1967/1969 Bonnie Rebuild Desert Sled Project

[grandpaul]

AHA! The spring is from the seal lip (crankshaft seal).

The puller point can bear on the crank stud nose.

 

[speedrattle]

Thanks for the tip. I will give this a try, gently that is. Perhaps I will need a puller later on in the rebuild?

a puller is always useful, but ive never had to do more with a rotor than wiggle it off with two pry bars.

but its possible that somebody stuck it on with red loctite, and that always changes the game. sometimes people weld them on. thats the worst case

you csn use a two jaw puller on the engine and gearbox sprockets, but its better to just to drill three holes in a piece of steel, thread the middle one for a bolt and make a puller that draws the sprocket off using the threaded holes in its side

 

[Sundance]

AHA! The spring is from the seal lip (crankshaft seal).

The puller point can bear on the crank stud nose.

Thanks grandpaul. I suppose then this is nothing serious to worry about - although I suppose if the seal was compromised it may have had some impact on the engine. I've yet to try again to get the rotor off but will soon.

 

[Sundance]

a puller is always useful, but ive never had to do more with a rotor than wiggle it off with two pry bars.

but its possible that somebody stuck it on with red loctite, and that always changes the game. sometimes people weld them on. thats the worst case

you csn use a two jaw puller on the engine and gearbox sprockets, but its better to just to drill three holes in a piece of steel, thread the middle one for a bolt and make a puller that draws the sprocket off using the threaded holes in its side

I will give it a try with a couple of pry bars and then go to a puller if needed. I bought a puller for the engine and gearbox sprockets from Lowbrow - hope to use is very soon.

 

[Sundance]

The last few days I made some more progress on my tear down. I’ve got the primary side off as well as the timing and transmission. I was initially stalled by the rotor, but was able to get a 3 jaw puller to get it off.


I noticed a small crack in the primary cover, it doesn’t go all the way through - wondering if this looks of or should I have it fixed?


The crank end on the primary side was hard coming off, it seems the reason might be that the end was a bit bunged up. The primary chain tensioner didn’t appear to have much wear - so perhaps it had been adjusted properly and is still in good shape? The drive sprocket seems to have some wear. Whoever build this before used a lot of goop on top of gaskets!

I had some difficulty getting the advance off as the interior threads would not take my puller. Looking closely it seems they have been damaged, so this should probably be replaced.

 

[grandpaul]

All of those wear parts should be replaced.

Test your alternator rotor for looseness-
View: https://www.youtube.com/watch?v=Nqq_gS_i1yc


Find a good welder and have them weld up that crack, or you can clean it VERY thoroughly, dress it with medium emery paper, clean it again with denatured alcohol, then apply JB Weld clear epoxy and let cure.

The AAU is still re-usable, as long as the springs have good tension and the parts are not sloppy loose.

Sure enough, the spring is gone from the seal.

 

[Sundance]

On to the timing side. Looking at the intake cam gear it looks like somewhere along the line someone beat on it a bit as there are some marks on the face. Also I had a bear getting the exhaust cam gear off because I couldn’t get my puller to engage the threads. I noticed the first couple of threads on the gear were messed up a bit. So I carefully filed the threads a bit with a jewelers file to try to remove the first thread a bit. I finally got the puller to engage by slowly threading it on and off with some oil. Perhaps this gear should be replaced when rebuilding or at least get the threads fixed? I couldn’t get the key out of the exhaust cam.

I seemed to get the gearbox out rather easily. I’m not sure how to evaluate the gears, but they all look pretty stout to me now.

I ended up with one part that I’m not sure where it came from - a thick washer or ? I’ve managed to keep everything else segregated.

Now to split the cases.

 

[grandpaul]

Too late now, but I would have left the cams and pinions in place and checked for runout, then NOT TOUCHED them unless it was excessive, checked against allowable spec.

That is one of two fork rollers that go on the little pins of the fork; they ride in the gearchange camplate slots.

(diggin' this cross-posting trip)

 

[Sundance]

Too late now, but I would have left the cams and pinions in place and checked for runout, then NOT TOUCHED them unless it was excessive, checked against allowable spec.

That is one of two fork rollers that go on the little pins of the fork; they ride in the gearchange camplate slots.

(diggin' this cross-posting trip)

OK, I'm not familiar with what "runout" is in this case. Is this something then that will have to be accomplished on assembly or is there some other way? On the fork roller, yes, I see now. Since this was the last thing I took off I can see why I wasn't sure of its origin. (cross posting)

 

[speedrattle]

OK, I'm not familiar with what "runout" is in this case. Is this something then that will have to be accomplished on assembly or is there some other way? On the fork roller, yes, I see now. Since this was the last thing I took off I can see why I wasn't sure of its origin. (cross posting)

dont try to take out the camshaft bearings. they last forever and yours are probably fine.

 

[Sundance]

dont try to take out the camshaft bearings. they last forever and yours are probably fine.

