Jetting and MODS


3 replies to this topic
  • pavementsurfer

Posted November 20, 2014 - 06:19 PM

#1

A few comments and questions on mods I've done.  Please read on!

 

I am having a real difficult time eliminating the "bog" from my 04 wr450.  I have researched the site extensively on the issue and ordered the jd kit (170 main 45 pilot blue needle 3rd clip) and a 40 leak( I'm at 400 ft asl).  The bog seems marginally improved.  I removed the p shooter have the yz throttle stop (although that doesn't do anything for the bog) and have done the o-ring mod.  If I whack the throttle open at 2500 rpm+ it does not bog only if I whack the throttle at 1700 to 2500 rpm ish it bogs, I have idle set at 1700.  Can the bog be eliminated right off idle or is it about as good as I'll get it?

 

Also I have found with the jd kit I have a noticeable increase in power :-).  The bike will easily bring up the front wheel with a roll on throttle in 3rd gear where as before it took some (very little) clutch.  4th gear feels like 3rd did prior to the kit.  However I found the bike now runs terribly in the cold 45 degrees the bike sputters under throttle and is difficult to start.  With the stock jetting the bike started easily in 32 to 95 degree weather and NEVER sputtered in any condition.  Is this normal for the JD kit?  Luckily I installed the kit on a 70 degree day and was very pleased with the result had I done it a day later in colder weather I would have been pissed at JD!  

 

Oh and I haven't done the airbox or grey wire.  How much of a difference will those mods  make in addition the the mods I already made?  I don't want to hack the airbox for nothing.

 

Also, bought a set of Rox 2" bar risers for stock bars and I am very pleased with them.  I wanted to get the 3.5" risers but am glad I didn't because the max the stock cables will allow for is 2" IMO.

 

Bought the Vapor Tech Computer and think its a great product for the money.  Even with the tach wired to the bare coils it jumps around.  Having engine temp on a street wr is very nice.

 

Self installed and balanced D606's with about 600 miles on them and they've held up well.  I don't beat them on the street (other then wheelies) but on the dirt its another story.  Still 90% or more tread on front maybe 80% on rear.  When I have the tires inflated for street use 30 psi they suck on hard dirt at 8-10 psi they work well which is expected but get squirrely on the street at 6-8 psi.

 

I have the Tusk ministalk street kit with flush mounts for the rear.  The kit looks great I used the stock brake light. I did blow 1 fuse so far. 

 

Thanks for reading.



  • Krannie McKranface

Posted November 20, 2014 - 07:28 PM

#2

You have incresed the fuel going to the apump cavity (smaller leak jet) but you have not updated the apump system.

You need to change the diaphragm, rod, and linkage spring.

Then it will have radically improved throttle response.

You also need to verify the squirt  by looking inside the carb (mirror, or lift up the subframe)

The apump nozzles get corroded too, if the carb sits with gas, so it might need cleaning out.

Links to parts in this thread:.

http://www.thumperta...ew-and-jetting/

 

Now that the bike is jetted properly, it will take MUCH longer to warm up. 

At least 3 min.

You will also need to re-look at how you start it. Usually, choke, three throttle twists, and go. 

For many of us, the best method is to actually turn the idle screw in a 1/2 turn till it's warmed up for the first few minutes, even with the choke.

You can change the power (choke) jet to one step leaner, if you want it to warm up faster.

 

Make sure you hot start plunger is seating down all the way, and is lubed so it won't leak. The plastic nut should be changed to an aluminum one.

 

You are crazy if you try and ride on the street with 6lbs of air. You will go down.

6lbs of air offroad will give you a pinch flat, unless you use UHD tubes, too.

D606 tires are DEADLY on anything but warm pavement. One of the worst tires ever made. Many will disagree with me.

You are better off with an adventure tire like the Avon Distanzias for dual sport, or a Real DOT knobby like the Kenda Parker DT's. 



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  • pavementsurfer

Posted November 21, 2014 - 07:30 PM

#3

You have incresed the fuel going to the apump cavity (smaller leak jet) but you have not updated the apump system.

You need to change the diaphragm, rod, and linkage spring.

Then it will have radically improved throttle response.

You also need to verify the squirt  by looking inside the carb (mirror, or lift up the subframe)

The apump nozzles get corroded too, if the carb sits with gas, so it might need cleaning out.

Links to parts in this thread:.

http://www.thumperta...ew-and-jetting/

 

Now that the bike is jetted properly, it will take MUCH longer to warm up. 

At least 3 min.

You will also need to re-look at how you start it. Usually, choke, three throttle twists, and go. 

For many of us, the best method is to actually turn the idle screw in a 1/2 turn till it's warmed up for the first few minutes, even with the choke.

You can change the power (choke) jet to one step leaner, if you want it to warm up faster.

 

Make sure you hot start plunger is seating down all the way, and is lubed so it won't leak. The plastic nut should be changed to an aluminum one.

 

You are crazy if you try and ride on the street with 6lbs of air. You will go down.

6lbs of air offroad will give you a pinch flat, unless you use UHD tubes, too.

D606 tires are DEADLY on anything but warm pavement. One of the worst tires ever made. Many will disagree with me.

You are better off with an adventure tire like the Avon Distanzias for dual sport, or a Real DOT knobby like the Kenda Parker DT's. 

Thanks for the input, forgot to mention the AP nozzle gives a good squirt so I have to look into modding the AP itself.  Thanks for the link.  The hot start plunger maybe the culprit for the starting issue.  The plastic screw is chewed up near the end when I had the carb off the bike last it was very difficult to reinstall it maybe leaking.  I'll look into the aluminum nut also. 



  • Krannie McKranface

Posted November 21, 2014 - 07:47 PM

#4

Thanks for the input, forgot to mention the AP nozzle gives a good squirt so I have to look into modding the AP itself.  Thanks for the link.  The hot start plunger maybe the culprit for the starting issue.  The plastic screw is chewed up near the end when I had the carb off the bike last it was very difficult to reinstall it maybe leaking.  I'll look into the aluminum nut also. 

 

If the nut is not brand new, it is leaking.

When it leaks, it makes trying to figure anything out simply maddening...

 

https://www.google.c...7.0.8U3GKGIA8pA






 
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