03 Cam Swap Not Working...

I have searched a lot on this forum and haven't found anything similar to my situation... I bought an 03 Autodecomp cam and took it to a shop where they put it in the bike. But they said the decomp lever still needed to be used, and left it in there. So sure enough I take it for a ride anyways, which by the way ran just the same as before with no new noises or nothing. But to start I still had to use the decomp lever because the kick lever wouldn't budge otherwise, same as before...

 

So I come home, do a bunch of reading trying to figure out why the shop that did my work would say it needs the lever, and after reading all I could I decided that it didn't. And to my understanding, the decomp mechanism in place was causing the kick start to not budge unless the hand lever was pulled in. So I ordered the rubber plug, and tonight I removed the hand lever and mechanism, and installed the rubber plug. 

 

So I get on the bike and attempt to kick it over with much enthusiasm, but the exact same issue is happening. And now I have no lever to help me out. I tried a couple more times, and got maybe one rotation. I fear I'm damaging something by trying any more. I'm really confused and have no idea what is going on. I am mechanically inclined, but I don't want to have to do the work myself that I just paid someone to do. It's a pain in the arse to have to bring the bike back to the shop which just so happens to be on the other side of a toll bridge...

 

Can anyone please tell me what the heck is going on? I'm very frustrated at this point and I need an explanation that I can't find, or even ask the person who did my work for me. FYI I printed off the Thumpertalk 03 Cam install and brought it to him, and he did everything that was listed like checking valve clearances etc. This is a fairly reputable shop as well.

 

Thanks in advance for any help.

Edited by 23027

Well, I know that with the cam swap, depending on which timing you use when you do the swap with what cam, you can run into issues.  Sounds like your issue is due to something like this.

 

As quoted from an old post i searched on the topic, a response by wrooster...

 

"the FAQ quote above is misleading and/or confusing, and rick and/or i will fix it.

let me clarify... (this is just different wording than we have in the FAQ, there is no new information here)...

the 2001 and 2002 YZF and WRF models have the same physical cam, with just the sprocket timing marking located differently on the two types.

due to the fact that the cams are mechanically the same, it is possible to retime an '01 or '02 WRF over to YZF timing without issue. it is a simple matter of repositioning the cam in relation to the crankshaft.

however...

the 2003 and 2004 YZF and WRF models have different cams altogether. while the lift and duration of the lobes are the same, there is an important difference...

the 2003 and 2004 YZF cam includes the auto-decompression mechanism, and the valve actuation bump ("nipple") is oriented such that it works best when the cam is set for YZF timing. if the the YZF cam is set for WRF timing, the valve actuation bump is in the wrong place at the wrong time. this can lead to difficulty starting since the auto-decompression mechanism is partially defeated.

the 2003 and 2004 WRF cam includes the auto-decompression mechanism, and the valve actuation bump ("nipple") is oriented such that it works best when the cam is set for WRF timing. if the WRF cam is set for YZF timing, the valve actuation bump is in the wrong place at the wrong time. this can lead to difficulty starting since the auto-decompression mechanism is partially defeated.

read the last two paragraphs again.

so the decision tree for '01/'02 WRF owners considering upgrading to an auto-decompression cam goes like this:
if you want auto-decompression with YZF timing, get a 2003 YZF cam.
if you want auto-decompression with WRF timing, get a 2003 WRF cam.

n.b.
i highly recommend the 2003 YZF cam for '01 and '02 WRF owners. the 250F engine was designed with YZF timing in mind, and that's how it makes the most power. alternate ("WRF") timing (read: blowdown) was introduced only as a remedy for the highly restrictive stock USA-spec WRF muffler w/stock insert (aka the "butt plug").


jim aka the wrooster
'01 wr250f"

 

So...

 

basically, you can use the yzf cam with yzf timing, or you can use the wrf cam, and grind 1mm off of the decompression nipple and TIME it like a yzf cam (12 pins on the cam chain). Which, running yfz timing would give you more power. Then again, you never tell us what model of bike it is, so im speculating!

