Yamaha engine KT-100 Tech

2010 | Comments Off

The crankcase

Measuring each case halves is useful to determine the crankshaft end play. Add the 2 mesures together and substract the crank size. The end play should be between 0.005” and 0.010” (Photo 1-2).

Yamaha engine KT-100

Yamaha engine KT-100 Photo 1

Yamaha engine KT-100

Photo 2

To change the case bearings, remove the old oil seals and place the case halves upside-down in the oven (clean it before) to allow the old bearings to fall out.  Once the old bearings are removed, put the new ones in place while the aluminum is still hot. Add a bit of 2 cycle oil as case halfs are still warm. Once the case halves are cold, insert bearing grease in the oil seals and put them in place.

To ensure a perfect seal, sand the case halves with a 400 grit wet paper.

High temperature silicone (Photo 3) should be used to avoid any leak.  Put a tiny layer on each case halves before closing it.

Observe the correct bolting sequence.

Yamaha engine KT-100 Photo 3

Yamaha engine KT-100 Photo 3

Yamaha engine KT-100 Photo 4

Photo 4

The crankshaft

Before installing the new connecting rod, it alignment should be assessed and corrected if necessary.

When rebuilding your crankshaft, great care is required.  The crankshaft width will be base on the crankcase width.  It should allow an end play between 0.005” to 0.010”.

The maximum deflection at each end should not exceed 0.001”.

Cylinder

The cylinder must remain stock exept at the intake and the exhaust were it is possible to make some modifications.

The height of the cylinder can vary within the technical specifications.  Two measures have to be respected.  First the cylinder must be low enough to allow the piston to travel at least 1.045” from the top dead center (TDC) to the opening of the highest exhaust port (Photo 4).  To measure it, bring the piston to the TDC and put the dial gauge to 0.  Lower the pistion from 1.055” and if a 0.010” filler gauge goes, the cylinder is too high. Second, the piston is only allowed to travel 0.875” from TDC (Photo 5).

To avoid excessive wear, the exhaust port bridge must be recessed (approximately 0.0005”).

Yamaha engine KT-100 Photo 5

Yamaha engine KT-100 Photo 5

Yamaha engine KT-100 Photo 6

Photo 6

Piston and ring

A 0.030” chamfer is allowed.

The Yamaha, KSI, and Burris piston are cam grounded so the piston to cylinder gap has to the measure at the skirt.  The gap should be between 0.0025” and 0.003” (Photo 6).

The correct ring gap for racing is between 0.008” and 0.015” (Photo 7). Use the piston to push the ring in the cylinder (in about one inch). This will insure you that the ring is straight. Be careful not to reverse the ring when the engine is reassembled.

Yamaha engine KT-100 Photo 7

Photo 7

Note that the arrow on the piston’s top should point at the exhaust.

The cylinder head

Yamaha engine KT-100 Photo 8

Yamaha engine KT-100 Photo 8

The squish band should not be smaller than 0.035”, otherwise the piston may touch the head at high revolution.  To check the squish band, install the head on the cylinder, lower the piston, insert a piece of 0.100” solder (Photo 8) through the sparkplug hole, and make certain that is touches the cylinder wall.  Rotate the crank until the piston is at TDC and the solder is pounded flat.  Then measure the solder. This will give you the squish band’s measure.

Yamaha engine KT-100 Photo 9

Photo 9

To measure the combustion chamber volume, buy a burette of at least 13cc, fill it with automatic transmission fluid to the zero mark, bring the piston to TDC, and fill the combustion chamber by pouring the fluid through the spark plug hole.  The legal minimum limit is 11cc including the spark plug hole.

Be aware of the correct bolting sequence.

The ignition system

The standard gap between the rotor and the stator is 0.020” (Photo 9).  The wider the gap, the more retard, and the narrower the gap the more advanced the timing will be.  A wider gap may be preferred for fast tracks, and a narrower gap may be preferred on tighter tracks.

Yamaha engine KT-100 Photo 10

Yamaha engine KT-100 Photo 10

The carburator

Be aware of the gasket order when reassembling your carburetor.

