Impression
I'm fairly sure that the W650 was first shown at a German motor show and it was three years since I'd parted a 650RS. I thought that the new W was made for me. Once it became available on the domestic market, it took me four years of saving before I could have the pleasure of ownership.  Once I had saved almost the full amount needed, I began a program of selling the idea to my family, which was helped by having made the final payment on our house. So finally, on February 2002 I became a proud owner.　Although I was happy with my long awaited new purchase, I had an almost immediate 'problem' with a light knocking sound that occurred between 2000 to 3000 rpm and sounded like 'KIN KIN KIN'. I took it back to the store to explain my concern and he suggested that I give it a little more time, so I rode it for another 1000 Km but the noise was still there.  Although the bike ran fine and showed no signs of the engines performance being in any way hampered, I wanted to located the source of this sound. Even though I asked around at various other message sites, I couldn't get a satisfactory explanation. 　W650 owners club can be known at such time, and I can become the member of Kyushu Okinawa branch. And I am allowed to participate in a spring meeting. Since many W650 could be seen and the talk was made with owner when participating in the meeting, it was expected that a key (noise of engine) could be held. Number less than 70 sets of W650 gathering, and the meeting was a magnificent view. The opportunity for me to be allowed to test-ride W650 of a formula two sets also fortunately in the same year was able to be got, and the sound of an example was able to be checked. When this noise was a peculiarly sound to W650, it could be checked, and I felt easy about it. 　Then, it will be what sound. If it says that it is peculiar to W650, isn't it the bevel gear drive of a cam? Backlash adjustment of bevel gear was carried out instantly. First time when a backlash is narrowed and a test run is carried out, it will become louder noise come out of sound increasingly. Next time, sound became small when it adjusted so that a backlash might be increased. I did it is this ! and the gloomy feeling cleared up. 　It was set so that the pilot screw of a carburetor might make fuel-air mixture thin, in order to raise acceleration power with pilot screw 3/4 loosing to counter clock wise rotation. Exceeding 2000rpm to be short and the noise goes to weak by those work. It seems that there are many people who have ridden without noticing since exhaust sound becomes large, many W650 riders are exchanging mufflers. 　Knocking sound of bevel gear began to be worrisome when reached in 3000km or more. For the reason, adjustment again which narrows a backlash was performed this time. If it becomes the backlash adjustment position of the almost same position as the time of purchase and rushes in 3000km as a result at this time. It will be said that adjustment of a backlash was unnecessary. However from the delivery of bikes of W650 necessary the break-in riding to serve and to keep until 3000km in mind. 　I participated in the meeting and it became one more reference that various muffler sound was able to be heard. So I wished to exchange when the finance allowed. Above all, the first harvest of a meeting what it was able to meet W650 friend and although on the day was having headache, two pleasant days were able to be passed.
1. W650 impression of a Full stock condition.
For backward of mirror and turn signal being as dressed-up parts are equipped soon after buy W650. I was riding in stock condition until indicate the odometer in 4000km. Although sometimes I tried to accelerate 7000rpm, the impression at that time was felt unsatisfactory [ power ] as 650 cc. Although it could be thought that surely surprised to turn around no less than 7000rpm for a long stroke twin, even if compared with W1 and W3, TX650, SR500, etc. It was the impression which lacks rising a acceleration somehow. In spite of larger capacity compare with the former years vertical twins, W650 does not have a expected performance as present day designed bike. I did not think that W650 could not be this performance like this. The attitude of torque is a flat to the top end rpm, and seems how near single engine to have been blown. Although it attitude of the torque which is very easy to ride on a beginner, it is unsatisfactory for a experienced motorcyclists. If a developer's report is read, for it engine feel of acceleration aim to design originally. Although that may be right, I could not be satisfactory in flat acceleration. An experienced rider want the acceleration must be rising up to high rotation quickly. 　Passing the time from W3 developed for 20 years or more, The CO2 is increasing today, global warming is accelerating. The CO2 emission must be degrade by under the control. The discharging of gas emission regulation had carried out with a KLEEN model also in Kawasaki W650, even though being avoided to motorcycle. Affected in the Kyoto environmental summit and etc, emission control was cleared in 2001 by KCA system for burning more exhaust and the catalyst was attached at exhaust pipe. 　Although dissatisfaction of various was written about a feeling of acceleration, if it thinks that it is made to suit such social environment and the motorcycle which cleared the severe regulations. I understand well that.... It can be convinced to keep the stock condition, until it carries out below-mentioned customizing... I want to carry out. Because it is a motorcycle as a hobby. and rides on the average only for 1 and 2 hours for one week.
2. Custom-made Phase1

