06 WR with YZ cam...starting

11 replies to this topic
  • Fullbore4

Posted December 08, 2006 - 06:18 PM


I've read back and nobody has given an explicit reason why my bike is hard to start with a YZ exhaust cam installed. I've heard its valves and I've heard its jetting. My guess is its got something to do with spark advance settings in the CDI but I admit I don't know enough about it. Does anyone know?

  • clark4131

Posted December 08, 2006 - 06:57 PM


You may not have it timed properly so the decomp pin is not functioning correctly. Double check your cam position per the YZ manual just to be sure...SC

  • MountainMax

Posted December 08, 2006 - 07:31 PM


the decompression pin is a different height imho which causes this, however with good jetting and use of the hot start lever mine works like a charm now when warm, and t twists of the throttle and choke on starts when cold perfect now also..... :worthy: Also the starter just barely spins fast enough to start these when timed like the YZ needing good jetting to allow it to go.

  • Fullbore4

Posted December 08, 2006 - 09:12 PM


Its timed per the YZ manual which is identical to the WR manual. It runs good too so I don't think I'm off a tooth.

Max, mine starts COLD with estart after turning over about 8 seconds. It starts very easy when WARM. What troubles me is why it doesn't fire right up when cold....Part number of WR CDI is 5TJ-85540-B0-00 and YZ CDI is 2S2-85540-00-00. I don't how to interpret yamaha's part numbers.

  • clark4131

Posted December 08, 2006 - 09:33 PM


Have you changed your starter jet? If not, go up a size and I'll bet you see improvment...SC

  • MountainMax

Posted December 09, 2006 - 08:01 AM


do you roll the throttle 2-3 times fully before starting it cold? it done the trick for me, fires right up every time now (with choke on of course) and again JETTING, i put a larger pilot jet and richer starter jet in mine.

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  • hoseman58

Posted December 09, 2006 - 10:34 AM


Mountain Max is right about rolling the throttle. My 06' 450 would not start cold. I would kill the battery before it would start. Now I crank the throttle 5 times and it starts right up. This is the easiest thing to try before jetting. Good Luck!:worthy:

  • MountainMax

Posted December 09, 2006 - 10:51 AM


if you roll the throttle a little slower, it will squirt in more fuel then more quick ones alo, try it and see what works best for you, then do it every time you start her cold......

  • Fullbore4

Posted December 09, 2006 - 01:33 PM


I have had a 70 starter jet (stock 65) for a long time.

You might be right about squirting with the AP. Apparently it depends on how much your AP is squirting as to how many times to roll the throttle. Mine is adjusted to squirt a very little bit. When I had it squirting enough to quench a horse's thirst, it started easy by rolling on the throttle when pressing estart. Now I just have to figure out how many times to roll the throttle before hitting the button without flooding it.

  • Wasabi

Posted December 09, 2006 - 04:45 PM


You shouldn't have to touch the throttle for starting your bike. Definately a jetting issue.

  • MountainMax

Posted December 09, 2006 - 09:41 PM


The yamaha manual says to give it two throttle rolls when cold!!!!!!!

  • jnybbad1l40

Posted December 16, 2006 - 01:45 PM


Its the decompression pin for sure. It is shorter by a few mill's I believe which causes the cylinder to not bleed enough compression for the starter to spin the engine fast enough. This is from HOT CAMS. I had the same issue when I used their YZ ex cam. Starts first touch of the button now that I have the WR ex cam.


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