ESE's works engine tuner

[chrisc]

I heard he came second in the first leg of the borrowed bike race and lead the second for most of the race to take the win.

I couldn't comment because he was far ahead of me and I didn't see the result but that doesn't sound incorrect at all

[bucketracer]

TeeZee has the result sheets, hopefully when he gets back to work tomorrow he can get them scanned and posted up.

[TZ350]

Mt Wellington Fun Day Results.

There are a few anomalies, like the races run anti clockwise had to do a lap before triggering the timer and I have forgotten which races ran the oval and which included the infield, it was a fun day and I wasn't paying to much attention. Maybe someone else can fill us in.



And another for the Team ESE bike prepared by Chambers and Thomas and piloted by Tim F, (Round 2 of the Borrowed Bike race).

[fixer]

Tim, the Aprilia looked like it went very well today!

Thanks for that pic Chris ... yeah, I had a ball! 8hp is all you really need to have fun. That said, I don't think Renee's 13mm carb is going to be attached to her for much longer. (Yes, she is an Italian bike with a French name - apologies to anyone who is offended).

I also had the chance to ride Avalon's bike at the weekend thanks to team ESE (RS125 chassis with ESE GP125 motor). I have to admit that it was an adrenalin-filled few laps. There's no doubt that it's got a strong engine, little weight, handles well and brakes like you've hit a brick wall, but it's a certainly a challenge to ride on a tight track. The power really comes on strong through the esses. And it was so fast on the straight bits, that I was constantly in danger of running into the back of slower riders.

I think that with a decent amount of practice, a good (and fit) rider would be very hard to beat riding that bike. An average rider would struggle to come to grips with it. I take my hat off to Avalon - she's clearly a very good rider.

Tim

[fixer]

Mt Wellington Fun Day Results.

There are a few anomalies, like the races run anti clockwise had to do a lap before triggering the timer and I have forgotten which races ran the oval and which included the infield, it was a fun day and I wasn't paying to much attention. Maybe someone else can fill us in.



And another for the Team ESE bike prepared by Chambers and Thomas and piloted by Tim F, (Round 2 of the Borrowed Bike race).

Each of the 3 fields (F4 A-grade, F4 B-grade, F4 C-grade plus F5) got 4 races:
Race 1 - full track anticlockwise
Race 2 - full track clockwise
Race 3 - oval track anticlockwise
Race 4 - oval track clockwise

Plus at the end we had the two all-in "borrowed bike races":
Race 1 - oval track anticlockwise
Race 2 - oval track clockwise

My thanks again to team ESE for the use of their little rocket. If I had more time to get used to the riding position, the race pattern shift and to figure out how far you can actually lean an RS125 chassis over, I would have gone a bit faster. :-)

Tim

[fixer]

By the way ... my apologies for the rather dodgy-looking differences in laptimes later in the day in the results that show each rider's individual laptimes (eg 4 hours). Not sure quite what happened there, but the race results and actual laptimes should be ok.
I think a couple of the full-track races were actually 4 laps rather than 5 laps, but hey ... we all had fun.

Though I must apologise to Max Olsen for rather vigorously removing my Aprilia from his bike after Rick, Max and I all fell down in a heap in the esses. This action may have further damaged his tailpiece. My enthusiasm to get back in the race might have got the better of me. I'm happy to donate a large roll of duct tape if it will help!

Tim

[husaberg]

The Rotax cylinder only has a single blade. The Aprilias have a two-stage powervalve system: first only the lower blade opens; then it takes the upper blade with it.
The drawing above left is from the RSA manual; the drawing above right is from the RSW manual. In typical Italian fashion the numbering of the parts differs between the two drawings.

RSW (right): When the shaft 7 turns, the lower blade 14 is lifted by the arm 2. When the lower blade hits the upper blade 13, both blades are lifted further together.

RSA (left): When the shaft 14 turns, the lower blade (not numbered) is lifted by the arm 15. When the lower blade hits the upper blade (also not numbered), both blades are lifted further together.

All other parts are to do with spring-loading the blades, converting the cable movement into turning of the shaft and fixing the cables to the cylinder.
In the 250 cc twins the shafts are coupled by push-pull rods which in turn are cable-operated. The 125 cc singles ared directly cable-operated. The picture shows the RSA's cables.

The idea behind the two stage blade is that with a single PV, as it is retracted it pulls away from the piston.
At 1/2 sroke it is virtually useless due to excessive leakage.
With the two stage as the lower blade retracts, the upper blade is still close to the piston.
At 1/2 stroke the lower blade is sitting flush with the uppers bottom edge.
They then both retract up flush with the roof.
This gives a sealed blade when down at say 100* atdc, and it is still sealed against the piston at 1/2 stroke, say 90* atdc.
This is why the Aprilia PV still works effectively, such that the blades are not fully up at the 80* atdc point till around 12,000rpm.
Exactly the same system in the RZ400, and that PV isnt fully up till 10500, in an engine that peaks at 11500.
The Honda dropping gate or the Yamaha rotary spool valve overcome this by keeping the seal face close to the piston throughout the entire stroke.

