Friday/Saturday 18th/19th April 2014 Thermal Explorer - All NEW and Unique
For Sale and available Mid May 2014
Engine capacity on the later year models is full 690cc
- Bike will have travelled around 20,000 kilometres at sale date
Bike sold in stock standard trim with no accessories included
( BIKE IN PICTURES IS FULLY ACCESSORISED )
Will have near new chain and sprocket set fitted at time of sale.
- Bike will have had it’s 20,000km service immediately prior sale date This motorcycle has been well maintained is in excellent condition and will serve the new owner well
- Selling as upgrading to latest model Get in quick to avoid disappointment $12,995 –
Ph. Jim on 021 517110 or email firstname.lastname@example.org hotmail.co.nz
Carburetor tuning instruction
Carburetors are mostly being phased out on the modern day bike replaced with fuel injection systems however there are still plenty of old school bikes that still use them. They are fairly simple when you get down to it. There are 3 circuits that control fuel air mixtures at certain throttle positions. For the carburetor to run smoothly it needs a balanced air/fuel mixture in all 3 circuits. Things that can effect air/fuel mixtures are cutting the top of your airbox out or adding a free flowing exhaust which translates into more air being allowed into the 3 circuits meaning fuel mixture needs to be increased to keep the balance right. Also the main reason for this introduction to carburetors is when running at altitude the air supply is limited somewhat (thinner air) therefore to counter this you need to make adjustments to your carby to ensure smoother running by leaning off the fuel supply to match the restricted air supply. You can drop the needle jet and decrease the main jet size which will cut back the amount of fuel in the fuel/air mixture making it more balanced.
Note to carry these adjustments out you will more often than not have to remove the carburetor from the intake manifold which means taking the seat and fuel tank off. Main jets can possibly be changed with the carby in position but you need to swap out the standard phillips head screws on the float bowl and top of the carby (4 total) for socket head allan screws for easy removal. You will need to carry the appropriate size allan key in your on the bike toolkit and check that you have a spanner to undo the main jet in position and carry some smaller size jets for this task. The standard phillips head screws are hard to remove as the heads are soft and will burr easily allowing the screwdriver no grip.
c). Mid range to high speed circuit - Controlled by the main jet. The main jet is what the needle jet fits into when opening and closing the throttle. When the throttle is fully closed the needle jet is sitting inside the main jet blocking off fuel supply then when the throttle is rolled open the needle jet starts lifting itself away from the main jet with it’s tapered section allowing more fuel to flow into the carburetor. When the throttle is held wide open the main jet fully takes over and the fuel is channeled through the hole in the main jet. Smaller size main jets restrict fuel supply whereas larger size main jets (larger diameter opening) will increase the fuel supply to the mixture.
To check you are on the right track when changing an air/fuel mixture you can take the bike for a short run and check to see if it is running smoothly then perform a plug check. i.e. if you have just altered the needle jet position then you need to run the bike at the half throttle setting (midrange) then stop it straight after this take out a spark plug and see what colour your plug is. Ideally it should be;
Light tan in colour meaning the air/fuel mixture is balanced and burning cleanly
Dark, oily or sooty colouring means the bike is running too rich in that throttle position = Drop the needle jet by raising the clip/groove to a higher position
Same can be done for the Main jet settings. Take the bike for a short blast at three quarter to wide open throttle then shut it down and read the spark plug colouring. If it’s too rich decrease fuel supply by installing a smaller size main jet and if too lean increase the fuel supply by installing a larger size main jet. The standard DR main jet size is around #140. When performing the airbox mods and changing to a free flowing exhaust the main jet size is usually increased to #150 to #155. I will be decreasing the main jet size by #5 when riding around Colorado and Utah at altitude to help the engine run smoother.
It is important that you make carby adjustments in small increments otherwise you may go too far and damage your engines internals.
If you have a fuel injected bike you have one less thing to worry about as your onboard fuel management system takes care of all the changes you may encounter.
A quick guide to how your carburetor works and was especially created for DR riders undergoing the Trans American Trail ride