Calling all professional engineers

[bogan]

The reciprocating mass is usually delt with by a counterbalance shaft. It is near impossible to eliminate completely with any inline engine. (I think)
Does that make sense or am I talking rubbish?

the analogy makes sense, but with an IL4, you have 4 weights to place, put the two middle ones on top, and two end ones on bottom, now how much vibration will there be?

Oh fer crying out loud...who's a qualified engineer on here ???

the two center throws of a four are in the same plane - both "up" if you llike...
this makes it a 360 degree parallel twin...think triumph,Norton etc etc..
easily rebalanced - particularly as it's so small and short stroke. OE balance factor is probably around 35-40% so simply rebalance to around 65 -70% static.
all 360 deg twins without a balance shaft are a compromise in balance so it doesn't matter if it's not exact first time round - just change it until it's acceptably smooth in the rev range you use.

me actually...

not really sure what you mean, can you balance a 360deg twin for high revs without a balance shaft? or do the CBR250 engines have balance shafts? for some reason I thought sports IL4s generally didn't.

[Brian d marge]

yes I did put that in the title ..

my idea was, that who practice those magic arts that could spare a few min, create , help , and maybe sponsor a young person
Towards a well set up, professional looking , run ,,, what ever ( I just thought buckets as there is a lot of room for creativity

Me I would be keepin it simple and not trying to reinvent the wheel

Stephen

[Moooools]

I will just take grumphs side because he is angry.
I am getting more and more lost. So I will probably end up just getting an engine and working it all out from there.

[robinm]

If you want to see some amazing modified motors, check out Allen Millyard, google him, some examples are 5 cylinder Kawasaki 2 strokes, a V12 Kawasaki, made from 2 x Z1300's, Honda V twin 100cc, made from 2x SS50 motors. All made in a single garage at his home in the UK, with no hi tech equipment, his main tools are a hacksaw and a file. A modern day Bert Munro!!

[bogan]

I will just take grumphs side because he is angry.
I am getting more and more lost. So I will probably end up just getting an engine and working it all out from there.

fair enough, though either way you're gonna have to learn the theory of it all, but it is possibly cheaper to figure out as much as you can now, in case it isn't going to work or require too much modification to get it to run as you hope.

[Yow Ling]

You guys should apply for jobs at honda. Who in their right mind would want to put a truck sized engine in a bucket and expect to win. Here is a clue - less weight = fast bike. You wont be getting a head start at the track , no point in designing a bike with a disability

[Moooools]

Who said anything about winning?

[Grumph]

Please read up on your theory before cutting metal....it's cheaper.

And I don't mean quicky magazine articles either - find any of the tuning for speed series or tuning automotive engines or Motorcycle Engineering all by Phil Irving.
local library should have something. The old bugger knew what he was talking about and wrote in an understandable manner too. The black art of balancing motorcycle motors hasn't really moved on from where he wrote it up either. Fours are just multiples of singles from a balance point of view.
Time has showed he was conservative in carb size & gas speed - cam specs are still ballpark stuff though.

[avgas]

I have to admit I know my knowledge limit, and its been a while since I had to do much mechanical these days. But I think Grumph is on the right track of advice for you Phil Irving's books were good for setting up a race engine. Sadly I think a lot of his books will show you how to modify existing engines and keep same "order of things" e.g. how many pistons it has etc.

What I was trying to say before was sort of a combination of what you all concluded - by simply removing a moving mass out of the engine, and putting balancer shafts in does not make it balanced. You have to think outside the engine - how are you going to bolt this thing down if it wants to go full gyro on you. There are very specific reasons why some chassis are completely rebuilt when the engine changes in them.

got me thinking last night though mabey we are thinking about this the wrong way. With learners bikes being at 250cc why don't you get a CBR400 motor, and make that a supercharged 200cc?
Would be the hell learners bike (I have no idea if you could race it though) - and cert costs aside would be 1 of a kind L plater.
And if you did it smart enough you could build yourself a "conversion kit" that could make you a bit of coin.

As for keeping it bucket racing......sorry man - but the best and cheapest option will always to buy someone else's work. There are reasons why motorcycle engine designers get paid the big bucks. Unless your willing to invest years (and $$$'s) in getting it right - your pushing shit up hill big time

[Bert]

Mechanical , electrical, Machinists ( and any of those young ladies on K road )

This idea has been rattling around in my brain and it wont leave, so I ll put it here.

There are some enthusiastic young fellas , mucking about with bikes on this site , such as in the Bucket forum,

There are others here who have a skills in Engineering,

Why dont we put them together? and help an enthusiastic young fella build and develop a bike ? and at the same time improve any skills that we want to get stronger in

Create a professional looking team ( sorry a bit scruffy some of those buckets )

...
Just a thought thats all ,

Stephen

Its a good thought Stephen.

There are a couple of classes worth thinking about:
the new GP125 (250's)
Buckets (ideally F5 50s; to get the class growing again; but F4 as the primary option).

Plenty of 50's and 125/150 fours in Japan...

Though there are some scruffy buckets, it does look that generally the guys are putting a lot of effort into presentation of their bikes these days. generally the fields (from looking at photos or being on track) look better presented than most classics and post classic fields.

NZ built "metrakit like" frame setup (good forks, shock,wheels, fairings?; maybe RS etc) that can be upgraded relatively simply from 50-150-250 (though 250 might require significant additional engineering)? to enable "young fellas" to move up without massive out lay (except initial outlay & rebuilds)..
I could also start my annual rant about the use of small dirt bike motors (due the share number of engines sitting in sheds), but I wont quite yet.

There are plenty of people/companies building these parts in NZ already, it would just be a case to get them together.

yes .....

my idea was, that who practice those magic arts that could spare a few min, create , help , and maybe sponsor a young person
Towards a well set up, professional looking , run ,,, what ever ( I just thought buckets as there is a lot of room for creativity

Me I would be keepin it simple and not trying to reinvent the wheel

Stephen

I'd be keen get involved time permitting and I'm sure there are others that would get involved.

Plenty of room for creativity in buckets and plenty of cheap racing these days; and we are starting to see them running at larger (big bike) meetings and embarrassing a fair few larger bikes.. which is what you really need to get something like this going. and it is still the best fun you can have with your pants on; nothing better than seeing 40+ bike fields at taupo/ruapuna and close racing.

[Brian d marge]

Yes I have looked at those Metrakits closely and seem a good choice,

So there is the target then ,, good idea
snip
There are plenty of people/companies building these parts in NZ already, it would just be a case to get them together.

Where are they???

Stephen

[Brian d marge]

Well are there any young fellas who would like some help??

Stephen

[avgas]

Is there still a 50cc racing class?

If so why is no one racing this:
http://www.trademe.co.nz/Toys-models...-348662175.htm

[koba]

Is there still a 50cc racing class?

If so why is no one racing this:
http://www.trademe.co.nz/Toys-models...-348662175.htm

Rules.

You could probably use it in the NZ50cc GP, I think thats been run once in more than a decade. F5 Buckets are the main one I know of and the rules don't allow that!

Edit: Fecking cool tho!

[avgas]

Yeah I would love to chuck one of these on a mountain bike and do one of those hub conversions.
Alas with a baby on the way I don't even have a $3,000 motorbike let alone that kind of money to spend of cool toys.
I notice also in the same section there is a jet turbine.