Last Updated on Saturday, 23 October 2010 15:17 Written by Mik Tuesday, 06 April 2010 15:02

 

Never ever run your carbies mixture lean as you will most certainly end up with melted pistons.

 

 

Want to give your carbies a good clean???

Then remove all the petrol from your tank, put in some Carbie cleaner a couple of litres should do the trick.

then run the bike, (it will knock like hell) for a few seconds. Stop the engine and leave solution sitting

in carbies for 2 to 3 days. Then remove as much of the carbie cleaner a possible from your tank, fill

with petrol then again start the engine, it will knock at first but will eventually disappear.

 

BALANCING YOUR CARBIES (read through this first before attempting)

When you have a 2,3,4,6 cylinder older motorcycle at some point in time you are going to need

to balance the carbies. if you have a mechanic do it for you expect to pay around $100.00. This is

not a really difficult job to do, but bear in mind you are playing with petrol so safety is of the utmost.

I bought a carbtune pro for around 55 uk pounds and have used it around 8 times so it has more

than paid for itself. The process takes me around 30 mins from disassembling the bike to ready to ride.

Click on the pictures for a larger more detailed pic.

Feel free to click on the images for a bigger picture.

I used an old ladder and butchered a coat hanger to hang the carbtune pro.

This helps keep all the tubes out of the way and enables a good view of the gauge.

The petrol tank has obviously been removed in this picture.

The image is showing you where the carby adjuster screws are.

Remove the Vacuum tube from off the carbies, you will need to remove

all 4 of them. Then attach the carbtune pipes in order to carbies 1,2,3 and 4.

the vacuum pipes you have removed, just leave them there, you wont be needing them.

This is what the carb nipples look like with the vacuum tubes removed.

Fit all of the carbtune pipes onto the carby nipples, it should look like

the picture when done.

 

Make sure that you move the petrol tank to

a level that is the same height as the tank when its on the bike.

if you have the tank too high you will get more petrol pressure and

likely to get a false reading on the carbtune gauge. I used a fish tank tube

to connect from the tank to the carby petrol inlet. its cheap to buy.

Remove the original petrol pipe and replace it with your

cheap and cheerful pipe you just bought.

After double checking my fittings,

I warmed the bike up (very important) and this is my first reading.

I then increased my idle to 2000 revs.

carby 1 is on the left of the picture and carby 4 the right.

as you can see the 2 outside carbies are higher than the inside carbies.

and the reading is also low.

This picture is showing the adjustment of the carbies.

you have to balance carbies/cylinders 1 and 2 first using the

outside adjuster (LHS) then balance carbies/cylinder 3 and 4 with the

adjuster on the RHS, once you are happy that carbies 1 and 2 are level

with each other and carbies 3 and 4 are level with each other (although

carbies 1/2 may not be level with carbies 3/4) then you find the middle adjuster

and balance both sets of carbies together.

 

This is my final reading and I am quite happy with the balance.

General Hints

Read your workshop manual. The engine should be warm and running at just enough above idle speed so it doesn’t falter and stop during adjustments. Don’t try to balance at high engine speeds. Adjust to makers specification or average of initial readings, but the readings should be balanced to within 2 cmHg (some models up to 4 cmHg) of each other.

Adjust in small amounts, waiting a few seconds between each part adjustment. Write each adjustment down so you can go back to the original settings if necessary.

A Guide to Carburettor Synchronizing

Carb balance will affect the response, smoothness, mileage, performance and running temperature of your engine.

Carb synchronisation consists of adjusting each throttle valve for carburettors or fuel injection throats so that they pass as much fuel-air mixture as all the others. This balances the load carried by each piston.

If one carb is opened further than the others that cylinder will run hotter than the others. The other carbs will also supply a richer mixture and mileage will suffer.

The absolute readings aren't important as long as they are within the manufacturers specifications. It's the comparative reading that's important not the absolute values.

If one carb has a significantly different reading to the others there can be several reasons for it.

It may be at the end of it's adjustment so you'll have to back off all the adjusters and start again.

It may be that a rubber tube has been wrongly routed so that you have been adjusting the wrong carb or that the rubber tube is kinked or flattened on its route to the carb or is loose.

Possibly there is a leak in the carb to airbox or carb to head joints.

It may be an engine fault and a compression test can help to pinpoint the problem.