The fulcrum arm level is 0.055” without the gasket (Photo 10).  To adjust it, bent it with a small screwdriver.

Yamaha engine KT-100 Photo 11

Photo 11

The carburetor must « pop off » at 10 to 12 pounds and hold 8 to 9 pounds for road race. The higher the « pop off », the leaner the mixture.  If the carburetor pops too low, try to extend the spring a little. If it doesn’t work, change it.  If it pops too high, compress the spring. (Photo 11).

Yamaha KT-100 Engine

2010 | Comments Off

Yamaha KT-100 Engine:

  • Junior and Senior classes
  • Cylinder volume 97.6cc
  • Bore/Stroke 52mm x 46mm
  • Carburator Walbro WB-3A
  • Compression 7.9:1
  • Monocylinder, 2-stroke, Pre-mix oil-gas
  • Electronic ignition
  • Single, forward inclined
Yamaha KT-100 Engine Outline Drawings

Yamaha KT-100 Engine Outline Drawings

When you buy a new Yamaha KT100 it’s not quite ready for competitive racing. A minimun of preperation is required. You will find in these documents some hints and tricks to help make your motor a bit more competitive and get a better performance out of it.

Motor Maintenance Frequency

In order to get the most out of your motor it is necessary to maintain your motor on a regular basis. Use the following chart to guide your self on the frequency to change parts on your Yamaha motor. NOTE: These numbers are in hours.

« Performance » Maintenance « Pleasure » Maintenance
Cylinder
Piston 5 15
Ring 5 15
Piston pin and Bearing 18 20
Circlip 5 15
Motor Base
Base Bearings 8 14
Bearing Seals 8 14
Crank
Connecting  Rod 20 30
Rod Bearing and Pin 20 30
Washers 20 30

Idealy, the piston, cylinder and ring should be inspected after every race. However, every 2 races is an acceptable compramise. In general, the piston should be changed every 2 to 4 races but if   the measures are still within tolerance and the piston does not show signs of wear, you do not need to change it.

Use the same routine as for the piston on the ring. However, if the ring gap is greater than 0.015”, replace it.

The motor base should be inspected and you should consider revising it every 4 races when using stock bearings. Particular attention should be to the oil seals and bearings. Note that certain brands of bearings are better than the originals. These are recomended as they are longer lasting (6 to 8 races) and will contribute to the perfomance. The down side is that they are more expensive. The connecting rod and bearings should be changed every 8 to 10 races.

Use the chart on this page to guide you in your preventive maintenance. Note that certain conditions such as a wet race day may contribute to premature wear and may require some parts to be changed sooner.

