Engine Rebuild - What do I need?

[TheNose]

I'm thinking about rebuilding my engine this winter. I would like to know what parts I should replace so I can order them and have them ready to install. Or do I need to take the engine apart and after inspecting parts, then order.

I'll need : Gasket set, piston rings, cam chain and what else?????

Terry

[SqDancerLynn1]

The big problem is that you don't know what you need until you take it appart Even rings, you need to measure to see if it needs rebore

[TheNose]

I thought that to be true, but reallly didn't know.

Terry

[biker66]

First of all, WHY do you want to rebuild it ? Smoke, noise, missed gears ?
If the problem isn't in the gearbox, crank or cam chain chances are you won't have to split the cases.
If you tear it down, the list of things to check for wear will be long...
cams, tappets, valves, guides, seals, pistons, rings, bores, crank, bearings, clutch baskets, oil pump, gears/dogs, forks etc.
But hey, it's fun, and afterwards you'll know your engine is in shape 8)

[Dink]

Regardless of anything else be certain to replace the gearbox bearings. If you unbolt the head , be certain to replace the o-rings at the base of the cylinders, and do the valve stem seals regardless, I tend to think replace the camchain whilst it is apart, whether it needs it or not.
Dink

[Hap Call]

If you do a rebuild you will definately need the following:

Rebuild gasket kit (make sure it includes the valve guide seals and head gasket)

Motor seals for the crank and transmission.

I agree with Dink, get the tranny bearings

Cam chain

Case sealer such as YamaBond 4 or Gaskacinch.

Assembly lube

After you disassemble the motor you may need to buy rings and possibly even pistons and over bore the block. Inspect the crank closely for any bearing problems (very unlikely but better safe than sorry) and inspect you transmission gears (both the teeth and dogs) for excessive wear or damage.

Buy a 6 pack of Shiner Bock and I may show up on your door step to help...

Hap

Hap

[TheNose]

First of all, WHY do you want to rebuild it ? Smoke, noise, missed gears ?
If the problem isn't in the gearbox, crank or cam chain chances are you won't have to split the cases.
If you tear it down, the list of things to check for wear will be long...
cams, tappets, valves, guides, seals, pistons, rings, bores, crank, bearings, clutch baskets, oil pump, gears/dogs, forks etc.
But hey, it's fun, and afterwards you'll know your engine is in shape 8)

The compression is low on some cylinders. I don't know if that warrants a rebuild or not. Maybe I'm a glutton for punishment, but I though it would be an interesting winter project. Should I re-think this?

Terry

[Anonymous]

First, make sure you are checking compression properly. Warm bike and hold throttle open all the way. Otherwise, your readings will be low. There is a minimum compression listed in your manual. Just as important is to ensure that the cylinders have similar readings and not vary more than about 10 lbs/in. The next thing, if you really do have low compression is to buy a T cylinder bore gauge and a digital caliper. You need to measure your cylinder bore (there is a procedure in your manual) and your pistons. If the clearance between pistons and bore is too great, replacing the rings won't help as they won't seal. You will need the first oversize pistons, the appropriate rings, wrist pins and circlips. If your clearance is within spec, you need to replace the rings and circlips. While you have your head off, get a spring compressor and remove your valves. Clean and lap them then insert them into the head. The valve stem length will be a good indicator if you need seats or a "valve job" which is where a machinist cuts the seats using three special bits to resurface them. If any of the valves are too cruddy or burnt (especially the exhaust), use new ones. Install new valve stem oil seals as well and measure the springs for their compression. A shop manual explains how this is done. You will obviously need a top end gasket kit which usually contains the valve stem oil seals. I have a friend named Jeff who owns Z1enterprises.com and he has great prices on rings. He can get them for your bike as well as the gasket kit. Tell him wiredgeorge sent you and ask for his best price ;-) You will also need sealant. Hondabond HT is the best for sealing cases and cam plugs and stuff and is likely made by Threebond and is the same stuff as their Threebond 1203. It won't leak.