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Discussion Starter · #1 · (Edited)
Hey All,

Quick question to you all learned people out there.
I have a 73 TR6RV which was apparently rebuilt before I bought it..I have no doubt that it was done as I know the person who did it quite well and he "seems" to know what he was talking about and every thing is clean inside etc..
Anywho after about 400 easy kms (sorry no miles conversion here) I kept hearing a loud metallic knocking sound on the timing side. Not good me thinks..Off with the cover..nice clean new oil etc etc..upon closer inspection and cranking it over by hand I saw that the intermediate gear was moving forward ..as in out.. on the shaft and rubbing the back of the oil pump...Not smiling at this point..
Further investigation revealed that the crank pinion would give a little jump at a certain point of rotation causing the said noise..definately not happy..
Doesnt appear to be a bearing as the movement is only about 3 thou on rotation (used dial indicator)..im about to pull it apart and have a further look ..any ideas

Thanks

Gav
Adelaide, Aust
 

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that's a pretty interesting problem. keep us tuned in to the fix.

just guessing without having some old hands around is a common dilemna.

seems like any 'jump' on the crank would indicate a chunk of something in the way of perfect rotation. a slightly tweaked primary gear tooth or groove? i'd imagine that the jump is in only in the same spot once a rotation? what direction is the jump? if it's away from where the gears are meshing that would indicate a gear mesh problem.

i'd watch for the jump and mark the gears where they mesh, pull the intermediate gear, even though you'll have to retime the set, and examine both closely. i wonder what would happen if you flipped over the intermediate gear and tried it that way? to retime without a hassle holding the cams against the valve springs you might have to take off the rocker boxes if backing off the valve adjusters does'nt give you enough play. might be worth finding another intermediate and crank gear to try out. check the intermediate gear shaft too and make sure it has'nt loosened from this jump pushing on it.

best of luck to ya, that's a significant problem. the rest of the gang should be dropping in with their experiences so you can get a few more options.
 

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Wow,

That is a hard one there, one of those I wish I was in your
garage to see for myself problems. Anyway, a small piece
of trash in a bearing is a good guess, or on the odder but could
happen, something on the primary side that is transfering a
load through the crank to the timing chest side.

Pookybear
 

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Discussion Starter · #5 ·
Thanks guys..Sunshine ..yep it is in the same position on rotation..Im checking out the primary side as we speak ..A friend of mine mentioned that it is not uncommon for primary chains to become stiff in a spot which causes similar symptoms..But I have the opportunity
to get it fully checked out so that is what I'm doing..
See how it goes..I will keep you all posted

Thanks

Gav
 

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ya, the intermediate gear kissing the pump is a major clue.

seeing the gear prob is not an easy eyeball diagnosis. i dropped a crank gear on a concrete floor once and messed it up. it had a tight spot that showed up when i was testing the bottom end after i timed the gears by rolling the crank through a few revs by hand.

when i took the gears off and fit them together and rolled them by hand the tight spot was obvious. the tight spot was on the crank gear and showed up in the same place every rev. I put machinist blueing on the gears and found the high spot that way and eased it down with one of the small thin whet stones i have for fine tuning router bits.

the high spot was on one tooth corner and changed both tooth sides slightly but by stoning the tight side mostly it came out with a few strokes. i did make a few passes on the other side to clear a tiny burr.
 

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If I am reading your post right, I had the exact same problem. The good news is it was an easy fix. In my case the drive gear (in the harley world we call it a pinion gear) on the crankshaft would rock with the backlash in the valve drivetrain causing a loud ticking noise. It sounded like the lower end was gonna go or I had a bad valve.

Tightening up the crank nut didn't help, I was outta threads. The problem turned out to be a missing "clamping washer". It goes behind the pinion gear. Check to see if yours is there. It was less than 3 dollars and now everything is nice and quiet.

How was mine missing? A previous owner had the lower end rebuilt and they left the washer out.

I hope this is your problem too.

Joe

P.S For what its worth, my bike is a 73 Tiger too
 

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Discussion Starter · #8 ·
Thanks Mendonjo..Ill have a look at that..but can't see any reference to a washer in any manuals...I know what they are like sometimes..but I cant see one behind it either..will obtain removal tool for pinion..
Anyway have motor out now and am about to take it to the mechanic to have a look at...did notice that after taking the rocker boxes off one of the inlet pushrods is slightly bent..perhaps part of the problem or just another one...

Just on that I have some spares that I got with the bike but they appear to be a bit thicker..same length and cup size the same but alloy body a few mm wider..anyone know about this..Different models perhaps..

regards

Gav
 

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Hi Gav

At least on my bike (750) the pinion shaft is not tapered, I was able to slide the pinon gear off.

The clamping washer goes betewwn the pinion gear and the right main bearing.

Clamping washer part number is 70-3300

Joe
 

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Discussion Starter · #10 ·
Ah..OK..maybe on 750 motor but not 650?? unknown...Any way quick update had to remove rocker boxes to facilitate engine removal...thought quick check of pushrods...inlet R/S bent not overly but enough out of shape to not be doing its job properly...Oh Dear
Anyway off to the engine doctors tomorrow to see what is going on..

Gav
 

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Discussion Starter · #11 ·
Hi Everyone,

Quick update, all internals of the motor are fine...load off the mind
it would appear that "something" has passed between the teeth of the intermediate or hunting gear which ever you like to call it and the crankshaft pinion and caused the intermediate teeth to become distorted..and after looking at it there were some definate marks on the teeth..changed over for a new one and appears to be turning over fine by hand...no jumping or anything other than what its supposed to do....so now to refit and fire it up...
Thanks to everyone who replied

Regards
Gav
 

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Discussion Starter · #12 ·
Finally back again...All went well...replaced the idler gear and ticked over fine...look at old gear found several teeth misshapen...maybe something went through..unknown...have external filter and screen...
is running very well now...but one thing leads to another one of the oil screen nuts decided to come off bolt and all...and of course is weeping oil...enough to be very annoying..where did I put the tap and die set..see what happens next

have fun
Gav
 

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Thanks for the update, mate. It makes a world of difference to us new kids when searching for answers. so many threads stop dead without a conclusion. Note to self .. revisit all my silly questions and make sure I concluded.
cheers
derek
 
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