Jump to content

Vinny's Build


Recommended Posts

Weeks back i blew the motor on my 650l. Decided to do a few upgrades while the motor was out

 

So far...

 

Installing some new plastics, plan on doing USD forks, and street rims.  A fellow member said he was very pleased with the dirtbike africa head pipe. Its a lot larger in diameter than stock as well. I plan on matting that to a DG muffler that i have.

 

HEAD:

-ported head

-new OEM valves

-springs mad by webcam

-Stage 2 Webcam

-Hardened cam lobes and hardened rocker arms

 

BOTTOM:

-Je 10:5:1 piston

-Slightly over sized to a 101mm

 

CARBURETOR:

-MIKUNI TM40

 

Heres the bike as it sits right now

 

 

20180610_185657.jpeg

20180610_185717.jpeg

  • Like 3
Link to comment
Share on other sites

17 hours ago, Hollerhead said:

I'm always interested to know more when folks port heads.  Was yours flow tested before and after?  Any before and after pics? New seats and guides? 

The metal inside is very rough. Was not flow tested. Will post before and after pics when finished

 

Link to comment
Share on other sites

17 hours ago, Hollerhead said:

I'm always interested to know more when folks port heads.  Was yours flow tested before and after?  Any before and after pics? New seats and guides? 

valve guides and seats were in good condition. Not installing larger valves either. Cleaning the surface that air flows through and sharping some edges. Nothing crazy. The surfaces are rough and gritty. air will flow easier when finished

 

 

Edited by Scaffold29
  • Like 1
Link to comment
Share on other sites

2 hours ago, Vinnym said:

Thumpnred i will look into the FCR carb. I like the mikuni because it seemed like a nice kit that came with everything you needed. 

The FCR does involve a bit more tinkering to get it to work, but the job is pretty well scripted out. You can buy a ready to run FCR, but they are pricey. The less expensive way to go is to find an FCR off of a CRF 250 or 450. A NOSS adapter and some jets and a needle gets it up and running. If you can find a used FCR with an extended pilot screw and an adjustable leak jet, all the better. 

Link to comment
Share on other sites

4 hours ago, Vinnym said:

valve guides and seats were in good condition. Not installing larger valves either. Cleaning the surface that air flows through and sharping some edges. Nothing crazy. The surfaces are rough and gritty. air will flow easier when finished

 

 

Be gentle.  Results are sometimes surprising (disappointing). 

Smoother surfaces are not necessarily the key to a good performing head.  A proper shape is great, and can be very beneficial, but without maintaining atomization through "good" turbulence you can end up with stale air and big ol' drops of gasoline in there and an air fuel mix that will cause you nothing but heartache when trying to tune.  Without a seat change, and the blending of them, any gains from port work can be completely lost.

Porting always sounds good in conversation but it is a science and requires some pretty fancy equipment to actually know if what's being done is helping or hurting.   

Edited by Hollerhead
  • Like 4
  • Helpful 1
Link to comment
Share on other sites

5 minutes ago, Hollerhead said:

Be gentle.  Results are sometimes surprising (disappointing). 

Smoother surfaces are not necessarily the key to a good performing head.  A proper shape is great, and can be very beneficial, but without maintaining atomization through "good" turbulence you can end up with stale air and big ol' drops of gasoline in there and an air fuel mix that will cause you nothing but heartache when trying to tune.  Without a seat change, and the blending of them, any gains from port work can be completely lost.

Porting always sounds good in conversation but it is a science and requires some pretty fancy equipment to actually know if what's being done is helping or hurting.   

So what would you recommend doing while this is being done?

Link to comment
Share on other sites

19 minutes ago, Vinnym said:

So what would you recommend doing while this is being done?

I'll put it this way.  I've never read of anyone being disappointed with one of these motors using a stock head with a similar set of guts that you list for your build. 

In the past few years of riding and rebuilding these I've never read of anyone that worked on these heads with documented results.  I'm fairly new to these but have found that there doesn't seem to be many folks that work on these heads enough to have developed a proven method to improve them.  There are some great parts changers around but none I've read about that truly know how to gain performance beyond the bolt-on parts. 

There is no doubt more can be gained from proper head work but finding the person to properly do the job is difficult.  Really experienced guys will work a little, flow it a few times to see the results, work a little more, etc. It's very common for even the experienced guys to make cuts that make things worse.   The flowbench is the only tool that will tell them whether what they are doing is helping or hurting.  Valve unshrouding, keeping the air "stuck to the port wall", and all kinds of other tricks seem be the normal on other heads and should probably be considered on these as well.

Edited by Hollerhead
  • Like 1
Link to comment
Share on other sites

On 7/12/2018 at 5:24 PM, Hollerhead said:

I'll put it this way.  I've never read of anyone being disappointed with one of these motors using a stock head with a similar set of guts that you list for your build. 

In the past few years of riding and rebuilding these I've never read of anyone that worked on these heads with documented results.  I'm fairly new to these but have found that there doesn't seem to be many folks that work on these heads enough to have developed a proven method to improve them.  There are some great parts changers around but none I've read about that truly know how to gain performance beyond the bolt-on parts. 

There is no doubt more can be gained from proper head work but finding the person to properly do the job is difficult.  Really experienced guys will work a little, flow it a few times to see the results, work a little more, etc. It's very common for even the experienced guys to make cuts that make things worse.   The flowbench is the only tool that will tell them whether what they are doing is helping or hurting.  Valve unshrouding, keeping the air "stuck to the port wall", and all kinds of other tricks seem be the normal on other heads and should probably be considered on these as well.

 

IMG951291.jpg

IMG951290.jpg

IMG951289.jpg

  • Like 1
Link to comment
Share on other sites

  • 1 month later...

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

×
×
  • Create New...