Won't restart after setting valve clearances


15 replies to this topic
  • SlowerJohn

Posted April 06, 2008 - 01:17 PM

#1

Being some kind of moron I checked and adjusted my valve clearances on my WR450F (07).

All seemed ok until I try to restart the bike, it turns over ok and gives the odd spit but that's about it.

Normally it start very well.

Could I have got the camshafts set to TDC on the exhaust stroke instead of compression? How would I check?

Why, oh why did I do that :thumbsup: :thumbsup: :confused:

  • William1

Posted April 06, 2008 - 02:28 PM

#2

There is no compression/Exhaust stroke once the cams out, just TDC.

Recheck the timing. Often, the crank moves slightly or you get cross eyed and mis-count pins or lobe position. Also, once the cam chain tensioner is in, you need to reconfirm the correct timing as this too, can cause a error in setup.

You did good by doing it yourself, just not perfect. Do not beat yourself up. Just recheck and adjust.

  • Frostbite

Posted April 06, 2008 - 02:35 PM

#3

Being some kind of moron I checked and adjusted my valve clearances on my WR450F (07).

All seemed ok until I try to restart the bike, it turns over ok and gives the odd spit but that's about it.

Normally it start very well.

Could I have got the camshafts set to TDC on the exhaust stroke instead of compression? How would I check?

Why, oh why did I do that :thumbsup: :thumbsup: :confused:


If you have good compression, then most likely you've got the cam timing off a bit. Sometimes it's tough to tell from the marks on the sprockets when it's bang on.

You couldn't have set it to TDC on the exhaust stroke. When you have the cam's out, there's no intake and exhaust stroke, TDC isTDC. The realtionship between the cams and crank create the intake TDC and exhaust TDC. If you sent the flywheel to TDC, and then installed the cams, you're close. You may be off a tooth on one or both of the cams. I've rarely seen the cam sprocket marks line up perfectly, and often they're out far enough that it's hard to tell whether a tooth this way or that way is correct.

Someone on here a few days ago suggested taking a digital pic of the cam sprockets before you dissassemble. I think that is one of the best WR tips I've heard in a long time. I realize that it's a lil' late for you now though.....

I'd recheck the cam timing.

  • Frostbite

Posted April 06, 2008 - 02:37 PM

#4

There is no compression/Exhaust stroke once the cams out, just TDC.

Recheck the timing. Often, the crank moves slightly or you get cross eyed and mis-count pins or lobe position. Also, once the cam chain tensioner is in, you need to reconfirm the correct timing as this too, can cause a error in setup.

You did good by doing it yourself, just not perfect. Do not beat yourself up. Just recheck and adjust.


Didn't mean to double up on the TDC information William, but I guess we were typing at the same time and you beat me fair and square.:thumbsup:

  • William1

Posted April 06, 2008 - 03:51 PM

#5

Not a problem. I think it is reassuring to a questioner when they get the same response as confirmation of a direction to go. :thumbsup:

  • mlynn450

Posted April 06, 2008 - 05:05 PM

#6

Don't feel bad if it is off. I recently got my wr 450 back from the dealer for the first valve service. They had the exhaust off by one tooth.It started but it ran like crap. Thats the last time I don't do things myself.

  • SlowerJohn

Posted April 06, 2008 - 09:45 PM

#7

Thanks for that. But if I was a "stroke out" wouldn't I be sparking on the wrong stroke? I'm thinking I'll be getting a spark between the exhaust and inlet strokes if I've got it wrong. Where is my thinking flawed?

Am I right in thinking TDC is the third (and last) mark to come into view as I turn the engine anticlockwise? The manual talks about one mark but I have three and none of them are as big as they look in the manual.

  • William1

Posted April 07, 2008 - 02:06 AM

#8

Your engine spark occurs every TDC, so there is a 'wasted spark' during the exhaust stroke.

The mark that sort of looks like an 'H' is a timing mark for the spark. Ignore it.

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  • Bamster

Posted April 07, 2008 - 03:37 AM

#9

When I adjusted my valves I always marked the chain and cam sprockets with a grease pencil. Never got the timing wrong.

  • SlowerJohn

Posted April 07, 2008 - 12:29 PM

#10

It's a runner!!

Thanks for the help all, I think I was one tooth out on the inlet camshaft.