I found this today. I missed it earlier (its was in a link elsewhere)
this is a neat little manual.
Both the pictures and words are in English
Interestingly the last of the RM250 the X model had a very similar looking valve set up.

[bucketracer]

And another for the Team ESE bike prepared by Chambers and Thomas.

Whats that make it, 11th ''A '' grade win this season.

I would be impressed with ESE winning.

There you are SS, its your opportunity to say something sincere and congratulatory.

[Moooools]

Though I must apologise to Max Olsen for rather vigorously removing my Aprilia from his bike after Rick, Max and I all fell down in a heap in the esses. This action may have further damaged his tailpiece. My enthusiasm to get back in the race might have got the better of me. I'm happy to donate a large roll of duct tape if it will help!

Tim

Haha it is not a problem. That's just how racing goes sometimes. I have two new tail pieces on the way so I will have a spare lined up for next time. Although I would love to stay on 2 wheels for a bit longer next race. And beat you. Definitely Beat you. I am a bit worried about you getting more power though. Certainly a bit disappointing to not be able to finish those races off. I think the warm up laps are pretty important on the 50s where they don't get as much heat as quickly. And not having them left us a bit cold for those first corners. Especially on the colder (right) side of the tyre. Something to keep in mind for the organisers I guess.

[chrisc]

[chrisc]

Sigh. I can't sleep.

Here you go guys, a Suzuki GP125 and GP125U service manual... all 136 pages of it. Thanks to Rob for the manual and may it serve to help many in their journey towards 2 stroke euphoria

Be patient, it's a large file (for those who still use windows 98) at 18.0 MB

Suzuki GP125 Service Manual

[Perra.S]

Hi everyone, my name is Per-Erik Sandblom, I'm from Sweden and I'm 22 years old and I got this PM from TZ350

50cc dragster
Hi, we would love to see some photos of your 50cc dragster and other small bike dragsters.

So, a year ago I built a turbocharged 50cc. At that time I didn't know as much as I do know so the project flopped. Well, it revved to over 18.000 rpm but it didn't produce any power to speak of. (And now after finding this forum and pit-lane and all the info posted from Jan, Frits, wobbly and everyone else I have understand the reason why it didn't and also learned a lot lot more of twostrokes.. Big Thanks to you all!) I also used a too big turbo, a garret gt15, and after doing some research now I think a MHI td02 or td015 would have been a much better choice.


A new frame was built thus the old one from the turbotesting was really useless


I then started to playing with n/a engines and building/testing different exhausts of my own design, in the end of the summer I had made around ~10 different. The exhaust nearest to the camera turned out to be the best and produced more power then a very respected exhaustbuilding company here in Europe. It produced 360hp/liter (50cc cylinder) with a smal 21mm carburettor and I'm feeling pretty confident it would have produced even more with a bigger carb.


Then there was some testing with methanol/nitromethane. I had some problems with the fuel not atomizing correctly so if I ever is going to try it again it would be with EFI.

60%methanol, 35%nitromethane, 5%oil



90%nitromethane, 5%acetone, 5%oil (Im just testing on gravel outside the garage so therefore the backwheel spinns the whole way, didn't got the chance to test it on asphalt because a too weak cylinderstud snapped and caused some damage)



So, I'm not sure if any of this is interesting for you but I posted it on request so I hope someone will enjoy reading it


By the way, Regarding Frits talking about rear pulleys with axial slots http://www.kiwibiker.co.nz/forums/sh...post1130482536

There is some pulleys were there is room to machine in you're own slots. Like this one from a Yamaha Aerox, and because it's a std. part you're allowed to use it right?
http://mopshop.de/shop/product_info....5g91mir0trpv33

Thus it's a std. parts and may not be any suitable in racing, just a tip though.

[Frits Overmars]

Hey Per-Erik, seeing your practice roads makes me jealous. I've looked it up:
Sweden: . . . .20 inhabitants per km².
Netherlands: 448 inhabitants per km². It's a wonder we can even breathe .
(By the way: the number for New Zealand is 16. Lucky devils).

PS: Perra, did you try pulleys with axial slots?

[Perra.S]

Hey Per-Erik, seeing your practice roads makes me jealous. I've looked it up:
Zweden: . . . .20 inhabitants per km².
Netherlands: 448 inhabitants per km². It's a wonder we can even breathe .
(By the way: the number for New Zealand is 16. Lucky devils).

PS: Perra, did you try pulleys with axial slots?

Yeah, living on the countryside in Sweden is really nice. It's just to bad I don't do that anymore.

No, I never tried that. But it's certainly a thing that I will try in the future.

[wobbly]

Looks like Gannet Guns are popular in Sweden as well.