Adjusting the Pekar K68 for your Dnepr or Ural Adjustment section translated from Pekar K68 manual

Transcription

1 Adjusting the Pekar K68 fr yur Dnepr r Ural Adjustment sectin translated frm Pekar K68 manual

2 Adjusting the Pekar K68 carburetrs n yur Dnepr r Ural. This dcument is intended t server as the primer fr prper adjustment f the K68 s. It als cntains the prduct specificatin sheet frm Pekar fr all f the K68 mdels. I will talk abut the use f different tls used fr the synchrnizatin step, but will nt g int detail n each tl. As part f this step, I will explain the ld timer methd f synchrnizing the 2 carbs withut the use f any special tls (placing the bike n the centerstand and using the speedmeter t determing carburetr flw). This is very interesting t say the least. Pekar Specificatins The fllwing is taken directly frm Pekar (translated): K6Е, K68D, K68I, K68M, K68R, K68T, K68U, K68CH Hrizntal flw Elliptical diffuser Cylindrical slide Centrally lcated flat chamber Lever type flat mechanism and detachable fuel line Adjustable idle Adjustable mixture and needle valve Hands free chke peratin Symmetrical chke and thrttle cable Synchrnizatin prt Flat vent system

3 Carburetr Transprtatin means Engine Cnditinal diameter f diffuser (mm) Diameter f mixing chamber (mm) The capacity f fuel jet (ml/min) Mass, is nt mre (kg) Overall sizes (mm) Drive f the starter К68 А К68 D К68 I К68 М the mtrcycle IZH the mtrcycle "IJ- Jupiter " the mtrcycle "the IJ- planet the mtrcycle IZH-'.902 IZH , ,55 77,5*81*155 Manual IZH- Ю , ,55 77,5*81*155 Manual IZH - П5, IZH ,55 77,5*81*157 Manual ,55 77,5*81*157 Manual К68 Р Lynx , ,55 77,5*81*144 Manual К68 Т Ural Mtrcycles IMZ , ,55 77,5*81*189 Electric К68 U Ural Mtrcycles IMZ , ,55 77,5*81*189 Manual К68 H mtrcycle "IJchpper" IZH , ,55 77,5*81*155 Manual

4 Specificatin Chart frm russianirn.cm K63Ø 'Dnepr-12' K750 K63T Dnepr 11/16 K63y Ural K65T Dnepr K65y Ural K68y Ural Chke size Bre at flange Main jet size (cc/min.) Needle jet size (mm) 2,78 2,78 2,78 2,65 2,65 2,67 Pilt jet (cc/min) Chke jet (cc/min) 'Diameter pening idle' (nte 1) 'Diameter transitin pening' (nte 2) 0,7 0,7 0,7 0,7 0,7 0,7 1,2 1,2 1,2 1,2 1,2 0,8 Slide type Flat Flat Flat Flat Flat Rund

5 Figure 1 K68

6 Frm Figure 1 1. thrttle cable; 27. balancing prt; 2. shielding caps; 28. balancing channel f flat chamber; 3. cable guide; 29. mixture adjustment screw; 4. cver f chke well; 30. spring f screw; 5. spring f chke; 31. mixing chamber; 6. ferrule; 32,34. transitinal penings f the system f idling; 7. husing; 33. air duct f idling; 8. slide; 35. saddle f fuel valve; 9. cable catch; 36. fuel valve in the cllectin; 10. cable stp; 37. regulatin element; 11. needle f chke; 38. flat; 12. lck f needle; 39. channel f starter; 13. spring f the cmpressin f needle; 40. axis f flats; 14. slide bevel; 41. air duct; 15. air duct f main system; 42. plunger f starter in the cllectin; 16. padding f the cver f flat chamber; 43. ferrule; 17. cver f flat chamber; 44. jet; 18. sprayer; 45. needle f crrectr- enricher; 19. main fuel jet; 46. pening dsing; 20. dsing tube f the system f idling; 47. fuel well; 21. stpping washer; 48. the fuel duct f starter; 22. drain hle; 49. needle f starter; 23. flat activatr (tickler); 50. spring f plunger; 24. slide (idle) adjusting screw; 51. guide f spring; 25. spring f screw; 52. Chke. 26. fuel-feed nipple; Preparatin fr K68 Adjustment 1. Make sure the ignitin timing is crrect 2. Adjust the valves as necessary t ensure prper peratin 3. Run the engine t warm it up a bit 4. Adjust the flat setting. T d this, remve the carburetrs (leave the thrttle cables attached), remve the bwl and turn the carburetr upside dwn (fuel will spill). The flat shuld lk like this: Adjust as necessary by bending the flat supprt (#37 in Figure 1). Reinstall.

