Bent fins

GoldenMotor.com

rocksalt27

Member
Oct 24, 2013
121
15
18
Portland, ME
Seems like the cylinder fins are pretty soft and bend easy. What do all y'all think about hardening the cylinder? Maybe with a bake and quench?
 

2door

Moderator
Staff member
Sep 15, 2008
16,302
175
63
Littleton, Colorado
No, no, no. Don't do that. You stand a chance of warping something. Also you don't want to damage the plating on the cylinder walls. Don't worry about the fins. If yours are bent they can be straightened with needle nose pliers and lots of care. Work slow and don't over do it.

Are you bending the fins or did the engine come with them that way? Bent fins from the factory/shipping isn't uncommon.

Tom
 

Venice Motor Bikes

Custom Builder / Dealer/Los Angeles
Mar 20, 2008
7,272
1,810
113
Los Angeles, CA.
YES... The fins break off very easy!

One trick is to heat the fins as hot as you can with a heat gun & then slowly bend them back with needle nose pliers as Tom mentioned above. ;)
 

maniac57

Old, Fat, and still faster than you
Oct 8, 2011
4,484
22
0
memphis Tn
While heat treating a chinagirl cylinder is theoretically possible, you would have to know the exact composition of the metal used in casting in order to gain any benefit, and it's not something you ca do with a used oven out back. It takes a long time at the proper temps and cooling cycles.
This assumes the Chinese factories even use alloy that CAN be heat treated.
You would also likely have to bore and replate the cylinder afterwards due to heat distortion.
 

Going2Hell

Member
Nov 22, 2013
137
1
16
Victor, Colorado
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Once again, NO NO NO... Aluminum is not something you want to cool abruptly and un-evenly.

The odds of the company in China knowing the composition of the metal are also pretty slim. Even if they did know, they probably wouldn't tell you; not a trade secret or anyting but they might not want the level of impurities known. You're pretty much boned if you just want to strengthen the fins, it's okay if they're bent. If you want to straighten them heat them individually with a torch and lightly bend them back with needle-nose. The best temp to bend Aluminum of unknown composition is 400-500 degrees F.