother. One thing I've found though is changing the rubbers on the spark plug cap and giving the HT lead a good going over with silicon oil made it a bit smoother when it was wet, not so much now its starting to dry out but still worth a go.

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at the time i changed the plug i changed all filters, gearbox flush + new oil, new HT cap and valve clearances and i got shit performance. as soon as i put the old CR6HSA back in as a retrace to try and locate the problem, it was running better than before the mini service.

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Still a surprising effect. Esp as its a reccomended option.

Out of curiosity. Was the poor performance in the cold weather we have finaly cleared (he says touching wood).

If the engine temp is v low the engine will perform badly. Just as the 6's performance would drop on a hot day.

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