Project My Fizzer

I looked into buying one to do four cylinder heads, only $4,000. I think I could buy a lot of thinners and brushes for that.

 

Hi all,
With regards to the carb cleaning vs just buy a jet kit option; obviously I have a vested interest in this but I will try to be impartial.

Carburettors can be a source of angst and if you fit the wrong part (o-ring from the local store) or do not clean them properly (cleaner in a spray can) then you may never get your motorcycle to run correctly. Then you might post on web forums asking for help; assuring all the readers that you have overhauled the carbs "so it cannot be the carbs". Finally you will give up and end your thread with the usual "I have had it with this heap of ****. I'm going to sell it". This conclusion may be okay for a personal relationship "I've had it with this bitch/bastard. I'm going to dump her/him", but it is not logical when dealing with a machine. Your machine needs fuel, spark and compression in the correct amounts. It is that simple.

Some points about the jet kit mentioned.
First of all we have to assume that all the jets in the "kit" are the correct size (I would need to check them with pin gauges to believe that, but that is just me). Also the jet kit does not contain the main jet square rings. Perhaps the makers of the kit deemed them unnecessary, but I prefer to trust that the engineers at Mikuni knew what they were doing. For some reason motorcycle owners often consider themselves to be smarter than the motorcycle factory engineers. I wish I had a dollar for every time I have heard "These **** Japanese phillips screws are made of cheese".

Your carburettor has orifices that MUST be cleaned anyway (see the attached image as an example), or you will become one of those forum posters previously mentioned. An ultrasonic cleaner is the best option for this. The ultrasonic cleaner is not some magical device that will return the appearance of the carb back to its original state. Although some people use cleaning solutions to achieve that result. If your carbs are filthy then soda blasting followed by ultrasonic cleaning could also be considered.

It all comes down to what parts you need to complete your carb overhaul correctly. If the needles and emulsion tubes are worn then the jet kit might be the best price, or the only source for those parts.

Now onto GreyImport's case.
If your seals and o-rings look anything like that then you have to replace all the seals (fuel tee seals etc) not just the internal ones that are supplied in the "jet kit". The throttle shaft seals will also need to be inspected and replaced if necessary.
Finally if you plan to keep your motorcycle and choose the "jet kit" option then you will have to replace the seals and o-rings on a regular basis as the ethanol, that is now being added to fuels in many countries, will drastically shorten the serviceable life of those parts. (source http://info.ornl.gov/sites/publications/files/Pub27766.pdf)
Note that in many countries it is legal for the fuel companies to add up to 5% ethanol without having to inform the consumer. You think you are buying gasoline, but it is not the case.


cheers
Blair

 

Risky,
Good info and hard to believe that a state government can control the fuel supply. Shouldn't logic dictate that to be a federal issue? What about motorists who cross the border? I see that the previous government had passed legislation to ban unleaded sales from 1st Jan 2012 and that this was subsequently overturned. http://www.biofuels.nsw.gov.au/__da...s_Release_15_Feb_12_-_Ethanol_Legislation.pdf

Mr Grey,
Some info on needle and needle jet (emulsion tubes) wear http://www.factorypro.com/tech/needle_jet_wear.html
Note that they say:

1. Small bore engines, used at higher, smoother, more even intake pressure rpms, will perhaps never have enough wear to cause a problem.

If the needles do not show any visual signs of wear then it is safe to assume that the needle jets will also be fine.

Differences in jet size are accounted for by altitude and state of tune of the engine when released in that market. For example, Californian model may be more restricted to meet EPA requirements etc.

The pilot jet issue is a probably due to previous owner. Go with Occam's razor on that one and revert to the parts book for the correct information.
cheers
Blair

 

Hey Mr Grey,
Have you played around with that cleaner yet?

 

Speaking of carbs and things. I have a supplement for the 250 service manual. Here is the carb spec, all in Japanese of course.

 

Is Kansha good?