  • William1

Posted April 07, 2008 - 03:30 PM

#11

Good deal you got her back up and running. Just like a carpenter, measure twice, cut once, a valve shimming is set the shims, check the timing nine times! :thumbsup:

  • Frostbite

Posted April 08, 2008 - 02:53 AM

#12

It's a runner!!

Thanks for the help all, I think I was one tooth out on the inlet camshaft.


Kool!:thumbsup:

  • SlowerJohn

Posted April 08, 2008 - 03:30 AM

#13

Going completely off topic (but this is my thread and I don't want to be accused of not reading other threads (which I have :thumbsup:))

What are your thoughts on the AIS removal kits for an '07 WR450F?

I've tried to find information about them on here but it seems to be a bit conflicting. Some say it improves performance, some say it doesn't, some say you need to rejet after, others say not.

I'm thinking it's worth doing just for the ease of access, am I wrong?

Would you recommend the TT or the GYTR one? Am I right that the TT one is none removable once you've fitted it?

  • William1

Posted April 08, 2008 - 04:39 AM

#14

Removing the AIS Pluses:
Less weight
Less clutter
Less decel popping/backfires
Must be removed or disabled to tune using a Wideband O2 setup

Removing the AIS Negatives:
Riding bike may be denied in some areas (Cali) where they frown on emissions systems tampering. In this case, you can disable it and no one could tell unless they did a tear down but then there is no point in doing this unless you tune with a wideband often due to varying riding altitudes or suffer from decel backfires that proper tuning cannot seem to get rid of. Open pipes increase the popping/backfires.

The 'cleanest' kit I have seen is the one from F2 Racing. You can remove the kit and reinstall your AIS with this kit. some of the other kits require you to pull the AIS inlet tube from the head, thereby effectively making the removal permanent. Some of them do have a fairly clean look to them but, I myself, like to keep my option open to reinstall if need be.

My own bike, I did the James Dean Jet kit, A Kouba brass extended fuel screw, an R&D adjustable leak jet (because swapping leak jets on an alloy framed bike sux), the F2 AIS kit. From my research, this was the best of all worlds for me.

  • SlowerJohn

Posted April 15, 2008 - 05:55 AM

#15

Removing the AIS Pluses:
Less weight
Less clutter
Less decel popping/backfires
Must be removed or disabled to tune using a Wideband O2 setup

Removing the AIS Negatives:
Riding bike may be denied in some areas (Cali) where they frown on emissions systems tampering. In this case, you can disable it and no one could tell unless they did a tear down but then there is no point in doing this unless you tune with a wideband often due to varying riding altitudes or suffer from decel backfires that proper tuning cannot seem to get rid of. Open pipes increase the popping/backfires.

The 'cleanest' kit I have seen is the one from F2 Racing. You can remove the kit and reinstall your AIS with this kit. some of the other kits require you to pull the AIS inlet tube from the head, thereby effectively making the removal permanent. Some of them do have a fairly clean look to them but, I myself, like to keep my option open to reinstall if need be.

My own bike, I did the James Dean Jet kit, A Kouba brass extended fuel screw, an R&D adjustable leak jet (because swapping leak jets on an alloy framed bike sux), the F2 AIS kit. From my research, this was the best of all worlds for me.


Thanks for the excellent advice. F2 kit on order. I'm thinking remove AIS, pull grey wire then get it properly rejetted (I think it's running rich anyway). I really don't need the power but it's almost free :thumbsup:

  • SJMC_DON

Posted June 11, 2008 - 11:08 AM

#16

So is there a pin count that we should be adhering to?

I am somewhat flustered... maybe William can help?

I swapped the WR cams out of my 07' for a set of 06' YZF OEM cams. I too had challenges getting the cam timing correct but then I read a post by Grey Racer that helped double check the rotor free play or chain slack positioning prior to putting in the tensioner, when it was all said done I had all timing marks dead on:thumbsup: But the YZ exh cam was dumping to much on the de-comp and the e-start just would not work so I went back to the WR cams, (the bike was already winning races with the WR cams in it:bonk:). Anyway I thought I had the WR cams timed perfect upon install but after the tensioner was installed I was a few degrees off on the rotor when the cams were at TDC so I will take them out tonight and do it again because the bike will still not e-start :thumbsup:

Anyway, I have heard conflicting posts about the pin count, is it 13 or 14 and does it even matter?

Thanks in advance guys!




 
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