94 Wombat Rebuild Tips

[Simonkav]

Hey all you pros out there,
I've finally got some time to commence the actual build of the '72 wombat that I'm rebuilding and looking for any heads up advice or tips. Specifically, I'm most curious about crank seals. I didn't take a good picture of how they were seated when I split the cases - flush, below, above, etc. I've seen mention of the mag side needing room. Anything tricky about bearings? Anything else that people miss or screw up regularly?

Quick background, I recently acquired the bike, know very little of it's history, but know it sat for a long while. Pressure test revealed air coming through the gearbox breather indicating either a bad clutch side seal or the case halves leaking. Tear down is done, everything is all cleaned up, new bearings, seals, gaskets, o-rings are in hand. Even made the makeshift stand to hold the right side case in my bench vise. I've been through the process of piecing together the counter-shaft/gears, kickshaft assembly, crank and cases and all seems pretty straightforward.

So, next steps:

Old bearings out, new in
New seals in
New o-rings
Assemble in right side case
Liquid gasket
Case halves together

What do I need to know?!!

PS - I'm not doing the bushes, they look great. Refreshing them seemed tricky. If there are simple ways to do this, i'd be happy to hear about them.

Thanks everyone,
Simon

[TheBevman]

Hi Simon,
I have the same '72 Wombat (M94) that I rebuilt last year and you're right, its really straight forward. Since you have it apart I'd recommend that you upgrade the kick roller retainer. Ensure you have the LH crank shaft washer in there before you seal it up and make sure that the LH crank seal doesn't cover the lube/ oil feed hole in the case mouth. Might want to look at the control shaft and the ball receiver too and replace the seal in counter shaft. Other than that just take your time.

Let us know if you encounter anything, there's a great wealth of knowledge here.

Bev

[Simonkav]

Thanks Bev
got the washer/spacers all set according to the shop manual
I'll take a closer look at the LH crank seal and the oil feed hole, I'm assuming this is why I've heard about needing some clearance on that side but haven't really inspected it.
Have the bearings and seals for crank, main and counter shaft so those will all be refreshed.
I don't have have an upgrade for the kickroller retainer. I'd rather not wait for one - I'll look for wear. Is that a common issue? Rather not be kicking myself later - ha, pun intended!

Nice bike list, I've got a '68 TR6R that I've been through just about top to bottom now. This hodaka has been a joy to work on comparatively. Can't wait to get it sorted!

[Bullfrog]

Kick roller retainers

I'd recommend waiting on the improved kick roller retainer, the original stamped item could have easily been "worn out"/flared the day the engine was originally assembled. Flared "legs" of the kick roller retainer will result in kick start slipping. Also be sure to check (with a magnifier) for cracks in the corners of the cut-outs in the kick roller retainer, if there are cracks there now - failure is imminent.

Mag side seal insertion depth

[viclioce]

It’s a good idea to order that upgraded kick shaft retainer. The OEMs were very thin and prone to cracking. Check yours very closely for cracks, swelling or other damage. No sense in putting it all back together, only to have the retainer fail just a ways down the road. Then you’ll be splitting the cases again, just to do that work, and need new gaskets forceverything as well. Why not do it now while you have it open? Here’s a link! Victor

http://hodaka-parts.com/item.asp?PID=1909

[MTrat]

Agreed, the OEM kick shaft retainers are inferior but kicking method is often the culprit which causes them to fail. Easing the engine up to near TDC and taking up slack in the kick starter before a brisk down stroke to start engine is easier on the system than the frequently seen vigorous repeated cranking tactic.

[Joe Ormonde]

It`s just good insurance to install the Heavy Duty kick Roller Retainer. Terry at HPI sells them for $41.00. Not only are they brutally strong, but it keeps the 5 needles spinning true: especially on the earlier models with the tiny needles. I rebuilt my Super Rat with all stock parts with exception of the kick roller retainer and Poppy Piston ring. I even stuck with the fiber clutch discs. Why? The fiber discs will shear before the gears fail. I sheared the clutch discs twice, upgraded to a Barnettes clutch kit then broke gears. In short, the factory clutch is weaker than the trans. It`s easier to fix the clutch than the transmission. If you race that`s a different story: By all means beef up the clutch too. The Model 94 is a GREAT Engine! Joe Ormonde.

[Simonkav]

I'll order the kick retainer

1) Preferred liquid gasket for the cases? I've used ThreeBond before on other motors, assume it works well here?
2) Any gasket sealer on gaskets? cylinder base gasket?
3) Head gasket isn't brass, so no annealing necessary. Any other treatment? Copper coat? Sealer?

Thanks everyone!

-Simon

[Dale]

1) Preferred liquid gasket for the cases? I've used ThreeBond before on other motors, assume it works well here?
2) Any gasket sealer on gaskets? cylinder base gasket?
3) Head gasket isn't brass, so no annealing necessary. Any other treatment? Copper coat? Sealer?

Thanks everyone!

