'98 YZ400F wanna do hot cams stage 1


16 replies to this topic
  • cuvalaj

Posted March 23, 2009 - 03:23 PM

#1

But im not very confident in doing the work myself. i have the tools but i've never done anything inside an engine before. So i was thinking about trying to find a shop in central Cali, but the last shop i talked to didnt instill a whole lot of warm fuzzies about their level of knowledge concerning this modification. how do i find one that would be able to do the work or have done it before?

  • 642MX

Posted March 23, 2009 - 03:28 PM

#2

If you can read and can do things like mounting tires, you can install cams. There is nothing to it. All you need is a set of feeler gauges, a 1/4 torque wrench, and about an hour.

  • cuvalaj

Posted March 23, 2009 - 03:39 PM

#3

Gah, i dont have the feeler gauges, but i can pick those up. i have a 3/8 torqe wrench, and i have a step-down adaptor would that work out ok?

  • 642MX

Posted March 23, 2009 - 04:04 PM

#4

Most 3/8 torque wrenches don't go down low enough. You need a wrench that goes down to 80 inch lbs. You don't have to spend big bucks on a Snap On, a Craftsman or Kobalt will work fine.

  • erickdj

Posted March 23, 2009 - 04:09 PM

#5

Most 3/8 torque wrenches don't go down low enough. You need a wrench that goes down to 80 inch lbs. You don't have to spend big bucks on a Snap On, a Craftsman or Kobalt will work fine.


You might be able to use the 3/8 wrench if you use an extension and/or a swivel adaptor. The crucial part is making sure the wrench can go as low as 80 INCH pounds, not FOOT pounds. The cap bolts are not tightened very much, 80 inch pounds is not very much torque, so it's a delicate and precise adjustment.

  • aj_yz426

Posted March 23, 2009 - 04:12 PM

#6

Swapping out the exhaust cam is pretty easy and just a matter of lining all marks up to get the timing right. Then you have to check valve clearance and adjust with shims if necessary, which takes more time but not too difficult. All that is easy if you can follow the manual and have feeler guages, and a torque wrench. The spaces were pretty tight so I would go with the 1/4" torque wrench and you may need adaptors and an extention to get into a couple of the tight spots right under the frame(can find cheap at harbor freight tools etc.) Also torque down the cam cap bolts in 3-4 increments so you don't get any binding. I would use no more than 80 in pounds so you don't strip the bolts out(Yes, its lower than the manual says. I actually used 75 in pounds).

Its recommended to replace the timing chain while your in there and that is the hardest part of the whole process. You'll also need a flywheel puller for that. Getting the timing chain off the crank gear was impossible for me and I ran out of patience so I just pulled it out to to the left side of the engine,covered everything with rags to prevent potential broken metal pieces from entering the engine and just cut the old chain with bolt cutters. Not pretty, but it worked. I then installed the chain with the help of the directions found here:
http://www.allthings...nt-guide-33228/

It took me probably 4 hours including all the valve adjustments, but I was very careful. I also spent about a half hour trying to get the cam chain off until I cut it. I also can't work for more than about an hour on something before having to put it down due to distractions (I have 4 and 7 year old boys:thumbsup: ).

Also I was able to reuse the left side cover gasket and cam chain tensioner gasket without a problem, but you may need those.
Hope this helps.

  • cuvalaj

Posted March 23, 2009 - 04:46 PM

#7

i really appreciate the inputs here, i think im going to try this out as freaked as i am about it LOL. i guess i just dont want to end up having to pay someone more to fix what i broke LOL . thanks again folks!

  • 642MX

Posted March 23, 2009 - 05:16 PM

#8

i really appreciate the inputs here, i think im going to try this out as freaked as i am about it LOL. i guess i just dont want to end up having to pay someone more to fix what i broke LOL . thanks again folks!


Stay calm! You'll be okay....lol. With the money you'll save in labor, you can buy the correct tools for the job and you'll have the satisfaction of doing it yourself.

Start with the manual. If you don't have one, there is a link Grayracer made at the top of the YZF forum where you can download one for free. Get your cams and then ask questions if you get in a bind. The great thing about TT is everyone's friendly and willing to help.

