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Workshop => Engine and Bottom End => Topic started by: Anthony0327 on November 25, 2014, 05:54:59 PM

Title: Counterbalance and primary drive gears
Post by: Anthony0327 on November 25, 2014, 05:54:59 PM

I had purchased a counterbalance that has the thicker gear on it than the 88-89. My question is that does it matter what primary drive gears I use, either the thinner 88-89 gears or do I need the thicker ones or does it even matter? Reason I ask Is I didn't even know there was a difference until recently and when I put my bottom end together I don't want to mess anything up. I was told from a builder earlier on that everything was interchange able from on year to the next.  The gears I have are the thinner style. Please advise. Thanks

Title: Counterbalance and primary drive gears
Post by: Pumashine on November 25, 2014, 06:01:53 PM

The thinner ones clear the basket easier. The new cranks are designed for the thinner ones. Just make sure it is secured by the bolt and washer without slipping.

Title: Counterbalance and primary drive gears
Post by: Anthony0327 on November 25, 2014, 06:07:09 PM

How will I know if I have the right crank? Is there a way to tell on the crank itself what year it is? I purchased one that was rebuilt by duncan racing. I know iIt's a long Rod but I'm not sure the year the crank came from.

Title: Counterbalance and primary drive gears
Post by: Pumashine on November 25, 2014, 06:52:14 PM

Like your builder says either one should work. I was just saying if you put it on there and the crank still sticks out after the gear is put on you would have to use the thicker one.

Title: Counterbalance and primary drive gears
Post by: Anthony0327 on November 25, 2014, 07:11:55 PM

Ok. Thanks for the info.

Title: Counterbalance and primary drive gears
Post by: Anthony0327 on November 25, 2014, 11:16:52 PM

Thanks for the info puma. I just looked at my rebuilt crank and compared it with an 87 I have and the shaft is definitely shorter. Would never have noticed if I wasn't told. Thanks again. The rebuilt crank that has the smaller output shaft on the clutch side also has a G stamped onto the tins on the flywheel side in line with the pin for the connecting rod.

Title: Re: Counterbalance and primary drive gears
Post by: croat1 on November 10, 2021, 10:22:10 AM

Bumping up this old thread with pictures.

Gear hits the basket.  Gear will need to be chamfered.

Title: Re: Counterbalance and primary drive gears
Post by: croat1 on November 10, 2021, 10:23:38 AM

Chamfered gear.

Title: Re: Counterbalance and primary drive gears
Post by: croat1 on November 10, 2021, 10:57:15 AM

Also, this is not right.  You don’t want this situation.  Gear won’t be held down.

Joe

Title: Re: Counterbalance and primary drive gears
Post by: Langbolt on November 12, 2021, 08:06:22 AM

How did you fix this situation Joe ?

The previous pic shows the gear farther than the end of the crank.....and this pic shows is inward ?

Was the Crankshaft collar too thin ?

Let us curious minds know :)

Thanks

Title: Re: Counterbalance and primary drive gears
Post by: croat1 on November 15, 2021, 06:28:36 PM

Quote from: Langbolt on November 12, 2021, 08:06:22 AM

How did you fix this situation Joe ?

The previous pic shows the gear farther than the end of the crank.....and this pic shows is inward ?

Was the Crankshaft collar too thin ?

Let us curious minds know :)

Thanks

John, crankshaft end lengths are different.  Also, gear thickness changed.  To “fix” the issue in the last picture a washer can be used (made).

Joe

Title: Re: Counterbalance and primary drive gears
Post by: atvmxr on November 16, 2021, 01:35:43 PM

good info and pics!

Title: Re: Counterbalance and primary drive gears
Post by: croat1 on November 19, 2021, 01:22:53 PM

One last pic for clarity…not a good situation here.