It exchanged to The plug got from the friend of DENSO Co. Ltd. on Wednesday September 11, 2002. The insulator has burned the NGK plug white clearly. It seems to be better to make fuel mixture seems to a slight thin. In order to remove a plug, a fuel tank must be removed either. the shim inserted in the needle jet which was changed into two sheets from one sheet. It seems that feeling of an acceleration became good, I went out for the test run for about 1 hour. In the state of phase1, W650 could be going up the slope in front of a house by 3speed gear. The performance was dropped at the state of phase2 should be chosen 2speed gear. Due to process two shim for needle, It seems that acceleration performance approached phase1. In a flat way, riding at the 1500rpm of top the 5speed gear, when the throttle was opened from 50 km/h, getting acceleration and rising speed is came to reach 100 km/h easily. Since season of winter temperature becomes lower 5centigrade, the amount of oxygen per unit for increasing and a oxygen/fuel ratio will go up. When a plug is removed and seen on September 24, an insulator has a light-brown color and it is burned in good.　In the state of phase2.1, the engine characteristic was measured by the chassis dynamo on October 4. The result is shown in graph. The left is an output power characteristic and the right is a torque characteristic. Although it is somewhat hard to see, the blue line of graph is the 1st time measurement, and green line is the 2nd time. The characteristic with a red line closes an air filter with a tape by the half. 　Although the torque characteristic shows badly air mixture higher at 4500rpm. Also I could say that the speed higher than 100 km/h shows degraded out put power. The red line which closed the half of an air filter with the tape, and measured it again. The red line reached up to higher rotation. According to this data, the air mixture obviously find out was thin. The mixture must be increased by rejetting. 　Meanwhile, there are only the highest torques of only 4.8 kg-m also highest out put is 42.6H.P. Since it was the actual output of a rear wheel, when it became a 10% decrease of an engine substance power. It was speaking about the direction of a shop owner. Kawasaki catalog specification shows maximum torque 5.7 kg-m and maximum power 50HP. Because of this reason, this time measurement could be converted 42.6x1.1=46.86 H.P. and 4.8x1.1=5.28 kg-m. It became clear that my W650 performance is less than a catalog data. Although it is said that it generally does not come out like a catalog, it will be disappointed if a result is seen. It seems that muffler exchange has caused the performance fall? I thought that what was necessary just to have measured the stock condition where it is entire for judgment of being right. 　A right-and-left separation type muffler will become a performance fall? I want to bring close to a stock performance somehow by using this muffler.
5.Custom-made Phase2.2

It came to carry out pleasant acceleration as it predicted from the result of a dyno, when I rejett the main jet No. 145 from No. 135. And the test run was carried out. I should go to measure by the dyno again.
6.Custom-made Phase2.3

A above plug photograph is in the state of phase2.2. An insulator is pure white, and plugs heat must be come down. There is a valley of torque at 3000rpm-5500rpm in the upper graph.　From these two reasons, I thought that the fuel-air mixture in the rotation region of 3000rpm-5500rpm would be made deep. Then, the washer was added to the seat of a jet needle and it was made a total of three sheets. 　Middle acceleration become good, when I went out for the test run in this state. It will become clear by next dynamo measurement whether this modification is right.
7.Try again Dynojet measurement
It carried out to dyno measurement again on October 17. It turns out that the growth after exceeding 100 km/h rather than phase2.1 of last time from output power characteristic graph (blue is phase2.3, green is phase2.1) is good. Moreover, it turns out that it is improved in the torque valley at 3000rpm-5500rpm. Please see phase 2.1 torque characteristic of the red line and phase 2.3 torque characteristic graph of the blue line. Phase 2.3 modification makes the gently-sloping torque curve is drawn. The maximum output improves to 40.6ps->43.6ps, and the maximum torque improves to 4.8kgm->4.9kgm. 　However, as fuel-air mixture was still thin a little also at Phase2.3, when the tape closed the air filter for a while, the characteristic became good slightly (red line of graph). Since the present air filter was attached or removed repeatedly, it has hurt very much. Under the present circumstances, if it changes to a somewhat small filter, I will think that it becomes good exactly.