If you suspect there is a leak in the intake manifold let the engine idle and spray a fine mist of water around the inlet area. A drop in engine speed can indicate a leak in the inlet system.

I didnt use any of the adapters that came with the kit as the tubes fitted straight onto the vacuum nipples.

I hope that carbtune dont get too upset with me as I stole some of their instructions, but then again it was their kit I am using.

the information that comes with the kit is very good, clear and precise.

Remember fuel is dangerous both as a fire risk and fume inhalation. Be very careful.

 

Ideally balance the throttle valves after you have serviced the rest of your bike.

Carb adjustments should always come last when servicing or rebuilding your bike. The rest of the bike should be in good tune before balancing, and that means the points, plugs, ignition, tappets, air filter and oil, should all be in proper service.

Air leaks between the airbox and carbs, carbs and cylinder head inlets, and in the exhaust system or any blockages in these systems will affect the carb balance and should be rectified before starting.

Next project tappets (When I am finished I will have to re balance carbies haha)

 

NOTE: THE BOOK SAYS TO BALANCE WITHIN 2.7KPA OF EACH OTHER, 2.7KPA converted to cmHg is just over 2.03, on the last pic I have mine at 2 (20)

 

OIls arnt OIls

Quite often I get asked "what oil should I put in the bike"

There are several  answers to this question, as I live in Australia where the summers are quite hot and winter rarely drops below 2 degrees centigrade

I put into my bike Castrol Aktiv 15w 50, When I was in the UK and the weather was much colder I put in a lower viscosity oil. I kept to the standard oil and NOT Synthetic as I found that the Synthetic oil caused me Gear changing problems. I hope this helps to clear up some of the questions.

 

 

 

 

 

Fuel Tap

 

There are 3 lever positions on the tap. RUN. RES and PRI.

RUN - With the lever in the RUN position, Fuel will not flow through the tap until the engine is started. This is the only position that the tap should be in during normal operation.

RES - This is the Reserve position, to prevent the tank running dry. If you run out of petrol on RUN, turning the lever through to the RES position should give you at least 30 miles range. Again fuel will not flow through the tap until the engine is started.

PRI - This is the Prime Position, and is generally used after the carburettors have been drained, or assumed to be dry. Turning the tap to this position will align drilling's within the tap and gravity will feed fuel directly to the carburettors. USE THIS POSITION WITH GREAT CARE.

Complaints are common to this type of fuel tap, and all of them must be rectified at the earliest opportunity, to ensure reliability, and avoid internal engine damage. All faults will manifest themselves by either poor running and/or cutting out, or by the tap delivering fuel when it shouldn’t.

 

FUEL LEAKS FROM THE TAP

Fuel dripping onto engine casings from the tap is due to an O ring or gasket failure.

FUEL COMES OUT OF THE TAP WHEN THE ENGINE IS NOT RUNNING.

Check that the tap is not on PRI. If the tap is on RUN or RES, and fuel is issued, it is almost certainly due to a stretched, or perforated diaphragm  and is “holding” a vacuum between it, and the diaphragm.  Replace the diaphragm , and return spring ,

 

 

 

 

THE ENGINE FADES WHEN IN THE CRUISE.

“Sudden death syndrome.” normally strikes when your sitting at a steady 80 - 100 Kph. Quite simply the carbs run dry, and the engine is starved of fuel. If you’re quick, you can spin the tap round to PRI, just as you would when switching from RUN to RES when running low. This should deliver fuel quickly enough for the engine to pick up, and get you home. If you do end up at the side of the road, turn it to PRI wait 10 seconds, and the machine should start. If it doesn’t and your convinced its fuel starvation, try opening the fuel filler cap. It may be that the fuel tank is not venting correctly, and is creating its own vacuum. This will oppose, and work against the vacuum provided by the engine, eventually becoming strong enough to pull the diaphragm shut.
Once you’re up and running again try to turn the tap round to RUN, it may well continue to function normally with no further problems. Check also the quality, and integrity of the connections of the vacuum pipe feeding the tap. If in doubt overhaul the tap.

 

Be aware of how the fuel tap operates, and learn to identify it’s shortcomings. Avoid aftermarket overhaul kits they are rarely effective, only use genuine Kawasaki parts.

 

Use the following tip for replacing spark plugs.