[Winter-Spring Project] Suzuki TS125R |

[J11]

Hello all,

I decided to make a project thread about my other bike, because someone suggested that at my other project topic (Derbi DRD 81,4cc).



About the bike..

I bought the Suzuki TS125R '97 3 months ago. It's engine had been completely re-build, but didn't work fine at all because of bad jetting.
It looked like a piece of shit.. and it still looks like a piece of shit.
But not for long.. next week the RM 125 '03 gas tank and plastics (used) should arrive. And I already have a SDG seat for it.

Next week I should get my YZ250 '90-95 engine w/o carburetor.
I've sold the TSR engine and waiting for the money of it.

The YZ engine is with 68x68mm bore x stroke and has 5-speed gearbox.
Because I'm a horsepower freak.. the engine won't be going to frame without porting work and machining.

To-Do (1-2 weeks)

• Check the YZ engine's condition and replace all gaskets, seals, piston rings and of course port the shit out of it
• Buy a Keihin PWK/PWM 38-39,5mm carburetor, HGS exhaust chamber (Honda CR250 '07), Doma Racing silencer, RM125 '03 subframe, Ufo Firefly headlight (used), new sprockets (14-45), chains (RK, gold) and better footpegs (RM 250).
• Modify the RM 125 '03 gas tank, plastics, subframe and seat to the frame.
• Carbon fibre sticker to frame (covering the paint)

I'm going to use the bike as my daily, but also riding a lot enduro.
Now it has new Michelin M12 Cross competition tires, so it'll be a blast to ride on snow/sand!

Before summer, I'll buy DID gold anodized supermoto rims (3,50x17" and 4,50x17") and Dunlop Sportmax Mutants.
Might buy a 310-320mm brake disc for it.. and smaller rear sprocket (42).

Everybody's interested about power goal.. so I'm going to try my best to achieve 55-57bhp at back wheel.
It's A LOT of a '90's 250cc smoker engine.. and even for the new 250cc 2-T MX engines it's a lot.

I'll try to keep the thread updated atleast every week, but best would be to update nearly everyday.
Not going to post any small updates, thought.

Until next update..
Comment & suggest what I could do the other way or etc.!

[Mclaren]

Oh wow, I'm really excited for this build.
If you'l get that kind of power out of a 250 I'l be very impressed.

[J11]

Heh, me too.
But I bet it's possible to achieve it with E85 fuel, porting work and machined combustion chamber.

Anyways.. even if I don't reach my bhp goal.. the TSR is going to litreally fly!

[Mclaren]

Yeah, I do think that that goal will be achievable, but even with 50+ bhp you're still planning on using it as a daily?

[J11]

Yea, well.. other option would be to ride the Derbi.

Today I picked up the RM gas tank and plastics.. their in okay condition. A little bit cleaning and they'll be nearly perfect.
Also got a smoke tinted LED tail light.

I didn't get the TSR engine out.. it's quite a bit challenge to get it out of the frame, which is filled with a lot of useless electrical stuff.. but tomorrow it'll be out and in the post office.

The YZ engine seller is going to send the engine on this week..

E:
Fitting the gas tank and seat..


Also found a 45H rear sprocket with 520 chain pitch. + it's made of aluminium.
So I'll try out 14-45 sprockets with the YZ engine..

And I got the TSR engine out and taking it to the post office today.

[tracing]

Nice! Looks much better than all black.

[J11]

Thank you! Doesn't look like a bike from the '90s?
It's going to look way better on next week with a RM125 subframe (aluminium) and all the plastics attached.. + the YZ engine and HGS exhaust chamber.

Need to sell some parts, so I can buy the Doma Racing silencer.

[ebervanroij]

Really looks nice those new plastics! Looks much younger

[royvi]

Very interesting project, sure one of a kind.

I would use a Keihin PWK 38 Airstriker, very good carburetor. Has proven itself at many dirtbikes and is a very commonly used way to improve power. Second, it would be a shame if you use a CR250 '07 exhaust pipe. A CR250 has for example totally different exhaust valves (Electronic) than a YZ250, so the power delivery of the YZ wouldn't align with purpose of the exhaust. Besides of that, you're planning to add roughly 8 bhp by changing the cylinder ports and all that. So an HGS exhaust made for a stock CR250 would constrict that poor engine. You rather use an exhaust special made for your particular engine. I don't know if there are any exhaust manufacturers around your place, but in the Netherlands we have a few of them that aren't that expensive.
You have to burn some money for an exhaust like that, but it surely improves your engine and helps you to reach that bhp goal.

Good luck, i'm following this thread.

[J11]

Thanks!

