450 cam mod- the skinny with pics

[cowboyona426]

This is going to be an attempt to explain in excruciating detail how to do the swap, time the cams, and shim the valves. I was going to include a necessary tool list, but it would be LOOOOOOOOOOONG I am going to show you one helpful tool ANY YZ-F owner must have... a long flex shaft. I managed to drop my 8mm socket into my motor while doing the mod, and without a flex shaft with a modified pick stuffed into the end, I never would have got it out. This is my "fishing tool," the magnet will stick to the cam chain and crank gear, but it wasn't hard (took about 1 minute) to grab the socket and pull it out. Without this, I would have had to pull the motor down to get the socket out.


Fishing tool


Flex shaft


Modified pick- the end is ground flat, and it has a magnet at the other end.

The only bad part about this post is that I don't have pictures of the original cam coming out, because I was so excited when the new one came in I just started wrenching But, here's the short-n-sweet version- remove the seat, remove the tank/shrouds (will come off as an assembly), remove the old decomp assembly, and remove the valve cover. Once the valve cover is off, remove the timing plugs, and using a 14mm socket, spin the crank counter clock-wise and get the piston at TDC, this will be then the cam lobes are exactly opposite each other. Once this is done, remove the header (makes removing the tensioner easier), remove the cam chain tensioner, and remove the exhaust cam cap.

After removing the exhaust cam cap, it's time to remove the old cam. These pics are of the 450 cam, but the method would be the same. Pull the cam up, and rotate it backwards in the chain. There is a small tab on the intake cam cap that will go between the cam gear and the bearing. Once the cam is in this position, you can pull the chain off and remove the cam. Don't worry about the cam chain, your intake cam is still in there and the chain won't fall into the cases.


Exhaust cam removal aligning tab


Exhaust cam removal position- front view


Exhaust cam removal position- top view

I think I can only do 6 pics per post, so I'll continue on the next post. PLEASE do not reply until I am done!

[cowboyona426]

Okay, now it's time to install the new cam and check your valve clearances. Put the new cam into the removal position, install the cam chain over the cam gear, and roll the cam forward into place. The hard part is getting the cam in the right spot so that it is properly timed when you roll it forward. Here are some pics to help.


Exhaust cam close-up timed WRONG. Notice the (very blurry, sorry about the quality) dot on the cam gear that is level with the front of the head.


Exhaust cam close-up timed RIGHT. The dot is now below the level of the head.


Pic of the intake cam close-up for comparison's sake. Notice that the chain rides only slightly higher on the 450 exhaust cam than on the 426 intake cam.

Once you get the cam timed right, reinstall the cam cap and check the valve clearances. Once you get that figured out and have the proper shims, remove the cam again. Right underneath where the cam lobes were, you will notice the two lifter buckets. You must remove these in order to change the valve shims, and getting them out can be a pain. Here's how I do it, but you could also use a small magnet to pull the lifter bucket up.


Removing the lifter bucket


Close-up shot

When you pull the lifter bucket out, if you've never done this before, you are going to panic because there are NO shims in there! They are just hiding, under the lifter bucket.


Valve shim location

Next post...

[cowboyona426]

When you install the new shims, rather than try to put them back into the bucket (kind of hard), you can just push them into there spot on top of the valve. With the lifter bucket removed, you will be able to see right where the shim will fit. Sorry I don't have a pic, I forgot to take one of this! : Once the new shims are installed, slide the lifter buckets back into position. They are kind of hard to get lined up right, but once they get started they slide right down into place. Almost done! Reinstall the cam, one last time. They should not look like this



but they should look like this from the cam gear side



and like this from the lobe side (brake side)



When the cams are timed right, there should be 14 cam chain pins between the dots on the two cams. Reinstall the cam cap- I should have noted earlier, this can be kind of tough because you have to get the holes all lined up right, but after a few tries it becomes easy. I also should have noted before... BE VERY CAREFUL with the C-shaped cam retaining clips, they can and will jump into the motor, and are much harder to get out, even with your handy-dandy cowboyona426 fishing tool. Once you've dropped them in the motor once, you'll never do it again though! Torque the cam cap bolts (doesn't take much- be sure that the cams can free-spin when the bolts are tightened up), install your Vibeguy aluminum decomp shaft plug (if you don't have one yet get one ordered!), reinstall everything and you're ready to ride!

Last but not least, here's a pic of my cat, Sponge, helping me out and making sure I did a good job on the linkage bearings.



I wasn't trying to moon the camera BTW, I was reinstalling the cam when this pic was taken

ENJOY YOUR NEW 450 CAMMED HOT ROD!!!

The low-end torque is AMAZING, and no more starting drill is excellent! No disappointments with this mod at all, period.

[cowboyona426]

PS- I'm sure I left a few things out, so don't hesitate to ask if you have a question

[Blitz393]

can i do the 03 cam mod for my TTR? please?

good job cowboy, now.... lemme ride it. i know i can start it

Rob

[Ranger_450F]

Nice write up Chase good Job. Moved to the Knowlege base.

[FFRacing11x]

Chase, nice write up... I can add a few tips ...

