ESE's works engine tuner

[TZ350]

Tales from my recent pilgrimage to worship at the Team GPR Temple of speed.



It is always great to get a look around someone else's work space. Scott's Barn is high up in the hills with a stunning vista of the valley below. Scott and Reagan were great to spend some time with. They made David and myself very welcome and allowed us to poke around and discover all sorts of interesting bikes.



The first thing I came across in my tour of this very interesting place was the number one GPR rider inspecting their new bike.

The current GPR bikes are great examples of motorcycle engineering art and frame building but it was the bikes from back in the day that opened my eyes to how much effort that has always gone into putting a competitive front running Bucket together.



Behind the latest examples of GPR racing machinery was what was Scot's first bike from back in the day. There were lots of bikes from yesterday, bikes that show how much effort and competitive thinking has always been put into this class.



I think this is Ziffles old bike and Pete Sales RG50 front end. Both very fast bikes and clever for their day. Pete's front wheel complete with alloy disk brake rotor.

[TZ350]

Pilgrimage - 2



It wasn't all Buckets, here is a rear right hand chain drive VMX Honda 125 in the process of being restored to near new condition.



And a 300cc NSR MC28 in a special Team GPR frame.



The home built Team GPR dyno. These home built dynos appear to be expertly engineered and read a lower but more accurate figure than our Dynojet. That makes their mid 20's hp FXR150's very frightening and puts them on a similar BMEP level as F1 race car engines.



More examples of cleverly engineered RG50's from back in the day. They could be resurrected and still be a very fun ride today.



Discovered among the Buckets in the dyno room was this Ariel Square Four.

[TZ350]

Pilgrimage - 3



Lots of special air cooled engines that had been converted to water cooling.



An air cooled 50 fitted with a water cooled head.



It's not all Buckets, there was an old Harley and the latest KTM in a special GPR frame.

I really loved visiting Team GPR, I hope I got most of the details right and many thanks to Reagan and Scott for their hospitality.

[Hemi Makutu]

I thought you'd been to 'Shangri La'
& found 120 y/o ex-Nazi fluid dynamics scientists still hard at work.. as sent by SS Kammler..



( & FYI, Kawasaki, who also had Nazi science input, had plasma sprayed Al-alloy racebike discs - back in the `70s).

[breezy]

so , between the small end of a 2t conrod and the big end , conrods have a familiar shape.. would anybody in the know tell me why its shaped like this? is there any reason why this is?

thanks for all the info

[peewee]

hey guys im near completetion on this engine and hope I can get some input for the head, im using methanol fuel by the way. cylinder is bolted to the crankcase and ive got a rough cut done on the head, ill check all measurements and do another final cut. because im using Honda piston with longer stroke crank I cut almost 2mm higher into the head and cut the squishband 17* to match the piston. where im needing help is on the comp ratio, width of band and piston to head clearance. heres what I was thinking for a approximate starting place. 16:1, 1.27mm piston head clearance, 50% of area band, dimensions are 90.5mm x 82mm, expected top rpm around 8,000 or so. does these head figures sound about right ? included is photos of piston at bdc and tpc. while im thinking of it I cant remember if I showed my newest bike yet either

[Makr]

so , between the small end of a 2t conrod and the big end , conrods have a familiar shape.. would anybody in the know tell me why its shaped like this? is there any reason why this is?

I-beam is the strongest and most efficient shape to manufacture. I-beam for the simple engineering principle of getting the mass as far away from centerline as possible.

[jasonu]

Pilgrimage - 3



Lots of special air cooled engines that had been converted to water cooling.



An air cooled 50 fitted with a water cooled head.



It's not all Buckets, there was an old Harley and the latest KTM in a special GPR frame.

I really loved visiting Team GPR, I hope I got most of the details right and many thanks to Reagan and Scott for their hospitality.

The buggars could have at least swept the floor before a celebrity such as yourself arrived...

[Frits Overmars]

16:1, 1.27mm piston head clearance, 50% of area band, dimensions are 90.5mm x 82mm, expected top rpm around 8,000 or so. does these head figures sound about right ?

The compression ratio is something for Wobbly, he has way more experience with methanol than I have. The squish clearance seems rather big to me.
Are you going to use that piston in combination with auxiliary exhaust ports?

[wobbly]

The combination of 8000rpm and the 82 stroke gives a piston speed of 22M/Sec, so thats getting up there with such
a big heavy piston.
But yes I believe as Frits says that closer to 1.2mm will be approaching the mechanical limit and this then gives a MSV close to 38M/Sec with 48% squish area.
Methanol at 16:1 will be fine in this engine, closest I have simmed was 78/72 for Land Speed and it was safe as, so you could go a bit higher for short track use.

[mr bucketracer]

The buggars could have at least swept the floor before a celebrity such as yourself arrived...

was part way through a clean up , mind you it did not get much better lol , was good to catch up with rob and met his friend

[jasonu]

was part way through a clean up , mind you it did not get much better lol , was good to catch up with rob and met his friend

Part way thru a clean up, yeah right...Tui etc.
I didn't see my CBR150 motor anywhere.

[peewee]

Are you going to use that piston in combination with auxiliary exhaust ports?

yes why do you ask? dont tell me i made a mistake some how

wob your suggestions sound like a decent place to start so ill give it a try. i figure 2* advance on the base timing is good to start with? i have no idea what the curve looks like

[wobbly]

No - dont advance the ignition.
The Methanol setup works best with the same curve as petrol - but using the high octane and latent heat to generate power with compression.
Once you have a working safe setup, and when you find out what the ignition is, you can then decide to raise the com or change the curve.

[Larry Wiechman]

yes why do you ask? dont tell me i made a mistake some how

Won't those cutouts on the side of the piston (wristpin area) link the exhaust sub ports directly to the transfer ports?