maico-mc 250 400 501 square barrel-68 71-service manual engine

7/18/2019 Maico-MC 250 400 501 Square Barrel-68 71-Service Manual Engine

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S Q U A R E B A R R E L

E N G IN E S E C T IO N

NOTE: ALL THREADS ARE RIGHT HAND

( Cl ockwi se t o t i ght en - count ercl ockwi se t o l oosen) .


2/29

I . Pr epar at i on For Di sassembl y Of TheEngi ne

1. Al l di r t , mud, dus t , and f or ei gnmat er i al must be t hor oughl y r e-moved f r om t he ext er i or of t he en-gi ne assembl y bef or e r emoval anddi s as s embl y.

I I . Engi ne Removal And Di sas sembl v

1. Dr ai n t he t r ansmi ss i on oi l by r e-movi ng t he dr ai n pl ug l ocat ed att he under s i de of c l ut ch cover j usta he ad o f t he f o ot r e s t . T he pl ughas a 17 mm hex. Remove f oot r est s.

The t r ans mi s s i on/ Pr i mar y hol ds l OOOcc ( 1 L i t er )

2. Remove car bur et or - medi um sc r ewdr i ver .

Not e: Di sconnect wi r e t o coi l i f mot or -cycl e i s equi pped wi t h ext er nalc oi l . The c oi l i s l oc at ed undert he gasol i ne t ank.


3/29

11. Remove t he i gni t i on cover - me-di um bl ade scr ew dr i ver . Notnec essar y f or t r ansmi ssi on r e-pai r .

12. Remove t he t hr ee sc r ews hol di ngt he magnet o housi ng - medi um

bl a de s c r e w dr i ver . No t n ec e s -s a ry f o r t r a ns m is s io n r e pa i r.

13. Remove t he el ect r i cal wi r e goi ngt o t he c oi l f r om t he poi nt s andpul l t hr ough t he case r emovi ngt he r ubber gr ommet .


4/29

14. Remove t he magnet o r ot or - smal lbl ad e sc re w dr iv er , Bm m wr en ch ,

i mpact sl i de hammer pul l er . Wer ecommend t he use of a sl i de hammerpul l er as shown.

15. Remove cyl i nder head - 13mm

s ocket .


5/29

16. Remove cyl i nder

NOTE: To r emove cyl i nder wi t h engi ne i nt he f r ame, r emove t he st uds wi t h as ma l l v i s e gr i p pl i e r s . Pus h t hepi st on t o SDC and r emove t he cyl i nde

17. Remove pi n c l i ps - needl e nose pl i er s .Push pi n t hr ough and r emove pi st ona nd be ar i ng. No t e t he s h op t o we l i nt he t o p o f c as e s t o k ee p f o r e i gnobj ect s f r om f al l i ng i nt o t he l ower endDo not r euse pi st on pi n c l i ps.


6/29

18. Pl ace engi ne i n engi ne st andwi t h cl ut ch cover up.


7/29

19. Measur e t he pi st on and measur et he c yl i nder bor e. I f t he c yl i nder bor e i s gr eat er t han . 006i nc h, r epl ac e t he pi s t on. I t i swi se t o check t he cyl i nder borei n at l east 3 pl ac es; t op, mi dand bot t om t o be sur e t hat t hec yl i nder i s r ound and i s t r uef r om t op t o bot t om.

Rebor e when t he t ot al dei vat i oni n t he cyl i nder i s gr eat er t han. 006 i nch f r om a new pi st on.

A new pi st on shal l have . 002 i ncl ear ance bet ween pi st on andcyl i nder wal l measur ed at bot t oof ski r t . The mac hi ne wi l l r e-qui r e 75- 100 mi l es br eak i n pr i t o r aci ng.

20. The pi st on r i ngs shal l be c hec ked f or end gap. A new r i ng has. 010 i nch end gap. When end gap

exceeds . 016 i nch r epl ace pi st onr i n~s .


8/29

21. Remove:

A. Ki c k st ar t er1. 360- 250 - Remove snap r i ng

and l oosen pi nc h bol t -i ce pi ck and l 7mm wr ench.

2. 400- 501 - Remove 6mm bol t10mm wr enc h.

B. Remove seven 6mm sc r ews f r omt he cover - medi um bl ades c r ew dr i ver .

C. Pul l t he c over s t r ai ght up

Not e: For ser v1c1ng c l ut ch wi t h en-gi ne i n t he f r ame, l ay t hemachi ne over wi t h t he r i ghts i de do wn. Pul l t he pl a s t i c

. t r ansmi ss i on vent hose out oft he case j ust above t he chai n.

