ESE's works engine tuner

[husaberg]

Less is better, we are aiming for only 2 changes per lap too, rowing the bike around with the gear leaver only slows you down I recon.

The Suzuki gp100/125s are 5 speeds (hence larger gaps between the gears)
Is that why you are concentrating so much effort on the power spread rather than outright power?
Or is it the circuit you race on is so tight? or both ?
With the 125 2s vs. 150 4s you should still almost have a torque spread advantage over the diesels but probably less overall rev range in rpm of useful power.
Wouldn’t a shallower pipe tapers give you an advantage if this is the case.

[TZ350]

The Suzuki gp100/125s are 5 speeds (hence larger gaps between the gears)
Is that why you are concentrating so much effort on the power spread rather than outright power?
Or is it the circuit you race on is so tight? or both ?

Both........

As I see it, at Mt Welly, easier to ride is the FXR's big advantage and outright big 2-stroke hp is no advantage at all. So our efforts with the V Tec and power range is all aimed at making an easy to ride stroker that can be turned on earlier in the corners.

There are a few things to try yet, like slippery pipe, water injection, ram tube, electric power jet carb, engine sucking through an intercooler packed with dry ice, bigger diameter rotary valve, quick shifter for the longer tracks, a dry clutch, hand made tripple ex port cylinder sleeve and maybe revisit the plenum as a way to tuck the carb and bits out of the way.



The plenum was conceved at a time everyone thought a 24mm carb would be a restriction on how much outright power could be made with a 125, but a 24mm carb proved to be less of a restriction than was thought.

The plenum or a variant could still be usefull in other ways.

[husaberg]

[/B]

Both........

.


The plenum was conceved at a time everyone thought a 24mm carb would be a restriction on how much outright power could be made with a 125, but a 24mm carb proved to be less of a restriction than was thought.

The plenum or a variant could still be usefull in other ways.

What carb were you using? (Doh just looked at the post pic an its a keihin semi flatslide so you have got it licked)

still might be relevent for others I guess?

The bell book that was for a long time my Bible had something along rhe lines of a mikuni carbs flowing less air than the others.

Another thing that sticks in my mind that he states a smaller carb say 22 bored to 24mm will flow more than a std 24mm
Something to do with the more streamlined venturi I think.
Of couse he was dealing with roundslide carbs.

A 24mm throttle body might flow better to without the venturi.
The rules say eq to 24mm carb afterall I know other don't agree on this point though!

Maybe a cv carb might offer better low down responce can't remember them on a 2 stoke though.

[husaberg]

Both........


There are a few things to try yet, engine sucking through an intercooler packed with dry ice,

.

have a look here http://autospeed.com/cms/A_110772/printArticle.html
IT would/could also be a very trick alternative to water cooling a barrel in combo with a water cooled head on a 100cc.

This site is one of the best resoures for all sorts of real interesting stuff.

Another thing to consider is an Marine oil cooler as an intercooler.

http://autospeed.co.nz/cms/title_The..../article.html

[Buckets4Me]

[/B]


The bell book that was for a long time my Bible had something along rhe lines of a mikuni carbs flowing less air than the others.

Another thing that sticks in my mind that he states a smaller carb say 22 bored to 24mm will flow more than a std 24mm

already been covered and I think it was found that a 24 could be made to flow a lot more air than anyone ever thought
do a search and spend a week reading this thread but it has been covered in detail

[bucketracer]

Thomas did a lot of work measuring the relative air flow through various carbs and I helped him and TeeZee with modifications. Between all of us we were able to get some serious flow out of a 24mm carb.

There are 1,600 or so photos on this thread.

They can be viewed by using the Thread-Tools option near the top of this page, click View-Thread-Images in the drop down box, then the pictures can be sorted using the Display Options.

1 Thread Tools
2 View Thread Images
3 Display Options

The images can be displayed 70 at a time by using the Display-Options and clicking on the little blue N/A under an image will take you to the related post.

From page 80 all the decade pages have link collections, they were collected together as the thread went along to make it easier to find the good stuff.

[husaberg]

I asked Dad (TeeZee) and he said he remembers the "G"s as piston eaters, the skirt edge on the inlet side would get hammered in by the bottom edge of the extra wide inlet port. As the piston thrust side is on the same side as the inlet and the thrust tipped the piston skirt into the inlet port, pistons would have to be replaced every meeting or so.

