NQ50 Crank removal - stuck bearing in left crankcase

[warnereg]

Ok, first off I am completely rebuilding an NQ50 motor. This motor is completely covered in oil, it did run however I figured Id clean it up, paint the cases, and possibly the cylinder (if it wont affect cooling, Its completely covered in rust as of rt now), and do everything else in between while Im at it, as this is my first motor rebuild ever, and will be a good fall/winter project.

Now onto the details, Ive been following dyehardfan's thread here:

http://www.hondaspree.net/phpBB3/viewto ... ilit=crank

He seems to have had the same problem as myself, except for the fact that he eventually got his crank removed from the cases. I have blasted the heck out of it in pb blast as well as heated the case with a heat gun and beat on the crank shaft from the left side with a rubber mallot, and to no avail its just plain stuck.

I know I need a bearing puller as well as a crankshaft puller/installer but it doesnt seem like the puller would do me any good in this case as I dont see the orientation.

And lastly the manual calls for a hydraulic press, shaft protector, and case puller tools, which seems like it would be quite the investment. Any ideas?

[warnereg]

Ok, update... I DID manage to get the crank out, however I managed to drop it on the concrete floot, I used a punch and a hammer not to damage the threads, however I dont think that matters anymore, it all looks alright, however there is small buff on the counter weight where it landed on the concrete... :/

Does anyone think this may still be ok? It seems plenty functional however without being able to do a proper runout I would'nt be able to tell...

Anyone got a new crank 85 spree crank that they want to come off of?

Leaning curve just increased, as well as the budget... grr......

[warnereg]

update... again...

I did a ghetto runout of the crankshaft with a steel ruler that has very very small increments, and I think I dodged a bullet on this one, everything looks pretty darn strait.

I did look at the parts fiche and I found a very interesting detail. The original 1985 spree crankshaft was superceded by the '86 and '87 years crankshaft. Which is very good news to me, and whoever else that wanted to know.

Still would like to know if anyone has a known good crankshaft... They are available on ebay, but who really knows the condition (one I found I saw in the pic that the threads were f'ed).

[speedy25]

Dont think that eyeballing a crank will suffice to check if its been damaged or not. Get someone with a crank truing fixture and have them check it for you. Theres plenty of people in MI that still know two-strokes.

Hint for those with the same trouble- DONT go bashing parts with a hammer. Either use a puller (best way) or use some heat from a propane torch. A little expansion goes a long way on press fit parts. Bearings and cranks slide out easily with some warmth. Works great for installation too. Warm the case, push in the bearing with your fingers and then a little more heat and you can push in the crank too. No hammers required to mess up that truing you just got!

Dont paint the cylinder. Even rust has more heat conduction than paint.

=SP

[warnereg]

Dont think that eyeballing a crank will suffice to check if its been damaged or not. Get someone with a crank truing fixture and have them check it for you. Theres plenty of people in MI that still know two-strokes.

But at what cost? Ive seen "good" cranks on ebay for under a bill, if I can get it checked for under $50.00 that would be a sweet score for use of ones knowlege, and their $600.00 on up eqipment. But we'll see.

Hint for those with the same trouble- DONT go bashing parts with a hammer. Either use a puller (best way) or use some heat from a propane torch. A little expansion goes a long way on press fit parts. Bearings and cranks slide out easily with some warmth. Works great for installation too. Warm the case, push in the bearing with your fingers and then a little more heat and you can push in the crank too. No hammers required to mess up that truing you just got!

Pullers are fantastic I agree, but from what Ive seen/read people have suggested using a rubber mallot not to mushroom the end of the shaft, no punn intended. Also I have not seen a puller or method otherwise, if you can push the crankshaft out with your bare hands and a blowtorch you must have an iron man suit or something. My mistake for dropping it on the floor, but otherwise it would have been unharmed,, it definitely took more force than I myself could muster, and I aint little.

I took your advice on the heat tho, however I used a heat gun instead, I dont really like the idea of flame vs. aluminum, probably just a prudent measure. Heat + patience + pb blast = a lot of success.

Dont paint the cylinder. Even rust has more heat conduction than paint.

Gonna take your advice on this one too, its not seen anyway so it wont interupt my scheme, black and yellow black and yellow

=SP