2007 WR450 Performance Mods

I hope this is the right section: I just bought a 2007 WR450 and I'll be doing AIS, intake mod just as soon as I get the parts. However, my question is what is the stock main and pilot jets? The manual I got off the net states main: 162 and pilot: 45, however the guide from RMATV states main:150 and pilot: 70.

Perhaps it is not necessary to know as I will be chaining them out when I get the AIS kit but I wonder if the jets with the AIS kit are the right ones for my riding area. I ride at ~4k-9,10k and wonder if the JD jetting kit will be a better choice.

Sorry for all the questions intertwined but I just wanted to do all my research.

Thanks everyone.

Stock is 162 MJ and 45 pilot. I ride the same bike and year and elevation as you. I tried a bigger pilot 48 and had issues, too rich.

I run a 160mj and 45 pilot and 50 leak jet with air box mod and a Lexx pipe. Seems about right. I replaced the stock needle with a NCVS 3rd clip and the mid is better then stock needle. Buy at boats.net for 10.00. I would also check the valves after the season, mine were off by one size. I adjusted, the bike was fairly easy to start before but know that the valves are in total spec it lights up in a half second on the magic button. Also make sure to get an after market brass fuel screw, well worth it. I like the merge racing one.

Stock is 162 MJ and 45 pilot. I ride the same bike and year and elevation as you. I tried a bigger pilot 48 and had issues, too rich.

I run a 160mj and 45 pilot and 50 leak jet with air box mod and a Lexx pipe. Seems about right. I replaced the stock needle with a NCVS 3rd clip and the mid is better then stock needle. Buy at boats.net for 10.00. I would also check the valves after the season, mine were off by one size. I adjusted, the bike was fairly easy to start before but know that the valves are in total spec it lights up in a half second on the magic button. Also make sure to get an after market brass fuel screw, well worth it. I like the merge racing one.

Thank you for the help. I was also able to confirm that the main jet is a 162 and the pilot is 45. I ended up buying the JD kit using the 165 MJ keeping th epilog jet at 45 and using the red needle on clip 4. I have yet to get a fuel crew and the one I want from MATV is out of stock util July 14... ugh However, they do have the R&D flex jet available and wonder if that one is worth it over the tusk one?

R&D:  http://www.rockymountainatvmc.com/p/1151/22925/R-%26-D-Racing-Flex-Jet-%28Remote-Fuel-Screw%29?v=5639

Tusk: http://www.rockymountainatvmc.com/p/1151/13581/Tusk-Fuel-Mixture-Screw?v=5639

 

Also, I cam across this guy: 

Boyesen Quickshot 3 Accelerator Pump Cover 

http://www.rockymountainatvmc.com/p/1151/-/200527/Boyesen-Quickshot-3-Accelerator-Pump-Cover?v=5639

 

Is this guy worth it? What benefit does this offer over the stock cover/non-adjustable one?

Do not buy the cheap aluminum fuel screw, not worth it. Spend the extra for the brass fuel screw best money you'll ever spend. Don't be tempted by those cheap ones.

http://www.mergeracing.com/products/FuelMixtureScrew.php

I did replace the accelerator pump spring. You can but a Ktm one for 5.00 off of Rockymountainatv. It's the same one guys put in to make it stiffer.

http://www.rockymountainatvmc.com/p/1151/41156/KTM-SXS-Acceleration-Pump-Spring

Works for all FCR carbs.

No comment on quick shot, but a 50 leak jet is a popular mod size.

Do not buy the cheap aluminum fuel screw, not worth it. Spend the extra for the brass fuel screw best money you'll ever spend. Don't be tempted by those cheap ones.

http://www.mergeracing.com/products/FuelMixtureScrew.php

I did replace the accelerator pump spring. You can but a Ktm one for 5.00 off of Rockymountainatv. It's the same one guys put in to make it stiffer.

http://www.rockymountainatvmc.com/p/1151/41156/KTM-SXS-Acceleration-Pump-Spring

Works for all FCR carbs.

No comment on quick shot, but a 50 leak jet is a popular mod size.

Good to know about the brass fuel screw. Makes sense if the stock one is brass. Seems the R&D one is brass plus it looks to be super easy to adjust. 

As far as the AP spring goes when I got the JD kit it cam with two O-rings. One think and one thinner one. I used the thinner one for now so as to get a feel for it. 

 

I believe when I got the AIS removal kit it came with a new leak jet but I did not install it. I think I will do that when I do the fuel screw. 