I have just found the Yamaha twins book which covers the development of the tzs and other twins and yes it was the inlet port I offer humble apologies and grovel profusely to all.
Brain fade.

The only excuse I can offer is,
When the TZ250g/h model development was happening whist I was not pooping my pants on a regular basis I was still having the odd accident.

Looks like I still do to .

It makes more sense in hindsight to as the cylinder wall on top of the exhaust port would provide a lot of support in a forwards running engine at close to and beyond TDC.

[husaberg]

[They can be viewed by using the Thread-Tools option near the top of this page, click View-Thread-Images in the drop down box, then the pictures can be sorted using the Display Options.

1 Thread Tools
2 View Thread Images
3 Display Options

The images can be displayed 70 at a time by using the Display-Options and clicking on the little blue N/A under an image will take you to the related post.

From page 80 all the decade pages have link collections, they were collected together as the thread went along to make it easier to find the good stuff.

Thanks for the tip makes the navigation so much easier.
I found the pages with the carb pics and the manometer testing but don't see the results maybe should pull a sicky all this week?

[TZ350]

I found the pages with the carb pics and the manometer testing but don't see the results maybe should pull a sicky all this week?

I don't think Thomas or Bucket posted any actual data or "results", as the manometer was only being used as a comparator and their notes would be meaningless to anyone else. There was some thought of using a rotary lobe gas meter to measure real air flow but in the end comparison with an arbitrary standard was good enough.

Although I remember that the Keihin semi flat slide was pretty good, better than the other name brand carbs of the same size and an OKO 24 (Keihin copy) machined well and could be modified to flow quite a lot of air and cheep enough to experiment with. There are probably posts about the different things that were tried.

The manometer posts were more about "for what its worth, this is what we are doing and how we did it" sort of thing, a sharing of ideas and anyone interested enough would be able to make a rig and develop their own carb setup.

Thomas would measure the gap between the upper and lower water levels (car anti freeze) in the manometer. The smaller the gap the better the carb was flowing in comparison to a std 24mm flow tube that Bucket had made. This way we were able to see what carb mods worked and which didn't.

a graph of Neds bike in its current trim.

As a matter of interest, NedKellys bike is still using the original 24mm GP125 carb and makes good power, the big thing was some 5mm nuts spacing the side cover off (pictured), that little trick was good for a couple of hp. The other engine details are on page 200.

[2T Institute]

Hmmmm, I didn't know all that goldmine of info I extracted from Frits and Jan had made it into the english speaking world.
Ah well .................................................. ..........

[F5 Dave]

Both........

As I see it, at Mt Welly, easier to ride is the FXR's big advantage and outright big 2-stroke hp is no advantage at all. . . .

Really? Nigel seems to lay waste on his 100 when he feels the desire. How often have you tried these bikes now the power is good, in decent chassis in the dry with a decent rider?

[cotswold]

Really? Nigel seems to lay waste on his 100 when he feels the desire. How often have you tried these bikes now the power is good, in decent chassis in the dry with a decent rider?

I know ease of use is part of the deal but I am with you I cannot see how an fxr could live with a 27hp 2 stroke in an rs chassis with a 1/2 decent rider on board.

[F5 Dave]

Well that 23hp curve above looks pretty easy to ride at fairly lazy revs. Perhaps this doesn't tell the full story on carburetion at other throttle positions & abruptness of Disc valve closed to open transition that on a small track may count for a fair bit if it is upsettingly sudden. I haven't ridden one. Well not for a long time & that was at Taupo over a decade, closer to two ago.

[kel]

How often have you tried these bikes now the power is good, in decent chassis in the dry with a decent rider?

Ouch! note to self pull the Zarco on F5 Dave if he ever comes up this way.

[husaberg]

=F5 Dave;1130081035]Well that 23hp curve above looks pretty easy to ride at fairly lazy revs. Perhaps this doesn't tell the full story on carburetion at other throttle positions & abruptness of Disc valve closed to open transition that on a small track may count for a fair bit if it is upsettingly sudden

It was mentioned earlier but I can find no pics of a trial.

It cetainly make the 100cc karts user friendly not to mention the ease of tuning.

I have sampled one on a mb100 and it sure screemed but it was high side city after comming back on the power after a corner but I think I found the remedy for that later.
Although the one I tried was huge and off a jetski.
plus if you positioned it side ways it could double as the v tech valve.