CR250 '04 Dyno


As you can see, the CR produces in stock condition (expect the jettings are different) about 47,5hp@8,000-8,500rpm.
I'm going to aim to 55-57hp@9,250-9,800rpm with E85 fuel.
-higher compression 8,8-9,5:1 corrected compression (I'm going to need a exhaust temp. meter for this, to find out the best compression ratio for top end power)
-different porting.. I need the cylinder first, before making ANY plans for it.

Differences between the CR and YZ engines:
-bore and stroke:
YZ=68x68mm (bore x stroke)
CR=64x72mm
-exhaust valve type (electronic vs. mechanical), like royvi said at above
-exhaust ports; YZ has triple exhaust port and CR twin exhaust port - they produce a different "gas wave", which will effect how the pipe works.

It would be the best to plan and build a few different pipes for the modified engine.. but there's a problem: money.
It costs about 300-400 euros to get one built by a professional - or even more. Depending of the builder.

I have a few friends, who can build great pipes.. I have made a few 2-stroke pipes too, but now I don't have a welder.
Going to buy a Stahlwerk AC/DC TIG on summer, when I get some money of the summer job.. the Stahlwerk is actually a chinese welder with a different logo and color.
It costs about 600 euros.. but some have actually said it's a good machine for an amateur/beginner. IF I earn more money (>1500 euros), then I'll just buy an used Kemppi/Esab TIG welder..

Anyways.. I'm going to try the HGS CR pipe at first.. since it doesn't cost a lot and has zero dents.
And I can't find any better deal of a 250 smoker pipe.

Edit. I'll pick up the YZ engine tomorrow from the post office.
________
Edit #2

So, I've picked up the YZ engine and today starting to tear it up. Tomorrow I'll check the parts condition and start planning the porting work.

Since I'm going to make the engine rev more and produce a lot more power at high rpm, it needs a lot of modifications.

February
-Boyesen Rad Valve
-'83-89 YZ250 connecting rod kit (+5,00mm longer)
-Keihin PWK 39,5mm carburetor (Eric Gorr tells at his guide, that it's the best choice for a revvy 250cc smoker)

[J11]

Now I have some information of the engine..

-Exhaust port: 191,4°
-Transfer ports: 121,4°
-Blowdown 35,1°
-Bmep: 9,6bar@8,000rpm (41,7hp)

I need to measure the squishclearance (mm), squishband (%), volume of the combustion chamber (ml) and then calculate corrected compression ratio.
Also I need to measure the area of the ports (mm2), so I can calculate the right size for them for +9,000rpm peak power.
+ I need to ATLEAST keep the bmep at the same.

Update (1.2.)

• Engine being fitted
• Ordering the rear subframe on next week's monday or tuesday
• Started porting work for the cylinder

Bad news:
• Cylinder has marks of a seizure (nicasil coating missing from below the exhaust port)

But that's not going to be a problem - the engine can be started, but won't last more than 20 hours of riding.
So the cylinder is going to be re-plated on the end of February (costs about 200 euros).. right now I'm planning on getting it bored to 72mm and using a KTM EXC300 piston (Wössner). Then the displacement would be 276,9cc's!

OR I buy a '96 YZ250 cylinder and get it re-sleeved to 82mm's and build a Öhlins 360cc -copy. That would be about 2 times more expensive option.. so I don't think it's that great idea at this point.




_____________

Update 5.2.

Buying on next week from my friend a YZ125 suspension..
and on Saturday I'm starting to fit the RM125 rear subframe,rear plastics and footpegs.


Seat isn't on the right position at this picture..

Also, going to post some pics of the cylinder on Saturday or Sunday.. depends how busy I'm on the weekend.

Next month, I'll do a re-build for the engine.. which is going to cost about 700-750 euros, including the cost of re-plating the cylinder. Not that bad, since my friend's GasGas EC125 '10 engine's re-build cost almost 800 euros..

[J11]

To-do:
- use sledge hammer to the frame (so the engine drops a little bit lower)
- weld the engine mounts
- remove the original rear subframe and make mounts for the RM's
- swap the YZ125 '93 suspension (KYB)
- buy a carburetor (probably a Keihin PWM 38mm, flat-slide.. because the seller of the PWK 38mm air striker is asking 150 euros of it)
- ride

On the #1 picture, there's a original seat of a RM125 '06.. because it has original mounts. Going to make new mounts for the SDG seat (so it can be attached to the rear subframe).
_______________

UPDATE 25.2.

The TSR is now nearly finished..
Suspension needs some maintaince, but it can be ridden at current condition.

