TS125 Powered Bucket

[jthespanner]

Hello Lads and Ladess's

I have recently built a new bucket bike specs as follows.

1989 GSXR250 (GJ72) frame
Front forks stripped and rebuilt, 20w oil, extra pre-load on springs
Standard rear shock.
GSX1300R Rear sets with custom solid pegs and sliders.
13mm GN125 front Master Cylinder
Single Tokico Front 4 piston Caliper
XJR1200 Front Disc
Standard 2 piston rear Tokico Caliper
GSX250 Rear Disc
1982 TS125ER Engine Standard Porting (at this stage)
Boyesen Reeds
24mm OKO Carb with 100mm alloy Intake Trumpet
TF125 expanion chamber TS125 Exhaust and muffler
Chinese CDI Ignition box

My Question is as follows.
I have a #30 idle jet. and #100 main jet currently fitted to the carb but my bike is not running right. Does anyone have experience with PWK or similar carbs fitted to these engines that can give me any idea of jetting I will require. I have some rolling road time booked in the coming weeks but any input will be much appreciated.

Cheers, see you on the track

[TZ350]

.

Before the dyno session I would get rid of the trumpet and buy a range of main jets in every step from 90 to 160. A 100mm trumpet will make any descent 2T run like crap. NIKAU on Trademe is a good trader to try for the jets.

[layton]

Cool! Can't wait to get out on the Nelson kart track

[jthespanner]

.

Before the dyno session I would get rid of the trumpet and buy a range of main jets in every step from 90 to 160. A 100mm trumpet will make any descent 2T run like crap. NIKAU on Trademe is a good trader to try for the jets.

I originally had a short 40mm or so trumpet fitted to the carb. I was getting a lot of fuel scatter. I would end up with oil residue on the surrounding frame. It definitely runs a lot better with the longer trumpet. It starts a lot better and will actually rev. Previously it would barely do these.

I have every size jet from 80 to 150

[F5 Dave]

The right jet should sort that, lose the trumpet, TZ is right, you really just want a ring to smooth air from all directions but that will be minimal increase.

My RG50 had same inlet layout but with much more timing. It was pretty messy despite being tuned to a very high level with like over 400 dyno runs over many years.

The right jet for your bike could be anything. You mean 30 pilot jet I assume.

Your peak power will be about 6-7000rpm with that setup I'd guess. They are super lame from std but will haul a sheep up to the top paddock and not judge you for what happens next.

Check out my build for Petes TF elsewhere . Heck he might even get it near a track one day if he'd just finish details off. Then we need a pipe moodded to get some revs so we can crank some real power.

[TZ350]

It definitely runs a lot better with the longer trumpet. I have every size jet from 80 to 150

Great, getting it to run well is the big battle and a good collection of jets is a great help.

If you want to start delving into two stroke tuning and porting theory, there is a lot of general 2S tuning tec info here:-

https://www.kiwibiker.co.nz/forums/s...tuner/page2000

And pages 500, 1000, 1500 are worth a visit too.

[jthespanner]

Ok so a few more main jets I ordered have finally arrived.

As of this afternoon #95 main jet fitted to carby. And I have reverted back to the 40mm trumpet I started with which is made from an intake boot out of an old GSXR1100 airbox I had lying around.

Fresh plug fitted BR7ES (one step hotter then standard) to help avoid fouling during tuning and I plan to run B8ES plugs (standard fitment) once tuning is sorted.

I have rewired the cheap Chinese ignition fitted to the bike. and tomorow I will wire an identical plug onto a spare TF125 CDI in case its the Chinese CDI that's causing my tuning woes.

Bring on the Dyno! I'll tke some photo's tomorrow. Any further suggestions would be greatly appreciated.

[F5 Dave]

Try a 9.

Erm std ignitions will hold you back to pedestrian revs,

[jthespanner]

Try a 9.

I thought NGK's numbers worked backwards. The smaller numbers were hotter?
https://www.ngk.com.au/technical_info/heat-range/

Erm std ignitions will hold you back to pedestrian revs,

I haven't fitted standard ignition. Just wired it up to quick change on the dyno for fault finding purposes if need be.

If I need to a programmable unit such as Ignitech is on the cards. Although I'll have to wire in a 12v battery total loss in order to run it..

[speedpro]

There's a couple of things you can try if you want to either blow a hole in the centre of the piston or nibble away the top edge.
1 - Use a hot plug
2 - Use poor fuel
3 - run it lean
4 - run it advanced
5 - all of the above.

I've had a lot of success with the above suggestions.

