Hi all,
Just thought I'd post these technical articles, they're a handy reference for a new starter or even as a reference when at the track. Don't forget these are USA based so some of the articles aren't relevant, so use you discretion!
http://srsengines.com/technical-library/shifter-kart-engines/
1 2001 Honda CR125 Power Unleashed
2 Stock Honda CR125 Cylinder Comparison
3 SRS Engines Hybrid Float-Twin Pump Carb System
4 Cooling Stock Honda CR125 Engines
5 Best Reeds for SKUSA Stock CR125 Shifter Karts
6 Honda CR125 Cold Weather Jetting
7 Pump-Around Carb System Installation
8 Why PWK or PWM - Stock Moto CR125 Carbs for SKUSA
9 Summer Tunes
10 VolksKart - Stock Honda Shifter - The People's Class
11 Best Stock Honda CR125 Shift Points
12 Shift Happens
13 Octane Requirements for Spec Honda 125 Shifter Kart Engines
Comments4
Re: Stock Honda Technical Articles
Dunno what exactly that means Squizzy, but here's some more technical articles for anyone who's interested. As with the first ones, these are from a US based supplier so I've added some notes to suit Australian Stock Honda's, but everything is more or less the same. http://swedetechracingengines.com/techinfo/?cid=62993
Spark Plug
Standard Size - NGK BR10EG or R7376-10
Shorty Style - NGK R7282-10
Must use the NGK TRS1225 Plug cap with short style plugs
** You must use a resistor type spark plug **
Spark Plug Gap – 0.024” – 0.028”
Transmission Oil
Motul Trans Oil 10w30 or Motul Trans Oil Expert 10w40
New engine-650ml (21.9 oz)
Use 50ml less for routine oil changes ( 20.0 oz )
We recommend changing the gearbox oil every 4 hours. Oil is cheap compared to the cost of replacing clutch or gearbox parts. If possible, change the oil while the engine is warm.
Two-Stroke Engine Oil
Motul Kart Grand Prix or Maxima 927
Australia Note: Many here also use Elf 976 and Castrol 747 without Issues.
32:1 for break-in and regular use (626ml per 20L )
20:1 has also been successfully used (1L per 20L)
** DO NOT USE PUMP FUEL ** Recommend VP C12 or AV Gas
Jetting
The Stock Moto Engine for karting application will not run properly run on pump fuel. SwedeTech recommends the use of VP Racing Fuel’s C12 product.
Keihin 38mm PWM - recommended by SwedeTech
Jetting range is based on Sprint Kart setup using the SwedeTech GFS system and a 1999 cylinder combo.
160 -180 main (centre of the carb, 6mm hex ) **Recommended to start with a 182 jet and work your way down from there
Main jet supplies fuel from ½ throttle to full throttle
50 - 60 pilot ( next to main jet, use 5mm flat screwdriver to remove )
Pilot jet supplies fuel from 0 – ¼ throttle
DGJ needle - 3rd from top. Experiment with 4th & 2nd clip from top.
Needle regulates fuel from 1/8 throttle to ¾ throttle
Air Screw (side of carburettor body, above fuel inlet ) – 1 Turn
* For new engines purchased directly from SwedeTech and engines maintained by SwedeTech, we offer a jet chart to help customers tune their engine for optimum performance.
Clutch adjustment
You need about 3/8" to 1/2" free play at the end of the lever lifter arm on the engine. You shouldn’t have more than 1 inch of travel when you engage the clutch lever. When the clutch lifter arm is at rest, it should sit at a downward 45 degree angle. As you engage the clutch arm, the clutch should start to have an applied load when the lifter arm is at a 90 degree angle to the case or flywheel cover.
Any more than that and the outer plate could jump out of the basket. Make sure your cables have the nylon inner housing and keep them straight and well lubricated. You should not need more than two fingers to engage the clutch.
SwedeTech Quick Tips
Break-in water temperature should be 150° - 155° F (65° - 68° C)
Normal running condition water temperature between 125° - 135° (51° - 57° C)
Take the reading anywhere between the cyl. head outlets and the radiator. Do not place the water temp sensor between the radiator and the water pump
Engine will lose performance after 135° (57° C) water temp.
