Overheating problem solved! (I think)

5 replies to this topic
  • Glen_T

Posted November 08, 2001 - 06:01 AM


Some time ago I posted a note about my 426 blowing coolant from the overflow. Many of you gave me some great suggestions. I replaced the radiator cap with one from an auto parts store rated at 13psi. Which didn't help. The original cap on these bikes is metric 1.1nm/cm2. After some searching for conversions on the net, I found that 1.1 is about 16psi. So I've purchased a replacement cap and will try it this weekend. I'll let you all know if it solves the problem.


  • Moto747

Posted November 08, 2001 - 04:30 PM


I had that problem on my 98. I bought a cap from the dealer for $40. It was expensive but it worked.

  • Glen_T

Posted November 08, 2001 - 07:34 PM


Thanks for adding the price to your reply. I couldn't believe it when I paid $30.00 at Honda! I about fell over. I've said it before here. One day I'm gonna up and sell this YZ and buy a late 90's cr500. Poor handling, heavy, overpowered, dated, runs forever. Sounds like my next bike. Maybe if I keep putting Honda parts on my YZ, it'll act like a CR. Sorry for the vent. My 426 was the first new bike I've bought since my 1980 xr80. In many ways it lives up to the hype and then some, but I've never felt like I could completely trust it to get me home from a long ride. I'ts never left me stranded, but I've worried plenty. On the other hand, this is a great board! I love reading about the bike I love/hate. Thump on!


Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • scottzx7rr

Posted November 09, 2001 - 05:59 PM


I hate to make you guys sick but you can go to the local Auto Parts Store(my example is O'Reilly and Auto Zone) and pick one up for 5 dollars. The Yamaha OEM Replacement is 1.1(15.6lbs) and the ones at the Parts Stores are 16lbs. I went that route as mine was getting weak and allowing the bike to overheat in tight woods. Not had a problem since.

  • Poindexter

Posted November 10, 2001 - 11:23 AM


My 98 over heated on a concrete starting pad about a year ago and did so just as the 30 sec. board went sideways (can you say %#*#@!) I was told by friends to up the pressure rating on the cap. That didn't seem like such a good idea to me. Beacuse your increasing the pressure of the entire system. What I did instead was started using a product called "Engine Ice". Its a toxic free, anti-freeze type product. I live in So/cal and race through the hot summer months, and I have never had another overheating problem.

  • Glen_T

Posted November 10, 2001 - 08:54 PM


Well it wasn't the cap! I guess I do have a head gasket problem. A local bike mechanic told me that cometic gaskets are junk. I guess I'll have to put a new yamaha gasket on it. Bummer.

Thanks again for all the advice and ideas.


Related Content


Snake pit oct 30th by The Anvil

Dirt Bike   Dirt Bike Regional Discussion   California
  • Hot  293 replies

Megabomb Fitment by 288yz450

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

Is it worth it? (Cam and High compression piston) by macgi77

Dirt Bike   Make / Model Specific   Honda   CRF 150/230 F/L
  • Hot  36 replies

2016 YZ450 by CaptainKnobby

Dirt Bike   Dirt Bike Technical Forums   Suspension
  • Hot  59 replies

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

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.