ESE's works engine tuner

[senso]

200 Wolf slugs @ 66mm, and a 57mm stroke ends up around 194cc per. It's legal to go out to 400cc two stroke in F3, might as well do it proper.

Do two strokes like to be that over square?

Around here its very common to use 54mm bores with 43 to 46mm stroke, even more over square than that, and there are engines pumping out more than 30hp reliably, go for it.

[richban]

Around here its very common to use 54mm bores with 43 to 46mm stroke, even more over square than that, and there are engines pumping out more than 30hp reliably, go for it.

With limited budget on the RGV project I think splitting the money between a mild strong engine and fixing the lazy handling and will produce a great little bike. If I come across another engine then it will get the stupid treatment over time. From riding a two bike's on the same track one with a 22.5 deg rake and 85mm trail and the other with 25 deg rake and a 94mm trail. Some changers need to be made to the RGV.

[Drew]

With limited budget on the RGV project I think splitting the money between a mild strong engine and fixing the lazy handling and will produce a great little bike. If I come across another engine then it will get the stupid treatment over time. From riding a two bike's on the same track one with a 22.5 deg rake and 85mm trail and the other with 25 deg rake and a 94mm trail. Some changers need to be made to the RGV.

It's not all about the headstock and triple clamps. If the RGV is shorter, it has the extra rake to accommodate. I'd get some nice cartridges for the forks, and a decent rear shock before I started fucking around with the geometry.

[richban]

It's not all about the headstock and triple clamps. If the RGV is shorter, it has the extra rake to accommodate. I'd get some nice cartridges for the forks, and a decent rear shock before I started fucking around with the geometry.

Nah. It is shit. Both bikes are running the same wheel base. Trustmeiknowiknowwhatiamdoing. Tiz the future.

[TZ350]

TS125 Exhaust Port

Attachment 285099

Rick with the exhaust port I figure, raise it to 25mm from the top of the cylinder and widen it to 40mm at the top and leave it the original width at the bottom.

We can set the port timing at work to open at 80 deg ATDC accurately using a degree wheel and the width at 73% when finishing up and radiusing off the edges.

Rick Dinamik2t posted this coloured picture of the transfer duct angles.



On the TS make the rear transfer ports as wide as possible and shape them like the red ones in Dinamiks picture. Don't raise them as they are close to what we need now and they can be finished of later using a degree wheel for accuracy.



This is Chambers RG50, with your pumper you will be able to follow the natural angle of the TS's inlet tract which is to steep for an ordinary carb.

Coker Race Products RG60 Racer, looks like some ideas there for modifying the TS's inlet port and read block.

http://www.cokerraceproducts.com/SUZ...especsWeb1.pdf

The divider glued into the inlet port floor and the way the angle of the read block is changed and the cutting away of the rear of the cylinder all look like good ideas to try on the TS.

[Drew]

Nah. It is shit. Both bikes are running the same wheel base. Trustmeiknowiknowwhatiamdoing. Tiz the future.

How does the swingarm pivot-headstock measurement compare?

It's your bike, do what ya like of course. But geometry should never be changed before suspension, it's like doing huge port and carb work an an old two stroke that has no chambers, before you do the pipe....Pointless.

[mr bucketracer]

How does the swingarm pivot-headstock measurement compare?

It's your bike, do what ya like of course. But geometry should never be changed before suspension, it's like doing huge port and carb work an an old two stroke that has no chambers, before you do the pipe....Pointless.

rgv's handle like crap even with suspension sorted. nsr's handle way better but found not as fast . guess more rgv's raced over nsr's is because there were 10 rgv's to 1 nsr in there hay day

[wobbly]

