ESE's works engine tuner

[F5 Dave]

The modern take on powerjets is to turn them off after peak power to extend the rev range. This assumes that you are happy for your engine to rev that much further past peak power & on many buckets perhaps this is not so good unless you have uprated the crank assembly. The jet will start to flow, depending on its position. Some don't seem to work well without an airbox if they aren't very prominant, or perhaps if the suction isn't so much (putting big carb on a smaller cylinder). In some cases they are best blocked off presumably if the air jet doesn't match very well & is tending to increasing richening with airflow as it is.

[wobbly]

With all the talk about wanting to utilize only a couple of gear changes per lap, I would have thought that the solenoid powerjet was a gift from heaven.
A late model well tuned RS125 will rev to around 12400 if the PJ is disabled,turn the PJ function back on and it will go to 13800+.
Its so simple and you retain exactly the same lower rev power,but with easily another 1000rpm to work with you have the choice of adding teeth on the back, getting better acceleration from torque multiplication, or keeping the same gears - but increasing the terminal speed.
And from the dyno curves I have seen, most of the 100 buckets with short stroke lengths, arent even beginning to stress the bottom ends - with less peak rpm than the 54.5mm stroke 125 bikes or karts that will easily run to 13000 all day.

[richban]

With all the talk about wanting to utilize only a couple of gear changes per lap, I would have thought that the solenoid powerjet was a gift from heaven.

No matter how much power you have, or how peaky or not the engine. I would think you would want to gear the bike to use the full gear box spread for any track. You don't want to be waiting around for the power to build. You want it all in your hand when ever you twist the throttle. We are not talking about 200hp here. Crack it open and smile.

Small disclaimer. I seem to hold the record for most high sides on a bucket in wellington. But don't let that stop you from cracking on the power in the most violent fashion physics allow. You will get the the next corner quicker I promise.

Problem solved.

Now pack you your bikes and come down to wellington this weekend for some racing.

[koba]

Small disclaimer. I seem to hold the record for most high sides on a bucket in wellington. But don't let that stop you from cracking on the power in the most violent fashion physics allow. You will get the the next corner quicker I promise.

That last crash when I almost ran you over was quite spectacular...

[Henk]

Now pack you your bikes and come down to wellington this weekend for some racing.

Oh all right then, if you insist, you're not going to call the day off because of crap weather or some other weak excuse are you?

[RMS eng]

With all the talk about wanting to utilize only a couple of gear changes per lap, I would have thought that the solenoid powerjet was a gift from heaven.
A late model well tuned RS125 will rev to around 12400 if the PJ is disabled,turn the PJ function back on and it will go to 13800+.
Its so simple and you retain exactly the same lower rev power,but with easily another 1000rpm to work with you have the choice of adding teeth on the back, getting better acceleration from torque multiplication, or keeping the same gears - but increasing the terminal speed.
And from the dyno curves I have seen, most of the 100 buckets with short stroke lengths, arent even beginning to stress the bottom ends - with less peak rpm than the 54.5mm stroke 125 bikes or karts that will easily run to 13000 all day.

or you could get a PJ carb off an old IT175

[Buckets4Me]

or you could get a PJ carb off an old IT175

Attachment 240858 just taking a look for one

[Yow Ling]

or you could get a PJ carb off an old IT175

Does it have a solenoid to turn it off ? Needs to be able to be controlled by ignition

[ajturbo]

That last crash when I almost ran you over was quite spectacular...

Almost..ALMOST... is not good enough!!!

[bucketracer]

I would have thought that the solenoid powerjet was a gift from heaven. A late model well tuned RS125 will rev to around 12400 if the PJ is disabled,turn the PJ function back on and it will go to 13800+.

Attachment 240865

Fitting an electric PJ carb won't happen over night but it will happen, as they say .......... an elec PJ carb is waiting its turn in the que of development ideas scheduled to be tried on TeeZee's bike.

[F5 Dave]

. . .
And from the dyno curves I have seen, most of the 100 buckets with short stroke lengths, arent even beginning to stress the bottom ends - with less peak rpm than the 54.5mm stroke 125 bikes or karts that will easily run to 13000 all day.

Sounds good, but often buckets are made from old beaters that have been lying around. That being said we used to rebuild our RG50 cranks every year, with std parts they were reliable to 12,500 over rev for ages, but take them to 13 regularly & they'd let go. Commuter parts. obviously some engines are better suited for revs than others. An MB will out survive a TS at revs.

[wobbly]

Most of the issues with the old cranks will be the cage construction of the big end bearing.
The "new" design has a flat outer shape, with no indented rib to support the rollers.
The flat design has no stress raiser corners, and this technology is what allows todays 2T engines to rev reliably to the mechanical limit of the parts - not the cage flying to bits..
The short strokers would be reliable to over 15000rpm as long as the rod is physically well designed using the good cage design.
Todays engines dont "wear out" the crank pin, the rollers ,or the rod big end, its the cage that rubs on the rod bore and eventually fails.
I have done 1500Km of racing miles on a pair of rods in a Rotax Superkart engine, and done this 3 times, just changing the big end assy with no discernable wear on the hardened parts.

[husaberg]

TZ mentioned how the Honda RS pipe inlet is larger than the GP exhaust port outlet, while this is common place on 4 strokes for the purpose of AR I wasnt aware it was used on 2 strokes but on reviewing RSA photos I came across this
Attachment 239992
Attachment 239993
Jan Thiel "One wants the pressure wave coming back into the cilinder but NOT the burned gases that are hot and can cause detonation!"
Makes sense.

as above found this on Honda rs125
Space bar now working again

[Kickaha]

I have done 1500Km of racing miles on a pair of rods in a Rotax Superkart engine, and done this 3 times, just changing the big end assy with no discernable wear on the hardened parts.

With that one sentence you've just made me doubt everything you've ever posted
(providing you're talking about the 256)

I find it extremely hard to believe a Rotax could complete one meeting with out exploding and requiring a total rebuild requiring incredibly expensive parts which take months to acquire

[bucketracer]

The latest 8 round F4 series is over. Finishing order of the bikes by engine type ......... new season starts in a few weeks.

RS80 (overbored Derbi 50 2-stroke)
CB150T (overbored CB125T)
RS80 (overbored Derbi 50 2-stroke)
FXR150
FXR150
FXR150
FXR150
FXR150
CB150T (overbored CB125T)
FXR150
CB150T (overbored CB125T)
FXR150
FXR150
FXR150
GP125 (2-stroke) highest finishing Team ESE bike.
FXR150
FXR150
FXR150
FXR150
TS125 (2-stroke)
FXR150
GL145
FXR150
Derbi 70 (2-stroke)
MB100 (2-stroke)
FXR150
FXR150
CB125T
CB125T
MB100 (2-stroke)
GP125 (2-stroke)
FXR150
FXR150
FXR150
FXR150
CB125
FXR150
CB125T
FXR150
CB125T
GP125 (2-stroke)
FXR150
FXR150
XL125

Damiens photos from round 8, Sunday 12-6-11 at Mt Welly http://www.flickr.com/photos/dty1/se...7626941175616/