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The Carbtune II, the accessories and the windscreens are available directly
from us:
Worldwide and UK sales. Phone, fax or send your credit card details.
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Send a bank draft in sterling. We normally dispatch all Carbtunes inside 24 hours. 1st class letter post inside UK. Airmail outside UK.
| 2-column system for twins | £37 | P+P inside UK £3
Airmail: Europe £4 Rest of World £6 |
| 4-column system
for fours, triples, or twins. |
£49 |
Tel +44 (0) 2890 239007 Fax +44 (0) 2890 274294
email: morgan@carbtune.com Using the Gauges. The gauges are calibrated in CmHg (centimetres of mercury). Hang the gauges vertically from the left handlebar grip or other convenient position (lifting handle on BMW twins) using releasable clip. The clip fits into the slot at top of gauge and you push it into the slot from the back of the gauge. (Release clip by pushing small tongue on catch). If your bike needs the brass adaptors remove the blanking screws from the inlets, then connect the adaptors to your bike. Remove and blank off any balance pipes. For difficult to get at inlets cut 1 inch of rubber from the end of one of the rubber tubes and push it onto a ball-point pen. Push the adaptors into the other end of the cut off rubber and use the pen as a flexible extension to screw the adaptors in and out of the inlets. Alternatively you can cut a slot in the end of the adaptor and use a screwdriver to screw it in. Make sure the adaptors are seated but don't overtighten. Finger tight using fingers not tools. (After tuning it is sometimes easier to remove the adaptors if you let the engine cool down.) Other makes have stubs on the inlets covered by rubber caps or tiny screws which you remove. Push the rubber tubes onto the spigots on top of the gauge. (On some bikes, like Honda ST1100 and CBR1000, the spigots are of a very small diameter and need a sleeve-down tube to connect. These are available from us). Make sure you have the correct tube connected to the correct carb. Keep rubber tubes and the gauge itself away from hot exhausts and make sure the rubber tubes are not kinked or flattened. Route rubber tubes over handlebar grip as shown in photo on the previous page. After use remove black rubber tubes from gauge first then from the carbs. Hang rubber tubes to drain any petrol from them. If there is any blowback of petrol into the gauges hold them high, upsidedown and connected to a running engine until all petrol has disappeared. General Hints Read you workshop manual. The engine should be warm and running at a fast idle, 1200-1500 rpm. Adjust to makers specification or average of initial readings, but the readings should be balanced to within 2 cmHg (GL1500 4 cmHg) of each other. Make sure that the points, plugs, ignition, tappets, air filter, exhaust and oil are all in proper service before balancing. Ideally balance your carbs after you have serviced the rest of your bike. Adjust in small amounts, waiting a few seconds between each part adjustment. If lending gauges to a friend please ensure your friend has a copy of the instructions and is familiar with the gauges. A Guide to Carburettor Synchronising. Carb balance will affect the response, smoothness, mileage, performance and running temperature of your engine. Carb synchronisation consists of adjusting each carb or fuel injection butterfly so that it passes 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 actual mechanics of carb balancing vary a lot. Some bikes are balanced by adjusting the relative length of the throttle cables (R series BMWs) while others have a system of levers with adjustment screws but they all adjust the relative position of the throttle slides or throttle butterflies of each carb to each other or to a master preset carb. A workshop manual for your model is very useful as the balancing procedure for different models can vary in detail. Familiarise yourself with the section on carb synchronising. 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. We assume that anybody using the Carbtune will have some knowledge of the mechanics of their vehicle particularly in regard to safely removing the fuel tank. If you feel unable to do this or the other tasks safely it will be better to leave them to an expert. Step 1: Fit the gauges to the carbs. Warm the engine until it will idle reliably without choke. The engine should not be at full operating temperature at this point as it may lead to overheating later. If you have a fan place it so that it blows cold air over the cylinder head or radiator. Don't remove the petrol tank at this stage unless it is necessary to do so to connect the gauges. Work in a well ventilated area so that the exhaust fumes will dissipate. Step 2: Set the engine to a fast idle of about 1200-1500 rpm by adjusting the master idle screw, then read the gauges. Some workshop manuals specify a vacuum reading, usually at a high idle. The full red scale lines on the gauge are 2cmHg apart and most factories specify the total difference between the lowest and highest readings should be 2cmHg. If the carbs need to be balanced then switch off engine and remove petrol tank (most bikes) so that you can get at the adjusters. On some bikes you can turn the tank back to front and set it on the seat or rear frame and still be able to reconnect the fuel lines. If the fuel taps are vacuum operated set them on prime. (For BMW K-series use T-piece. This is available from us). Secure tank with plenty of luggage straps. Remember petrol is dangerous both as a fire risk and fume inhalation. Be very careful. If you use an extension fuel line with a remote tank keep it roughly at the same height that your petrol tank would normally be. If you are very experienced you may be able to balance your carbs with the fuel left in the float bowls. Make sure that the vacuum gauge lines are correctly routed so that you don't find yourself adjusting the wrong carb.
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