Topic: After a rebuild how long until rings seat?

[ncstatecamp]

I have a 750k2 that I did a rebuild on earlier this year (more then 500 miles less 1000) and im only getting 90 across the board. I kept stock piston size, new rings, lapped valves, new valve seals (*edit not guides), new gaskets all around, new plugs, honed cylinders. Everything was in spec (except rings) when I started, I rebuilt due to puck under valve train leaking and low compress/hard start. I was told on here my compression would build a bit as the rings seated but 90's what I started with and it hasnt changed....

My break in has been least amount of idle possible, least amount of staying in the same rpm range (varying as much as possible), the first 20 miles were pretty much me riding the engine up to 5k and slowing back down. Changed the oil at 100 miles, and again 500-600. First time had the typical flakes of break in, second time oil wasnt even that dark feel like I could have held off. Starts are hardish (but old bike). Burning a bit of oil (rings not seated?).

Timing is spot on, best ive ever seen it.

Thoughts?

[MRieck]

I'd do a leakdown test to see where you are losing pressure. After installing new guides you really should do a valve job as the valve centers differently to the valve seat. The leakdown will tell if air is moving past the valves, the rings or both.

[ncstatecamp]

I'd do a leakdown test to see where you are losing pressure. After installing new guides you really should do a valve job as the valve centers differently to the valve seat. The leakdown will tell if air is moving past the valves, the rings or both.

Not to sound like an idiot but what do you mean exactly by valve job? Cutting the seats, or lapping or? And I meant seals not guide.

[AJK]

Just some thoughts.

A lot of it should have settled by now. Most of the wearing in would have already happened, but its a continual process that will take more riding. The type of oil you run it in with should be a mineral oil without friction modifiers, otherwise it won't run in properly.

Is your compression gauge one for a car (with a long or fat hose) that won't read correct for a bike? It could be that your compression readings are actaully ok, but your gauge is not reading accurate for the bike, so bear that in mind. There are threads on the forum about this.

The flake in the oil, then no flake on the 2nd change is normal and expected, but you shouldn't be consuming much oil. You only mentioned a 'bit' so if its truly just a bit, then everything is normal & the lack of oil consumption will continue to improve as things continue to wear in.

I've done the same as you, now up to 3000kms. I have no oil consumption at all. I just run 20W50 mineral, but i broke it in on 10W40 & even then it didn't use much.
 I'd say give it another 1000kms and re-evaluate what its drinking oil wise. If possible, get a mate to ride behind you and see if he can see much smoke coming out of your pipes when you ride (coast) normally. There shouldn't be much, and after another 1000kms, shouldn't be anything at all.

Does the bike feel good on compression when you kick it over by foot? When giving the bike some acceleration, does it feel like it has a good bite when you give it some? A rebuilt motor that has just worn in should feel like it wants to go if everything is reasonably tuned.

Re the valve job, you have new guides, so that is good. Obviously you must have installed new valve stem seals as well, because if not, then that is also a source of oil consumption. The valves should be lapped in at a minimum with valve lapping paste, but if the valve face and seat are not reasonably married to each other due to new valves, then the valve job mrieck mentioned is to cut the valve seat at various angles to marry to the new valve. This is done first, then followed up with a valve lapping job.

I'd say keep riding it & it might continue to improve (& just check your compression gauge for bike suitability). You may have nothing to worry about.

PS: Its good that you didn't let it idle much.

[PeWe]

http://www.mototuneusa.com/break_in_secrets.htm

[ncstatecamp]

Just some thoughts.

A lot of it should have settled by now. Most of the wearing in would have already happened, but its a continual process that will take more riding. The type of oil you run it in with should be a mineral oil without friction modifiers, otherwise it won't run in properly.

Is your compression gauge one for a car (with a long or fat hose) that won't read correct for a bike? It could be that your compression readings are actaully ok, but your gauge is not reading accurate for the bike, so bear that in mind. There are threads on the forum about this.

The flake in the oil, then no flake on the 2nd change is normal and expected, but you shouldn't be consuming much oil. You only mentioned a 'bit' so if its truly just a bit, then everything is normal & the lack of oil consumption will continue to improve as things continue to wear in.

I've done the same as you, now up to 3000kms. I have no oil consumption at all. I just run 20W50 mineral, but i broke it in on 10W40 & even then it didn't use much.
 I'd say give it another 1000kms and re-evaluate what its drinking oil wise. If possible, get a mate to ride behind you and see if he can see much smoke coming out of your pipes when you ride (coast) normally. There shouldn't be much, and after another 1000kms, shouldn't be anything at all.

Does the bike feel good on compression when you kick it over by foot? When giving the bike some acceleration, does it feel like it has a good bite when you give it some? A rebuilt motor that has just worn in should feel like it wants to go if everything is reasonably tuned.

