What Is The Purpose Of This?


7 replies to this topic
  • 02YZ426

Posted June 06, 2006 - 11:19 AM

#1

Is there a reason why Yamaha put this small hole in the cylinder head? I was just wondering what it does, since I noticed water dripping out of there after I washed the bike and wondered if that was a bad thing or not.


Posted Image

  • Jaycycle

Posted June 06, 2006 - 11:40 AM

#2

Is there a reason why Yamaha put this small hole in the cylinder head? I was just wondering what it does, since I noticed water dripping out of there after I washed the bike and wondered if that was a bad thing or not.


Posted Image

EFI Duh! JK I have no idea, was wondering the same thing....

  • deadeye1340

Posted June 06, 2006 - 11:42 AM

#3

That is a whichahoozit valve. With out that, your four stoke would sound like a two smoker! Well, not really. That is a real good question! I will guess and say something to do with compression release.

  • ridesblue

Posted June 06, 2006 - 11:46 AM

#4

not sure whats its real purpose is but if you shoot a little air in there it makes it real easy to pop the sparkplug boot off

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • 2012 450 xc-w

Posted June 06, 2006 - 11:51 AM

#5

If indeed it pops the plug boot off wouldn't it seem this is a drain hole for the cavity that the plug sits in?

  • NYMXer

Posted June 06, 2006 - 01:06 PM

#6

If indeed it pops the plug boot off wouldn't it seem this is a drain hole for the cavity that the plug sits in?


That's exactly what it is and you should cover it up when washing our 250F or riding in wet/muddy conditions to prevent clogging it or getting dirt up there. It's all in your owners manual...............read it sometime. :applause:

  • Ga426owner

Posted June 06, 2006 - 01:16 PM

#7

That's exactly what it is and you should cover it up when washing our 250F or riding in wet/muddy conditions to prevent clogging it or getting dirt up there. It's all in your owners manual...............read it sometime. :D


AGREED NYMXer! :prof:
very very important to stick a golf tee 0r equivilent in this hole when washing - otherwise the sparkplug will rust from dirt and water over time - which is no big deal until you remove the sparkplug and all that crap falls into the cylinder....not good....
I always spray contact cleaner from the top after removing sparkplug wire to remove as much debree as possible....
Oh yea....one more thing, remove that golf tee ASAP after rinsing as it will swell up and be very difficult to remove later :applause:

  • MrTVDNR

Posted June 07, 2006 - 07:29 AM

#8

That hole is the drain for the area around the spark plug. Either from washing or from water when riding. It is best to check that it is free from debri so it does drain and not let water build up around the plug.





Related Content

Forums
Photo

Chubby dad, looking at bikes , First trip to the orange/black forum ! by Slow_ride


Dirt Bike   Make / Model Specific   KTM   250-530 EXC/MXC/SXC/XC-W/XCR-W (4-Strokes)
  • Hot  28 replies
Forums
Photo
Motocross

Thinking about Yamaha 250... by Arctic Pride


Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  491 replies
Forums
Photo

Michigan Motocross Tires by 288yz450


Dirt Bike   Dirt Bike Regional Discussion   North
  • 1 reply
Forums
Photo

2016 YZ450 by CaptainKnobby


Dirt Bike   Dirt Bike Technical Forums   Suspension
  • Hot  59 replies
Forums
Photo

Megabomb Fitment by 288yz450


Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • 1 reply
 
x

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.