Couple of Questions.



8 replies to this topic
  • scottzx7rr

Posted April 11, 2001 - 06:37 PM

#1

My bike info: 99 YZ400f.

I have heard a lot of discussion about people removing the backfire screen on the XR-650s but haven't heard one comment about the YZ/WR bikes. What is everyones recommended stance on this?? I was just curious.

And my second questions is recently I placed a Hebo clutch system on my bike. After initial fitment problem(weird bend of the lever and it different throw) I got it where I liked it but the fiber plates were trashed after a racing(harescramble race and very slow deep mud track) accident knocked one of the oil lines loose and fried the plates. So when I started to notice the bike start to slip in 3,4,and 5th gears I changed out the fibers(the steels were fine, check for warpage and thickness) springs were within specs, and they had been on back order. Mind you I have been on a Spodefest in TN during this time. So I get the new fibers in and go for the first ride in the morning to a very grabby clutch that as the engine heated up. Wrote it off to new plates that need to be broken in. But I rode the rest of the fest and finally got so frustrated with the grabbiness that I adjusted the hebo unit to give me more throw but didn't resolve the problem. So this last weekend I was try to adjust the hebo thinking it was needing some fine tuning for the plates and initial installation. But I got so frustrated that I pulled it off and went back to the cable unit. Not dragging and back to the old faithfull in throw. But I noticed when I got into a really slow and technical section that I actually lost tension on the lever. It had never happened to me before, but as I got into some wide open spaces the lever got back to the normal tension. I noticed it again when I get the bike really hot from slow tight woods riding. Seeing how I have only ridden the bike in winter(got it in Jan) and all my two strokes never did this before I didn't know what to think it was or if it is just normal. Or do I need to get the new springs in the bike as they get hot they lose tension???? Any help would be much appreciated.

Carb Info:
Stock Main(lowered one clip), 150 pilot. Plug reads light black.

And my last question is I have the White Bros. E-Series silencer and stock header and was wondering what the recommended number of disks is. I had been running it with 12 disks because I was told that is the best but I seen somewhere that it was recommend to run the bike with only 6-8. So I was wondering what others run or recommend.

Like I said Thanks in Advance and sorry for the long post.

------------------
Scott #410
Some Fear Racing "Cause if you don't have any you ain't going fast enough"
'99 YZ400F(Coming to a Theater near you soon)
'92 ZX-7R and '97 ZX-7RR
"Doesn't hurt till the bone is exposed"
"When cut do you bleed green? I do!"
Pics

  • Bill

Posted April 12, 2001 - 02:49 AM

#2

DO NOT remove the screen, you could have a fire. It has happened.

Clutch?????

12 discs correct for performance. You need to figure out where the bike is rich (fuel screw, pilot jet, needle or main) and adjust that jetting circuit. Don't assume it's all.

Bill

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97 KDX220, 86 TTR225, 99 WR400f, WR timing, throttle stop trimmed, air box lid removed, White Bros head pipe, silencer and air filter. De-octopussed. Works frame guards and Thumper Rad Guards, Scotts steering damper. Odometer and headlight removed. Moose hand and mud guards. YZ stock tank, IMS seat and number plate. Renthal Jimmy Button "highs" and Renthal Soft half waffle grips. AMA, SETRA, Happy Ramblers MXC.

  • JBM

Posted April 12, 2001 - 05:13 AM

#3

I agree with Bill on air filter screen, leave it in.
Generally, the more disks you have in the more it will flow and the louder it will be, hence the performance. Take out disks and you may gain on the bottom with some taken off the top. Experiment and find the setup that suits your riding style.

  • Hick

Posted April 12, 2001 - 06:47 AM

#4

Scott,

Did you put OEM friction plates in? Maybe the plates are too thick or expanding too much when hot.

Does your basket and/or boss have grooves in it? Maybe the plates are hanging up OUTSIDE the grooves when disengaged and not engaging immediately (in my imaginary world this would feel like a loss of tension at the lever).

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  • scottzx7rr

Posted April 12, 2001 - 02:08 PM

#5

Thanks all,

That is what I was assuming on the backfire screen but just wanted to hear others input.

As for the clutch fibers they are aftermarket EBC. Tucker Rocky(I think is the supplier for my shop) was out of the White Bros kit so I went with the EBC setup. They were slightly thicker than the OEMs in the bike but would be since the OEMs were worn. They basket, pressure plate and inner basket all are clean and no marks. It was one of the first things I checked after hearing all the probs the 2000 has.

One thing that I did notice normal wear and tear on was the clutch accuator rod(the one that moves the throughout bearing) in terms of it starting to mushroom the end that rides on the lever. So I got another one of those today. It is only a extremely small amount of difference(about the amount of your finger nail thickness). But I am going to put that in the bike and see if the grabbiness of the hebo goes away with that change.

------------------
Scott #410
Some Fear Racing "Cause if you don't have any you ain't going fast enough"
'99 YZ400F(Coming to a Theater near you soon)
'92 ZX-7R and '97 ZX-7RR
"Doesn't hurt till the bone is exposed"
"When cut do you bleed green? I do!"
Pics

  • JBM

Posted April 12, 2001 - 02:35 PM

#6

Scott,
I have heard of EBC clutch plates being out of spec. That may be your problem. As far as clutch plates go, I would always go with OEM stuff, but that's just me. Hope you get it straightened out.

  • scottzx7rr

Posted April 12, 2001 - 07:22 PM

#7

Does anyone new what the specs are on the factory plates???? I can compare them to the EBCs that I have.

------------------
Scott #410
Some Fear Racing "Cause if you don't have any you ain't going fast enough"
'99 YZ400F(Coming to a Theater near you soon)
'92 ZX-7R and '97 ZX-7RR
"Doesn't hurt till the bone is exposed"
"When cut do you bleed green? I do!"
Pics

  • Guest_Guest_*

Posted April 13, 2001 - 05:42 PM

#8

O.K. I just reread my info that came with my pro-meg pipe and on the fifth page in the grahp it suggest that for the 426 in motocross use that the factory team uses it without any disc. This is the confiuration that I run and am very pleased. Up one clip on the needle and 162 main and stock on air screw. I have a clean electrode and center cone with some black on the outside dia. of threads. Have any of you changed the main? I am thinking of going to a 160 to clean the plug up. Got to love em'

  • JBM

Posted April 15, 2001 - 07:11 PM

#9

From the '00 426 manual:
Friction plate thickness:
2.9 - 3.1 mm or
0.114 - 0.122 in.
Limit: 2.7mm or 0.106 in.

Since I'm looking at it, I'll throw it in.
Clutch plate warp limit:
0.1 mm or 0.004 in.

Clutch spring free length:
Standard: 44mm or 1.73 in.
Linit: 43mm or 1.69 in.

I just realized that you have a '99 400F. I'll leave the info anyway, don't know if it's the same or not, sorry.





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