Jump to content
Sign in to follow this  

DRZ port work

Recommended Posts

I started working on a head for a 485 and thought I'd take some pictures of my progress. The seats have been cut for 1mm over Ferreas intake and exhaust. I'm going to epoxy the floors and raise the port roof to create a larger and smoother short turn radius. I'm also going to end up with a port with a cross section no larger than it was in stock condition to keep port velocity high. This is the second head I've done with epoxy, The first flowed over 160 cfm @ 10 in. of h2o with smaller ports than stock. It's on my bike now. I'll post pictures as I go.

 

Just getting started, ruffing ports and dimpling the surface to hold the epoxy.

IMAG0445_zps96286536.jpgIMAG0448_zps2f57bdad.jpg

  • Like 4

Share this post


Link to post
Share on other sites

OK, The epoxy has set up and I've had some time to start cutting it out. I'm setting the port height at 65 % of the valve diameter. This will be the choke point of the port and will probably end up being close to the start of the divider wall. From there I will start the short turn radius to the valve seat making it as smooth gradual as possible.

IMAG0458_zpsc9b9ce58.jpgIMAG0467_zpsec34b0b4.jpg

  • Like 1

Share this post


Link to post
Share on other sites

Pardon my ignorance and complete lack of knowledge. If you are going to use bigger valves, wouldn't you want to increase the volume of the air travelling into the head versus restricting it down (and increasing the velocity and air drag)?

Share this post


Link to post
Share on other sites

I know on bbc if you use the big valves in the small port heads it gives you more torque because the velocity is much greater making more cylinder pressure. More velocity gives you higher rpm power and the potential for higher revs I don't know about small engines but I build a lot of chevs

Share this post


Link to post
Share on other sites

Thanks Gillham, I still have quite a bit of work left. I'll be going back and forth to the flow bench to fine tune things. I still need to work on the combustion chamber and backcut the valves. I am using 1 mm over Ferrea valves in. and ex.

 

This is my second epoxy head and I've done many DRZ standard and big valve heads. With epoxy, I've been able to get very good flow numbers with ports that have a smaller cross section than a stock port. The last head out flowed by best head without epoxy. Over 160cfm @ 10 in. at .400 lift. The higher velocity certainly has it's benefits, Once you get the air moving, it doesn't like to stop and will keep cramming air and fuel into the cylinder during  the end of the intake event even as the piston is back on it's way up. There are other advantages too like being able to run a larger duration cam without losing as much bottom end as you normally would. Check out this guys website, interesting stuff on smaller ports. http://mototuneusa.com/thanx.htm

Share this post


Link to post
Share on other sites

Some full on trick work going on there, be interesting to see the results

Share this post


Link to post
Share on other sites

I've read about this before... Just wondering, does this also add benefits to a completely bone stock DRZ?

Someone around here said the stock DRZ head flowed so well for stock engine purposes that this wouldn't be any good... But I haven't tried, so I have no idea!

Share this post


Link to post
Share on other sites

Doesn't jb weld melt with gas? Just my experience

It better not.  lol.  I've used JB in ports over 20 tears ago without any problems. Pat Mcgivern has probally done hundreds of heads using JB Weld. The slow curing one not the 4 minute stuff.

Share this post


Link to post
Share on other sites

I've read about this before... Just wondering, does this also add benefits to a completely bone stock DRZ?

Someone around here said the stock DRZ head flowed so well for stock engine purposes that this wouldn't be any good... But I haven't tried, so I have no idea!

Not sure that it would help a stock motor, but it might. wouldn't help nearly as much as a 440 kit. The stock head flows pretty well, good enough for 50 HP with just a good valve job.  I'm try to find every ounce of HP I can. This head is going on a 485 stroker with an Ice Cube cylinder, custom ground Web cams, 41 FCR and a ton of other goodies.

  • Like 1

Share this post


Link to post
Share on other sites

Ok, I've had some time to get a little more finished. I've got the ports pretty much finished at this point. I ran it on the flow bench and it didn't quite hit the numbers I was hoping for. It's not too bad, Has good flow at low lifts but is a bit low at .400 thou. It's at 152 cfm and I'm trying for 160. I still need to backcut the valves and shape the chamber, and the port needs to be finished sanded and shaped so I'm sure the numbers will come up.

 

IMAG0480_zps4f60790b.jpgIMAG0476_zps3a0ec3b0.jpgIMAG0482_zpsb355e71e.jpg

  • Like 1

Share this post


Link to post
Share on other sites

I just had James509 port the cyl for my DRZ and Man does this thing run AMAZING!!!! I think the best part of it is the awesome power curve, massive power esp from about 6500 rpm and up. I'm sure I owe that to the cyl head porting by James509. This guy does outstanding work. I would HIGHLY RECOMMEND him if you want one of the fastest DRZ's around.

  • Like 1

Share this post


Link to post
Share on other sites

I just had James509 port the cyl for my DRZ and Man does this thing run AMAZING!!!! I think the best part of it is the awesome power curve, massive power esp from about 6500 rpm and up. I'm sure I owe that to the cyl head porting by James509. This guy does outstanding work. I would HIGHLY RECOMMEND him if you want one of the fastest DRZ's around.

am i the only one expecting james509 to get an increase in business? since people arent sending stuff to colorado anymore?

  • Like 3

Share this post


Link to post
Share on other sites

am i the only one expecting james509 to get an increase in business? since people arent sending stuff to colorado anymore?

 

I am sure if he wants the work it will be there for him.....He has done some good development work already and is striving for perfection.....

  • Like 2

Share this post


Link to post
Share on other sites

am i the only one expecting james509 to get an increase in business? since people arent sending stuff to colorado anymore?

+1

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

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

Reply with:

Sign in to follow this  

×