The Hodaka Club Forum

I used a torch , PB Blaster, and rubber or plastic mallet to get my last top end off. The key is a lot of heat on the outside of the cylinder to expand and soak it with blaster. Start tapping the cylinder but don't break those fins in the process! I then start trying to insert
some small wood wedges between the cylinder and the cases. It took me three days to get it done and you can't get in a hurry. Hope it works for you.

Yes it does, Dale. I fiddled around with muriatic acid for etching aluminum billet parts a friend made for me while he was practicing with a new CNC rig at work. It gives it a nice warm golden metallic look.

Yes it will Dale. The good thing about Muriatic acid is it dissolves rust much faster than non-oxidized metal, including aluminum. That’s why I’m using it sparingly. It’s even eating thru the top of the piston.

I’m just trying to get the damn thing free so I can pull the cylinder off the cases. At this point, I figure the cylinder is toast, unless I save it for a 97 Piston/RT crank/94 rod assembly and then bore it out.

I’ll probably just get another Std Model 03 cylinder and a Std piston so I can make it run. I just need to be able to get at the seals & bearings to change them out at this point.

I had hoped to salvage the cylinder, hone it & put another Std piston in it, but it looks like it’s just too far gone with the seized rings to NOT need a bore job.

I’ve cleaned it for the night and will continue tomorrow. My son in law is going to bring 2 double sided hammers from his shop tomorrow and we will see if we can beat it into submission.

The funny thing is, I can only fit about an 1/8th if a cup of acid into the top of the cylinder. After an hour, the acid becomes as thick as pancake syrup & I have to clean it out & start fresh.

So I’ve been checking & cleaning it hourly. But she’s still seized to the cylinder wall..... Victor

I wonder if the crank and and rod bearings are actually seized too. Try lifting the cylinder (gently) to check for and see if you can get any wiggle independent of the immovable piston.

I have a 250 where I threw ATF and naptha, toilet bowl cleaner, muriatic acid, as well as a variety of penetrating fluids at it. In this case the rust seized crank was just as culpable as the stuck top end. Actually I find that Pine Sol is more effective for getting things apart.

Whoops, I looked further back in the posts and see that the crank turns. Try the Pine Sol in any event.

What is wrong with pulling the cylinder studs and splitting the cases. Beating on the center of the piston would expand it, I hope that a beginner out there somewhere does not thinks this is all good advice. If you do not care about the piston you could use about a 1/8 or 3/16 long drill bit and just drill down on the outside edge of the piston all the way down that should relieve some of the stress and mabe it would not work.?? How about soaking 7 days withe pineapple juice. you would not try and beat the piston out with hammers but to soak it with a penetrant and give it a few jarring whacks each day for a couple of weeks?. The machine shop sounded like a good idea. Some times there is something stuck between the cylinder and the piston. *************Clarence

I don't think I would ever use acid in this case. Not around all of the aluminum...

If the crank is movable, then get it rocking until the cylinder lifts upward. Once up, cut off the connecting rod. Then you can press the piston out. Cylinder saved!

The piston is closer to TDC than BDC. The cylinder only lifts about 3/8” total. I’ve never split a crank apart to change a piston rod. What does it require? I’ve been fortunate that all my cranks have been low mileage & didn’t need bearing work for the lower rod bearing. What does rebuilding a crank require? Any special tools? Victor

Crank rebuild requires an expert. But... way easier and cheaper to replace the connecting rod than the cylinder. And especially an 03 cylinder.

But the crank change requires 3 parts. A Road Toad crank, (which I don’t have) a 94/95/97 rod & a 97 piston. So I’m going to see about getting this apart first. Victor

My guess is that if 03 wombat pistons are scarce, then the rods probably are also.

Taber. I WISH I could just pull the cylinder studs. But this is a Model 03 and the top of the cylinder studs are below the top of the cylinder. The only possibility would be to cut the cylinder studs below the cylinder & above the case. And then it would still require cutting the piston rod. Cutting the rod would mean rebuilding the crank as well as buying a new cylinder & full piston assembly. For the cost of those alone, I could likely find a complete Model 03 bottom end......... Victor

Victor you are correct on the studs. I wish you weren't so far away in the state of the bear. I would do it for you. Clarence.

Thanks Clarence. I’m not afraid to do it. I just want to explore every avenue. This isn’t a “needed motor,” it’s a “Would be nice to have motor.”

If I get it working, I can put it in the Model 03 frame and move the 94/95 motor into another frame I have waiting. But that’s only if I can do it reasonably. It’s not an “At Any Cost” proposition! Victor

Nothing was penetrating the rings free. So I drilled holes in the top of the piston. 4 front, 4 rear. Tried to loosen with my punch in the holes. No movement. Then I put the punch in the center. Top of piston started breaking away. Now it looks like this & the damn thing still won’t move! Is there a way to break through the top of the rod? Or should I just cut it from below and be done with it??? Victor

There is a better way. After all the chemicals and tapping, plus the cylinder heating then dry ice on the piston, you can try this. Block the engine under the front mount (a hardwood block works well) so that the exposed piston top is horizontal. Use a steel shaft about 1.5" to 1.75" diameter and 3-4 feet long. Stand it vertically on the piston top. Use a steel fence post driver (typically 15#) to drive the shaft down on the piston. The directed inertia will normally move the piston and frozen cranks. Of course this won't work at TDC or BDC

I found a better way! Bought this from Bruce today! I’ll just remove the piston & get a std cylinder & piston kit from Terry Larson!!! Victor

You gonna freshen up the bottom end? Seals and gaskets? Check the clutch? Etc?

Yup. All new seals & bearings/bushings. Check rod bearing for excess play. New std. piston with new wrist pin, circlips, top end bearing & std cylinder to fit std piston. Rebuild clutch pack and blueprint it. That’s my goal. Also make sure the oil pump works. If it doesn’t, I have several more, at least 3 or 4 of them! I can make sure I have extras to use as spares if needed.

Are there any old Resonator articles on servicing or rebuilding oil pumps???? Victor