 

BTW, if you are mechanically inclined as you said, and you have the time, dont pay a shop to do this stuff, lol. It's not hard. I mean far as grinding the nipple, itd take some care, but its not rocket science.

Edited by J_WR2fitty

Sorry! I originally had that info in my topic but edited it out because I thought it was too long. Forgot to throw the info back in my post.

It's an 01 wr250f and I said to make sure to keep WR timing. I bought the 03/04 WR cam. I don't know how they timed it, the guy said he had his Yamaha tech do the work so I trusted him to follow the thumper installation that I handed him well.

Edited by 23027

Oh, hmm, may need to pop the cover and check the timing, to make sure they didnt just assume YZ timing and do that.

 

Expecting things out of shops anymore seems to be a asking too much lol...why I just do all my own work. Least if it doesnt work, I only have myself to blame and I get to learn what I did wrong. Not saying they did it wrong, and this IS the problem, just seems to sound like a similar issue, may be worth a look.

 

This will shed some light on the timing for ya

 

http://www.thumperfaq.com/cam_timing.htm

Edited by J_WR2fitty

Even if it were to have been set for YZ timing, would it not still at least be able to cycle through, just slightly firmer though?I don't understand why the possibility of one chain link off would cause an un-kickable (basically locked) scenario.

And in this case, why would it have operated as normal when I took it for a test ride? Is it actually possible that the timing being off by so little would cause the auto decomp to basically not work giving me my no-kick scenario without my manual lever, but still be useable and almost unnoticed after having to use the hand lever to get her going?

Either way I will be bringing her back to the shop I had work on her. I was hoping there was some simple 2 minute fix to this. I'd just like some sort of insight to be able to pass on.

Edited by 23027

Assuming the technician installed the cam with the timing marks aligned correctly, the possibilities are that either they sold you an old style exh cam w/o the auto decompression feature, or, the auto decompression feature is stuck in the "run" position.

With the auto decompression cam, you should be able to push the kickstarter thru with your hand, and toss the manual decompression release in the trash can.

I definitely have the auto decompression cam there's no doubt about that. What should I expect to see visually to know the cam is working properly when installed? I guess I need I start with the basics and go from there. Just want to be able to tell the guy who will be doing the work what to look for, it seems he's never done this job before so he's as new to it as me.

with the cam cover off

 

take the weight on the gear and move it back and forth and see if it moves the steel stud on the cam in and out.

if it doesnt then thats the issue.

 

if the spring doesnt hold it so the steel stud is out, then the spring is the issue.

Did they actually do the work they said they did....? I did this swap myself, it very easy as long ad you set the timing right takes less then a half hour total. If pop the cover and make sure they put the right cam in, just playing devils advocate that some shops aren't trustworthy

Forgo to add. My timing was off and it still kicked over just wouldn't run for me.

I definitely have the auto decompression cam there's no doubt about that. What should I expect to see visually to know the cam is working properly when installed? I guess I need I start with the basics and go from there. Just want to be able to tell the guy who will be doing the work what to look for, it seems he's never done this job before so he's as new to it as me.

Why would you pay someone to do a job hes never done before? You might as well do it. This guy f'ed something up.

going to a shop and asking the mechanic to install cams that are made for another bike -where you have not done Your Homework

and found out what actually needs to be done --its all on You -- mechanic can not waste his time figuring out things you did not-

So the problem has been sourced out. The vendor I purchased the cam off of sent me the wrong cam... Not really stoked about this. I'm amazed and frustrated that there is no stamp or p/n on the physical cam to eliminate confusion such as this. I'll be having some not so kind words to say to this vendor, cost me more than double the shop time to figure this out.

 

I had done my homework and purchased exactly what I was told to purchase from the thumpertalk cam swap instructions. I brought the instructions to him and he did a great job doing just that. But he did seem to have some difficulty wrapping his head around the purpose of the swap

Glad to hear you got the problem sorted out!

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