Burris Racing / Frequently Asked Questions / Yamaha YF200R1

YF200 R1 Piston Travel in Inches and Degrees

Burris Tech Info — Mon, 16 May 2005 11:59:52 GMT

Yamaha YF200 Piston Travel
BTDC/ATDC

Degrees

Inches

0.122

0.131

0.141

0.151

0.161

0.172

0.183

0.194

0.206

0.218

0.230

What plugs have been working well in the Yamaha F-200?

Burris Tech Info — Wed, 20 Apr 2005 12:20:06 GMT

We have found that the NGK BPR6ES (or equivalent) is the best all around spark plug to use in the YF200. Lately we have been using the NGK BPR6EIX Iridium which gives a little better throttle response and lasts quite a bit longer. For sustained high RPM's you could go a step colder and try the BPR7ES or BPR7EIX. Remember, with the Yamaha, good plug color with low CHT's is the way to go.

What is the best cylinder head temperature for the Yamaha YF200?

Burris Tech Info — Thu, 31 Mar 2005 17:20:23 GMT

Actually, there is no “correct” temperature because of the many variables like weather, track type and length, etc. What we would recommend is tuning to get a proper light tan spark plug color and note the CHT.

This way if the engine is rich or lean you just tune the carburetor to bring the temperature up or down a few degrees to fine tune it. Typically the longer you are on the throttle the hotter the engine will run so if you are running on a small oval or sprint track, where you are on and off the throttle, you will see readings in the low to mid 300 deg range where if you were at a track like the Milwaukee Mile where you didn't lift, readings in excess of 400 deg wouldn’t be a surprise.

Also, the practice of taping off the flywheel screen to increase engine temperature is not recommended since the Yamaha , like other air cooled engines, needs to run as cool as possible. That is because the elevated temperatures tends to weaken and distort components like the block and head, which could cause the engine to "fade" or be down on power..

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