Wr400 Hotcams Backfiring Hard Start???


3 replies to this topic
  • venom8tt

Posted June 17, 2009 - 06:37 PM

#1

hello i had this problem when i got the bike without the backfiring part..the slide plate broke in the carb on previous owner...
sorry it is a 1998 wr400..street lagal...i junked that keihin and bought a edelbrock(best thing ever wow) 1st kick hot or cold in michigan winter...i love it...i also had my cylinder big bored and renicked by us chrome i sent them both barrell and new wiseco 12.5-1 piston...i also put new wiseco steel valves in and relapped for pefect seet.....new springs also....also has a powercore 4 pipe...

this bike screems and runs better than any other around at 417cc 94mm bore....
i wanted to get rid of decomp handle and add power at same time so i bought the hotcams cams for this bike....
i put these on reshimmed to spec .15 in and .20 exhaust lash.....

bike would not start it backfired few times out exhaust and i kicked like 50 times i got it to start by hitting my throttle accelerator pump and cracking it as i kicked and when it did start it had seemingly very rich condition spitting black out muffler and ran like poo....i shsut down after it warmed up a lil and it wouldnt start againand started popping again...
i took apart double check everything..lashes timing...
got the ex cam dots at 9 and 12...even with head...
and the in cam dots there was no blue paint just 3 indents 9-12-3 i aligned as you do stock cam even with head... lobes outward at the "I" just past the "H" on flywheel.......i just put new camchain on too..woodruff is good and not sheered.....

same thing happened....

i ripped it apart angrily again and put the decomp lever back on and stock cams back in.....
had to reshim them twice to get to same spec as obove...
and she rips....
runs awsome 1st half a** kick she fires up and idles perfect...no throttle....

what the heck is the deal....ive read couple people with same problem but all slightly different scenerios and no help.....always ends up being something little on mechanics side...
im very competant of the mechanics but not the best...
i just ride on the road and a lil up north trails.....

please please any suggestions are very welcome....no one seems to be able to help me at other sites so i made this acct just to post....

sorry so much detail but its always bad not to have enough info....

venom8tt

  • Krannie McKranface

Posted June 17, 2009 - 07:20 PM

#2

Cam timing is off.

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  • venom8tt

Posted June 17, 2009 - 07:30 PM

#3

yeah i thought so...i tried a 2nd time but still same issue...
i must be missing something or the sprocket on the intake valve is off.....
but if it backfired out exhaust like it does then that would seem like the exhaust valves are open when they are not supposed to be....if they are open at tdc then thats how you get backfire.....

im putting the 9 oclock indent on ex cam at like 9 oclock even with the head and the 12 oclock dot is up......maybe one off?????
id really dont want to just try to experiment....
yikes.....
the indents on intake are lined up with head.....
am i missing a step somewhere???
i even watched the videos and stuff from hotcams.....
all have the paint marks...

any way to get pics of cam with indents and paint marks maybe on a bike????

i guess at tdc if my clearences are not bottomed out then i guess i can try it....
i dunno tho..
thanks.

  • flyer05

Posted June 18, 2009 - 05:07 AM

#4

Did the same to my 400. Except the new valves. The Hot cam"s went in with no problem. Hope you get if figured out because the auto decompression is very nice. It does sound like the cam timing is off. Call Hotcams and see if they will exchange the cams for you.
Good luck




 
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