OK, thanks for the advice. I think I heard something about that. There must be some way to determine if the are OK?

 

[Sundance]

I got the cases split today. I still have some challenges ahead. First off it was difficult getting the cases apart, I had to heat them a bit before I got some movement. There seems to be an awful lot of gasket cement and other goo on all the joints.


So, the intake cam is not original. I’m wondering if any forum members might be familiar with this brand - Megacycle Cams from California?


I wasn’t able to get the rods off the crank. These say “JRC” and have 6 point star bolts. I got one loose but the other won’t budge with a long breaker. Any advice on how to get these off - many thanks! Do I finally need to get an impact driver?? Plus - any knowledge of these rods? They are obviously not original and I imagine I need to determine if they are still OK to use in the rebuild. I’ve got to get them off first. And one more thing - these do not have bushings in the small end so not sure how to manage that when I build it back.


I could not remove the exhaust cam because I can’t get the key out of the end. It looks almost like whoever assembled the beast deformed the top of the key a bit. I’ve tried picks and such to get it out. Any ideas on how to remove this so I can take a look at the cam?


I’m curious why someone would have filled in the hole with some compound (silicone?) on the end of the smaller transmission shaft?


One end of the crank is buggered a bit from some PO. Not sure if this is still ok for the rebuild. Notice the bearing is still on the crank. I’m wondering what kind of puller is needed to get this off the crank?


There is a number engraved on the flywheel of the crank - #10595 - any idea of what this is for? I am impressed by the weight of the flywheel!


So, I’ve got to get the rods off, bearing off the crank, then I should find someone close by to do some hydro-blasting.

Thanks for any comments or advice!!

 

[speedrattle]

OK, thanks for the advice. I think I heard something about that. There must be some way to determine if the are OK?

you can measure the inner diameter of the camshaft bushes using telescoping gauges, but realistically if you can't rattle them up and down vertically theyll be fine.

JRC rods were hot rod parts from the 1970s. they were alloy, but were much meatier than the original alloy rods. if theyre not damaged i'd keep them. try warming up the aluminum with a propane torch to see if you can loosen the threads around the steel bolts. i wouldnt use an impact except as a last resort.

megacycle is a current manufacturer of high performance cams. what are the numbers on your intake cam? to get the key out of the exhaust cam, take a small punch or a small sharp chisel and tap the outboard end of the key up and out of the slot in the cam. maybe use the torch gently here as well first.

the silicon on the end of the layshaft needle bearing is to keep gearbox oil from oozing out around the bearing housing.

the crank end looks okay to me. you may carefully dress it with a small file. but look at the timing end-- people sometimes beat on that with a hammer and it screws up the seal surface. your sludge trap plug is pretty buggered as well. is there a center-punched dimple holding it in? you'll want to remove th eplug and clean the sludge tube and cavity inside. there are things you should be careful about with that plug.

that main bearing should be a tight hand push fit on the crank. you can warm it up and use the blunt screwdrivers, or buy a small bearing separator that looks like this:

https://www.amazon.com/Shankly-Bear...t=&hvlocphy=9015133&hvtargid=pla-573263744292
put up a picture of the nuts that were holding your oil pump on. the correct nuts are thin six-point steel, flat on one side and domed on the other. theyre designed to position the oil pump correctly so that the aluminum slider block doesnt get misaligned. there should be an internal-tooth star washer behind them.

this is what i see. other people will spot things in your pictures too

 

[Rudie]

I removed the long shouldered nut from the rotor and this is how it was.
Here is a photo prior to removing the nut on the rotor.

If you look in a 69 650 parts book, "CRANKSHAFT AND CONNECTING RODS" pages, the drive end of the crank should be exactly the same as 67 - "the long shouldered nut" securing the rotor (part #25) should screw on to stud #7, the other end of the stud screws into the end of the crank.

The stud has not come out of the crank still attached to the rotor nut?

I was initially stalled by the rotor, but was able to get a 3 jaw puller to get it off.

View attachment 51446

Test your alternator rotor for looseness-

I would not bother. The "6 68" indicates it was made in week 6 of 1968. It should have been a sliding fit on the crankshaft, although the gouges on the crank's rotor mounting area might have had something to do with the removal difficulty. You have pulled on the outside of the rotor to extract it. In the grand scheme of what you are spending on this engine, a new rotor is not expensive.

When the crank's rotor mounting end is cleaned up, it should measure 0.7500"-0.7505" - i.e. within half a thou. - throughout its full length.

The primary chain tensioner didn’t appear to have much wear

View attachment 51451

You are mistaken, enter "triumph 70-6061" into an internet search engine, look at the returned images to see what a new one looks like.

I had some difficulty getting the advance off as the interior threads would not take my puller.

Or the wrong thread puller was used? 69 'should' be 5/16"-24 (UNF), if the engine builder used an earlier one, the thread would have been 5/16"-26 (Cycle).

advance
should probably be replaced.

