Wr426 01 Lost Compression


17 replies to this topic
  • DMMEYER

Posted September 02, 2005 - 09:23 PM

#1

I recently torn my engine all the way down to change a shift fork and two gears that were making my bike jerk back and forth in 5th gear. While putting it back together i put in a new vertex piston and kept the advance timing on the intake cam (1 tooth)
Well today i got everything back together, all new fluids and filters. Put new gas in it and it wouldn't kick over, so I jump started in down my driveway. It ran just fine but when i stop (bike still running) the idle seemed to stay a little high, so i adjusted it 1/4 turn and it went down a little but when i rolled the throttle back it stay high for about 10-15 sec than settle down. ( it didn't do that before)
I was able to kick start it once when it was hot everytime after that i had to jump on it. Also i can kick the starter thru TDC, I don't have to use the decompression lever to get it past TDC, it didn't do that before?
Did i screw up on the cam timing or could it be something else. The bike runs great once it's started.

  • poffer

Posted September 03, 2005 - 09:05 AM

#2

exhaust cam 1 tooth clockvise, NOT intake cam!

  • DMMEYER

Posted September 03, 2005 - 02:12 PM

#3

So your saying that I should have turned the exhaust cam 1 tooth clockwise to get the yz timing.

If im understanding this corectly is that i lost the use of my decomp lever because one of the 5 valves is always open causing me to loose compression and i'm not TDC then??????????

  • DMMEYER

Posted September 03, 2005 - 10:27 PM

#4

I put the cams were they are suppose to be (stock) but still no good compression.
So I took the cams back off and elevated the chain then pushed on the kick start with my hand, much more compression but I was still able to push thru TDC with my hand on the kick start. :D :D

Any help would really be appreciated

  • DMMEYER

Posted September 03, 2005 - 11:59 PM

#5

Well I found 1 of my shims out of place (on the side wall of the bucket) and now i can hear a small air leak when i start to turn it over, the compression is much higher now. So should i continue to take it apart, maybe carbon on the valve head or should I put it together and redline it to see if it clears itself. :D :D

  • poffer

Posted September 04, 2005 - 01:52 AM

#6

dont know what you should do but i recomend you to be 100% sure about your timing because if something is wrong you can damage piston and valves... Read this thread:http://www.thumperta...ighlight=messed

Here are some picture of what you are dealing with.

  • DMMEYER

Posted September 04, 2005 - 09:52 PM

#7

Thanks poffer, those theads did it, i got it fixed. Had a shim off center in the bucket which was keeping the valve open :eek: :D :D

Now I just need to know if I should put the cam pin at 12 or 11 b/w punch marks. Moto393 site shows moving from 12 to 11 but does that apply to all 98-02 models??????
:D

  • poffer

Posted September 04, 2005 - 10:44 PM

#8

The thread link i gave you may have been a little bit comfusing, but count the number of chain links between the to top marks on the cam gears. 12= YZ timed. 13 = WR timed.

You can also take a look at this: http://motoman393.thumpertalk.com/ under engine section, yzf timing and

http://www.thumperfaq.com/ under free mods and then yzf timing

A friend of me did the yzf timing on his wr400f year 2000 yesterday but he did not think that it made a big different so he changed back to wr timing again... he have done other free mods on his bike (open airbox, yzf exhaust pipe, rejetted carb) and this bike performe great!

  • DMMEYER

Posted September 05, 2005 - 01:08 AM

#9

motoman393 shows moving from 12 pins to 11 pins :D Am I counting this different than everyone else?

if i start counting from right to left, starting with the pin on the exhaust cam up and to the right of the punch mark and count 12 pins over it makes all 4 of my punch marks on both cams align up perfectly (horizontally) if i move the exhaust cam 1 tooth clockwise it looks like the picture in the threads but i count 11 pins stopping on the pin up and to the left of the intake cam punch mark. If I'm confusing or frustrating the @#&% out of you I'll take a picture tomorrow and post it

If I am truly at 11 what will happen to it??????/

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  • dominator426

Posted September 05, 2005 - 01:18 AM

#10

Actually, motoman's pic shows the cam already switched back one tooth to 12 pins (YZ). The exhaust cam's right hand red mark shows where the red chain mark originally lined up with WR timing.

  • DMMEYER

Posted September 05, 2005 - 01:38 AM

#11

From the far left red mark, the one on the punch mark, counting to the right and stopping on the pin up and to the left of the intake cam punch mark i count 12.
Counting from the red mark on the exhaust cam, the red mark thats to the left of the exhaust cam punch mark, and counting to the right stopping on the pin up and to the left of the intake cam punch mark i count 11 pins.

  • dominator426

Posted September 05, 2005 - 02:02 AM

#12

Counting from the red mark on the exhaust cam, the red mark thats to the left of the exhaust cam punch mark, and counting to the right stopping on the pin up and to the left of the intake cam punch mark i count 11 pins.

The second cam mark is actually on the RIGHT of the intake cam punch mark. It was lined up with chain's red mark when at WR timing, when 13 pins could be counted. You do need 12 pins for YZ, from 13 (WR).

  • Gadsen

Posted September 05, 2005 - 05:07 AM

#13

...count the number of chain links between the to top marks on the cam gears. 12= YZ timed. 13 = WR timed.

Do you mean "pins" not links, right?

  • poffer

Posted September 05, 2005 - 08:29 AM

#14

jeppz your right!

  • DMMEYER

Posted September 05, 2005 - 10:15 AM

#15

I have the pictures of where my punch marks are at when at TDC.
How do I attach them to this post

  • DMMEYER

Posted September 05, 2005 - 10:52 AM

#16

[quote name='DMMEYER']I have the pictures of where my punch marks are at when at TDC.

Would you say this is wrong. I'm counting 11 pins b/w the marks at 12 o'clock


http://www.streamload.com/App.asp

  • dominator426

Posted September 05, 2005 - 02:52 PM

#17

YES, 11 pins is wrong!! :D You need 12 pins! You can easily add pics by clicking on the yellow square with mountains and sun...

  • DMMEYER

Posted September 05, 2005 - 03:19 PM

#18

Well i took your advise and moved it to 12. I didn't want to take a chance.
It fired right up on the first kick. :D
Now all I have to do is dial in my new zip-ty, it back fires a little when I let of on the throttle.
it :D :D
I definitely learned allot in the last 4 days and nights after adjusting the cams 6 times and in the middle of those 6 I chained the timing chain.
Now I can go :eek: :eek: :eek: :D :D :D :p :D :eek:

Thanks for stick-en with me on this, I really appreciate




 
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