Maintenance of a hyper-racing cylinder

[mxyzptlk]

OK, I'm at a complete loss here. I plan to get a hyper-racing setup some time in the future (Polini or Malossi probably, after having discarded Hebo), and am trying to gather some information. However, I get different answers depending on who I ask. So now I thought I'd try asking the good pro people of this forum.

I emphasise that I will NOT be using this setup for racing, I will run it hard from time to time (pretty often probably), but much of the driving will be calm and in accordance with traffic laws.

1. Breaking in. Some people say that a hyper-racing setup shouldn't be broken in at all, some say let it warm up and break it in MotoMan-style (hard going from the start, full revs and hard breaking, repeat), some say break it in old-school style (10km on a low rpm, the next 10 on a slightly higher, etc). What's the solution here?

2. Piston ring. Some say you have to change piston ring every 10 hours of driving with a hyper-racing cylinder. I assume this means if you're racing? Others say the piston ring is the main part you're "breaking in", and it'd take 5-10 hrs of normal driving to break it in anyway, so it should be changed much more seldom.

3. "Staying power". Some say the piston is not going to last more than 20 hours of driving. Again, if this figure is correct I assume they mean while RACING. My dealer suggested that such a piston could last 3-4000 km of "normal" driving. Again, I wonder what's true here. And again, how about the piston rings?

PS. I realize no-one can give me definite numbers or anything, I'd just like your rough opinions and wild (but hopefully educated) guesses. Thanks.

 

[Browni]

OK, I'm at a complete loss here. I plan to get a hyper-racing setup some time in the future (Polini or Malossi probably, after having discarded Hebo), and am trying to gather some information. However, I get different answers depending on who I ask. So now I thought I'd try asking the good pro people of this forum.

I emphasise that I will NOT be using this setup for racing, I will run it hard from time to time (pretty often probably), but much of the driving will be calm and in accordance with traffic laws.

1. Breaking in. Some people say that a hyper-racing setup shouldn't be broken in at all, some say let it warm up and break it in MotoMan-style (hard going from the start, full revs and hard breaking, repeat), some say break it in old-school style (10km on a low rpm, the next 10 on a slightly higher, etc). What's the solution here?

2. Piston ring. Some say you have to change piston ring every 10 hours of driving with a hyper-racing cylinder. I assume this means if you're racing? Others say the piston ring is the main part you're "breaking in", and it'd take 5-10 hrs of normal driving to break it in anyway, so it should be changed much more seldom.

3. "Staying power". Some say the piston is not going to last more than 20 hours of driving. Again, if this figure is correct I assume they mean while RACING. My dealer suggested that such a piston could last 3-4000 km of "normal" driving. Again, I wonder what's true here. And again, how about the piston rings?

PS. I realize no-one can give me definite numbers or anything, I'd just like your rough opinions and wild (but hopefully educated) guesses. Thanks.

It will be an interesting topics!

I think you will see totally different answers for these questions!

First of all, you are right nobody can predict you these (piston life etc)!
Because of too many factors. Usage, Lubricant, Maintance, Airpollution your hair color etc..

Because you buy racing products and usually they are used for this purpose, it's hard to talk about "street conditions". For racing usage the unit is hour on the street we can talk about km, it's hard to convert these!


1. breaking in, like you said there are many versions!
These NiCaSil plated cylinders are very well made, very precise parts, the piston and the cylinder perfectly matched together. So we can say the only part you have to runnig in is the piston ring. The ring should adapted to the cylinder bore perfectly! The piston is the key for the performance. Because not the ring's own tension responsible for the fitiint, but the pressure in the combustion chamber, you have to running in the ring (near) at it's operating rpm. (the compression pressure increases if the rpm increases).
So if you runing in the ring at lower rpms the sealing won't be good at high rpm.
The running in procedure isn't vey long but you need gradation. A proper warming up, a few minutes normal usage, and some hard accelration, then moderate speed again for a short time, and repeat this procedure a few times.

2. Changing the piston ring, when? -> the most important is to check the parts quite often (for racing usage this can be after every races, or after few hours). If the ring's shape, and the clearance is good between the two end's of the ring you can use it again!
However you have to now your bike (engine), if you feel your engine looses power, or it's sound changes, or you feel any sign (it revs more, but not as good as before), check your engine, these can warn you, "No it's time the change the parts). Or after a few time, you can make a trend, for example the first piston sustained 3223 km the second one 3866km, so you may calculate the third one will be sustain quite the same. The third method is check it every 1000-1500 km it doesn't matter you can't fell any abnormal thing (this is an example).


3. (in racing condition we can talk about a very wide spectrum), depend from the circumstances.
Like the (2.) you have to check the piston with precise instruments!! Usually on normal street usage the piston's lifetime can be 3000 or even more km's.

So as you can see there are a lot of servicing methods!
There are racers who changes the piston and the main parts after every (checking) disassembling, because they want the maximum (the same) performances in every race. For sure it's good for reliability too!
This one not necessary if the parts are in good condition, moreover you waste some good parts too! So if you are not a racer but a "street racer" it's useless. However if you have the money for this king of servicing you can choose this method!

Maybe I wrote some silly things, cause it's quite late now. I tried to correct it, but I gave up! But I will check my text when I am fresh again!

 

[Big B NRG]

1. Breaking in is not really needed. The thing you could do before you drive is make sure that the pistonring gap has the right clearance (,15 - ,2mm, I prefere ,15).

You can measure it by putting only your pistonring in the cylinder and measure the gap with a feelerplate? (thin metal plate with different thicknesses, don't know the correct english word).

If it's to small (<0,15mm) you can use some sandpaper to make it bigger. Sandpaper it and check untill it has the right value.

Also it's important that you let the engine come up to working temperature, that makes quite the difference. Good working temps for these cylinder are between 45 - 65 C. At 90 C it gets critical and at 100(+)C it's game over.

This is how I "run in" my engine. Has worked for me over and over.

2. Changing pistonring. If you can use it for max. preformance all the time 8-10 hours is the limit for a piston(ring). For the purpose you are going to use it, you can change piston ring every 10 hours and change complete piston every 20 hours (so piston + ring). These hours depent a little on what oil you use etc. Quality oil makes a big difference.

3. 3-4000 km is alot I think for a Hyper setup. When you are doing 14k RPM, things wear out pretty quick, offcourse, you won't be doing that RPM all the time, but still, you will be doing 10-12k rpm most of the time, because beneath 10k rpm there issn't gonna happen much and every time you drive away from the stoplight you will be accellerating with high rpms (maybe even top rpm), because otherwise you won't be able to drive along with the traffic.

I have this guideline to change piston/bearings etc every year (I also don't drive alot), just to be sure everything is in tip-top-shape.

Another thing that also helps is setting up your engine to be reliable instead of on-the-edge-max-hp.

For example; set your squish alittle bit higher (0,55-0,6) and use quality oil like Castrol A747 or similair, also use the right sparkplug and make sure the cooling is stable enough so temp will be around 55 C.

That really helps giving your engine a longer lifespan.

 

[mxyzptlk]

Thanks so much guys, I feel a lot wiser now. I will definitely keep this in mind for when I get my own racing setup! Much appreciated!