Hey Y'all. Just wondering if anyone else has done this mod to there quad, and got the same results as I have. First off, the thing runs awesome, you can really feel the power gain. I went this route, because I heard, by doing the "cam mod" it moves the decomp pin and you'll end up messing up your electrical system. So I spent the $140 on a yz cam, with the decomp pin in the proper place. Well, since I have done this mod I can not get the quad to start up very easily. I think it is getting too much gas on start, due to the fact that Im almost fowling spark plugs trying to get the thing to go. On warm starts, I have to have slight throttle pressure, just enought for the slide to open a tad, and let more air in. It will then lite up.
The stock starter jet is a 90, and a stock yz jet is a 72. I went ahead and ordered an 80, and I'll see where that gets me. I was just wondering if anyone else has run into this problem?? The thing started fine before this, so the timing changed something on starting.

 

my friend ordered his yz cam wednesday...........I will let you know if he has the same problem..........
may be a week or so....but i'll let yah know

 

I read about some people that went the route you did and have the same starting problems. Some of the guys went back to the YFZ cam and did the mod. The starting problems went away and they had the power increase. They could not figure out why the YFZ with the decompression pin in the "wrong" place started fine, but the YZ450 cam had problems. Some of them even tried to sell the YZ450 cam as they like it better with the cam mod.

 

The yzf holds the ex valves open to long and make it start hard.Go back to the stock cam and retard it one tooth. Then the ex valves will open at the same time as the yzf but the will close about 15* sooner and start easy.(Iam talking about the decompression timing not cam timing.)

 

hmmmm. Im just not tooo excited about having that decomp pin in the wrong place, and messing up my electrical system, like many have. I am going to try less fuel to begin with, if that doesnt work, maybe I'll try what you are talking about.
Doesnt make much sense to me. The yz works fine. THey are essentially the same thing, except one has a longer stroke then the other. Cant figure out why it makes starting difficult. The thing runs absolutely awesome, once you get it started, alsmost toooo fast, if there was such a thing.

 

The pin is in the same place as the yzf when you retard it back.The pin sticks out more on the yzf then the yfz, thats why the yzf hold the valve open longer. It is better on the starter if you use the stock cam and it is the same duration cam as the yzf.