20 HP Vanguard Engine Outline Drawings

2010 | Comments Off

Air Cleaner Side

20 HP Vanguard Engine Outline Drawings - Air Cleaner Side

20 HP Vanguard Engine Outline Drawings - Air Cleaner Side

Front View

20 HP Vanguard Engine Outline Drawings - Front

20 HP Vanguard Engine Outline Drawings - Front

Oil Filter Side

20 HP Vanguard Engine Outline Drawings - Oil Filter Side

20 HP Vanguard Engine Outline Drawings - Oil Filter Side

Oil Fill Side

20 HP Vanguard Engine Outline Drawings - Oil Fill Side

20 HP Vanguard Engine Outline Drawings - Oil Fill Side

PTO Side View

20 HP Vanguard Engine Outline Drawings - PTO Side

20 HP Vanguard Engine Outline Drawings - PTO Side

Footprint

20 HP Vanguard Engine Outline Drawings - Footprint

20 HP Vanguard Engine Outline Drawings - Footprint

Crankshaft Data

20 HP Vanguard Engine Outline Drawings - Crankshaft Data

20 HP Vanguard Engine Outline Drawings - Crankshaft Data

Raptor III Engine Outline Drawings

2010 | Comments Off

Top

Raptor III Engine Outline Drawings - Top

Raptor III Engine Outline Drawings - Top

Front

Raptor III Engine Outline Drawings - Front

Raptor III Engine Outline Drawings - Front

Side

Raptor III Engine Outline Drawings - Side

Raptor III Engine Outline Drawings - Side

Back

Raptor III Engine Outline Drawings - Back

Raptor III Engine Outline Drawings - Back

Cutaway

Raptor III Engine Outline Drawings - Cutaway

Raptor III Engine Outline Drawings - Cutaway

Dino Race Karts 2001

2010 | Comments Off

Triton

Dino Triton Kart

This kart unites elegance, low weight and pure strength. The Triton is the top-of-the-range model and is FMK homologated for the ICA junior class. However, it is also suitable for national and international classes. High performance is essential in these classes, which is why we have developed the chassis for use with soft tyres so that the kart has optimal road-holding even in the most extreme conditions.

1-1060 TRITON Kart

Chassis 30 mm tube
Axles Ш40 mm
Hydraulic brakes,  turbo discs
Magnesium wheels 130/212
Bodywork
Engine, seat,  tyres are not included

Saturn

A good kart for beginners, and specially designed for engines with inboard drive (max. 30t 1/2У). The kart is also well-suited for four-stroke classes, fitted out for example with a HONDA GX160RH. The chassis is constructed in 28 mm piping and performs at its very best with hard or semi-hard SL tyres. Aluminium wheel rims and hydraulic brake with steel brake disc are standard features. Turbo brake disc, magnesium rims and an assembly set for HONDA engines are available on request.

Atlas

Dino Atlas Kart

A strong and supple chassis made of 28 mm tubing, specially designed for hard or medium-hard SL tyres, makes this kart a likely winner in national classes. The rigid front ensures a stable, neutral kart which is easy to adjust. The kart is supplied with 40 mm axles as standard.

Jupiter Prokart

Dino Jupiter Prokart
A race kart for two four-stroke engines built in line with the English Prokart regulations. Can be used both for sprints and long -distance events. Also available in a hire version with roll bar.

Dino Pluto Kart

2010 | Comments Off

Dino Pluto

Dino Pluto

A fast little kart for the 8 to 12 year olds. The kart is well-suited to a 60-85 cc engine, but can also be fitted out with choked 100 cc engines.

The PLUTO  is a favourite choice in many countries for the increasingly popular MINI and Bambini classes.

Dino Pluto: Kart Parts

Dino Pluto: Kart Parts

Dino Pluto Fun Kart

2010 | Comments Off

Dino Pluto Fun

Dino Pluto Fun

The idal choice for a fun kart or rental kart for children in the 6- to 12-year-old age group. The kart is based on the design of the DINO MINI. The DINO PLUTO FUN is supplied ready to run com plete with a Honda G100 engine, tyres, seat, side pods, and front panel. The engine is fitted with rope rewind strater and a centrifugal clutch, and is easy to operate and to maintain.

Dino Pluto Fun: Kart Parts

Dino Pluto Fun: Kart Parts

Dino Neptune: Kart Parts

2010 | Comments Off

Dino Neptune 2001

Dino Neptune 2001

Dino Neptune: Kart Parts

Dino Neptune: Kart Parts

Dino Mars Kart

2010 | Comments Off

Dino Mars Kart

Dino Mars Kart

A fast little kart for the 8 to 12 yearolds. The kart is well-suited to a 60-85 cc engine, but can also be fitted out with choked 100 cc engines. The DINO MINI is a favourite choice in many countries for the increasingly popular MINI and Bambini classes.

Dino Mars: Kart Parts

Dino Mars: Kart Parts

Dino Atlas Kart

2010 | Comments Off

Dino Atlas Kart 2002

Dino Atlas Kart 2002

This kart unites elegance, low weight nd pure strength. The Atlas  is the top-of-the-range model and is FMK homologated for the ICA junior class. However, it is also suitable for national and international classes. High performance is essential in these classes, which is why we have developed the chassis for use with soft tyres so that the kart has optimal road-holding even in the most extreme conditions.

Dino Atlas: Kart Parts

Dino Atlas: Kart Parts