It has been a little surprised that the length of the carburetor jet needle on either side which Mr. Bravo told me that Left-hand side (under of the photograph) is shorter 1mm than right-hand side. Then, I bought the short jet needle (about 8 dollars per piece) ,equipped both carburetor was made the same. The main jet was simultaneously raised to No. 150. Although the three sheets washer was carried out on both sides at the needle till December 7, Due to having raised the main jet and the needle were united with the shorter one, all washers had been removed. 　The test run was carried out in this state. Acceleration with the that it can blow going up about the same as Phase2.3. It seems that rotation of engine became smooth. Was the depth of fuel-air mixture on either side different before changing needle? Even if checked with the carburetor synchronizer, the variation in on either side was almost as unchanging as [ before arranging the length of a needle ]. 　The characteristic chart shows actual power and torque by dyno measurement. The red-line shows phase2.4, green-line shows phase2.3. Only phase2.4 without 2 shims has torque valley from 4000rpm to 6000rpm. Because of it, I put the 2sheet needle-shim. 　From phase2.3 to phase2.4, the maximum out put power raised up a little 43.9 to 44.6HP and maximum torque also up 4.9 to 5.0kgm. Mr Dennis who is member of W650Group shows me stock condition W650 dyno chart, marked maximum out put power 46.6HP. I regret that my W650 never measured stock condition by dyno. Now I consider that K&N air filter dose not suite for W650 engine, no require the many air capacity, seems more important things is air flow velocity at inlet. 　I am going to research any better set up such as Mr Dennis advising.
10.Custom-made Phase3

When K&N power filter put the carburetor directly, seems air flow efficient comes down. It may be needed to use the air-funnel in order to rise up to air flow efficient. but to develop the air-funnel is not easy for me. Because of that reason, the stock air filter has been equipped again. 　I tried 130 main-jet using is badly, acceleration could not rise up higher 4000rpm. The 120 main-jet using get good feeling to accelerate to 7500rpm. Those state has been adjusted by just riding feel. The left chart shows comparison of Phase2.4(red line) and Phase3(green line) dyno measurement. Maximum output rise to 45.5HP, maximum torque same as Phase2.4 is still 5kgm. Although maximum output power raised a little, middle range output degraded. I have a plan that it become increase again by modification of air filter.

11.Custom-made Phase3.1

When I measured dyno Phase3, another test was performed. Try to measure with pulling up the half both of the air filter was got plus 5HP on middle range rotation. This principle shows that the stock air filter need to more air flow. So I perform to modify to my air box. Obstruction of air flow was removed and rejetting which I called Phase 3.1. 　The detail of this air box modification was described on Mr. Jake web page 　Although I expect that Phase3.1 will become to get more out put power than Phase3, out put power degraded form 45.5HP to 44.6HP. But Maximum torque increased from 5.0kgm to 5.1kgm. According to bike shop owner, since temperature grade increased about 7℃　compare with previous measurement, therefore maximum out put power might be degrade. 　Out put power and torque rise a little bit lower than 5000rpm by obstruction removing of the air box. Maximum torque get at 2500rpm can be useful on the street ride and mountain path ride. This is emphasized the characteristics of W650 what I think.

12.Custom-made Phase3.2

I want to confirm the performance of the stock exhaust system. The blue and sky blue lines are Phase 4.0 characteristics(using the stock exhaust). The red and green lines marks under condition of using the Daiwa full exhaust. The stock exhaust better than Daiwa's out put power under 5500rpm. Daiwa's out put power is reversed over 5500rpm. I can ride comfortable and fast with stock exhaust, but too silent...

15.Custom-made Phase4.1

The red line shows performance chart with the mainjet #130, blue line shows it with the #135. I try the #135 main jet become degraded the out put power from 41.8PS to 41.3PS. So I rejet back to the #130 main jet, since become a rich fuel with #135 main jet. 　Daytona's exhaust pipe absolutely similar performance with the stock exhaust pipe as I described at the exhaust comparison page. The differences are a little louder sound, a little advanced performance, and shapes. But I like this pipe has rich torque, can realize ride fast in the mountain load. I don't have to forget to say this pipe cost is inexpensive, just 68000 yen.

17.Custom-made Phase5.1

I tried to remove the shim and ride to the mountain road, was not good result acceleration in the middle range rotation.　Although easy to put shim back, it is not interesting, I tried to shape the needle 0.5mm shorter than stock condition NAZN.　Making the shorter needle is simple, set the needle to drill machine, sharpen it with rasp and finishing it with sandpaper. 　I got same riding feel result between shorter NAZN and NAZN with 1 shim.

After second time valve clearance adjustment work was success with an exceeding expectation, mechanical noise of motor is decreased and rotation is stabled in spite of the 700 rpm idling.　It is not felt the difference of tune at the middle or high rotation range, but the difference is clear around idling rotation.　Motor is turning lightly, my feeling also become fine.

DUNLOP K300GP 　This new tire is a K300GP produced by Dunlop as same as TT100 in stock tire. K300 has match better road grip than TT100. It could be relief to wide open the accelerator even while the rolling deeply. At the approaching the corner, it easy to put lean the bike. After into the corner, fully banked W, I feel good road holding performance. 　Appearance I also like. thinner rear view and round shape looks is suit on W650.

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