Butcher

2and3cylinder, I was never complaining about myself being cold. The post is about the bike engine running cold below 75F at freeway speeds which in my area is a round 80mph. The bike not going into closed loop costs me about 4-5 mpg when not getting to 175F.

RaYzerman, bike runs at consistent 158F at freeway speeds when ambient is under 75F. With the block off installed engine runs at 175F which gets me an additional 4-5 mpg like in summertime.

Hello All,

Like most of you our bikes run cold under 75F ambient. In winter i get 4-5 mpg less than summer time. So experimented around last winter with blocking off the radiator as the t-stat checked out good and 3 yamaha dealers blew me off. A 4.5in tall plate does the trick to get the bike up to the 175F mark for the better mpg. Bike has 89K miles, ridden daily on the freeways splitting lanes in Southern California. 

I split some vacuum tubing and glued it around the metal plate and added some foam tape to the back to protect the radiator and hold it in place with HD zipties.

Hope this helps anybody that is interested.

Skip,  so i filled up the bike hot today. The burping little trick didn't work. 

Torbeach, I have checked my vent tubes and they are ok. 

Just for info the bike is completely stock and has 41k miles. It first stated happening around 22k miles.  After the valve adjustment it did go away for a little bit( about a month).

Its a 2015.

Hello BBB, it just happens when the engine is hot and it's hot out. If it sits for a few minutes.  Anything more than ten minutes it will start and idle fine. I have tried different gas stations as well. Do these bikes have an idle valve?

I'm thinking I'm dealing with vapor lock,  except if I hold the throttle open for a few seconds after it starts then let go it will then idle fine.  Any ideas or thoughts?

Glendora California 

Just seems weird to me. I do mostly commuting albeit well above the speed limit but just wish I could get the temp up because when it's hot out the bike gets another 4mpg better.  I even tried tapping up the radiator this past winter.  It helped a little bit.  If this was a car I would have put another t-stat in it already. Thx everybody. 

Have noticed that unless it's hotter than 75 degrees out there bike temp when running down the road it won't warm up past 160 unless it's just idling. Once i start moving again the temp comes back down to 160. Is this normal?