View Full Version : A 3-angle valve job ?
JD400exrider
03-12-2003, 07:01 PM
Getting ready to do a 416 kit with a HRC XR400 cam and new timing chain Plan on some cleanup porting. Ordered all the parts just wondering Is it neccessary to do a 3 angle valve job also. Is the 3 angle the same as stock or a updated way? How many of you guys that are doing the piston and cam doing valve job? I guess i won't no untill its opened up.
dj416
03-12-2003, 07:07 PM
i would recomend it. u have to have the valves out anyeaws to do the porting job if u want to do it right so why not go ahead and cut the valves.
JD400exrider
03-12-2003, 07:22 PM
dj, what kind of increase did you see in performance
dj416
03-12-2003, 07:57 PM
alot more power across all rpm range, i need change the sprockets cause 1st gear has no use now i can idle in 2nd and stomp it with hardly any bog and all it does in first is wheelie. i only got to ride it twice after it was togather then the axle bearings craped out on my and i'm waiting on my new carrier and bearings. im taking it to the dyno soon as i get it in and i'll post the results. i was still playing with the jetting but it was still fast
shamisc
03-13-2003, 12:07 AM
The 3 angle works in conjunction with everything else. Basically it provides better flow. With a port job, the valve job would help it even more. A cam will help that. A bigger head pipe would help that. You get my drift. Every little thing can benefit from another and they all work together to make more ponies. But yeah, if your in the head, do the 3 angle VJ. You won't be disappointed. :D
PHIL_B54
03-13-2003, 07:13 AM
the bike comes with a three angle valve job from the factory
so i dont beleive you would flow any more or gain performance unless the seats were trashed to begin with
you might want to verify that but im pretty sure they come that way
Originally posted by PHIL_B54
the bike comes with a three angle valve job from the factory
so i dont beleive you would flow any more or gain performance unless the seats were trashed to begin with
you might want to verify that but im pretty sure they come that way
I"ve heard that too...
JD400exrider
03-13-2003, 08:58 PM
Hows the power bomb head pipe going to flow with this set up.
BigThumper33
03-13-2003, 09:51 PM
When I took a powers tech class, my instructor says that the only really true way to get a good valve seal is by doing a 3 angle. Performance gains are minimal, being it comes factory with it, redoing it will probably show nothing. The three angle makes the valve seal on the seat in a smaller area(if I remember right) causing more spring pressure to be put on a smaller area, thus a better seal.
There was talk of a 5 angle valve job on here awhile back. Search around a bit and see what comes up.
Joe
I just installed a ROSS 416 piston and a stage2 hotcam. I went a head and replaced all 4 valves and had the seats cut while it was apart. Do it right the first time and you will be happier in the long run. Good luck!
Bigthumper33 is right you do get a better seal, plus less heat is transmitted to the valves with the smaller contact area.
True!
MIKE400EX
03-14-2003, 02:08 PM
I've only taken apart 6-8 stock 400EX motors but the original Honda valve job leaves a LOT to be desired. When I first took mine apart with maybe 20 hours on it, the valves did seal but looked like they should have had 100K miles on them.
REC, actually the valve contact area is meant to draw heat out of the valve head. Still the same idea, the better the contact point the better the heat transfer.
Steven
03-14-2003, 02:17 PM
Mike's right. You can't beat a good three angle valve job done by a professional, rather than a factory robot.
A good three angle valve job will increase volumetric efficiency at all throttle settings and rpm's. As I understand it though, the valve come cut and the seats are cut to match. Right?
Anyway, it will increase your flow and cylinder pressure.
Steve
Ralph
03-14-2003, 02:41 PM
Originally posted by BigThumper33
When I took a powers tech class, my instructor says that the only really true way to get a good valve seal is by doing a 3 angle. Performance gains are minimal, being it comes factory with it, redoing it will probably show nothing. The three angle makes the valve seal on the seat in a smaller area(if I remember right) causing more spring pressure to be put on a smaller area, thus a better seal.
sorry to let u but it comes with the all mighty THREE ANGLE VALVE JOB from factory, so unless they are starting to round off u dont need it and u prob wont eaven feel an increase in power if needed it will make ur vavles seal better...
sucks hearing that from a 15y.o eh?
Ralph
03-14-2003, 02:43 PM
Originally posted by Steven
Mike's right. You can't beat a good three angle valve job done by a professional, rather than a factory robot.
A good three angle valve job will increase volumetric efficiency at all throttle settings and rpm's. As I understand it though, the valve come cut and the seats are cut to match. Right?
Anyway, it will increase your flow and cylinder pressure.
Steve
yeah and i bet u can draw a circle better free hand than a computer, right? and weld better then a quality machine. face it technology has perfected so much humans cant competed to the perfection...
mikeboone
03-14-2003, 02:47 PM
LRD--re read BT33's repsone. He stated the valve seat comes cut 3 angle in his post. He means you can/may gain some improvement by RECUTTING the 3 angles.
Ralph
03-14-2003, 03:03 PM
Originally posted by mikeboone
LRD--re read BT33's repsone. He stated the valve seat comes cut 3 angle in his post. He means you can/may gain some improvement by RECUTTING the 3 angles.
and re-read my post stating that unless they are starting to round there will be minimal gains
BigThumper33
03-14-2003, 05:31 PM
LRD, my posts says it comes from the factory with it. Your not letting us in on any secret, so drop the smart ***** attitude.
Whats this about a computer cutting circles? You do valve angles with round stones......there is no "computer perfect cut". Drop the attitude, your not helping anyone out. Instead of wasting your and our time with your posts.....how about ya go out and recalibrate your computer so it will cut some better seats...... :cool:
Check out your ex frame. Look at all the splatter and the weak welds. There is no perfection there. Computers turn out the products faster, nothing more.
JD400exrider
03-14-2003, 05:40 PM
Thanks for the posts guys. I have talked to a couple shops and an going to send it in for a freshin up on the valves and port and polish. I am probably going to replace the valve is needed. A couple shops have told me the intake valves are a little soft. Has anyone herd this.
don't forget to check your stoichiometric ratio!
trx400ex
03-15-2003, 03:30 AM
Originally posted by Lrd Mx400ex
yeah and i bet u can draw a circle better free hand than a computer, right? and weld better then a quality machine. face it technology has perfected so much humans cant competed to the perfection...
you dont know what your talking about.
sucks hearing that from a 15 y. o. EH?
Ralph
03-15-2003, 03:39 AM
sry man, i guess the hetrcik racing was wrong when the told me that exact thing, and dr.bobs, and alot of other people, so i took all those experienced opinions+some commen sence and tried to make a point
Powered by vBulletin® Version 4.2.1 Copyright © 2024 vBulletin Solutions, Inc. All rights reserved.