No need to install the cam chain to check the valve lash...chances are it will need to be adjusted and the cam will have to come back off.
I strongly recommend measuring cam journal clearance with "squish" strips.
I strongly recommend using some type of assembly lube when installing new cams.
I strongly recommend the proper "new" cam breakin procedure...on first start up bring it up to 2000-2200rpm and keep it there for several minutes...this will allow the cam to better "mate" to the buckets...after that, go for it!
NEVER use a magnet on valve train parts!
And be very careful to not mar or scratch the bucket or bore when removing.
What did you use to close the decomp hole?

[Ranger_450F]

FFR,

Got a question on the assemly lube I see this refered to all the time. Can you use RG3 silkolene grease or is there a specific type of lube you buy at cycle shops or shucks or something that should be used. I assume your just putting some lubrication in the cam bearing for the initial start up until the oil gets curculated. But you need some type of assembly lube that is fairly light and will not clog the lubrication system after it is wahed away.

[FFRacing11x]

There are several good lubes, but this is what I use and recommend...


Designed to be used a lubricant to apply to potential wear surfaces before assembly in order to prevent metal contact upon startup before adequate lubrication is supplied. Provides three times greater film strength than conventional black Molybdenum Disulfide greases and will not clog oil filters. This product clings to all surfaces and is an excellent rust inhibitor, allowing the storage of parts for years. A thin film of protection is all that is required on mating parts. Red Line Assembly Lube will mix with our motor oil and can be used on all lubricated parts such as cams, followers, pistons, and bearings, and bolt threads. Use only a small amount on bearing and piston surfaces - too much can make it difficult to turn over the engine. Red Line Assembly Lube is an excellent corrosion inhibitor and can be used on machined surfaces to provide long-term corrosion protection. Do not use on exhaust bolts or other high temperature bolts which require an anti-seize.

[cowboyona426]

Tryce- I used a Vibeguy aluminum plug- see the end of the last post. I never thought of leaving the chain off to check the clearances, but it's good practice anyways Why shouldn't you use a magnet on valve train parts?

[InvolvedPatriot]

Great write up Cowboy! I'm copying this to my own "knowledge base" and studying it for my upcoming install.

What is the difference in compression braking? (thought it was supposed to be reduced)

What is the noticable difference in stall at low RPM? (thought this also was supposed to be reduced) ...can you lug it out alot more? Will the bike be better on tight single track?


congratulations

[FFRacing11x]

Originally posted by cowboyona426
Tryce- I used a Vibeguy aluminum plug- see the end of the last post. I never thought of leaving the chain off to check the clearances, but it's good practice anyways Why shouldn't you use a magnet on valve train parts?

Sorry, I missed the part about Vibeguy's plug...I use one as well.
The reason you don't want to use the magnet on shims, keepers and buckets is a bit over kill, but one I have always followed.
Any time you use a magnet and touch another ferrous part, you have what is called magnetic transference. What this means is the part that was picked up or held by the magnet has, to some degree, become magnitized. Theoretical scenario...you have valve float or a bucket hung up in the bore...that shim could "possibly" become displaced(by the magnitism)...get the picture?
Could it happen? Possibly. Has it happened? Sure. Will it happen to you? Highly doubtful, BUT...

[huffdaddy70]

Great job Chase! Glad your tickled with it!

[cowboyona426]

Tryce, correct me if I'm wrong, but doesn't the lifter bucket have a small magnet inside, which is why the shims stick to the inside of the lifter bucket?

IP, my jetting was in the toilet (high idle that wouldn't go away) so I can't really comment. I did stall a few times, but I think it was jetting related. My bike was already a low-end monster with 13/52 gearing, but the 450 cam gave it MORE low-end! Picking up the front tire is a non-issue now (I have a stock flywheel BTW). Once I get the jetting straightened out, I'll let you know about the stall ability and compression braking. The compression braking seemed less, probably more due to my high idle though. I did purposely pull in the clutch and kill the motor on a downhill, let it back out, and it fired right back up though Just do it, you will NOT be disappointed

[InvolvedPatriot]

cool, thanks cowboy

[cowboyona426]

The Easter Sunday verdict, after cleaning the carb...








WOW! What a bike! I was pulling 3rd gear wheelies like nobody's business. The power is smoother, but pulls FOREVER! I couldn't be happier. My jetting felt like it was spot on today too, which is a first for me! I had a bit of a hanging idle, but I'm sure I could have cleared it up by adjusting the fuel screw had I not been wheelying and grinning ear to ear Hands down, this is the best mod I have done to my 426. NOTHING has made as big a difference as the 450 cam. NO disappointments with this mod! My bike is going to the dealer on Tuesday to show it off, since they were thoroughly convinced it would never work! WOOHOOOO!

[dauk]

Since it is time for me to check the valve clearance on my WR426f I am considering doing the 450 cam swap. When I called the dealership to check availability of shims and the cam, they asked if I wanted the WR cam or the YZ. I assumed that I should get the WR450 cam. Is this correct ? Thanx.

[Satch0922]

I would recommend getting the YZ cam. I have only heard of a few people going with the WR and it is a little more difficult to get timed properly etc.
You won't be disappointed with the powerband of the YZ cam.

[cowboyona426]

I second that

[dauk]

Right on, thanks Satch. I'm gonna roll this over and I'll let you guys know when I've finished the mod (and which cam I decided to use).

BTW: Sorry folks! I seem to have posted this question here *and* started a new thread. I didn't see the question pop up in this thread, so I started a new one. I guess I figured this thread was just archival and couldn't be posted to anymore.