ESE's works engine tuner

**andreas** · 30th October 2021, 11:33

Oh, it's a more complex engine, I see.

**speedpro** · 30th October 2021, 15:11

Originally Posted by F5 Dave

A 4% increase in power?

The Toyota 3.5L V6 I have has cam timing that varies about 40 degrees on both intake and exhaust cams. The peak could be higher I suppose but the spread is what makes it a great engine. I've driven a Holden ute with a LS 5.7L and they are surprisingly similar. Both rated at about 300hp. Point is that peak hp isn't everything.

**philou** · 30th October 2021, 20:37

I'm looking for the rotax 256 workshop manual.

do you know where i can find it?

**andreas** · 30th October 2021, 22:43

Originally Posted by philou

I'm looking for the rotax 256 workshop manual.

do you know where i can find it?

http://www.artmotorsport.com.au/new/...nual%20Pt1.pdf

**philou** · 30th October 2021, 23:24

Originally Posted by andreas

http://www.artmotorsport.com.au/new/...nual%20Pt1.pdf

this is not the workshop manual. just the parts list.

**TZ350** · 31st October 2021, 07:10

2STROKE STUFFING gives a really good explanation of the theory behind his project.

What is needed now is one good, problem free run with the supercharged externally scavenged 50cc nitro concept engine. Did it happen?

**TZ350** · 1st November 2021, 06:52

.

2Stroke Stuffing is building a dyno to test the supercharged 50cc engine. https://youtu.be/9agOt7QbR0c

.

**Henrik Y** · 1st November 2021, 10:23

Hello, I'm going to share some pictures of my Suzuki GP build that I've been working on over the last 1½ years. I'm partially paraplegic after a paragliding accident in 2016, I can stand with support but use a wheelchair for all my daily movements but it is enough for me to be able to sit on smaller light weight bikes and balance them with my legs so that's why I got this bike.

10 years ago I thought cafe racers where cool but now I've got quite feed up with them and puke as soon as I see one of those generic cafe racer seats from ebay. So instead of that I skipped the coffee and went full fairing vintage racer instead.

One of the first test rides.

**Henrik Y** · 1st November 2021, 10:32

The bike was a wreck ready for the scrap yard when I got it, the frame was broken and swing arm where so worn the rear wheel could move like 20mm side to side. So first thing I had to do was fix the frame, cut out the broken parts and weld in new material. I did also add extra tubes and stiffened the frame.

I started making the fuel tank just to see if I could pull it off or not and if it turned out okay I knew I could get on with the build and order a fairing and such. It wasn't easy having nowhere to be but outdoors, setting up wind covers when welding and having to pack up if there was any risk for rain.

**Henrik Y** · 1st November 2021, 10:40

The swing was so worn that the rear wheel could move like 20mm side to side, I can't understand how they where able to even ride this bike in the past along with the broken frame. But then it hasn't been in traffic since 1992.
I cut of the old bushings and replaced them with KTM 65cc swing bearings. And then I made bushings to press into the frame that I drilled out as it was worn as well from the swing bolt.

Then I ordered a VMC ET7 Vespa cylinder. Diameter 58mm and original stroke 51mm so close enough for my GP125.

**Henrik Y** · 1st November 2021, 10:52

Got a HPI ignition, they had a kit for Suzuki TS50 so I took that flywheel as the cone angle is the same but the stator plate is different so had to measure and take the closest available. It's tight against the inside for the screws and it need's to be spaced out a bit.

The engine case requires some welding to make the cylinder fit. Turned down the cylinder head to get the right height and then added a grove for an o-ring. Filled up the holes around the intake with JB-weld so I could increase the size and shape it.

**Henrik Y** · 1st November 2021, 11:04

By this time I've got a tiny little shed on wheels where I have a little Chinese lathe and a work bench so I could do some work during the winter(here in Sweden we get snow and -20°C).

I built up the intake with weld and then bored it to size and it's 32mm inside just as the carburetor. Then I bored the clutch case and made a grove and a top plate to seal it with an o-ring. Made the seat pad and it is "plopp" mounted with studs and cable rubber grommets, I used the same style of mounting for the side covers as well.

And then I made the front fender, now I've got the cheapest Chinese English wheel which helped a bit with smoothing it out but all the shaping is done with the mallet and then chasing small bumps with it as well so the wheel is not some magic tool that spits out perfect parts. I also have a bracket under the fender to help stiffening the fork.

**Henrik Y** · 1st November 2021, 11:16

I built the pipe for a little wider power band and at first it got a little high so couldn't use it all before the vibrations got to crazy and I couldn't rev out in 4th gear to get into the power band in 5th, so I lengthened it a little bit and lowered the cylinder so the exhaust got around 189° and it got better. But crank balancing is still to come.

Braced the swingarm, built a cooling shroud for the cylinder, battery holder and silencer. I got a zinc plating kit so I could plate my own parts and freshen up the old. It has to pass MOT so important the get the exhaust sound down as much as possible.

**Henrik Y** · 1st November 2021, 11:34

I balanced the crank after the Dragonfly75 calculator and it turned out very well, got rid of the nasty vibrations and I can rev it out so now the power band is between 8-11krpm. I had to fill in the original holes with aluminium and then put hollow steel plugs on the opposite side, not what you normally expect when putting on a slightly heavier piston.

The wider range pipe makes it possible to over rev a bit but a bit less peak so it doesn't quite reach 11krpm in 5th gear and tops just above 150kmh at the moment. Of course it's fun to chase a high top speed but for riding on the twisty country roads it's "just perfect"(in Allen Millyards voice).

As I said in the first post I'm partially paraplegic and 100% paralyzed in the red areas, I can put my feet up and down on the pegs but that's it, and it's hard enough in this crunched position. On more upright bikes I can use pedals with slight modification like enlarged toe heal and such. First I tried with a lever on each side that I just hade to kick forward to shift up on one side and down on the other. But it away to much focus and interfered with my riding position a lot so I scraped that idea and tried a hand shifter instead and it worked out just perfect. Now I can shift in a split second with my chest against the tank not having to look down at my feet and not missing gears 20% of the time.

**Henrik Y** · 1st November 2021, 11:43

I also built a hydraulic clutch, took a Hope bicycle brake handle and modified it to maximize the effective stroke with a new piston with different lengths and sealed a hole in the reservoir. Then made my own slave cylinder using a seal from the bicycle brake caliper which turned out to be just the right size. 10mm diameter in the lever and 19,7mm in the slave cylinder. Gives me about 2,5mm travel on the slave cylinder.

The bicycle brake lever is smaller and easier to handle with the rear brake on the handlebar as well. It's a little heavy for 1 finger use but 2 fingers is very comfortable and easy.

And that's my last post for now.