visit the link below.... it's what an OEM supplier of piston rings (Hastings mfg.) has to say.

http://www.hastingsmfg.com/ServiceTi..._procedure.htm

 

This causes lots of confusion. Setting the piston rings calls for something a little different from the rest of the engine, but you can't do two contradictory things at the same time.

Cylinder bores work harden and develop a glaze, after which normal running has no further effect. On two strokes in particular, it's possible to break this glaze after fitting new rings by thrashing the engine. After that, normal bedding in can take place. The ring manufacturer seems to be suggesting a version of this. A better idea is to do the job properly and hone the bore. Honing removes the glaze. Plated bores may need re-plating. Again his suggestion will do the job, but not perfectly. His suggested speeds are inappropriate for a high revving motorcycle engine though.

The bore mut be smoothed down before the work hardening takes place, but still progressively to get the best possible seal. Good enough for a truck or car isn't good enough for the biker who wants the best from his bike. Unfortunately the plain bottom end bearings like smoothing over a long time, and friction in these bearings will cause more power loss than a good but not perfect ring seal. On a new engine, as opposed to a top end rebuild, you must balance both sets of requirements, and in terms of minimising internal friction and maximising oil pressure and longivity the bottom end probably takes priority over the ring/bore interface.

That's why progessively loading and working the motor over a few hundred miles gives the best overall results for a complete new engine.

Rob

 

My bike also needs the choke to start but I don't really feel like waiting for it, so what is the best way to do it while going into motion? Do I start it in 1st gear, clutch in choke open, or nutural choke open shift into 1st?

 

I did this, easy riding and low rpms for the first 250-300 miles or so, then I started to open it up and rev it a little higher as time progressed as per Hastings recommendations.

Strange thing is, to break in a cam (this is the 'standard' way I was taught, as in if we were to break in a Chevy 350 or something) is to run it between 2000 and 3000 rpm for 30 minutes, varying the revs, no load.

In an ideal condition, I'd break in the cam first, then drive easily with variable rpms for the bearings until ~300 miles then increase revs and load to seat the rings. I feel this is a good compromise.

get a fuel injected bike, or be patient with it and let the engine warm for 30 seconds to a couple minutes (air temperature dependent) then ride conservatively until everything is at operating temperature to prevent piston slap.

 

Cam lobes and the tappet or shim are very hard and don't really break in. The journals do, and I can see why you might suggest running off load, but in fact the load on the cam journals is pretty much constant whatever the load on the engine. Cams are loaded so lightly that they usually run direct in the alloy head with no bearing insert, and as long as the engine isn't red lined too early I don't think there's any real issue with the camshaft. It's only turning at half engine revs anyway.

Rob

 

Its better to use your brakes more then engine braking right? How do you do that? Just pull the clutch in and brake then downshift release clutch repeat?

 

It isn't that big of a difference...look at it this way.

If something breaks while you are already babying the thing during break-in, it is great because you caught it early and can get it fixed. If engine breaking, going a little over the suggested rpms, etc., tears up the bike it is a lemon. I would not worry so much about finding ways to baby the bike, focus on riding well and having fun.

 

"Its better to use your brakes more then engine braking right? How do you do that? Just pull the clutch in and brake then downshift release clutch repeat?"


Almost. Pull in the clutch and pull on the brakes. As you slow, downshift without releasing the clutch, so that if you need to accelerate again you're in the correct gear for the speed you're at and you can just release the clutch and open the throttle. Hold the clutch in until you're down to the speed you want to be at.

This isn't a break-in issue. It's just good riding technique for optimum control. It also saves wear on the chain and sprockets - brake pads are cheaper and easier to replace.

Engine braking should still be used for gentle slowing down where you don't need to downshift, or where you only need to shift down one gear. Use it in conjunction with the brakes, not instead of the brakes. It's not a hard and fast rule, but the technique above should always be used when slowing to a halt, or to a very slow speed for an intersection.

Rob