Ok, so, I probably have quite a few years even if I maintain 12,000+ miles a year before I have to worry about this, but I am curious. What is involved in an engine rebuild? I obviously don’t know the first thing about engines. I see talk on here about installing hotter cams and I have some basic idea of what that accomplishes, but I don’t know much about the innards of a motor to be quite honest.

Can it depend on what fails that dictates what you do to ‘rebuild’ your motor or is there a point where you need to go through the whole thing and replace parts to make it reliable again?

I’m not particularly interested in making my bike faster at the cost of reliability, but if it came time to rebuild anyway I can see bumping it up with a big bore kit and maybe some mild cams or whatever if it didn’t sacrifice too much reliability. Is a big bore kit just going to add tremendous cost to a rebuild?

I apologize for being so ignorant on the motor stuff! I’m not a bad shade tree mechanic, but I have just never gotten inside a motor of any kind before and it’s still a bit of a mystery to me what all is going on in there.

Thanks!

 

Truthfully? For the most part, the engines that we have (TC 96s) are really quite reliable. It is really similar to a car engine, in that it will just wear out. Things actually 'breaking' inside is rare anymore.

Wear out would be the oil usage would finally be too much to bear! You know that you have pistons moving up and down inside of the cylinders. Attached to those pistons are 'rings'. These rings are like metal windshield wipers and 'wipe' the cylinders each time the piston moves. Eventually, the rings get old and wore out and oil starts escaping past the rings and get mixed into the gasoline fuel charge, and burnt up.

Also, you know that an engine has 'valves' right? There is the intake valve and the exhaust valve. The intake allows the gasoline fuel mixture into the combustion chamber, and the exhoust valve allows the spent charge to escape the chamber. These valves go up and down in your head (beside the spark plug and inside of your rocker boxes). The valves are made of very very tough metal to be alble to take the heat of combustion. The valves dont 'ride' in the aluminum of the head. They ride in a 'valve guide' a hardened steel tube inside of the head. The guides can eventually 'wear out' and allow oil to sneak thru besides the valve and the guide and get burnt up. And... on top of the valve guide, is a valve 'seal'. THe seal is basically a rubber/plastic small piece that sits on top of the guide to help the guide keep the oil inside your rocker box, and not leak down into the guide.

Your engine will 'wear out' when the rings, guides, and valve seals get old and your engine burns too much oil. This will be a LONG time from now for you. 100-150k is when you seriously will need to think about this.

As opposed to car engines, in your bike, you do NOT have to worry about rod and main bearings. In a car, the bearings are flat surfaces that the crank and rod has to ride on WITH A SKIN OF OIL TO SUPPORT THEM. In your bike... you have actual roller and needle bearings to take care of this.... built for longevity!

Crap happens, and things break, for sure. MY crankshaft actually 'bent' and I had to replace it. But, stuff like that is rare.

Kept 100% stock.... your bike will go a very long time! Keep that stock air cleaner and it will last forever.

Change the air cleaner, and start on the road to 'more power' and all bets are off. One has to PAY ATTENTION after this, or longevity can be affected. Simply changing the air cleaner allows your bike to suck more air into it. That means that now the 'fuel mixture' has been altered and you have to make it right again or it WILL break.

One can make gobs more power from a Harley, no doubt..... but to do so, and have any semblance of the original bikes longevity, takes a LOT of thought and MONEY. There are NO short cuts to reliable power. Remember That I Told You This!!! Most guys on here will try to tell you to do 'this or that' but there are but a handful that will tell you the real deal! Every single thing you may do, in a quest for power, will end up costing one TWICE as much, or more(!) than first thought.

 

Thanks for the rebuild 101! I can’t believe I’m 38 years old and I don’t know what happens with a motor rebuild. LOL I would have guessed that the cylinder walls would wear as well and need to be bored out too. Requiring bigger pistons in my mind – thus why I questioned if perhaps just buying a big bore kit might be in order at that point.

They seem fairly reasonably priced: http://www.sscycle.com/modules/feature/bigbore/

That’s not with the heads or whatever though with the valves and whatnot…….then I guess you’ll need a Power Commander or something to tune it all (I’ve just got a remap). Would a Power Commander compensate for a bigger bore motor?

I’m happy with my lowly 65hp and 79ftlb ‘stage 1’ 96” motor (a little disappointed in my numbers, but not devastated). It’s my understanding that hotter cams are just that – hotter? Reducing reliability?

Just curious what the future has in store for me if I continue to pile on the miles at the rate that I am going at it. Good to know that it will be a pretty long time before I will have to deal with it.