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  • yzhaulin

Posted March 23, 2009 - 06:52 PM

#9

cuvalaj, where in Cali are you? If your close I could help you out if needed. I'm in Benicia, just east of S.F. I did the swap earlier this year. Like everyone says it's not that hard just a bit intimidating.

  • BRY_426F_

Posted March 23, 2009 - 07:13 PM

#10

if need be! remove all the neccessary parts to access the cover, take the cover off look inside and see if you can make some sense out of what you have. if too intimidated take it to a shop and have them install.. should only cost 45-70 bux for a half or full hour of labor.. not exactly DIY

  • grayracer513

Posted March 23, 2009 - 07:20 PM

#11

Getting the timing chain off the crank gear was impossible for me and I ran out of patience so I just pulled it out to to the left side of the engine,covered everything with rags to prevent potential broken metal pieces from entering the engine and just cut the old chain with bolt cutters.

Unbelievable. What do you do for a living?

The cam chain is removed very simply by removing the cams, and the two bolts holding the lower end of the rear chain guide, then just dropping the chain onto the crank and slide it off. Put it back in reverse order.

http://www.thumperta...405#post3150405

  • Birdy426

Posted March 23, 2009 - 07:24 PM

#12

Do it! It's easy! For what it's worth, I wouldn't try using adapters, extensions and swivels on the torque wrench. You have to make corrections for changes in the arm length that swivels and such add. Get a 1/4 in drive with a small head. Park tools (the bicycle tool company) makes several good ones. A beam type (not a clicker) is going to be cheapest, easiest to find, and have the smallest head. 70-75 in-lb works well for torquing the cam cap bolts.

  • grayracer513

Posted March 23, 2009 - 08:05 PM

#13

A beam type (not a clicker) is going to be ... easiest to find, ...

I'll agree with everything you just said except this.
They've become nearly impossible to find.

  • Birdy426

Posted March 23, 2009 - 08:19 PM

#14

I'll agree with everything you just said except this.
They've become nearly impossible to find.


Here in Pompton (Palmdale), the local NAPA and Harbor Freight both have beam types. Harbor Freight also sells a cheap clicker, but the head is too big to fit in where the intake caps are. A couple of our local bicycle shops that specialize in high end bikes ("The Bike Shop" at avenue L and the 14, and both Bicycle John's) also carry the Park beam type (it seems that the inserts used for "braze ons" on all of the thin-wall Al and Carbon Fiber frames spin fairly easily, so even simple tasks like bolting on a water bottle cage require a torque wrench!)

Other than that, just about any 1/4 in torque wrench is hard to find. I have an old Craftsman (probably 25 years old), but even they don't make one any more.

  • aj_yz426

Posted March 24, 2009 - 04:27 AM

#15

Unbelievable. What do you do for a living?

The cam chain is removed very simply by removing the cams, and the two bolts holding the lower end of the rear chain guide, then just dropping the chain onto the crank and slide it off. Put it back in reverse order.

http://www.thumperta...405#post3150405


Figured I'd catch flak for that, I'm definitely not a mechanic for a living:lol:, I did have the chain guide loosened, but got frustrated and had a kinked chain dropped down the left side so I just pulled it out and cut it, like I said, wasn't pretty. Wouldn't recommend it, was last resort when I was in a rush. The new chain rolled right on without a problem just like you describe.

  • flyer05

Posted March 24, 2009 - 06:29 AM

#16

I used a cheap 1/4 inch clicker from Harbor Freight. I just had to grind the 8mm socket down a bit and it fit just fine.

  • cuvalaj

Posted March 24, 2009 - 02:32 PM

#17

cuvalaj, where in Cali are you? If your close I could help you out if needed. I'm in Benicia, just east of S.F. I did the swap earlier this year. Like everyone says it's not that hard just a bit intimidating.

i am near fresno, at NAS Lemoore, its about a three hour trip to S.F. from my house. i would sure welcome the help from someone whos seen the insides of their machine before LOL. but so far i think i got the support i was hoping for from all you guys. thats the best thing about this site! im going to get the torque wrench tomorrow before work and the only thing left would be the shims, but i read in another thread that its alot cheaper to do the measurement and figure out which one you need and just buy the ones you need from a local shop service department. so ill follow that advise as well.





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