7 Figure 2 Installatin and idle adjustment 1. First yu must adjust the idle. It is acceptable per the manual t adjust the idle by using the idle adjust screws (11). This usually invlves screwing them then backing ut 1 t 1.5 turns. Or yu can adjust lking at the sliders 2. If installing the carburetrs: a. Remve the cver (2) b. Remve the slider (3) c. Place the thrttle cable thrugh the guide (18) with the spring (4) n the cable. d. Rute the cable thrugh the slide catch (6) e. Insert the slide assembly int the chamber and make sure it easily slides up and dwn. Direct the needle (8) int the pening f the diffuser (angled side visible). f. Screw assembly tgether and verify via thrttle mvement that slide mves freely. Attach fuel delivery lines t (12). 3. Using the idle set screw (11) raise the slider s the lwer edge is 1-2 mm. 4. Assemble t engine using the prper gaskets (paper felt paper). 5. Using the lcknut (26) adjust the free play f the thrttle cable (2-3 mm) 6. Adjust the idle mixture screw turn in cmpletely then ut 1 t 1.5 turns. Starting using the K68 s (cld weather) 1. Verify fuel flw. Apply chke (pull 52 in Fig1). 2. Using the ticklers (13) allw fuel t enter the bwl until fuel drains frm (14) 3. With the ignitin ff, kick 1 r 2 times 4. Turn ignitin n, and as sn as engine is warmed up (maybe sner) push chke mechanisms t pen chke

8 Idle Adjustment (engine running and warm) 1. Remve ne f the spark plug caps, and with the cap shrted, adjust (11) t decrease RPM s t a pint f being minimally steady. 2. Adjust the mixture (15) ut until RPM s decrease. Turn in until RPM s increase slightly. Then turn in screws ¼ t 1/3 revultin. 3. D the same fr the secnd carburetr with the first spark plug cap shrted. 4. With bth cylinders, adjust each idle (11) n each carburetr the same amunt each until it s at a steady, minimal RPM. Use small changes. (at this pint yu can use yur airflw tl t check). 5. Sharply increase, then decrease thrttle. Then engine must return t lw RPMs smthly. If the engine ges belw limits, readjust (11) frm step 4. Synchrnizatin f the K68 Nte: Rather than using the ppsite cylinder shrted t test the pull f the live cylinder carburetr, yu can use smething like a Twinmax cnnected t the test prts (27 Fig 1). Or, if yu have a mdel withut these prts, use a Synchrmeter (Appendix 2) held against the face f the carburetr. These tls merely shw airflw passing thrugh each carburetr (which is dependent n the psitin and wear n the slide). If using these tls, it s nt necessary t d the fllwing steps. Yu wil want t use a thrttle guide (Appendix 1), t shw airflw at varius thrttle settings. Using the flw meter f yur chice make sure each carburetr is the same at the varius thrttle settings. 1. Place the mtrcycle n the center stand ensuring the rear wheel is suspended 2. Make sure yu have large area t wrk with (safety issues here) 3. Shift int the highest gear with the engine running 4. Shrt ne spark plug cap t the cylinder (using a nail r smething in the fins) 5. Increase the speed t km/hr 6. Fix the thrttle using the thrttle (maybe using a thrttle stp screw under the thrttle husing). 7. Recnnect ther cylinder and using the ppsite carburetr determine the speed which shuld be the same as the first. 8. Adjust the psitin f this slide t achieve the referenced speed using the lcknut at the tp f the carburetr. Adjustment f the mixture due t climactic cnditin changes. This invlves changes t the needle vale (8 and 9 Fig 1) (11 and 12 Fig 2). With the needle mved upward, the mixture is leaned, mvement dwn and the mixture is enriched. Needle mvement ccurs thrugh remval f the lck and mving the needle t the next grve (carse adjustment). Fine adjustment ccurs thrugh transpsitin f regulatin washer (9 Fig 1) (19 Fig 2).

9 Special Operating Instructins Discnnect the fuel befre maintenance n K68 s. Must be used with a tightly cnnected air filter f manufacturers specificatin nly. A mdificatin f filter r manufacturer is nt allwed. Fuel used must be cleaned and filtered f all impurities. Carburetr parts must be washed in gasline nly. Washing is nt allwed with slvents. After washing, blw with cmpressed air t dry. Cleaning any f the metering hles (20,21 Fig 2) r nzzle hles (22, 23, 24 Fig 2) with metallic bjects (wire, needle, etc.) is nt allwed.

10 Appendix 1 Fixing the thrttle and stages f peratin

11 Appendix 2 Synchrmeter (an alternative t tuning) Used this n my 912 and it wrks great

12 Appendix 3 Cutaway K68

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