Good to know about the brass fuel screw. Makes sense if the stock one is brass. Seems the R&D one is brass plus it looks to be super easy to adjust.

As far as the AP spring goes when I got the JD kit it cam with two O-rings. One think and one thinner one. I used the thinner one for now so as to get a feel for it.

I believe when I got the AIS removal kit it came with a new leak jet but I did not install it. I think I will do that when I do the fuel screw.

If your going to do anything with accelerator pump etc do this kit. This is popular for FCR carbs.

http://crfsonly.com/howto/keihin-fcr-carb/honda-crf-fcr-carb-update-how-to-install/how-to-install-honda-accelerator-pump-update-crf450r.php

YES!

I did this along with the tokyomods stiffer acc pump spring. Worlds difference. No bog ever on the throttle, instant response every time.

Nice!

So you did the 2008 Honda FCR upgrade kit? Did you have to adjust the pump squirt at all? You also removed your check valve right?

Nice!

So you did the 2008 Honda FCR upgrade kit? Did you have to adjust the pump squirt at all? You also removed your check valve right?

Yep did all that! The 2008 diaphragm was pretty easy. I did have help from a friend who did it to his 2005 crf450x a week before me so it was all fresh in his mind. But yeah removed check valve and adjusted the squirt. Adjusting the squirt is easy, just get it to barely miss the slide and make sure it's a string squirt.

Hardest part was the spring replacement for the acc pump linkage, but that really wasn't hard. All I did before that was the GYTR AIS removal a few years before this upgrade. This weekend I'm installing a JD Jet kit. But all that along with my 08 yz450 full exhaust bike hits hard and pulls great.

Yep did all that! The 2008 diaphragm was pretty easy. I did have help from a friend who did it to his 2005 crf450x a week before me so it was all fresh in his mind. But yeah removed check valve and adjusted the squirt. Adjusting the squirt is easy, just get it to barely miss the slide and make sure it's a string squirt.

Hardest part was the spring replacement for the acc pump linkage, but that really wasn't hard. All I did before that was the GYTR AIS removal a few years before this upgrade. This weekend I'm installing a JD Jet kit. But all that along with my 08 yz450 full exhaust bike hits hard and pulls great.

Good info. Did you try the NCVS needle or you going to the JD needle?

I think the AIS kit comes with the ncvs needle, not sure on that though. Either way I'm gonna run jd needle after this weekend and rejet, I think I've been a bit too rich. 175 main and a 48 pilot.

Gonna try the 170 main and see how it is.

Edited by JMundy

I have an '07 WR450 which has had the GYTR derestriction hoopla installed, along with the GYTR jet kit.  I believe it has a 175 main and 5 position needle, which it's at #3.  Is the needle taper different with the GYTR vs. the JD?

Also, I did the ghetto accelerator pump mod with a zip tie and tied the arm together.  No bog, but makes downhill trail riding a bit sketchy as every time I shake the throttle it's constantly squirting gas.

Does the JD AP spring make it not quite that twitchy?

Yes. There are a dozen needle options. JD Red or NCVS are your best bet, unless you want to use an A/F meter to get it closer to 14.5 ratio.

Ideal-stoichiometry.jpg

No it doesn't. The linkage mod is just a 'delay reducer'. You want less fuel to squirt, you need to change the leak jet (larger)

Just get used to having it 'correct' for a while.

I have an '07 WR450 which has had the GYTR derestriction hoopla installed, along with the GYTR jet kit.  I believe it has a 175 main and 5 position needle, which it's at #3.  Is the needle taper different with the GYTR vs. the JD?

Also, I did the ghetto accelerator pump mod with a zip tie and tied the arm together.  No bog, but makes downhill trail riding a bit sketchy as every time I shake the throttle it's constantly squirting gas.

Does the JD AP spring make it not quite that twitchy?

 I would recommend losing the zip tie and running an o ring.  Reason - it will probably help with the twitchy throttle. Zip ties or safety wiring it together gives zero play at all, so it is very touchy.  An o ring has a small amount of give, and MAY help with the twitchy throttle.  I believe that is one of the main reasons the JD Jet kit comes with an o ring instead of wiring it together.

with the JD kit, the O ring is secure the AP to the arm, or is there a stiffer spring to help decrease the delay?

Tokyo mods makes a stiffer ap linkage spring

It works much better than the oring, and it will not fail and break.

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