Tur n t he hos e 1800so t hatt r ansmi ss i on o i l wi l l not r unout . Havi ng t he mot or cycl el evel wi l l gr eat l y assi stwhen r epl aci ng t he cl ut ch spr i ngs.

22. Remove t he cl ut ch snap r i ngswi t h speci al pul l er and t wosmal l bl ade scr ew dr i ver s.


9/29

23. Remove by hand t he cl ut ch pl at ecl ut ch gui de, and not e di r ect i oo f f i ber pl a t e a nd s p r i ng s t a ckup.

2~. Cl ut ch spr i ng hei ghtnew . 075 - r epl ace . 070


10/29

25. Cl ut c h spr i ng heav y 360 - 400Pl ace t wo spr i ngs f ace t o f ace,t hen add t wo mor e spr i ngs oneon eac h si de, maki ng a set of 4 spr i ngs. Use 18 spr i ngs, ma-k i ng 4 1/ 2 set s. Twent y spr i ngsmay be used - 5 set s - f or mor es pr i ng pr es s ur e.

26. Cl ut ch spr i ng l i ght 501 ande ar l y o va l ba r r e l 250 a n d 36 0.

Ta ke t wo s pr i ngs f a c e t o f a cef or s et of 2. Us e 20 s p r i ngs ,maki ng 10 set s of 2 spr i ngs

.

Lat e model 400 and 501cl ut ches t hat ar e t he l i ghtwei ght model uses 18 spr i ngsst acked as shown above.


11/29

-

-

27. Thi s pi ct ur e shows t he pr opersequence of assembl y f or t he alst eel cl ut ch. I t i s r ecommendeduse 20 spr i ngs when r eass embl i n

For 250, ) 60 and ear l y 400 onl y .One f i ber pl at e.

Thi cknes s new ~Thi cknes s r epl ac e ~

Thi cknes s new ~Thi cknes s r epl ac e . 080

Thi cknes s new ~Thi cknes s r epl ac e ~

Not e: When al l f i ber cl ut ch i s usedt hi s pl at e wi l l have no wear .Check f or f l at ness .

-

-

-

-

Driven plate

Driving plate

6 required.

6 required.


12/29

: LUTCHES

27a. 250 & 360 f i ber cl ut ch5 f i ber pl at es ~ s t eel pl at es 18 t o 20 spr i ngs doubl e

~7b. 250 & ~OO st eel cl ut ch. 20 spr i ngs doubl e

~OO & 501 bi g cl ut ch

Fi r st desi gn bi g cl ut chused i n most 1971 ~OOccmote crossers.

6 st eel sl pi ned pl at es7 f i ber pl at es1 t ermi nal pl at e - Snapr i ng i t i nt o t ermi nalpl at e gr oove.

~7c

: ot e: Cl ut ch body ( cent er ofcl ut ch t hat i s sl pi ned)i s l onger on 1st . desi gncl ut ch t han 2nd desi gn.

Thi s cl ut c h us es 20_ sprin.ss stacked single()()() ()()()() (),i ()

--

Not e: The cl ut ch pl at ess hal l be i ns t al l ed t ot hr ow t he oi l out .


13/29

-

-

-

27d. Second desi gn bi p,c l u t c h u s ed i n a l l1972 400 & SOl cc model s.S st eel spl i ned pl at es6 f i ber pl at es1 t er mi nal pl at e. The

nar r ow machi ned r i nggo es o ut s i de . The wi demachi ned band p, oesi nsi de.

Not e: Thi s c l ut ch body ( cent ero f c l u t c h t h at i s s p l i ne di s shor t er t han t he lst-desi gn-

Thi s c l ut c h us es 18spr i ngs st acked s i ngl e()()()()()()()()()

Not e t he heavy washer bet weent he i nner & out er cl ut ch bodi es

The s pac er r i ng not s hownmay go ei t her on t op orunder t he spr i ng washer s.


14/29

NOTES TYP! CAL TO ALL CLUTCP. ES

Not e: The c l ut c h ? l at es s hal lbe i nst al l ed t o t hr owt he o i l o ut .

- Not e: The cl ut ch t hr owoutbear i ng r equi r es 14bal l bear i n~s on al lmode l s .

-

Not e: The c l ut ch nut must bei nst al l ed wi t h " Loct i t e".I f t he c l ut ch nut comesl oose t wo ~ear s wi l lengage at t he same t i me.

-

-

27e. Thi s i s t he engi nef l ywheel used on t he501 onl y.

-


15/29

28. Remove t he l ock t ab f r om t hec l ut c h gui de nut by l i f t i ng out .

The l oc k t ab i s r eus eabl e.Shown i s a new l oc k t ab and onepr oper l y bent t o s ec ur e t he nut .Not us ed i n 501.

NOTE.