Re the valve job, you have new guides, so that is good. Obviously you must have installed new valve stem seals as well, because if not, then that is also a source of oil consumption. The valves should be lapped in at a minimum with valve lapping paste, but if the valve face and seat are not reasonably married to each other due to new valves, then the valve job mrieck mentioned is to cut the valve seat at various angles to marry to the new valve. This is done first, then followed up with a valve lapping job.

I'd say keep riding it & it might continue to improve (& just check your compression gauge for bike suitability). You may have nothing to worry about.

PS: Its good that you didn't let it idle much.

The compression gauge is I believe for a car but when I tested another engine (cb750) ive gotten a 150 (what these bikes got from factory) reading on a cylinder so I know it tests just fine for my bike. Plus its the only damn thing I could find with an adapter. Ive seen the thread youre talking about, but psi is psi, atleast in my mind.

Im running Valvoline motorcycle oil 10-40 at the moment, when/why would a move to 20-50w be necessary?

Kicking over it does feel ok on compression, but cold it never starts on the first hit of the starter, i gotta play around with throttle/choke/kicking over to clear out fumes etc til it decides it wants to catch... Warm she starts up like a champ.

I mistyped in my first, not new guides, just new seals (ill be editing that now), the guides were fine, no wobble what so ever, I cleaned and lapped the old valves and used those. I did not cut a new seat.

[AJK]

Just some thoughts.

A lot of it should have settled by now. Most of the wearing in would have already happened, but its a continual process that will take more riding. The type of oil you run it in with should be a mineral oil without friction modifiers, otherwise it won't run in properly.

Is your compression gauge one for a car (with a long or fat hose) that won't read correct for a bike? It could be that your compression readings are actaully ok, but your gauge is not reading accurate for the bike, so bear that in mind. There are threads on the forum about this.

The flake in the oil, then no flake on the 2nd change is normal and expected, but you shouldn't be consuming much oil. You only mentioned a 'bit' so if its truly just a bit, then everything is normal & the lack of oil consumption will continue to improve as things continue to wear in.

I've done the same as you, now up to 3000kms. I have no oil consumption at all. I just run 20W50 mineral, but i broke it in on 10W40 & even then it didn't use much.
 I'd say give it another 1000kms and re-evaluate what its drinking oil wise. If possible, get a mate to ride behind you and see if he can see much smoke coming out of your pipes when you ride (coast) normally. There shouldn't be much, and after another 1000kms, shouldn't be anything at all.

Does the bike feel good on compression when you kick it over by foot? When giving the bike some acceleration, does it feel like it has a good bite when you give it some? A rebuilt motor that has just worn in should feel like it wants to go if everything is reasonably tuned.

Re the valve job, you have new guides, so that is good. Obviously you must have installed new valve stem seals as well, because if not, then that is also a source of oil consumption. The valves should be lapped in at a minimum with valve lapping paste, but if the valve face and seat are not reasonably married to each other due to new valves, then the valve job mrieck mentioned is to cut the valve seat at various angles to marry to the new valve. This is done first, then followed up with a valve lapping job.

I'd say keep riding it & it might continue to improve (& just check your compression gauge for bike suitability). You may have nothing to worry about.

PS: Its good that you didn't let it idle much.

The compression gauge is I believe for a car but when I tested another engine (cb750) ive gotten a 150 (what these bikes got from factory) reading on a cylinder so I know it tests just fine for my bike. Plus its the only damn thing I could find with an adapter. Ive seen the thread youre talking about, but psi is psi, atleast in my mind.

Im running Valvoline motorcycle oil 10-40 at the moment, when/why would a move to 20-50w be necessary?

Kicking over it does feel ok on compression, but cold it never starts on the first hit of the starter, i gotta play around with throttle/choke/kicking over to clear out fumes etc til it decides it wants to catch... Warm she starts up like a champ.

I mistyped in my first, not new guides, just new seals (ill be editing that now), the guides were fine, no wobble what so ever, I cleaned and lapped the old valves and used those. I did not cut a new seat.

Sounds like everythings in order and you just need to get a few more miles on it. I'd retest in another 1000 miles or so & keep an eye on oil levels, etc. You are using your gauge at wide open throttle i'm assuming?
 If your guides were fine and you lapped the valves back in, then that should be ok. Plenty of oil threads to pick from, so its personal preference. Hondaman says the top end of these engines is particularly hard on the oil and chops it up fairly quickly. I've found that on 20W50, the shifts are nicer and oil pressure is maintained better when hot (i can see it on my gauge). In winter i'll probably run 10w40 again. Stick with a low detergent high zinc oil as flybox mentioned in one of his posts.

[cougar]

BIG +1 on PeWe's link !! Some may not agree, but I can see Mototune's line of thinking and will use his process on the next motor I build !!! Sounds logical to me.   ...cougar...

[grcamna2]

Start 'running it out' more,ride it harder and faster now

[ncstatecamp]

Using gauge at wide open throttle? No.... Just screwing it in and turning the engine over no spark until the pressure stops climbing.

[750K]

Do it with the choke off and the throttle wide open, motor warmed up when you do the compression test.