Overheating and engine damage can occur with temperatures past 160°
New engine break-in 15-20 laps.
New Top End break-in 12-15 laps
Increase main jet 1-2 sizes for break-in
RPM Range – 7,000 – 12,700
Top End Maintenance
Top End Kit – Piston, ring, circlips, wrist pin, bearing, head gasket, exhaust o-rings, and base gasket.
For normal use – 6 – 8 hours
For optimum performance – 4 – 6 hours
Normal use – for the recreational racer that is looking for longevity and cost effectiveness. Typical normal use includes jetting the engine on the richer side.
Optimum Performance – for the avid racer that is looking for every performance advantage. Optimum performance includes jetting the engine for best performance.
Note that the above schedule of maintenance is based on our experience. You may find that these times may be adjusted based on your needs, driving conditions, and overall engine maintenance. Many factors affect wear and tear on components.
Lower End Maintenance
Lower end maintenance will require that you send the engine to SwedeTech. We recommend that this service is performed between 30 - 40 hours of use.
Note that the above schedule of maintenance is based on our experience. You may find that these times may be adjusted based on your needs, driving conditions, and overall engine maintenance. Many factors affect wear and tear on components.
Regular Maintenance
Inspect fuel filter and fuel system for debris (Daily)
Drain transmission oil (4 hours)
Rebuild GFS rectangle fuel pump (4 hours)
Rebuild GFS round fuel pump (16 hours)
Drain GFS pulse lines (Daily)
Replace carburetor float needle valve (with each Top End)
Frequently Used Parts and Part Numbers
Piston, 13110 KZ4 506
http://dev.shopswedetech.com/product.php?productid=85&cat=67&page=1
Ring, 13121 KZ4 A91
http://www.shopswedetech.com/product_p/13121%20kz4%20a91.htm
Bearing, 91103 KZ4 B01
http://www.shopswedetech.com/Bearing_Top_End_Wrist_Pin_91103_KZ4_B01_p/…
Circlip(2), 94601 15000
http://www.shopswedetech.com/Circlips_94601_15000_p/94601-15000.htm
Wrist pin, 13111 KV3 000
http://www.shopswedetech.com/13111_KV3_000_Wrist_Pin_p/13111-kv3-000.htm
Gasket, head , 12251 KZ4 701 (99) --
http://www.shopswedetech.com/product_p/12251%20kz4%20701.htm
Gasket, base ,12191 KZ4 J00 (99) --
http://www.shopswedetech.com/product_p/12191%20kz4%20j00.htm
o-ring, exhaust
http://www.shopswedetech.com/Exhaust_O_ring_p/o-rings%20-%20exhaust.htm
Torque Specs
Nut, 8mm cylinder head 28 nm, 20 ft / lbs
Nut, 8mm cylinder base 28 nm, 20 ft/ lbs
Stud, 8mm Cylinder (case/head) 12 nm, 9 ft / lbs – apply loc-tite
Stud, 6mm Cylinder (exhaust) 10 nm, 7 ft / lbs – apply loc-tite
Impeller, water pump 12 nm, 9 ft / lbs
Re: Stock Honda Technical Articles
This what I have run for the last 4 years. Hope it helps out a new comer
Brake Pads
Soft compound front & rear
Sprockets
Front 20
Rear 23, 24 & 25
Chain
DID 428 Gold (non o-ring)
Tyres
Dry - MG Yellow
Wet - Dunlop KT14
Spark Plug
NGK BR10EIX
Gearbox Oil
Castrol MTX (650ml dry, 600ml routine drain & change)
Two Stroke Oil
Castol A747 @ 20:1 for break in and racing.
Chain lube
Motul Road (every race)
Bearing lube
Lanox MX4 Lanolin (Front - flush & spray every race meet. Rear - every race)
Fuel
AVGAS 100LL
Jetting
Required mains 175 to 185 (needed a 188 for Mallala the other week!)
Needles DGH, DGJ, DGK
Pilot 60 - Never changed it
Hope it helps someone
NP
Re: Stock Honda Technical Articles
Re: Stock Honda Technical Articles