Most Revving Kit?

The standard cranks with 10mm pins for the piston can't take as high revs as the 12mm pins of the racing cranks. The racing cranks are much stronger in construction and have better bearings.

With really light rollers and a standard crank, you risk the very high revs causing the small end bearings to fail due to overheating, as they aren't designed to take that level of punishment. This will cause lots of needle bearings to fall inside the engine and fcuk it up big time.

The lubrication on a standard crank also isn't as good as a racing crank, as racing cranks have oil holes drilled into them to lubricate the small end and protect the needle bearings.

 

when disamble your engine, so when you get your crank out, ALWAYS! change the bearings!

Don't reuse them, becouse of placing and getting out and placing again itsn't ways good for bearings.
Myself always place new bearings.

If you have seen my project topic.
The 2fast4race engine, when building my engine up and placing the crank i had the problem one of the boults wich hold the engine cases snapped....
So i disambled the engine again ( with the brand new bearings )
i didn't took any risk, and placed inmediatly new bearings.

So yes, in fackt i trowed 20euro away
becouse i didn't use new bearings i just placed.

becouse if u re-use them, and when your engine is completed again and then one of them isn't good becouse it took to much damage when getting of the crank or with placing it again, all your work is done for nothing.....

Don't try to be cheaper and reuse those parts.
Also for gaskets ( paper gaskets ) Metal squish gaskets or rubber gaskets from the cilinder head is something differend, those u can reuse if they are not to old or took to many running hours from the engine.

but bearings, becouse it always takes a little pressure to get them into the bearingcases, its not recommended to reuse them, not even if you mounted the engine and it didn't run or not long and have to disamble again, i recommend in that case even to place new bearings.

becosue if something goes wrong, you have to take in the first point disamble everything again.... and on seccond point, it can destroy your engine inside and than isn't it just only the bearings, but may couse also damage to other parts.

 

Hmm, but is this 100% to happen?

 

Let me put it this way.

Your engine is designed to top out at about 7-8000 RPM maximum. Putting lighter rollers in allows the engine to spin a little faster but anything over 9000 RPM is asking for trouble and you will be past the power band at that RPM anyway.

 

So there is no benefit in revving that high (>9000 RPM) if im past the powerband right?

 

You got it.

You are better off improving the torque in the mid range rather than going after the maximum revs, as I told you earlier.

 

you can never say its gonna happen, i took my stock crank pretty far over the limits where most people have recommended already a long time again a racing crank.

But noo, you can drive with a stock crank in combination with a polini evo for 1000km and still have no problem.
Or you drive with a damn slow malossi sport 70cc cilinder and your crank or bearings break after a spinn arround the block....
Its just not to say.

Normally if the crank didn't made a lot of km's ( pretty new scooter or crank )
and if it doens't has any feelable slack of the connecting rod on the direction the piston moves, you can drive it for a while in combination with a lowrange 70cc cilinder like a dr70 or a malossi sport 70cc.

But with your cilinder and with the other stuff from your speclist its a midrange cilinder, and your c16 allows to have a rev of about 12.000RPM, Wich is more than a low range 70cc ( about 7000/9000RPM max )

You never can say something is gonna happen, all you can do is to build up the engine as properly as you can, and play everything on safe! especially if you want to drive it daily on the road, it needs to be reliable, that means you don't have to try to be cheaper off with not replacing the crank of bearings.
Just do it, its way safer, and has a way better feeling when driving arround.
Becouse if you know you take risks, you don't drive arround with a rest feeling.

 

This is why I mentioned heavier rollers, as these will help at the top end but they will tend to limit the max RPM as they are heavier and take more power to move them.

A gear-up kit would lower the RPM versus your top speed but a lot of these Polini and Malossi kits have straight-cut gears and can howl like an air-raid siren when you are revving hard. Normal gears in scooters are bevelled cut, to reduce noise.

Racing bikes aren't generally built for endurance, as they only have to last for the length of the race and they get completely rebuilt afterwards - your bike has to be reliable in the medium to long term and that's what we are trying to tell you.

 

But this is adjusted by the exhaust, yes?

Yep, you're right!

 

Yes Leo, the exhaust does this, if you get the right one for the job.

 

Yep that's what i've been thinking and didn't install the Malossi MHR Racing with the TEAM II exhaust i already have at home. And that's why im all over the internet trying to find the most powerful, daily use able cylinder
And from what others have told me on this forum also, this is the S6 Sport Pro. Even better than the MHR Replica which is a two ring kit.

 

powerband is a combination from the cilinder timing and the exhaus, but i'm off to bed, will give more information about that tomorrow if got questions

 

Ok mate thanks

 

You will have already changed the cylinder timing by using the Sport Pro cylinder. The heights and shapes of the ports will have been modified to produce more power and torque. If this is what you have already assembled, then you need to move on to getting the carb settings right, then finish off by adjusting the roller weights if you need to.

 

Fuck sake man, just do the crank rather than change every other part just to avoid it. Itll also save us all laughing when it blows up, then your 5 quid saving is ruined

 

Hah yep that's what im going to do. Stage6 HPC good? Or Motoforce Evo?

 

He's already spent quite a bit already and may not have unlimited funds.

 

Yea Merlin gets me i've spent 500 4 days ago so yea its not easy going for a crank now

 

@ A-LY

You could always buy him a late Christmas present...

 

I know that the funds aren't always as full you can keep spending money.

But instead of the cilinder, you should ordered the most important part, wich is the hardest to change.

Is your engine still running? or is it broker, otherwise i would recommend to just wait to install the parts, and first collect some money for a crank.

Stage6 has pretty nice cranks, but in my eyes overpriced, same as malossi or polini cranks.
There are cheaper cranks with the same quality.