JOHNDOE83
03-11-2012, 08:23 AM
The rules:
1. 450r carbs HAVE to have the hotstart blocked off properly to work on a 400ex.
2. Some modification is needed to attatch a stock airbox.
3. Every quad is different, I didnt have to do alot of what other members did to install their 450r carbs but theres some minor differences between every EX that might mean you have to do extra stuff for a proper fit. "like drilling and tapping the vent"
4. JETTING.
There's alot of controversy on how to properly block a hotstart, I used the RTV gasket sealer method while others have used a bolt and a screw or the standard method of just using a hotstart.
If your carb didnt come with a hotstart and you dont wanna spend 25-30 dollar's to order one, here's what you can do.
I filled mine with RTV, the place most people make a mistake is by only filling the big hole the hotstart goes in, you have to fill another tiny hole inside the carb port just under where the hotstart is on the carb.
here's some pics "not best quality"
hotstart filled with RTV
http://i953.photobucket.com/albums/ae15/johndoe83_2010/SUNP0167.jpg
tiny hole inside the carb port "Need's filled"
http://i953.photobucket.com/albums/ae15/johndoe83_2010/SUNP0168.jpg
Another member instead of using RTV used a bolt and a tiny screw, which it would seal it but at some point "in my opinion" that screw might come out and go straight to your valves.
Beside's RTV is made to be a "sealer" and not only that its made to be a "gasket" replacement. Its worked in my atv for many years now and has worked flawlessly. Its the exact same thing as sealing a actual hotstart with RTV anyway.
To attatch the carb to the air boot a 2in rubber plumbing adapter is needed, it can be bought at lowes or home depot for $4.
I went with no airbox but used the same rubber adapter, it can be seen in my 450r carb install thread, it makes a great seal and super easy to install and fits the stock ex air boot nicely. here's my thread http://www.exriders.com/vbb/showthread.php?s=&threadid=425850&highlight=450r+carb+install
You can either use this $4 plumbing adapter or use one of ZR's adapters, which ever you choose is fine they both work nicely.
As far as the vent goes, I did drill mine out and put a screw in it but after installing I saw that I didnt really have to do anything to it other then pull the vent tube off.:rolleyes:
After you take care of the basic's its time to jett your ATV, this is also a contoversial subject for me, Ive tuned many four strokes and built many bike's for many different applications from MX, tt, trail's, mudd everything all the way to full out drag bike's. "not like mine"
I trust and approve the www.jetsrus.com method for tunning for your main jet. Starting very large on main jet's till you sputter like a rev limiter on the topend rpm's then backing it down till it stop's is the only way to jett for main jett without a plug chop.
Plug chopping for main jet isnt specified ANYWHERE in ANY thread Ive ever seen, the plug chopping method where you just simply pull the plug out and look at it DOES NOT show anything about main jet reading on a plug.
I have a plug chopp/jetting thread that can be seen here http://www.exriders.com/vbb/showthread.php?s=&threadid=441780&highlight=plug+reading
I think we need to stay away from this is right and this is wrong threads, This is what worked for me and a few others.
PLEASE feel free to post your thread links here relating to 450r carbs and Jetting, the more there is the better.
Post your install threads and Pics of what you did to make your carb work so other's can get idea's and learn.
:chinese:
1. 450r carbs HAVE to have the hotstart blocked off properly to work on a 400ex.
2. Some modification is needed to attatch a stock airbox.
3. Every quad is different, I didnt have to do alot of what other members did to install their 450r carbs but theres some minor differences between every EX that might mean you have to do extra stuff for a proper fit. "like drilling and tapping the vent"
4. JETTING.
There's alot of controversy on how to properly block a hotstart, I used the RTV gasket sealer method while others have used a bolt and a screw or the standard method of just using a hotstart.
If your carb didnt come with a hotstart and you dont wanna spend 25-30 dollar's to order one, here's what you can do.
I filled mine with RTV, the place most people make a mistake is by only filling the big hole the hotstart goes in, you have to fill another tiny hole inside the carb port just under where the hotstart is on the carb.
here's some pics "not best quality"
hotstart filled with RTV
http://i953.photobucket.com/albums/ae15/johndoe83_2010/SUNP0167.jpg
tiny hole inside the carb port "Need's filled"
http://i953.photobucket.com/albums/ae15/johndoe83_2010/SUNP0168.jpg
Another member instead of using RTV used a bolt and a tiny screw, which it would seal it but at some point "in my opinion" that screw might come out and go straight to your valves.
Beside's RTV is made to be a "sealer" and not only that its made to be a "gasket" replacement. Its worked in my atv for many years now and has worked flawlessly. Its the exact same thing as sealing a actual hotstart with RTV anyway.
To attatch the carb to the air boot a 2in rubber plumbing adapter is needed, it can be bought at lowes or home depot for $4.
I went with no airbox but used the same rubber adapter, it can be seen in my 450r carb install thread, it makes a great seal and super easy to install and fits the stock ex air boot nicely. here's my thread http://www.exriders.com/vbb/showthread.php?s=&threadid=425850&highlight=450r+carb+install
You can either use this $4 plumbing adapter or use one of ZR's adapters, which ever you choose is fine they both work nicely.
As far as the vent goes, I did drill mine out and put a screw in it but after installing I saw that I didnt really have to do anything to it other then pull the vent tube off.:rolleyes:
After you take care of the basic's its time to jett your ATV, this is also a contoversial subject for me, Ive tuned many four strokes and built many bike's for many different applications from MX, tt, trail's, mudd everything all the way to full out drag bike's. "not like mine"
I trust and approve the www.jetsrus.com method for tunning for your main jet. Starting very large on main jet's till you sputter like a rev limiter on the topend rpm's then backing it down till it stop's is the only way to jett for main jett without a plug chop.
Plug chopping for main jet isnt specified ANYWHERE in ANY thread Ive ever seen, the plug chopping method where you just simply pull the plug out and look at it DOES NOT show anything about main jet reading on a plug.
I have a plug chopp/jetting thread that can be seen here http://www.exriders.com/vbb/showthread.php?s=&threadid=441780&highlight=plug+reading
I think we need to stay away from this is right and this is wrong threads, This is what worked for me and a few others.
PLEASE feel free to post your thread links here relating to 450r carbs and Jetting, the more there is the better.
Post your install threads and Pics of what you did to make your carb work so other's can get idea's and learn.
:chinese: