50 rwhp!!!


8 replies to this topic
  • panteramatt

Posted October 23, 2004 - 07:50 PM

#1

What do I need to do with a stock 400 motor to get 50rwhp? Does anyone know what these came with stock?

  • chrome-crf

Posted October 23, 2004 - 08:19 PM

#2

You'd have to do a whole lot to get 50hp out of a 400. Lets see, big bore/high comp piston kit, ported head, cams, race gas and bored carb, maybe even a stroked crank. My 426 with a 450 cam, no airbox, Uni filter and race gas is 46hp. My CRF with everything mentioned above except the stroked crank is 60hp :cry:

  • Flattracker60

Posted October 24, 2004 - 07:48 AM

#3

Hey Chrome, have you put your bike on the dyno after the recent mods(carb mod, etc.)??

  • panteramatt

Posted October 24, 2004 - 09:12 AM

#4

So the crf's are putting that much more hp?

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

Posted October 24, 2004 - 04:40 PM

#5

Below is a link to dyno runs and specs on SFO's 54 rwhp 444. He managed 52 rwhp on pump gas using the stock cams (reindexed) and stock valve sizes. I built a similar combination using a 98 YZF400 and got similar results. We got to 444cc using the 426 rod on the 400 crank and 426 barrel overbored 2mm. This spring I'll be testing this combination with a new big center valve head using Kibblewhite parts, Hot Cams, and a new crank fitted with a Falicon CRF450 rod. Should be interesting. :cry:

http://www.four-stro...s/SFO_index.htm

  • panteramatt

Posted October 24, 2004 - 07:46 PM

#6

Cool, so all I would need to make 444cc is a 426 cylinder bored out and rod? Are hotcams worth the price and will I notice a difference?

  • Rich_Rohrich

Posted October 24, 2004 - 08:47 PM

#7

Are hotcams worth the price and will I notice a difference?


We've installed a lot of them and we've never had a customer that wasn't totally thrilled with them. It's a great match for the big bore engine.

  • panteramatt

Posted October 24, 2004 - 08:49 PM

#8

But will I notice a big difference with hotcams on a basically stock 400? Also does the auto decompression make kicking it over easier?

  • Rich_Rohrich

Posted October 25, 2004 - 07:44 AM

#9

But will I notice a big difference with hotcams on a basically stock 400? Also does the auto decompression make kicking it over easier?


The Hot Cams are NOT a good match for a basically stock 400, you are much better off with the OEM cams.

Yes the auto-decompressor cam works wonders for starting.





Related Content

Wiki
WR Camshaft Swap Info - last post by jamesm113

WR Camshaft Swap Info


Articles
  • 0 replies
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

The "going back to the other darkside" adventure... by Monk


Dirt Bike   Make / Model Specific   KTM   250/350/450/505 SX-F & XC-F (4-Strokes)
  • Hot  113 replies
Forums
Photo

James Stewart back on a YZ450F by YamaLink


Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  47 replies
Reviews

Yamaha YZ450F 2017 by Chris.GVS


Yamaha YZ450F 2017
  • * * * * *
  • 1 review
  • Last review by Tommyk_55
  • On January 15, 2017
 
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.