HD EVO CYLINDERS

[powdersparky]

I would like to powdercoat my own evo cylinders and was wondering if I do is an overbore absolutely necessary.The cylinders were previously rebored and have about 6000 miles on them since the rebore.

[powdersparky]

Re: HD EVO CYLINDERS

I have been told in the past that the heat and cool down distorts the bore.The twin cam cylinders I have done in the past were going from 88 to 95 C.I. These will only be going up to 375 f so I was wondering if anyone had done a pair without the rebore.

[tedsfab]

Re: HD EVO CYLINDERS

i did a set of evo cylinder on the bike i built at the beginning of this year , and no re bore . they where fine . actually i would venture to say that the "jugs" get more than 350degs if sitting in traffic . thats just a wild guess but a rebore is not nessacery .

[powdersparky]

Re: HD EVO CYLINDERS

Thanks Ted, I will give it a try on monday and I will have my bore measured out by my friendly neighborhood harley mechanic and I will give feedback next week.

[tedsfab]

Re: HD EVO CYLINDERS

the only time i ever heard of a re bore was on an automotive engine when they get filled for racing applications becuase the "cement" can actually make the cylinders distorted .

like i said it worked fine on the motor we put together so you should be ok . here they are below the engine parts , and the bike

[baz]

Re: HD EVO CYLINDERS

i have done many heads and cylinders for many diffrent shops and they seem to all have a different opinon on this , some shops say there is no problem and some say that they rather do the machining after the powdercoat because of the distortion issue

Re: HD EVO CYLINDERS

You should see the temp. on just the oil alone sitting in traffic at bike week in Daytona. I got rid of the fancy-hi priced digital temp. dipstick after I seen those numbers! Scared the crap out of me!

[baz]

Re: HD EVO CYLINDERS

You should see the temp. on just the oil alone sitting in traffic at bike week in Daytona. I got rid of the fancy-hi priced digital temp. dipstick after I seen those numbers! Scared the crap out of me!

yes but don t forget that an assembled motor is all bolted and torqued together so any expansion of metal should contract to its original shape when it cools down

Re: HD EVO CYLINDERS

How are you guys prepping these engines for coating. Chemical dip to remove HD coatings or just media blasting? Tape the hell out of it for powder?
I am getting ready to do one and want to make sure I don't screw it up.

[powdersparky]

Re: HD EVO CYLINDERS

These are from a 1990 fxr with many miles so there wasn't a whole lot of paint left. lol.
Polished by nature look.The lower part of the fins had next to no paint left but the top part was still nice. I blasted these with no.80 aluminum oxide in my cabinet and in less than 2 hours heads and cylinders were clear of all paint. HD went to powdercoat in the late 90's and these are quite a chore to cleanup.I use aircraft stripper to strip them before blasting.

[powdersparky]

Re: HD EVO CYLINDERS

OK so here is finally my feedback from powdercoating the cylinders. The bore did not distort, but the cylinders will have to be rehoned because their is a little rust on the walls from heating and cooling and their is some dried up crap/powder stuck on the cylinder walls even though they were perfectly clean before shooting and all taped up.

[BeeBob]

Re: HD EVO CYLINDERS

Have you tried getting the cured powder off with MEK and a rag?

[powdersparky]

Re: HD EVO CYLINDERS

No I haven't tried Mek. My mechanic/buddy just thought I should rehone just to make sure everything was perfect before we reassemble the top end.