Us e L oc t i t e on t he 501

cl ut ch nut .

I f t he c l ut c h nut c omes l oos et he t r ansmi ssi on wi l l engaget wo gear s at onc e.

29. Remove cl ut ch cent er - speci alcl ut ch hol di ng t ool and 17mms oc k et .

.

Not e: Removi ng t he cl ut ch cent erwi t hout t he Speci al c l ut cht ool can cause damage. Thidamage wi l l cause t he cl ut cpl at es t o bi nd up and t hec l ut ch wi l l s l i p or notpr oper l y r el ease.


16/29

30. P ul l c l ut c h c ent er f r om c l ut c hcase, r emove br onze bush.

Remove cl ut ch cas e an~ pr i mar ychai n and cl ut ch t hr ust washer .No t e c ondi t i o n, i f be nt o rgr ooved r epl ace washer .


17/29

501cc not shown

r eassembl i ng, gr easesi de of engi ne spr ocket

Do not g2ease l ock washer

Not e t he pi n t hat keeps t hef l ywheel s f r om r ot at i ng. Thepi n i s i nser t ed bet ween t he conr od and t he engi ne cases.

2. Keep t he f l ywheel s f r om r ot at i ngby i nser t i ng pi n bet ween connect -i ng r od and case. Remove engi ne

spr ocket nut and l ock washer ,pul l spr ocket , and spacer .

To ol s , 3/ 8" pi n, l ar ge s cr ewdr i ver and 24mm wr ench.

Not e: Whenbacknut.

1. Remove spr ocket nut

2. Remove ext er nal f l ywheeland t he s pac er r i ng.

32. Engi ne spr ocket1 . 2 5 0- 4 00 c c Remove l ock t ab

f r om engi ne s pr oc ket nut -chi zel and hammer .


18/29

) ) . Remove l ock t ab, shi f t l i nkagec ov er pl at e, and s hi f t l i nk agepul l r od. 10mm wr enc h, c hi s eland hammer . See Mi sc. sect i onf or pr oper i ndexi ng of s hi f tmechani sm when r eass embl i ng.

34. Remov e k i c k s t ar t er s haf t andspr i ng by wi ndi ng spr i ng andl i f t i ng st r ai ght up.

35. 250 and 360 model s have ei ghti nt er nal c as e s c r ews . L ar gebl ade s c r ew dr i v er .

) 6. L at e model 250, al l 400' sand 501' s have seven i nt ernalc as e s c r ews and one ext er nal .L ar ge bl ade s c r e w dr i ver .


19/29

37. Remove spr i ng f r om hook r acheneedl e nose pl i er s.

38. Remove l ef t hand case - by hanand. r awhi de hammer .

39. Remove cr ank shaf t assembl y -by hand.

40. Check f l ywheel al i gnment by r o-t at i ng on kni f e edges. Max. mi s-al i gnment i s . 002 i nch at t he endof t he magnet o shaf t , r e- al i gn i fne ce s s ar y . Thi s mus t be do ne bya mot or cycl e shop or a machi ne shop.

NOTE. I t i s suggest ed t o r eass embl e t he f l ywheel s usi ngLoct i t e gr ade 35 and Loc t i t e pr i mer gr ade T. Todi sas sembl e l oct i t ed f l ywheel s heat t o 450- 5000Fi n an~. Do not us e a t or c h.


20/29

41. The connect i ng r od si de pl ay shal lbe . 019 - . 020 i nch when new. Af eel er gauge may r epl ace t he di ali ndi cat or . The t hi cknes s of t hebi g end of t he connect i ng r od whennew i s . 665 t o . 670 i nch. I ti s per mi ssabl e t o have mor e t han. 020 i f t he connecti ng r od has

wor n i nt o t he f l ywheel sur f ace.

42. The r ef er enc e di s t anc e ac r os s t hef l ywheel s i s 2. 475 - 2. 490 i nches.

Thi s di mensi on shoul d be used asa r ef er ence onl y as t he measur e-ment of t he si de cl ear ance of t her od i s t he onl y accur at e met hod.

43. Remove shi f t i ng f or k spi ndl e byhand. Check t o s ee t hat i t i snot bent .

44. Remove gear st ack - by hand.Not e t he shi ms. Some t r ans-mi ssi ons do not have shi ms.The shi ms cont r ol t he 1st .gear t ol er ance t o o . 3mm( . 012) . I f t he t r ansmi ssi oni s i mpr oper l y shi mmed i t i spossi bl e t o engage t wo gear sat once.


21/29

Gr i nd her e. 030 i nch Hax.

