Starting my 2001 YZ250F

[Davetul]

I've had my bike for about 4 months now, and I"ve broken the kicker shaft twice. Is there some trick to starting this bike?

It has a compression release, but being that I'm new to the sport, I have no idea what it's for other than not pulling when it's running (made that mistake at the top of a hill once...).

Right now, I just get up on the kicker and, well, kick it. Couple tries later the bike starts and I'm off. The first time I broke it I figured it was a weak part and since the bike was used when I got it I expected a couple mechanical deficiencies. But now after I broke the second one I'm starting to think I'm going about it wrong. Any ideas?

Dave

 

[Tony Eeds]

OK guys, those of you with YZ250F bikes, post up your technique for starting the bikes.

Dave:

When I start my XR650R, I slowly roll through the stroke until I hit the top of the compression stroke. Then I pull in the compression release and roll the piston just past top dead center (usually avout 1 inch of throw of the kickstarter) and then very delibertly kick the engine through. The XR motor is very cold natured, so I suaually havce the choke full on and do not touvh the throttle. In fact I usually grip the master cyinder, so I don't even think about grabbing a bit of the throttle.

If the engine is warm, the procedure is the same, but I don't have to use the choke.

I seem to remember the 2001 is before the added the automatic decompression cam.

 

[CaptainObvious]

The easiest way to get that '01 started would be to replace the exhaust cam with an auto decompression cam from the 2003 and newer bikes.

A few other things to consider:

- When the valves go out of adjustment and begin to close-up, the bike will get very hard to start. If your valves are that far out of adjustment, stop riding the bike NOW!

- Your timing may off, check the cam timing when you are checking your valves.

- Sometimes a fresh spark plug can make a world of difference.

 

[biglou]

It has a compression release, but being that I'm new to the sport, I have no idea what it's for...

It's for breaking the piston past TDC when starting. Push the kicker slowly with your foot, when the kicker stops moving and hits resistance, pull the decomp lever, push the piston just past TDC, release the decomp then kick it hard. Repeat as necessary.

 

[dfitzsim1]

Yeah if your not using the compression release you could definately breaking the lever. Also once you do push it past TDC let the kick start lever return to the top and then kick.

 

[zcookie49]

I have to say to spend the $130 or so and get the '03 exhaust cam that has the decompression. I soo Loathed having to go thru "the drill". That had to be the absolute worst wrecking and mounting back up and using the decomp lever, pulling the hot start out and all. SUCKED. In the meantine, follow the above suggestions, right on with the technique.

 

[Davetul]

Thanks a lot for all the suggestions.

One question - if I get the new cam, is it going to fit in my engine? Also, how involved is replacing it? I am mechanically apt, but I have never worked on a motorcycle before besides the first time I changed out the kicker assembly.

Thanks again

Edit - when I put in the new cam, will I need to remove or deactivate the manual compression release?

 

[zcookie49]

I have an 01 and it was pretty easy if you are somewhat mechanically inclined. I would take off the tank, clean the bike real good (dont want any dirt to fall into the engine). Make sure you have your owners manual that shows the positioning of the cam marks. Take off the head, I secured the cam chain with a bungie/string- you dont want it to fall down inside.Theres a little more to it than I wrote in here, I did mine in 2003 so its been a while. You can search threads here or at thumpertalk.com. I removed my decompression lever last year, you have to put an insert into the motor where the cable used to go---- Rich R recommended a billet plug over at thumpertalk.com, I purchased it and it works great-also blue annodized... Some have said that the plastic plugs pop out. You can leave the lever all attached, I took it off to clean up the bike and shave some lbs....
.
I saw again that you said you havent worked much on motorcycles, you may want some help or , like I said, search for other threads about it. It can be intimidating once the head cover is off and getting it back on correct. good luck....

 

[Davetul]

Alright thanks. I have rebuilt auto engines, and various small engines, but the bike engine just looks different from anything I've ever toyed with. As far as the compression release, I'm not too concerned with weight, as I don't race so if leaving it in there won't hurt anything then it stays.

Again, I really appreciate the help. I just ordered the parts to get it fixed this time (when the kicker shaft broke I also cracked the casing (outer one) beyond repair, and while I'm in there I'll just keep digging and put the new cam in as well. I just hope it all fits with no spare parts heh.

Dave

 

[zcookie49]

I forgot to mention, I downloaded instructions for installing the 03 cam off of ThumperTalk.com. Do a search over there and you should be able to retrieve the info, it will come in hand.