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Motorcycle Repair/HD TWIN CAM UPGRADE


Hello Mike,
I have a 1999 FXDWG. Last summer I acquired some parts and installed the following on my otherwise stock 88:

SE 110 ACR heads decked .040" (2.020 dia. intake valves)
.030" Cometic head gaskets
3.885" bore cylinders
SE 10.5 to 1 pistons
SE 251 cams
SE lifters
hydraulic cam chain tensioner & high output oil pump
SE roller rockers with supports
Crane adjustable push rods
SE 51mm super bore carb.
SE 7000 RPM ignition module

My next modification will be:
SE crankcase to receive 4.060" pistons
SE 4.625" stroker crank
SE 4.060" pistons & cylinders

My question is:
Will I be OK on 93 octane gas if I use 10.5 to 1 pistons with the 110 ACR heads decked .040"? Should I go back to a stock HD head gasket or a .030" cometic head gasket?
I am not a racer....just an old man playing here!

On the octane, you really wont know until you start riding and see if there is any pinging. But I would say you would be fine.  I would go with the .030 cometic gaskets. Make sure you check all your clearences while you install everything
Good luck and happy riding

Motorcycle Repair

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Mike Wells


PLEASE READ BEFORE ASKING A QUESTION!!! I CAN ONLY ANSWER QUESTIONS ABOUT HARLEYS !!! I DONT KNOW ANYTHING ABOUT OTHER MODELS!!! IF YOU ASK A QUESTION ABOUT A NON HARLEY BIKE IT WILL GET REJECTED!!!I have a Harley only shop with 30 years experience located in Ohio. We specialize in complete and total repair, restoration, hi-performance, and custom bike building. I can work on Flat Heads to Twin Cams. Please, dont ask how much somthing is going to cost to fix. Labor prices differ all over te country as well as shop to shop!


If its broke on a harley we can repair it. We do complete restoration from the frame up, engine and trans rebuilding, remapping and custom bike building

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