New Combat Wombat Engine Project

[dcooke007]

Rebuilding and refinishing another engine for one of our forum members.
Look at that. Clutch lever pin sticking about half way out. Great timing to pull this motor down. A few more minutes of running and this hardened pin could have gone through the gears and caused a lot of damage.

No safety wire on the clutch screws and pinion gear thrust washer scored. Fortunately the pinion gear will be ok with a little work.

Crank looks a little rough but only needs a new rod kit and some tender loving care.

Carb has the typical grunge, worn float valve and stuck pilot jet. I don't think I have seen a float pin worn like that though.

Danny Cooke

[Bullfrog]

Interesting! I've seen several float pins worn like that . . . but have never had to use an extractor bit to remove a pilot jet.
Ed

[dcooke007]

Interesting! I've seen several float pins worn like that . . . but have never had to use an extractor bit to remove a pilot jet.
Ed

Prior owner buggered up the pilot jet slot. Nothing left that I could get any turning force on. There was some pucker factor going on drilling and removing the pilot jet. Worked out ok though.

Danny Cooke

[dcooke007]

Looking a little better now. Drilled clutch cover for better oil flow.

Danny Cooke

[thrownchain]

If you don't mind me asking, how did you get the crank to look so good?

[dcooke007]

If you don't mind me asking, how did you get the crank to look so good?

In this case it really wasn't that difficult. All the gunk on the crank was soft and I would guess it is unburnt two stroke oil reside. A good soak in some old school carb cleaner removed the bulk of it. I soak a lot of engine parts in this solution but care has to be exercised....rubber parts and seals will be destroyed. After soaking, crank was dis-assembled, crank shafts polished with some gray scotch bright and new rod kit. Cranks that need more attention get soaked in Evaporust and sometimes glass beaded. All this assuming a complete crank rebuild is being performed. These processes are not for cranks that are going to be reused with out rebuilding.

I originally purchased the carb cleaner from NAPA Auto Parts and am keeping my fingers crossed that it is still available. Cost about $80 dollars for a five gallon bucket some time ago. Chemical resistant gloves are required with this product. The little bucket of Beryman's carb cleaner you find in Walmart and some of the auto parts store is no where near as effective.

Danny Cooke

[thrownchain]

I know the issue, the carb cleaner I used to get, when you dropped a carb in it it bubbled like Alka Seltzer, good stuff. The newer stuff works, but no where near as aggressive. People buy it that don't have a clue and then complain or sue when they get hurt because they had no clue, so the stuff gets watered down. Nice work by the way.

[dcooke007]

A little delay making progress on this project but getting there.

Carb cleaned up well with a little pitting inside but only cosmetic in nature. Exterior turned out very nice.

Remember the worn float pin? Not only was the pin worn on the ends but the interior of the carb float pin holes were worn slightly over size also. Found a used drill bit that was a little over size. Cut drill bit shank to length and fit to carb. Staked pin to secure and prevent float pin rotation.

Thought I would also share a couple of tips. Removing the grunge build up in these old carbs presents a challenge. One would think soaking in carb cleaner, pressured air and the use of spray carb cleaner would get the job done....but not always. The Fuzzy Sticks are used as pictured to get access to difficult to clean carb passages. They really do get into some very tight areas. Double them up for larger passages. There is a very small diameter wire core so some care must be exercised...but perfectly safe when used with care. Spray the passages with carb cleaner and swab.

And last. A set of pin gages being used to compare two # 210 main jets....one new and known to be unmolested... the other used. Jet flow rate is not solely determined by bore diameter but are usually very close. Jets of the same size are usually within .001 inch bore diameter of each other and often the same size. If it has been drilled you can easily tell by comparing a new to old this way. Pin gages are made in .001 inch increments and plus or minus tolerances of .0002 inch. This set goes from .011 to .060 inch.
Danny Cooke

[viclioce]

It's always so interesting and informative to follow your posts, Danny! I envy the person getting this motor back from you! ; D Victor

[dcooke007]

Almost ready to ship back to owner. Still have to bolt into rolling frame, heat cycle engine and make basic adjustments.
Danny Cooke

[hodakamax]

Hey Danny, I always enjoy your posts and fixit ideas. You do good work! keep it up and thanks for posting.

Max

[Bill2001]

Interesting topic, as usual.

"Drilled clutch cover for better oil flow"
Any specs? Look like 8mm holes about halfway between the outside and inside edges of the cover.

[dcooke007]

Thanks Max.

Bill,
The late production 934008 clutch covers are factory drilled and I just use it as a pattern for drilling the early production covers. I have a drill set with fraction, letter and number size drills. Select the closest size drill bit from the letter or fraction size as is appropriate to fit the existing holes in the late production cover. Simply screw the late production cover on top as a guide, drill and debur.
Danny Cooke

[Bill2001]

Ah, that should be easy enough-- I see what you've done. The important thing is to keep everything symmetrical for balance.