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Compression in the cylinders


Forum Tech corner Compression in the cylinders




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František
2016-08-10 19:25:49

I will describe only třistapadesátky since they own. As every knows about bikes in Jawa during their manufacture from Perak to even the Jawa 638 type designation too big visible changes in the combustion chamber of the engine there, but that little had an effect on engine performance. Not only changes to the engine itself but also in carburetors and exhaust pipe and muffler samotmém. During the development of motorcycles Jawa tried to keep poměrhluku and pollutants according to standards not only changed the ratio of gasoline and oil gradually from 1:25 to 1:50 but the imposition of the connecting rod and piston pins. All these modifications have had an impact on engine performance. Some might argue that modifying overflow channels also changed a lot, but inaccuracies casting it was not so giddy. Changes to achieve when everyone who wanted their own initiative, took šmirgl, file or other abrasive and either using templates or from the eye of channels adapted and attuned so that he is without sharp edges and pretty as one another.

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František
2016-08-10 19:28:01

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Now I'll describe engines only known me and the type referred to as 633 bison. 63x series engine labeled the era of round engines. The truth that must Jawa 362-00 type had squared the war but kulatej engine based on the concept angularity 360. The engines were caused by the increasing požadavkama for more. It showed the necessary cooling and increase the cooling surfaces of the ribs placed on the rollers and the heads of engines. Šesttřitrojek war should fit the exhaust pipe as Čezeta one screw and suction channel same as the previous model being described, 360. Rollers were already squared. Heads with similar ribs as the heads of the previous type 360 ​​but with that replicate the shape of the square rollers and the slant from the front it was low and rising to the rear. Compression ratio was adjusted to 9.2: 1 by reducing the dead space to 18.6 cc. The performance of this engine was 15,5Kw. Numeric designation of the head do not know as to those who got no not have enough size photo of the dead space from edge to edge I measured 38.5 mm.

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František
2016-08-10 19:29:32

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Jawa 634 type designation belonged had also boxy engines last in a series of what was in each cylinder , three bolts . Compression ratio remained the same as 633 and 9.2 : 1 only the power was different and 14.7 kW . What was it caused by ? Each engine had its best performance and torque jinejch speed. Rollers had the same shape as the 633 with the difference that the exhaust knee was caught in the inner nut rolls. The head is higher hranatej replicating the shape of the rolls in front of the larger ribs gradually decreasing in the rear. Ribbing heads is different than with previous models .

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František
2016-08-10 19:31:53

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So that now every thought to confuse the head and roller type for what had Jawa 634, and will have hnedle about two kilowatts to exercise more. It's not that. With the gradual development of engines Jawa also improved the intake, exhaust and transfer ports in the cylinders and the block itself motoru.To itself to increase performance, not even need to have the appropriate exhaust and carburetor filter, and not only that, when produced VELOREX and drove on another kind of gasoline I guess it was about eighty octanoic normal. It also has an influence on the running of the engine. Today, driven mainly octanoic 95 Natural, who's burning faster and has greater extensibility gases. This implies that if we go back engine development as varied as the compression ratio and the quality of fuel on who's rode it all. Thus, in terms of timing and engine fuel that the engine goes. If you take a similar concept as the engine třistapadesátky VELOREX and Jawa 354. It had a compression ratio of 7.2: 1 and about 3.5 millimeters advance before TDC. Well, he poured into him eighty octanoic normal. In contrast Jawa 638 already had a compression ratio of 10.2: 1 advance about 2.5 mm before TDC, and drawn into the special gasoline 90 octane. Despite the fact that the feed motor is also changed diameters of main nozzles in order to maintain a proper ratio of air fuel about 12.5 to about 15: 1. regulate this main tryskama diameters from about 110 to 80 well level of the fuel in the carburetor. Certainly lounge is open for folks noticed that if there is gasoline in the carburetor idle speed increases and then it dies. Adjusting the level in the float chamber discover follows. Float chamber should supposed to be such that when gasoline into the carburetor begins without flooded ! and after a steady fuel supply shuts down

Subdivide gently float cap are two screws. Then squeeze the floats gently to the bottom for a needle and levels should supposed to be at the same time of the float when the float will be more tough or if you do not seal the needle is lehkej min. The reasons why this is so everyone can read clever books in here or on wabu in articles I wrote.

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František
2016-08-10 19:36:54

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I drew information from various sources and I noticed the frequent differences in compression ratios and performance of reading in the same machine because the information described here consider it just as a preview to my observation of changes in engine development Jawa .

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František
2016-08-10 19:38:19

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Here is a photo of my Jawas pressures of 350/638 .

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František
2016-08-10 19:41:56

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That 's a meter on the compression in the cylinder

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František
2016-09-02 10:57:02

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Total look at the meter compression in the cylinders.


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