Yamaha yzf450 09 sump conversion how to find tdc?

Hi all always come here to fix my problems buy could not find anything about the forum I have a yamaha yz450f with a yamaha rinaldi sump conversion done rebuild, now stuck in a rut with timing as it has a different case on with no engine plug to find tdc markings anyone have any ideas?

Thanks

Don't know what a sump conversion is but I had a 04 with a cover that didn't have a timing plug. I used to remove the spark plug and use a depth finder to find tdc. If your cam lobes angles don't look right rotate motor around again and you should be there.

Yeah was thinking that take spark plug out and use somthing to see when it goes back down .

Would it be right if i done it that way could i get it close enough?

Also if i take the head back off and put the piston to the top of the cylinder? Would i then need a new head gasket? Even though i Haven't fired it up yet

Thanks

Yeah was thinking that take spark plug out and use somthing to see when it goes back down .

Would it be right if i done it that way could i get it close enough?

Also if i take the head back off and put the piston to the top of the cylinder? Would i then need a new head gasket? Even though i Haven't fired it up yet

Thanks

I only did that trick to check the valves. I did have the oem case I put on it to really verify if was concerned.

Your idea if taking off head to set piston to tdc should work fine as long as the chain doesn't move the piston when installing cams.

The head and base gaskets are a one time use. It would probably work fine since it hasn't run yet, but their inexpensive and cheap insurance not to have to open it up again

A Phillips screwdriver or similar can be used to feel TDC with what will be plenty enough accuracy for setting cam timing. 

Well i tried the screw driver, found tdc what i thought was tdc done cams timing all looked good. Started her up after few kicks ended up smashing head to bits snapped valves and messed up the new piston and cylinder!! Devastated

If it ran, then the question of whether or not you correctly located TDC was answered in the positive.  Sounds as if you overlooked something with the tensioner, the condition of the timing chain, cap torque, etc. 

It made a noise and cut out when i gave it a little gas do you think i havent torqued the cap on the timing chain tensionor to the right spec ? Would that make it do that ? I did follow the manual for all torque settings but my friend put in the cam chain tensionor and silly me should of double checked it big lesson learned

It also smashed one of the inlet buckets

Edited by Adamparky

Cam caps.  The tensioner is automatic, and not torque sensitive in any particular way.  Cam caps are another matter.  They are spec'd at 86 inch pounds (7.2 foot pounds), and should always be run up in the specified sequence, and in 3 incremental steps.  The caps should also always be seated by hand or by a gentle tapping with a soft faced tool.  IMO, the torque spec is uncomfortably high, seeing as it also specifies oiled threads.  I always set them at 75 in/lb (6.25 ft/lb) instead, and haven't ever had a problem. 

 

If the cap torque was the issue, you should see some galling/scoring on the bearing surface of the cap.

 

Another thing that's possible is the chain itself.  If it has ANY stiff links so that each and every pin does not pivot completely freely, it needs to be replaced.

 

The incident as described definitely sounds like it skipped time for one reason or other.

Aww that sucks... Sorry for you. Did your friend release the timing chain tensioner?

Thank you for your help! I checked everything over and i think i found the problem one or two of the cam chain links was tight not moving freely like the rest. Is this what made it skip time?

It can be, yes. 

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