Max RPM 66cc

The secret is the computer spin balanced cranks. Something only Screaming Roo is doing to my knowledge. The rpm and speed claims reflect the investment in the expensive spin balancing. Speed costs money.
All the go fast parts in the world are wasted on a unbalanced stock crank. 99.999% of all the chinadolls on earth would not spin 9krpm if you fed them 70% nitro! And what good would it do to have a stock crank spinning 9k rpm when your hands couldn't hang on the bars from the mind-numbing vibration levels anyway!
Don't believe everything you read about fast chinadolls...
 
maniac57 said:
The secret is the computer spin balanced cranks. Something only Screaming Roo is doing to my knowledge. The rpm and speed claims reflect the investment in the expensive spin balancing. Speed costs money.
All the go fast parts in the world are wasted on a unbalanced stock crank. 99.999% of all the chinadolls on earth would not spin 9krpm if you fed them 70% nitro! And what good would it do to have a stock crank spinning 9k rpm when your hands couldn't hang on the bars from the mind-numbing vibration levels anyway!
Don't believe everything you read about fast chinadolls...
Click to expand...

Spot On Mate about the Roo Prints...

Just spoken with Dino at Screaming Roo about the new motors for my Mad Dogs - bad news is that a new Crank/Engine Platform is being developed by him and the motors will not be ready until March...

I'm gonna buy a few others and do some work on them and run some tests on the various combinations... I'll film the tests - not scientific type things - real world track testing around my area...

We have a Freeway - good roads - bad roads - dirt roads - dirt track roads and a bloody big State Forest Park in the hills set up for biking & trial bike riding... Real world testing under real world conditions...

Today is 35 degrees Centigrade where I am - bloody hot - lets see what a Roo Print 66 can do in this heat...

drn2
 
I have one China Girl that is similar in smoothness to the Roo's, But a total freak/fluke, the Roo crank is far superior to the majority.
But also note, everything else is the best that Dino could source also, with the barrel having beautiful port timing, and a 'quick' touch up to the ports. The 'Monster Mag" and plug wire, the tank and petcock, the exhaust, the bearings even the studs and fittings are all top quality.
And best of all, It wasn't assembled in China!
10 000 RPM and as smooth as any other, straight out of the box.
 
No problem with vibes over here either... Maybe I just got lucky on this one but it's a DAX bottom end with my old top end installed and even at cruising speeds and well above, no vibes at all on the bars or at the seat and I'm running between 8500 and 9200 rpm most the time.
i was going to do the whole take out the crank, true it up on a lathe, then balance it with the bob weight and set a balance factor so it would run smooth but after I installed it and ran it a while it runs dead smooth so I'm not messing with this one... I already did that on another engine to smooth it out and it worked good, but if it's already this smooth, no reason to mess with it.
 
Theon said:
I have one China Girl that is similar in smoothness to the Roo's, But a total freak/fluke, the Roo crank is far superior to the majority.
But also note, everything else is the best that Dino could source also, with the barrel having beautiful port timing, and a 'quick' touch up to the ports. The 'Monster Mag" and plug wire, the tank and petcock, the exhaust, the bearings even the studs and fittings are all top quality.
And best of all, It wasn't assembled in China!
10 000 RPM and as smooth as any other, straight out of the box.
Click to expand...

Theon,

Mate you think the old Roo engine is good - after talking with Dino on the phone I can assure you it is but a baby compared to what is now coming our way...

One piece crank and lots of other go fast bits... Yep Mate - we are spoiled...

Mick

drn2
 
He was claiming the American release was holding him up from giving us the good stuff?
He'been talking about Hot up parts for a while now?
 
Theon said:
He was claiming the American release was holding him up from giving us the good stuff?
He's been talking about Hot up parts for a while now?
Click to expand...

Yeah - there has been a few issues which had held him up - but most of them are sorted now... He's trying to find a casting firm that will do the job to the specs he has set - tooling is costly so he don't want to have to do it twice...

I don't reckon I can say too much cause it ain't my business - but after talking with him and knowing what I now know - I am gonna wait for the new engines even if I do have to take a number... :)

drn2
 
Stock unbalanced cranks in all my builds, and my max has been 10,500 as well.

Although I am incredibly interested in the fabled Roo Cranks.


Going to be experimenting with CR Machine Balanced Cranks pretty soon here, as I think I can actually buy those....
 
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