[PeWe]

BIG +1 on PeWe's link !! Some may not agree, but I can see Mototune's line of thinking and will use his process on the next motor I build !!! Sounds logical to me.   ...cougar...

I found the link in a Swedish guy's thesis where he had compared 2 ways of breaking-in. The old style driving really easy for 1000km (620mi) and the harder style from the very beginning. The pistons looked much better after the harder break-in.
I remember my break-ins for my 2 sets of 836 pistons. It was difficult to not twist the throttle back in the days.

This year with the 3:rd setup I twist really good from the beginning.
One thing though, I ran the engine a lot when tuning the carbs finding proper jets. A  bad Ultimate coil with bad contact of 2-3 wires tricked the carb tuning with too much idle. I revved 1500-2500, 2500-5000rpms when warm but probably not enough, pistons just moving up-down.
I'll hone the cylinders again next time when I have a reason. This break-in will hopefully be better than before anyway.

[lrutt]

I'd recommend giving it a good thrashing. Really rev that sucker. Ride it like you stole it. That should help. I know on a Trumpet I freshened up that sucker smoked like a steam engine at first. Taking it easy did not good for the first 100 miles so I spent 1 tank of gas and flogged that old gal. She cleaned right up and has not smoked or used a drop of oil since. The rings just needed to be forced into bedding. You can be too easy on a break in.

Also, the oil, is it syn? You never want to break in a new motor with Syn, the lighter the better so your 10 / 40 is good.

[Airborne 82nd]

I'm with MRieck if you really want to know beg,buy,borrow or make a leak down tester then you will know where the air is going simple quick and no more guessing. You might be able to borrow one from Advance or AutoZone But for your purpose a home made one will be just fine.

http://forums.evolutionm.net/evo-how-tos-installations/481133-how-make-your-own-faa-spec-leakdown-tester.html

[grcamna2]

I'd recommend giving it a good thrashing. Really rev that sucker. Ride it like you stole it. That should help. I know on a Trumpet I freshened up that sucker smoked like a steam engine at first. Taking it easy did not good for the first 100 miles so I spent 1 tank of gas and flogged that old gal. She cleaned right up and has not smoked or used a drop of oil since. The rings just needed to be forced into bedding. You can be too easy on a break in.

Also, the oil, is it syn? You never want to break in a new motor with Syn, the lighter the better so your 10 / 40 is good.

+1 

[ncstatecamp]

Do it with the choke off and the throttle wide open, motor warmed up when you do the compression test.

Choke has been off, motor was warm. Not makin any sense in my head as to throttle open would make a difference but next time I'll give it a try.

A leak down test is just putting in conpressed air when cylinder is at TDC to see where it's leaking right? (exhaust,air box or oil tank right)

The oil is non-synthetic. Just 10-40w motorcycle oil from advanced auto.

I'll ride it like I stole it then and see of that helps.

[lucky]

Throttle MUST be wide open during compression test.
Battery must be fully up.

[grcamna2]

When you do each cylinder's compression test hold the twist grip Wide Open(Full Throttle)so you'll have the least air restriction through the carbs. and airbox.

[750K]

When you do each cylinder's compression test hold the twist grip Wide Open(Full Throttle)so you'll have the least air restriction through the carbs. and airbox.

+1

[AJK]

Do it with the choke off and the throttle wide open, motor warmed up when you do the compression test.

Choke has been off, motor was warm. Not makin any sense in my head as to throttle open would make a difference but next time I'll give it a try.

A leak down test is just putting in conpressed air when cylinder is at TDC to see where it's leaking right? (exhaust,air box or oil tank right)

The oil is non-synthetic. Just 10-40w motorcycle oil from advanced auto.

I'll ride it like I stole it then and see of that helps.

If you close your mouth and pinch your nose, then try and take a big breath, your not going to get much air. The motor is the same. You must do the compression test with the throttle wide open. Pewe's link is an old one and I also agree with it, but the run in needs to be progressive. You are past that point now so give it some herbs.

[bjbuchanan]

Ride that thing like its some crappy 80cc dirtbike, it needs to be run hard. It would have blown up already if it was gonna from assembly errors, you need to get it run in good now

[ncstatecamp]

Bat outta hell status it is then

[grcamna2]

I think a lot of freeway on-ramps will help    keep an eye in the mirror for the local Constabulary 

[dave500]

Ride that thing like its some crappy 80cc dirtbike, it needs to be run hard. It would have blown up already if it was gonna from assembly errors, you need to get it run in good now

+1 except don't peak rpm it yet or downshift heavy,you didn't install any rings upside down?they look square but the top have a slight taper,the chrome one?any manufacturing marks on rings go upwards,i still gotta rematch tim on this drag race,i wasn't ready!kr250 two stroke versus new rebore 550,hes geared down six teeth on the rear since then,it fair flys!two bloody fifty!
kr drag

[grcamna2]

Dave,
Have you scheduled the re-match yet ?