trx 450r valve clearance

hondaman450 · #1 06-12-2011, 05:33 AM

hello guys i had just recently baught a trx450r and i was checking my valves to see if they were in spec on the stock cam it is an 05 and looks too be in good shape well i got everything the way its suppose to be at tdc and on the intake i cant get a feeler guage in either left or right they are tight with no clearence i got a .007 guage in but had to force it in and pry to get it back out very tight anything lower would just bow well i did mic my shims left was .068 and right was .069 do i need to start at zero or do i go by the .007 which i had to force to get in and if so how do i get my calculation. i also baught a stg 1 hotcam for it and been wanting to try it out i did install it but same thing cant get a clearance on the intakes again too tight i did take it back out and put the stock cam back in did not want to screw up anything so untill i can get some help im not going to ride it but my bike does start up first or second kick all the time and has good compression and runs out good it has stg 2 jet kit a hmf slip on and uni aftmrket filter everything else is stock so where would u guys start at do i just start at zero because there is no clearence at all very tight no gap sorry for the long thread just trying to get everyone on what im dealing with and how to fix it thanks

69quadracer · #2 06-12-2011, 11:09 PM

Sounds like you have some wear on the valves and seats, need to get a hotcam shim kit so you have an assortment to choose from not sure about the clearancd on the 05 but mine are set a .006 int and .011 ex not sure how thick of a shim you will need but their is a limit to how thick of a shim you can use if you are past that limit you will need a valve job

Here 2 help · #3 06-13-2011, 03:41 AM

Get a service manual and follow the instructions. You can learn by the mistakes you made.

hondaman450 · #4 06-13-2011, 04:09 AM

thanks for the info guys might as well get some new valves and be done with it so i know what i have maybe a shim kit too which is good to have if u own a 4 stroke

69quadracer · #5 06-13-2011, 10:41 AM

yes a shim kit and a set of micromaters is a must have

joeylowthers450R · #6 06-13-2011, 03:21 PM

Quote: Originally Posted by hondaman450

hello guys i had just recently baught a trx450r and i was checking my valves to see if they were in spec on the stock cam it is an 05 and looks too be in good shape well i got everything the way its suppose to be at tdc and on the intake i cant get a feeler guage in either left or right they are tight with no clearence i got a .007 guage in but had to force it in and pry to get it back out very tight anything lower would just bow well i did mic my shims left was .068 and right was .069 do i need to start at zero or do i go by the .007 which i had to force to get in and if so how do i get my calculation. i also baught a stg 1 hotcam for it and been wanting to try it out i did install it but same thing cant get a clearance on the intakes again too tight i did take it back out and put the stock cam back in did not want to screw up anything so untill i can get some help im not going to ride it but my bike does start up first or second kick all the time and has good compression and runs out good it has stg 2 jet kit a hmf slip on and uni aftmrket filter everything else is stock so where would u guys start at do i just start at zero because there is no clearence at all very tight no gap sorry for the long thread just trying to get everyone on what im dealing with and how to fix it thanks

from the looks of your numbers, you should start with 0.062(to replace the 0.068) and a 0.063(to replace 0.069). these shims will be 0.006 smaller, your required intake clearance. this will prob not be bang on but it should get you close enough to calculate what size you need.

69quadracer is correct on valve clearances
set you decompression to an additional 0.006 on top of your 0.011 exhaust clearance

you may want to replace the air filter because the 04/05 models have all steel valves that don't wear as bad as the new models. normally they are a very dependable valve train in your model, makes me think there must be a reason for the seats wearing(dirt making it into your engine)

joeylowthers450R · #7 06-13-2011, 05:29 PM

Quote: Originally Posted by Here 2 help

Get a service manual and follow the instructions. You can learn by the mistakes you made.

why don't you tell us what mistakes he made!
i tired of your a$$hole remarks to people. i see that you do help some people but if you don't know the answer then you turn into a A$$.

if you don't have anything useful to say or are in a bad mood, stfu! people don't need you to tell them to "take it somewhere and have it fixed right". they will figure that out on there own if none of the nice guys on here help them out

Here 2 help · #8 06-14-2011, 03:21 AM

Quote: Originally Posted by joeylowthers450R

Quote: Originally Posted by Here 2 help

Get a service manual and follow the instructions. You can learn by the mistakes you made.

why don't you tell us what mistakes he made!
i tired of your a$$hole remarks to people. i see that you do help some people but if you don't know the answer then you turn into a A$$.

if you don't have anything useful to say or are in a bad mood, stfu! people don't need you to tell them to "take it somewhere and have it fixed right". they will figure that out on there own if none of the nice guys on here help them out

OK. Since I cannot quote the service manual, you will have to bear with me if my explanation is not fluid.
Now it makes no difference if you are using the stock cam or an aftermarket cam. In therory, all the cams have the same base circle for the engine they are designed to be used in. The maximum thickness of a shim is of no concern. The minimum thichness of a shim is critical. When you reach the mininum thickness shim, you have to replace the valve.
Since no feeler gage can be inserted (without force) you have to presume the clearence is zero or less. (less meaning the valve is actually open a thousandths or two or more) Since the shims are measured in millimeters it is redundant to measure the shims in thousandths. Each shim is marked with it's thickness to one one-hundredth of a millimeter. You should measure the clearence in milimeters.
Since a little extra clearence is more desireable than too little clearence, you should calculate the desired shim thickness by checking the thickness of the installed shim and subtracting the desired clearence (or in this case, the specified clearence).
Compared to the valve seat, the valve is soft. As the valve face erodes, the clearence between the cam and valve lifter decreases. Running "high flow" air filters will speed the erosion by allowing a greater amount and larger particles of dirt to enter the engine. The intake valves usually wear faster than the exhaust valves because the exhaust valves are harder (to resist the heat) and the intake valves are closing on dirty air.
Each time the shim is changed it is prudent to rotate the engine to open and close the valves to "seat" the valve and make the clearence measurement more accurate.
I race a Honda. When I adjust my valves, I set the clearence to the loose side increasing the length of time between adjustments and reducing the possibility of the valve clearence "zeroing" out while riding before the next service interval. These are "race bred" engines. The valves need to be checked regularly and frequently. The piston and rings need to be replaced at the specified interval to prevent engine damage. Don't whine about a dime. You purchased a high performance vehicle and high maintenance cost are incidental.
So, there you are. I spent an hour typing this explanation (with few or no mispellings and gammatical errors) while I could have physically performed the service in less time. Now you can attempt to service your own engine and with luck, not damage anything beyond repair. While you are working on yours' I will be riding mine.

hondaman450 · #9 06-14-2011, 03:55 AM

man i do appreciate ur time and everyone is so helpfull thats why i am in this forum u guys are so helpfull like i said i can do some things but u can learn alot more by talking to others just rather be safe than srry.

joeylowthers450R · #10 06-15-2011, 03:16 AM

well i checked my shim kit,
your 0.068 is actually 0.0679=1.725mm
dropping your 0.006 for clearance puts you at 0.062=1.575mm

your 0.069 is actually 0.0689=1.75mm
dropping your 0.006 puts you at 0.063=1.6mm

these #s will only be correct if your valves were not being held open at all(chances are slim)

you still have some life in your head, you can go down to a 0.0472=1.2mm. that is 15 shim sizes smaller then the 0.062 you need to install(and recheck)

you will prob end up needing between a 0.062=1.575mm and a 0.060=1.525mm ind the end

i hope this helps you, don't be intimidated its not too hard. july dirtwheels has a article on how to do it with pics if you think that would help you. oh and i hope you have fun riding heretohelp