1972 450 engine questions

Splitting cranks is something I never had any interest in doing myself so I can't help you with the proceedure. Heres the page from the workshop manual that covers the rod to disc clearances and the runout.

Yeah Crash, I read that also. But, jerks at 0.02mm that's 0.0007874016 of an inch!! I don't have the tools to measure that low as I don't work at NASA anymore.HaHa
Anyway, I got the drum and ratchet today, and they look new with top and bottom spacers and shifting pawl pin. Also a detent with spring. Now I don't use the detent anymore? Correct? Just the plug?

Is that helmet NASA issue?

About the crankshaft, give John LeFevre a call I'm sure he'll help you out.

Regarding the shifting drum, you're correct in that theres no longer a need for the detent pin or spring but the old plug is used. However you'll still need a pin and spring under the ratchet pawl. As you know theres two of each (pin and spring) in a stock motor.

When setting up the ratchet gear to the drum gear make sure you follow the 6spd method. Off the top of my head I think its one tooth showing at the bottom and two teeth showing at the top when in fourth gear.

Before assembling the trans in the cases install the drum by itself and snug two or three case screws next to the drum to make sure that the correct number of thrust washers are used, as there should be .5mm to .75mm lateral movement in the drum. In my experience just one washer, on the bottom next to the drum gear, is all that's needed but I've seen exploded views with a washer on each end of the drum and that's been one too many in my experience.

Thanks Crash, I'll assembly it this afternoon for a test. That pic is why I'm not welcome at NASA anymore, It's taped to the security house wall.

Looks good assembled and you are correct Crash that it only needed one washer. It's pretty snug with both, if I ran it with both I think it might stick, so one it is. Talked to John and he said .001 is good for the crank. So, paint and lower end assembly this weekend, and tackling the cylinder next. My cylinder, with standard bore has been ground on in the past and the liner to cylinder seams are not the cleanest. I have seen your pics from another thread and that is what I'm hoping for. I have a Dyna file that should make easy work of repairs, hopefully the timing hasn't been change on the ports, any advise would be welcome. Where can I get a drawing of a stock liner for reference?

I've never seen a schematic of the stock ports but there is a Husky service bulletin that shows port mods for performance purposes. I've included a PDF circa 1974 if you're interested.

Thanks Crash, I have that as well. My problem is I don't know how far the PO went with their mod. The barrel is ground and the sleeve/liner is ground as well but the skirts haven't been trimmed to the bulletin, and the alignment of the sleeve to barrel is off, like the sleeve and barrel were cut while apart. I don't see one clean transition.

The ports in the center of the barrel were not aligned in those days, the transitions weren't clean up by the factory until the next generation magnesium engine that started in 1975. You'll just have to do your best to clean them up without changing them much. I think a millimeter of material will get rid of the sharp edges in most cases.

The big transfer ports on either side of your barrel can be matched to the cases by putting the barrel on one of the half cases one side at a time. From this you can see what needs to be trimmed to get the desired alignment.

BEFORE MODS





AFTER MODS

I rekon smoothing and matching the ports gives a smoother and stronger engine. my story and im sticking to it...

Not knowing what the stock cylinder ports are I just worked the skirts and intake, not removing any from the intake ports just a cleanup. While not perfect it looks good to me. After mocking the trans a few time I found the shift fork rollers are letting the 6th gear touch the first gear so it goes click click click as it's rotated. So after they get here I should be able to close it up for good. Now that the cylinder mods a finished I can blast and paint it and the head.

looks ideal. least you know its as good as it can be without altering the ports.

I'm going to call John at Husky Restoration and see if he has the measurement down to the ports, if not it should be ok anyway. I still have to chamfer the edges of the ports so I don't snag the ring. I think it turned out well. We'll see when I try to start it. Hope to ride vintage this year. It's gonna hurt.

OK so I have it painted and re zinced some fasteners. Dropped the piston in the cylinder and found that it sits above the exaust port. My question is, with an 82mm stroke and a base gasket what kind of squish am I supposed to have? Or does the piston come all the way to the top of the sleeve.

Also I have a good condition shift fork for 3/4 gears and rollers on the way from John at HR. My original fork was loose apart at the solder joint where the tube goes thru, both sides of the fork were well grooved. So that should take care of the clicking gear.

Don't know what the squish is suppose to be but I do know from looking at the under side of a head from this era 450 that if the piston went to the very top of the sleeve it would hit the head.

I also don't know where the piston sits at bottom center relative to the exhaust port. In your case maybe the port was ground lower during porting and if so I don't think it matters as long as the piston skirt covers it completely when at TDC.

Ill have to check on that, just trying to avoid a second disassembly. I think I will install the crank into the cases alone and check the porting, that will give positive evidence of where the piston is going to be tdc/bdc. if there is a problem I can better address that without the trans. You can still see the faint ring line at tdc about 2mm shy of the top of the sleeve, but I want a positive look at it in action. I bought the assembly tool, and have seen the disassembly tool so I can make one. I'm going to the York swap meet sunday and maybe pick one up there, maybe an un molested cylinder as well, hahah I can only dream.

Checked the piston on the crank and it does cover the exaust port completely, so that's good. Then I disassembled the crank from the cases and go to install the crank seal in the left case and lo and behold... they used 2 different sizes 28-52-7 mm and 30-52-7 mm.. who knew my crank is a 30mm! Well now I do, and another day gone. So I must not have a 1972 drive end on the crank, it's probably a 73-75. Now I do have a 28mm drive end but the seal surface is not the best so I guess I'm looking for one of those at the swap meet tomorrow. I will WIN!!!

Never Give Up

I don't see any reason that a 30mm seal wouldn't work in your 450 but it is odd that your crank would have that 30mm stub shaft in the first place. I have a 30mm left stub shaft on the shelf out of a 76 360WR and its a few mm longer than the 28mm found in your 450. A longer stub shaft would result in the primary gear misaligning with the clutch gear-ring. I suppose it may work but it would be perfect.

In any event I hope your search for a left stub shaft isn't to painful. One other option may be a crank from a 73 360RT. They use the same engine cases and the crankshaft discs are the same diameter as the 450.

Believe it or not Halls has the stub and seal.. ordered this morning! The crank must be from a later date, but I don't see how the two stubs could be different lengths as the MK/ML manual says they used two different seal sizes and to check the seal surface diameter to tell which you have. Also they don't give a measurement for the overall length of the crank, only the cheek width and depth of the right stub. So It looks like I'm building the crank one more time. At least I'll get to use my new 2lb brass hammer. lol Alright now I'm headed for the vintage swap meet in York.