extremely frustrated with 450!


33 replies to this topic
  • corndogg

Posted June 07, 2013 - 06:10 AM

#21

it should still run with the old one for now untell the new one comes in though i would think. new one is on order. i sat all season (11 months ) out with a shattered tib an fib with rods an im itching to rip haha. new bike next year so as long as it runs for the rest of this season im happy

  • corndogg

Posted June 07, 2013 - 06:12 AM

#22

im going to try that test tonight, appreciate it bud.

  • thefickler

Posted June 07, 2013 - 06:33 AM

#23

I'd redo that lak-down test and let us know what both of the guages were reading.

Before I changed my chain out, my bike was very hard to start, hence that's what prompted me to have a look. You might be having the same issue with your old chain as well.

I'd run KTM_Pat's test and verify everything he said, re-do that leak down test so we have some actual numbers, and in the meantime wait for the new chain.

  • corndogg

Posted June 07, 2013 - 09:30 AM

#24

for the timing should i go with my first or second picture?

  • thefickler

Posted June 07, 2013 - 09:45 AM

#25

Get the new chain, and those pics won't matter. Once you get the new chain in, the timing marks should look very similiar to how they look in the manual. You can count the links as a precaution, but you still need to line up the dots on the cams in the 9:00 and 3:00 positions so that they're timed correctly.

  • KTM_Pat

Posted June 07, 2013 - 10:26 AM

#26

for the timing should i go with my first or second picture?


I'd go with first picture if your going to test it tonight. That "to me" looks to be correct. The test I gave ya will speak for itself. Do it and if fails go to second pic and see.

How many hours are on that cam chain?

Plus if it was me I would prep for a leak down test. Keep the spark plug hole open and take cams out. This way the valves (should be) garenteed closed. Then rotate the piston down to bdc and insert the leak down gauge. (Note try keep cam chain from binding up while rotating).Then manually rotate the piston and the compression should go up pretty high. This will prove that ur piston and valves are seatedsealed properly. If it leaks and doesn't feel like bicycle pump then valves are not seating, where you could have a bind somewhere on the valve guides etc.or the piston ring isn't right(doubtful).

Good luck pls keep us updated! ;)

  • grayracer513

Posted June 07, 2013 - 10:38 AM

#27

The second of your two pictures is correctly timed, but clearly shows the wear in the chain. Assuming that you had the engine right at TDC when the picture was taken, the only thing wrong with the picture (other than the exposure) is that both cams are about a third tooth retarded; they're rotated too far rearward as you look at the pair. Looking at your third picture, taken from the right side, you see the same thing, exhaust cam pointed too far up, and the intake too far back. The simple reason is that the chain is that much longer than it should be between the crank and the exhaust cam.

This leads to compression problems. Normally, if the cam timing shifts from chain wear, it does affect cranking compression, but not really noticeably. But with auto decompression being built into the camshafts, the cam timing affects the timing of the decompression event. The AD system works by preventing one exhaust valve from seating until later in the compression stroke. With a new cam chain in place, the exhaust valve will be held open until about 20-25 degrees before TDC, leaving only that much for the compression stroke that you normally start with. If the cam chain wear allows the cams to become 11 degrees retarded (half a tooth), that will bring the exhaust valve closed only 9-14 degrees BTDC, and at that point, the ignition may fire while the valve's not seated, producing some marvelous muffler fireworks.

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  • KTM_Pat

Posted June 07, 2013 - 11:42 AM

#28

Wow lookin at it again I see that.

Grey u think single cam bikes like my ktm ate better with chain wear?

  • grayracer513

Posted June 07, 2013 - 01:10 PM

#29

No, not really. The chain runs over about the same number of teeth, and so on, and you're still pulling about the same load using one cam to open 4 valves as using two to open 5 (the intakes are way lighter). Using good oil and changing it is the key.

  • KTM_Pat

Posted June 07, 2013 - 01:34 PM

#30

No, not really. The chain runs over about the same number of teeth, and so on, and you're still pulling about the same load using one cam to open 4 valves as using two to open 5 (the intakes are way lighter). Using good oil and changing it is the key.


It sucks there is no way to fine tune the lobes just a degree to two. I've used pro curcuit cams before were "in theory", looked like I could grind off the tac weld and reset to where I want and just re-tak it. Of course I've never done it and never really had reason too but could see iy being done.
You ever do anything like that? Customizing valve timing..

  • grayracer513

Posted June 07, 2013 - 07:18 PM

#31

I have, but the ones that I actually pressed sprockets off of were a long time ago. Since then, I've done stuff like that by choosing among the available factory cams. On YZF's, the intake cam can be re-indexed easily by pressing off the sprocket, shifting it, and pressing it back on. It's advisable to run a small tack weld, something that can be removed later, just to keep it from slipping after it's been pushed of/on again.

You can move the exhaust that way, too, but the auto decompression linkage complicates things and limits how far you cam move stuff.

  • corndogg

Posted June 13, 2013 - 07:34 AM

#32

sorry its been so long since i got to reply, got called out to bushfire to firefight. i let my timing like the last picture and i tried the suction test. bike is extremely hard to kick over now takes everything i have to kick down the starter and im 235 pounds. could this just be because everything on the top end is new? should i continue trying to start it?

  • KTM_Pat

Posted June 13, 2013 - 06:31 PM

#33

sorry its been so long since i got to reply, got called out to bushfire to firefight. i let my timing like the last picture and i tried the suction test. bike is extremely hard to kick over now takes everything i have to kick down the starter and im 235 pounds. could this just be because everything on the top end is new? should i continue trying to start it?


You mean u put everything back together with timing setup. Make sure your cams are installed properly and your not bindng a cam. Try loosining the cam clamps a little and see if easier. You might not have the cams seated right.

Edited by KTM_Pat, June 13, 2013 - 06:34 PM.


  • corndogg

Posted June 14, 2013 - 04:56 AM

#34

found the problem why i couldnt kick it over, the cylinder was full of coolant haha changed the gaskets once again and put ultra blue sealant on them last night, going to finish putting the bike back together tonight. must have pinched the base gasket or head gasket when putting on the cylinder and it wasnt sealing properly. thats the only thing i can think of as the crank case was not apart. just been one thing after another with this bike, but tonight i have faith she will fire.





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