-Simon

Opinions vary. Here is what I use.
Case halves - Yamabond. Use very very sparingly. I apply mine with the end of a small craft stick.
Head gasket - Apply dry. Do not apply any treatments. I always use new.
Base gasket - Coat both sides with grease and wipe off excess.
Clutch cover gasket - Gasgacinch one side, grease the other. Apply Gasgacinch to one side and install the cover with it wet. Let it dry for 10 minutes then remove the cover and apply a coating of grease to the dry side and install. Now your gasket is glued to one surface (your choice which surface) and the other surface will release when you remove the cover. You can now remove the cover multiple times over years of use and your gasket will still be in perfect condition.

[Bullfrog]

What Dale said! (except I'm partial to the anaerobic automotive sealants - the sealant is EASY to clean up on the exterior AND also easy to clean off when the next rebuild comes around)
Ed

[Simonkav]

I got the kick retainer today! Looks like I'm going to spend some of my memorial day weekend in the garage. Stoked.

Do you guys have any tips for pressing in seals? Just thumbs? If they are tough to go in, will a drift do damage? Any lube before seating them?

Bullfrog shared the service bulletin for the LH seal, thanks for that. I would have probably just tried to press the seal flush. What about the other two. Do they need to flush up to the case? Will they be flush to the bearing of will there be room between them?

I did the bearings last weekend while I was waiting on the kick roller retainer. They are all in, seated nice, rolling smooth, snap-rings in. Before I do the seals, I figured I'd ask.

Thanks again!

-Simon

[Bullfrog]

No drifts. Forces are too concentrated and liable to cause deformation of the seal body. I often use a large socket, selected to pretty closely match the OD of the seal. Tap carefully and keep the seal "square" to the bore it fits into. Yes, I oil the seal before inserting in the cases, dry rubber being driven into a dry bore just doesn't sit right with me. Mag side seal drive depth per the Service Bulletin - all the others can go in to the "flush" position.

Ed

[Simonkav]

Hey guys,
Just wanted to thank everyone for their help. This rebuild has gone 100 times better with your help. I got the motor back together over the holiday weekend. Everything went very smoothly. I just got back in there today and everything holding great. I ran a pressure test and holding pressure like a champ, took at least a few minutes to come down from 6psi toward 5. Night and day from before. Put in new condenser and points. Gapped the points best I could, I'm really not that experience with them. Connected the wiring and I've got spark! I'll strobe time it when it's running. I tried the continuity method but I couldn't ever tell a difference in tone. Anyway, I don't want to curse myself, but feeling close. Carb is new so should be sorted. I can fine tune jetting later but it's setup with the stock 94a jetting/slide....just dying to get her running.

I'll post pics once I'm all done.

One question: the shop manual says 6mm (.25 in) of chain slack with no rider weight. Does that mean with with the bike on a center stand or with sag from being sat on the ground (not that it has much weight to it anyway). In general, seems very tight....tight chains make me nervous.

-Simon

[Bullfrog]

That is with shocks fully extended (since the stock shocks provided virtually no "sag" with no rider aboard). You can provide yourself with some mental comfort on the seemingly "tight" chain tension setting by holding a yardstick up beside the machine - and you will find that with shocks extended, the center of the countershaft, the center of the swingarm pivot and the rear axle center are in nearly perfect alignment. This is the "maximum chain tightness" position . . . all other positions of the swing arm (as the shocks compress) result in more chain freeplay (looser chain). So the spec of 6mm freeplay with shocks extended is basically saying . . . this is the tightest the chain is going to get, and we want just a bit of freeplay at the tightest point. ('Cuz we'll have toooooo much freeplay at the loosest point if we don't set up at the reasonable limit of "snug" at the tightest point).
Ed

[locknut]

I'm in the middle of my engine rebuild as well (Super Combat) . I did not mark my primary gear when I removed it and now don't know which way it goes back one side is dished out slighty more than the other . Any help would be appreciated.

Thanks

Locknut

[racerclam]

If you look closely at the center hub you will probably see a shadow marking where the splines were and that will go toward the shaft. Im thinking that its the same either way but you can verify by how it lines up with the small primary gear

Rich

[locknut]

I'll try that ,
Thanks

[Simonkav]

One odd side effect of my rebuild - I checked the free play on the clutch cover lever and it seems to have increased post rebuild. I can obviously add more spacers, but is there anything else i should be worried about related to this changing? Seems odd.

thanks,
Simon

[TheBevman]

If you didn't rebuild your clutch then I would look to ensure you installed the inner clutch thrust washer.

Bev

[Bullfrog]

Actually, that is exactly what one should expect. Putting in new friction disks increases the "thickness" of the clutch pack . . . but that effectively "moves" the overall clutch body toward the engine center line (and increases lever freeplay if the same spacers are used). As the friction disks wear, you'll see lever free play decrease - that's why some gung-ho, clutch fannin' racers purposely set up lever free play really loose (so disk wear in a moto won't decrease lever free play to zero with the resultant clutch slippage). Sounds to me like all is well.
Ed