Put in a cold plug, fresh fuel, start with the biggest main jet you own, go easy on the timing, run rich oil mixture(40:1 with Motul 800)

Shit ignitions don't retard with revs so you either end up with too much advance at revs, it runs great at lower revs and blows a hole in the piston, OR, you back it off so it is good up top and it is weak at lower revs. What can feel good blasting up and down the street, or on the dyno, can wreck pistons on a track when thrashing.
Cold plug, good fuel, slightly rich, slightly retarded may knock the edge off but it should survive a thrashing. Extra fuel is useful to assist with cooling and keeping the motor perking once it gets real hot on about the 3rd lap.

Whatever you do, don't buy a 4-stroke

[TZ350]

If I need to a programmable unit such as Ignitech is on the cards. Although I'll have to wire in a 12v battery total loss in order to run it..

Team ESE uses light weight racing Lifan units and re wind them for 12Volts to run their Ignitec ignitions. They use a voltage rectifier/regulator and a capacitor. No battery required. For all the details follow the link below.

Attachment 329021

How to make a decent light weight racing 12 Volt generator stator for the Suzuki GP/TF/TS RG50 from a Lifan after market magneto kit. We have spun these to 14,000 rpm plus on the dyno and they have proved reliable on the track.

[husaberg]

I thought NGK's numbers worked backwards. The smaller numbers were hotter?
https://www.ngk.com.au/technical_info/heat-range/
.

Hotter plugs glow practically incandescent in a highly tinned bike, useful for cold stating a diesel but not on a race two stroke.
As speedpro says hot plug = hole in piston.
You should not use anything below a 9.
With correct fueling it will run fine without fouling a NKG10 or higher.

[F5 Dave]

There's a couple of things you can try if you want to either blow a hole in the centre of the piston or nibble away the top edge.
1 - Use a hot plug
2 - Use poor fuel
3 - run it lean
4 - run it advanced
5 - all of the above.

I've had a lot of success with the above suggestions.

Put in a cold plug, fresh fuel, start with the biggest main jet you own, go easy on the timing, run rich oil mixture(40:1 with Motul 800)

Shit ignitions don't retard with revs so you either end up with too much advance at revs, it runs great at lower revs and blows a hole in the piston, OR, you back it off so it is good up top and it is weak at lower revs. What can feel good blasting up and down the street, or on the dyno, can wreck pistons on a track when thrashing.
Cold plug, good fuel, slightly rich, slightly retarded may knock the edge off but it should survive a thrashing. Extra fuel is useful to assist with cooling and keeping the motor perking once it gets real hot on about the 3rd lap.

Whatever you do, don't buy a 4-stroke

I run 40:1 in my dirty big slow revving 300. 30 for my 50 or 100.

But you wouldn't believe how awesome my 300 is.


Bwaaaarp. Fuk its amazing.

Sorry been out riding today. So much better than a poxy foul stroke.

[jthespanner]

I purchased an expansion chamber of a Malaysia special RGV150 (the air cooled one not the watercooled RGV150 people race).


I had to chop and weld a small bend into the down pipe as the exhaust port on the TS125 engine obviously comes out at a different angle to the RGV150 exhaust. No muffler fitted yet (hopefully this arrives Tuesday).

Took my bike for a quick blast around the block. HOLLY FECKBALLS what a difference!!! Clearly my original bodgy TF125/TS125 chamber and exhaust was the main restriction.

Cheers for all the info regarding hot plugs. I'll revert back to a colder one.

[jthespanner]

So I welded up some tubes chopped off an old bicycle trailer (of all things) to make up a dodgy looking exhaust using the standrd RGV150 muffler for now.

So results are in. My bike runs 100% better! The way it should have been in the first place.

I managed a few tuning runs around the streets outside my place of work. #95 main was way too lean. I jumped straight to a #110 knowing FXR's like a #118 (ish) on a 28mm OKO carb. Still a touch lean & confirmed this by looking at the sparking bolt.

Swapped in a #115. Reverted plug back to a B8ES (standard temperature plug for the TS125). Quickly re-checked the idle mixture adjustment. and added another 1/4 of a turn out to suit the shorter intake trumpet.

One last quick tuning run, and then pack up my tools and head out for afternoon tea with my family.

I plan to fit a B9ES plug (on advice from previous posts, cheers lads) and I will check the plug and probably swap in a #118 and maybe even a #120 main jet. I still need to replace the main gearbox seal behind the front sprocket as it has developed a leak due to the engine having previously sat dormant for a few years before I got off my arse to piece this bike together.

Also I need to lighten the flywheel as I have been informed from a couple of reliable sources that the crank will break at the flywheel when I rev the engine to higher than sheep shagging RPM.

I'm so relieved to finally be making some headway with the tune of my Bucket, as previously I felt like I was going round in circles with the tuning on this bike.