Depens how you look at it.
If both bikes have shit suspension, then the one with good geometry will always be faster.
Thing is its insanely easy to get good working geometry.
Drop the forks 20mm thru the clamps and jack up the rear ride height 10mm,and it will change the angle from 24 to 22 and the trail from 90 to 80 in a few minutes work.
Unless the rear is fixed, then making different dogbones is easy etc etc ( name a tech that would spot that trick in 250 proddy ).
Emulators are cheap as,and then you get to fiddle with oil to adjust the rebound/comp rates real easy, without paying RT a fortune to get cartridges in there.
Then start looking at sprocket sizes to get more anti squat working, to stop the wobbly front end from unloading and shaking the shit out of you around the Hampton sweeper.
But of course ,good tuneable suspension makes going faster a doddle to organise - as long as you know what to do.
As an example all it took was 2 clicks of Ohlins rear comp damping and 10mm of fork drop for Discombe to loose 1/2 a second of lap time at Puke and take the 82 Junior non slicks lap record without breaking out a 70 year old sweat.

PS - over square Vs square in a 2T is shit, end of story.
Just look at the years Yamaha's suffered with 56/50.6 at the hands of Mr Square - Hondas engines.
It took till 2000 when the 500s square setup was bolted onto Jaques and Nakano's 250 that they even looked like building a fast engine.
And in the same year,the factory Yamaha 125 was a second a lap faster with Harolds square cylinder and crank on board.
Any perceived advantage of the revs capable from a short stroke is far outweighed by the lack of bore real estate needed to achieve the STAs required for better power ability.
But, its the old story of whats available and what can be achieved without too much brain or bank account damage.
A well oversquare 400 will be way faster than a closer to square 250 if done properly.
At 70 Hp the road based 250 is verging on unrideable, the 400 would be tame as shit - I got 96 with nothing outrageous.

[Rick 52]

TS125 Exhaust Port

Attachment 285099

Rick with the exhaust port I figure, raise it to 24.5mm from the top of the cylinder and widen it to 40mm at the top and leave it the original width at the bottom.

We can set the port timing at work to open at 80 deg ATDC accurately using a degree wheel and the width at 73% when finishing up and radiusing off the edges.

Magic! Thanks Teezee

[Rick 52]

Bloody hell, I go away for a few weeks and you're tuning the competitions bike. Wait, team mate

I little healthy competition between team mates is ok Kel

[richban]

Depens how you look at it.
If both bikes have shit suspension, then the one with good geometry will always be faster.
Thing is its insanely easy to get good working geometry.
Drop the forks 20mm thru the clamps and jack up the rear ride height 10mm,and it will change the angle from 24 to 22 and the trail from 90 to 80 in a few minutes work.

For me it about creating a bike that when you jack the back and drop the front it is a fine tune to something already good. If you adjusted the NSR as mentioned it would be a twitchy nightmare.

You mentioned a 400 were you talking the inline or a possible RGV 400 hundie. That would be something I would be keen to look at down the track for sure.

[wobbly]

Na I disagree, when you HAVE to drop the forks that much and have to lift the rear as well, it sure as hell isnt a fine tune - its a major change to get
the piece of shit into the ballpark.
The NSR is pretty good in that respect, and a fine tune plus suspension fiddling would work well straight away.
But the RGV is a mile away from good numbers,and it would be mandatory to put in serious work before you could even begin to see benefits from Emulators etc.

I havnt looked into a big bore RGV seriously at all.
But I have all the bits here for a NSR300 that will be a rocket when done properly ( which it hasnt been yet with that bunch of Honda Fags on their forum rubbishing the "non HRC " work done by Tyga etc).

[Drew]

But the RGV is a mile away from good numbers,and it would be mandatory to put in serious work before you could even begin to see benefits from Emulators etc.

Since the VJ22 has cartridge forks, I think something would need to be really fucked before emulators made an improvement.

[wobbly]

Sorry, yea I know now the 22 has cartriges,but what I was trying to point out was that even with trick shit SP forks revalved with Ohlins stacks etc
all that would be a waste of time unless the chassis geometry was corrected to something like decent numbers we all know about.
And the fact it costs virtually nothing to get those numbers, easily, why would anyone go ahead and spend up on the suspension before fixing the chassis for free.

[F5 Dave]

My RG/RGV/RZ hybrid has VJ22 front & rear, but with Race tech & ohlins back. When I got it it steered like a chopper. Some serious elevation till I got 23deg & then transformation city.