The AAU is still re-usable, as long as the springs have good tension

Points and mechanical AAU are a crude way of making and timing an ignition spark, even if the springs have good tension. Otoh, electronic ignition for these bikes has been around for half a century.

One thing an electronic ignition will require for complete reliability is a good complete electrical system. As you are intending to replace the alternator stator and I have advised replacing the rotor, Lucas produced 'high output' 3-phase stators from mid-1978, that are exactly the same size and mounting as the stator you have removed, one will cost the same as any other stator of lower output but, combined with a reliable regulator/rectifier and good wiring will give the desired complete reliability.

 

[grandpaul]

Your crank was Dynamically balanced MOST LIKELY (no way to be sure, unless you can track down the etched number that was likely put there by the party that balanced the crank).

The balancer clamps the appropriate weights to the journals to represent the rods & pistons' weight, then the entire affair is balanced. Better than static balancing, and most likely was used when you consider all the other parts you have there.

If you have to re-bore, you'll need to replace anyway, and likely a re-balance would be in order unless you can SOMEHOW match larger pistons' weight to the existing pistons.

 

[Sundance]

Your crank was Dynamically balanced MOST LIKELY (no way to be sure, unless you can track down the etched number that was likely put there by the party that balanced the crank).

The balancer clamps the appropriate weights to the journals to represent the rods & pistons' weight, then the entire affair is balanced. Better than static balancing, and most likely was used when you consider all the other parts you have there.

If you have to re-bore, you'll need to replace anyway, and likely a re-balance would be in order unless you can SOMEHOW match larger pistons' weight to the existing pistons.

OK, so this, like the head, is going to be best left to an expert. Once I've gotten it figured out what barrels I will use and then the appropriate pistons, etc, I should find someone who can dynamic balance this crank.

 

[Sundance]

I was able to remove the rods with a longer breaker bar. I see there are no bushings in the small ends so this seems strange. I suppose it will be an issue when trying to fit new pistons. Also the big end bearings read: 70-3586. I appreciate comments on this reading!

I removed the valves and it looks like they will need replacing. I noticed that one of the guides is different from the rest - the right side exhaust guide. I see lots of gunk near the guides, perhaps from too much gasket cement? The valve ends do show some indentations on the bearing surface and I wonder if this is normal or excessive?

There was a question about the oil pump and the nuts used to secure it. The nuts securing this were lock nuts without washers.

I’m still waiting on a bearing puller to get the bearing off the crank.

Cleaning the gunk and oil off the cases is much more difficult than I imagined!

 

[speedrattle]

i lusted after those rods years and years ago. still have the JRC catalog. dont worry about not having a bush. if the little end bores are undamaged then the pins are getting enough oil through those holes. but look in there.

icant remember. do you have parts books? kyle at cbs has free downloads

https://www.classicbritishspares.com
pitch those nylocs in the bin. the right nuts and washers cost nothing, and really the oil pump was not the place for your PO to get creative.

 

[Rudie]

oil pump
nuts securing this were lock nuts without washers.

pitch those nylocs in the bin. the right nuts and washers cost nothing, and really the oil pump was not the place for your PO to get creative.

+1.

All holes in components that either fit over studs or take bolts must have a little clearance around the stud/bolt. However, particularly the oil pump also has feed and scavenge holes that must line up exactly with corresponding holes in the crankcase, the clearance in the mounting holes cannot be allowed to misalign the feed and scavenge holes even a little. The correct pump securing nuts have a convex surface on one side, two screwed equally into the concaves around the pump mounting holes should centre the pump feed and scavenge holes over the ones in the crankcase. Standard engineering solution afaik.

Depending on your budget, have you considered a new Morgo pump? Based on the later 4-valve pump and with a little extra oil volume.

Morgo also do the hemi nuts and spring washers; they unhelpfully list "T140" and "T120" when the actual difference is respectively UNF (1/4"-28) and BSC (1/4"-26); certainly according to the '69 650 parts book, your nuts should be UNF.

 

[Sundance]

+1.

All holes in components that either fit over studs or take bolts must have a little clearance around the stud/bolt. However, particularly the oil pump also has feed and scavenge holes that must line up exactly with corresponding holes in the crankcase, the clearance in the mounting holes cannot be allowed to misalign the feed and scavenge holes even a little. The correct pump securing nuts have a convex surface on one side, two screwed equally into the concaves around the pump mounting holes should centre the pump feed and scavenge holes over the ones in the crankcase. Standard engineering solution afaik.

Depending on your budget, have you considered a new Morgo pump? Based on the later 4-valve pump and with a little extra oil volume.

Morgo also do the hemi nuts and spring washers; they unhelpfully list "T140" and "T120" when the actual difference is respectively UNF (1/4"-28) and BSC (1/4"-26); certainly according to the '69 650 parts book, your nuts should be UNF.

Thanks for the detail on getting the pump aligned properly! I have considered a new pump. You are referring to their plunger pump or the rotary pump? I've heard from some that too much pressure might be a bad thing - but it seems this would be much better for the engine.