Tomorrow I'll go pick up the carburetor (Keihin PWK 39mm Air Striker) from the mail office..
Then the bike is ready for the #1 start.

On April:
- full maintaince for the engine, brakes & suspension
- more horsepower!
- supermoto wheels (3.50x17 & 5.00x17)
- GoPro

and some other cool stuff..

PS. I'll post you some fresh pics of the bike tomorrow (26.2.).

[J11]

Sorry for delayed update.
____

Not too much has happend in two months.. mostly, because of lack of money and time.
The TSR needs new 'frame pipes' for the engine, so I can be sure it'll be strong enough.
The frame will be a lot stiffer and stronger without too many welds. + I'll be using 25x2,5mm steel pipe to build
a frame for the engine, and then fit it to the main frame by welding from 8 different places.

I'm going to port the cylinder on weekend.. if I have enough time.
Bought 500g's of Loctite 3479 epoxy - love it! That's what I used on my Derbi's cylinder (when I ported it to it's final stage).

I sent a question for Airsal, if they could bore and re-plate the YZ cylinder to 72mm.. it costs 449,03€ including a 71.93mm Wössner piston kit and taxes. Probably about 500€ including the postage costs.
But I could buy the piston kit from Finland for cheaper.. probably sending the cylinder to the Airsal's factory on summer, if I get a summer job. Or sell my Derbi (which isn't going to be easy - 'cause it's way too fun ride).

I also have been thinking about buying the '99/newer YZ250 crankshaft, because it's stroke length is 72mm.
Thought the current crankshaft could be modified for longer stroke.. need to think & calculate things to find out, which will be more reliable and cheaper option.

What I have been planning so far for the engine..
- 72mm cylinder; ported for more top-end power
- Cylinder head with interchangeable combustion chamber; 1.25mm squish clearance, 42% squishratio and 9,6:1 corrected compression ratio
- Wössner piston kit (KTM EXC300)
- Longer connecting rod (Pro-X) ; '83-89 YZ250 OR Maico 400/440 conrod. Depends of the crankshaft
- Reedvalve riser block (5,0mm) with KTM SX250 '04 bolt pattern
- Moto Tassinari VForce 4 reedvalve & KTM SX250 '04 intake manifold
- Keihin PWK 39mm Air Striker (already have)
- Hinson clutch basket
- Barnett clutch plates & springs with 2mm spacers
- New bearings & seals by SKF
- Stock ignition with lighting coil + stronger ignition coil and Ignitech's fully re-programmable CDI unit
- Custom made exhaust chamber with Doma Racing silencer

This setup should be producing more than 57bhp from back wheel.
Going to be running on E85 fuel or if possible.. methanol, which I am going to need more than 1 000 litres to be able to ride this bike the whole summer.


Here's what the TSR looks like currently.. waiting for the KYB 46mm USD forks to be fitted.


Custom made "dog bones"


Rear.. it needs the RM125/250 '03 airbox. Looks kind of stupid without it.



Currently the biggest goal at this month is to get this thing fired up and make it rideable!
I still need to work with the wiring.. got to connect the lights, kill switch, Trail Tech Vapor.. etc. etc.

If everything works out fine - I will achieve the goal.

[Mclaren]

Can't wait for it too be finished, those plans sound really good.

[davedb]

Great project mate. I always thought you lads from Suomi drove Gasgas 125's most of the time.

Regards

Dave

[J11]

Thank you!

@davedb - Well, GasGas EC 125 isn't the most popular.. but are pretty common - when compared to Suzuki TS125R or Honda CRM 125.

Picked up yesterday my headlight..
Doesn't look that good on the TSR, but it'll do it's job.
When I have more money for "tuning stuff", I'll probably buy a Racetech Genesis or Ufo Firefly headlight.

With headlight.. HP Master (aka KTM EXC headlight -replica)


Tomorrow I'll buy a JT 48H rear sprocket and order new axles for the wheels and swingarm.

Found a mint HGS exhaust chamber and silencer, made for YZ250 '05.
The seller asks 200 euros for the whole set - for me it sounds like a great deal.
Probably going to order it next week.

[D25]

let me guess most popular is ktm in your country?

[J11]

Yes, the KTM EXC 125 is the most popular of 125cc 2-stroke enduro/supermoto bikes.
The owners are quite hilarious sometimes.. "45bhp from back wheel and top speed +180km/h"

[J11]

Got sick last weekend, so didn't start porting the cylinder.
I'll start the work on Saturday.

I have planned, that the TSR will be rideable next weekend.. if everything goes as I have planned.

[D25]

nice bike only it look a little bit .... how do i put it.... empty?