Hotcams, the autodecomp does`nt work

8 replies to this topic
  • OlaGB

Posted November 19, 2005 - 04:51 AM


I mounted my new hotcams and a FMF q pipe yesterday.. Going to pu in a JD kit and ziptye screw today :applause:


When i was hitting my el-start at my first attempt of trying to start it, it would`nt turn.. Tried the kick starter, and felt that the autodecomp did`nt work well..

Got it started anyway`s, and it seems to work great (allthough with choke ON since i have`nt jetted it yet)

I am 110% sure of that the timing is correct.. Checked it 5 times, and turned around the motor several times before starting.

The autodecomp worked fine when i held the cam in my hands, but did`nt try it so much after mounting.. But i saw that it was out, in position to lift the exhaust valve.

What`s up with this? Anyone got a clue? :ride:

  • OlaGB

Posted November 19, 2005 - 09:15 AM


I took off my cover when i jetted the bike today, and found everything to be allright..

The only thing i now can think of, is that the little knob thats supposed to push down the valve, perhaps does`nt push it far enough down..

But i have to remove the camshaft to measure this, so i will let it be this way for a while :applause:

The bike really woke up now :ride:

  • jbrooks26

Posted November 19, 2005 - 06:00 PM


Did you reshim the exhaust valves? I had to increas my shims by .20 mm to get back in specs. Possible that your autodecomp is just not hitting the bucket. Hope this helps.


  • OlaGB

Posted November 19, 2005 - 11:12 PM


They actually seemed perfect... A little tight 0.15mm intake, and a tight 0.25 exhaust.. I`ve only got 0.05 increasment on my feeler gauge, but how wrong could it get?

But i have`nt checked it after running the engine.. I will pull the cover again today to check up on this again.. Got 2 sets of shims, so i was prepared :applause:


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  • OlaGB

Posted November 20, 2005 - 08:16 AM


Checked again..

Valve clearance is perfect, but i think maybe the decomp button is`nt far enough out of the camshaft :applause: The linkage from outside the sprocket and in to he "button" seems to be a little "sloppy".. :ride:

  • jbrooks26

Posted November 20, 2005 - 11:08 AM


Did you try pushing on the ball to see if it was loose? If the little arm on the outside of the sprocket is returning completely to the outer edge of the sprocket, and the ball is still loose then you may have a defective cam. Just a thought, Hope this helps.


  • OlaGB

Posted November 20, 2005 - 12:10 PM


This seems to be exactly the problem.. :applause: I managed to move the ball aprox 0,5-1mm in/out when i was supposed to be all the way out..

I see that it opens the valve a littlebit, but probably not enough..

  • jbrooks26

Posted November 20, 2005 - 05:00 PM


Is there maybe some imperfection on the face of the gear that is not allowing the arm to retract fully outbound? I just installed mine yesterday and before I put it in I tried to push on the ball and could get no movement at all out of it. without pushing the arm to the center of the cam. Please keep us informed on how this turns out. If it is new, I would think Hotcams would warranty it for you. Good luck.


  • OlaGB

Posted November 21, 2005 - 12:49 AM


Well, when i engage the arm mself, i can move the arm a littlebit before i can see movement on the ball.. Therefore i guess i must be somewhere between the arm and the ball..

I have sent Hotcams a mail, and are waiting for a reply.. The sad part for me, is that i guess i have to send them my cam before they can send me a new.. Thats 2-3 weeks with no bike..
That aint so cool, now that i just got my new Trelleborg icestud tire`s, and the snow has showed up hehe..

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