Two Stroke Tuning and Engine Rebuilds for the Street

The only real way to obtain power from a two-stroke is to have it professionally tuned.Some customers want a mild tune while others want the most from their machines. To cater for everyone we offer three stages of tuning. Each stage can be added at a later date to bring it up to a higher stage and is done at a reduced price. We have carried out extensive development and Dyno-testing to ensure there is no loss of reliability at any stage.
Our work includes modifying the barrels, flowing the ports, altering the port angles, timings and port areas, machining the cylinder head, modifying and matching power valves and/or altering disc valves. We require just the top end of your engine for this work.

  Stage 1 Stage 2 Stage 3
Singles inc TZR, LC, DT, NS, RG, KMX, RS
Twin inc KR1S, RGV, TZR, LC, RD, RG YPVS
Triples inc GT's, KH's, NS400
Fours inc RG 400, RG500, RD500		 £55
£100
£150
£175		 £100
£200
£250
£300		 £150
£300
£395
£395

For big bore kits and tuning of individual bikes go to the correct page for your bike i.e. Sports 125, RGV250/RS250, KR1S, RG500, RD500, Classic, Racing, Moto-x.

Engine rebuilds

We specialise in engine rebuilds and have unsurpassed experience of all Japanese two-stroke engines. All parts are accurately measured, checked and meticulously rebuilt as you would expect from a race workshop. Below are the prices of labour + parts to carry out an engine rebuild. Obviously it is impossible to know what parts are worn or damaged until the engine is stripped for inspection. Before rebuilding an engine, we strip it and give a fully priced estimate before carrying out the work.

Strip & Rebuild
Top End
Full Engine
Single cylinder engines
Twins-TZR/ LC/ RG/ PV
RS/ RGV/ TZR V/ NSR/ KR1
Four cylinder engines:		 £50
£75
£75
£200

 £200
£200
£240
£300

 

Below a schematic drawing showing the basics of tuning

 

  • 1: Exhaust port. Reshaped & flowed height & area altered
  • 2: Harder plug
  • 3: Head. Machined to raise compression
  • 4: Combustion chamber. Squish band machined, volume measured with Burette
  • 5: Reed valve. Race reeds
  • 6: Crank. Overhauled and trued
  • 7: Inlet port. Reshaped & flowed.
  • 8: Piston. Prox, Mitaka or Wiseco race piston
  • 9:Transfer ports. Reshaped, re-angled and matched

 

Rebores

We bore exactly true to the crankshaft, hone them and chamfer the ports. We stock pattern and genuine pistons. Price per cylinder: £25

Crank Rebuilds

Single cylinder; to strip, rebuild and true crank: - £25 + parts.
Twin cylinder; to strip, rebuild, reset at 180 and true: - £50 + parts.
RD500: £50 per crank + parts. RG500:- £50 per crank + parts.

YPVS Power Valves Repairs

On Yamaha engines ( esp. YPVS350 & TZR250) the PV bushes wear the alloy cylinder barrel. Replacing the seals will not help. We machine the worn area and fit a sleeve that makes it better than new. Re-bush per barrel is £30.

125 cc Sports Bikes:
Aprilia RS125, Cagiva Mito, Honda NSR 125RR, Yamaha TZR 125RR etc

The Race Replica 125's imported into Britain really look the part but are restricted in performance. In most cases the derestriction is fairly simple, if you want to do the work yourself ring me on my "Two Stroke Helpline" for instructions of what to do.
When the full power is released you will still want more performance. This is obtained by Tuning which is done by machining the ports in the cylinder barrel and modifying the cylinder head PRICE: £150
We also supply race exhausts.

We stock most engine parts usually at discount prices.
We specialise in engines but do not take in the complete machine. If you have an engine or gear box problem contact us, our expertise in engine rebuilds is second to none.
Complete Engine/Gear box strip & rebuild - Plus parts PRICE: £200

The cylinder barrel on the RS 125, TZR 125R, NSR 125RR, Mito, KMX125 and NS125 is Nicosil Plated and cannot be rebored.

If the barrel is worn or seized we can replate it PRICE: £95
(If the barrel is scored or cracked we can weld and repair it for an additional £30)

Stage 3 Tune
£150
Complete Engine rebuild
£200 + parts
Nicosil replate barrel
£95
Weld /Machine any damage to barrel
£30
Crank Strip and rebuild
£25

Sports 125
RS 125
Mito
NSR 125RR
TZR 125R
Arrows Exhaust inc Carbon can
£219
£219
£221
n/a
Piston Kit
£60
£65
£44
£37
Con-rod/Big-end kit
£60
£45
£90
£35
Pair of main bearings
£39
£33
£19
£44
Pair of crank seals
£9
£9
£11
£9
Top end gasket set
£15
£13
£10
£10
Full gasket set
£22
£22
£19
£12
Polini 155cc kit
£310
£330
£330
-
Athena 170cc kit
-
-
-
£340
Athena 190 cc Kit
-
-
£320
-
Arrows DT125 R 2004 onwards
£203

Earlier 125's
KMX125
KMX200
TZR125 DT125R
RG125
NS125
Piston kit
£40
£45
£37
£33
£33
Con rod kit
£39
£39
£35
£35
£35
Pair main bearings
£17
£17
£32
£14
£21
Pair crank seals
£8
£8
£11
£9
£8
Top end gasket kit
£15
-
£13
£7
£7
Full gasket kit
£18
-
£16
£12
£12

head

Stan Stephens RS125 Aprilia Special Edition Cylinder Heads

New Aprilia RS125 Special cylinder heads. They are a completely new design. The heads are red anodised and feature upright central plugs with detachable combustion-chamber domes. The heads and domes are fitted with 'O' rings, The heads have far greater water volume around the domes resulting in a cooler running engine. The combustion chamber domes use the latest 2-stroke Grand-Prix technology with a dual angle squish area and a toroidal shaped combustion area.

SS Cylinder Heads
£195

 

 

Please send heads, barrels & cranks to us by Post Office

for Courier delivery please call us to arrange.

All prices are plus VAT

web statistics