97cc crank oil seal failure

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chazdaddy

New Member
#1
#1
I guess probably not, but anyone have experience replacing 97cc crankshaft oil seals?

Finally had a failure on 97cc. Flywheel oil seal let go, funny sound and leaks oil. Found a couple of places to buy OEM seals, but would like to get a little better oil seal. I think the OEM crank seal for Hensim 97cc are just flat black plastic.

This engine is clone Honda GX100 which takes 17x30x6 single lipped seal. OEM Honda and generics are readily available. I'll will take it out and take some measurements to make sure what I have, then order something.

Engine was running pretty awesome for 97cc. Mods were: rejetted carb, drilled out exhaust, filed off compression release on cam, installed black clutch spring. I weight approx 180#'s, with stock 11x70 gearing and tires hits 35mph top speed quick enough, drives around on lawn no problem. I have DB30's one with 97cc and one with 5hp Briggs FH. 97cc not fast like 5hp Briggs FH, but just as fun to ride IMO. :thumbsup:
 
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Camjamsdad

Active Member
#2
#2
Quick question i've been meaning to ask you. What was the jet size you found best to work on a 97cc? And did you do the idle jet as well?
 
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chazdaddy

New Member
#3
#3
Hello Camjamsdad,

These carbs are not all the same. You will get better results if you get a micro drill set, carefully check the jet size with the drills, then drill to the next larger size. Then try it, see how it runs. Also, temperature makes a diff. What runs great on 100 degree day, will not run on 40 degree day and vice versa. Try a stock 6.5 clone idle jet in the 97cc carb, it fits and runs better with it.

Yes, I re-jet both idle and main jets.

New 21pc Mini Micro Drill Bits Set Index 61 80 w Aluminum Hand Drill | eBay
 
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chazdaddy

New Member
#5
#5
Turns out my seal is fine, but is loose in the pocket.

Engine builder at the kart track said to use a punch to dimple the pocket for a tighter fit. I was thinking gasket adhesive would be the trick, but he said better to just use a punch. So, I guess I will dimple the inside of the oil seal pocket.

By the way, the seal looked good, looked like the regular oil seal I am used to seeing.
 
Clayon

Clayon

#6
#6
Whenever I rebuild a motor I use Loctite 518 around the outside of the seal because it stays flexible and is oil and gas resistant.


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chazdaddy

New Member
#7
#7
Hello Clayton, Thanks for suggestion. I researched for something like this, but could never really decide. I may try it.

I cut the head 1cc on 97cc and will test soon, see it makes diff. :shrug:
 
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