45. Remove mai n s haf t and s hi f t i ngf or k f r om l ower s c r ol l - by hand

46. Remove l ay shaf t and shi f t i ng f of r om upper sc r ol l . CHECK t o see t he shi f t i ng f or k on t he l ay shai s not t ouchi ng second gear on tmai n shaf t . I f " i t i s t ouchi ng,gr i nd f or cl earance.


22/29

47. Gear st ack showi ng t he posi t i o-ni ng of t he s hi f t i ng f or k s .

48. When f i t t i ng a new 1st gear t ot he l a y s h af t be s u r e i t ha s t hesame amount of i nt er nal cl ear ance( s l op) as t he 3r d gear on t he l ays haf t .

Cl ose Rat i o

1 2 3 4

Mai n 17 20 22 22 Teet h

Lay 20 18 16 13 Teet h1. 99 1. 52 1. 23 1. 0 Rat i o t o 1

Wi de Rat i o

1 2 3 4

Mai n 14 18 21 * Teet hLay 23 19 ,~ 1: Teet h

2. 78 1. 79 1. 29 1. 0 Rat i o

Pr i mar y Rat i o 19/ 39=1. 86 t o 1

*Cl ose Rat i o ~ear s ar e used i n t he w id e r at iot ra ns mi ss io n a t t hese l ocat i ons


23/29

53. Repl ac i ng " 0" r i ngs on s hi f t i ngcam spi ndl e.

54. Remove engi ne seal s and r ei nst al l .Cases must be heat ed appr ox. 2500.Us e an oven or hot pl at e. Us e of a t or ch i s not r ecommended.

. 501 engi ne s e al sar e ext er nal t ot he m ai n b e ar in gs .

55. Cases must be heat ed appr ox.2500r f or r emoval of any bear i ng.

The s c r ew dr i ver s ar e poi nt i ng t ot he bear i ng l ocat i ons.

Cr ank shaf tRemove bear i ng r ace by l ocal l yheat i ng r ace r ed and wedgi ng as ha r p c hi s e l behi nd t he r a ce . T apchi sel l i ~t l Y wi t h hammer . Ther a c e ma y r e mo ve d wi t h a bl a depul l er onc e i t has mov ed. I t i s

suggest ed t hat t he l ocal mot or -cyc l e shop per f or mes t hi s oper at i on.The s ea l l and mus t be checked f o rany r oughness caused by r ace r emoval .

56. The engi ne i s now t or n down f arenough f or maj or ser v i c i ng. Donot d~sass embl e any f ur t her un-l ess absol ut l y necessar y.


24/29

57. Removi ng t he f el t wi ck and rt ai ni ng spr i ng.

58. Removi ng t he ci r cl i p f r om t hs hi f t i ng pawl .

59. Removi ng t he s hi f t i ng pawl .

60. Removi ng t he pawl spr i ng.


25/29

T E C H N IC A L

S E C T IO N


26/29

61. Shi f t ear n bus h and s hi f t pawlst ud ar e not normal l y r emoved,however , i f wor n, t hey ar eav ai l abl e f r om Mai eo par t s di s -t r i but or .

62. Fuel t ap as s y

63. I gni t i o n poi nt as s y


27/29

64. Car b adapt or s, and ai r c l eanassy.

65. Foot st ar t er assembl y

66. I gni t i on si de ass embl y showi ngengi ne seal , r ol l er bear i ng, aoi l seal .

501 engi ne seal s ar e ext er nalt o t he mai n bear i ngs.


28/29

. 7, Dr i ve si de ass embl y showi ng sealand bal l bear i ng,


29/29

68 TECHNI CAL DATA

Engi ne: I gni t i on:

360cc

SOl ce12: 1

Two- s t r ok e. s i ngl e

::isplacement:

Compr essi on r at i o:ruel:

Lubr i cat i on:

cylinder engine

250cc ~OOcc

247cc 386cc

12 , 3: 1 12 : 1Regular petrol

Pet r ol eum t ype r aci ng oi l ,e. g. Cast r ol GP 50 wt . mi xi ng

r at i o of 20: 1 ( 5\ )

Appt . magnet o separ at e hi gh- t ensi on coi l .Ti mi ng: 250=2. 9 8TDC, 400=3. 6 BTDC,

501=3. 6 BTDCCont act br eaker gap: . 014- . 018" ( 0. 35- 0. 45)Spar k pl ug: Champi on L3G=250, L2G=400,

N2G=501

Fr ame:

Power t r ansmi ssi on:

Oi l - damped t el escopi c f or k. 7 i nchesmovement . Oi l capaci t y: 60z ( 0. 2 l i t r e)per f or k l eg. Oi l r ecommendat i on: Engi neoi l SAE 20- 50 dependi ng on t emper at ur e,r i der and cour se.

Fr ame i s wel ded chr omemol ybdenum s t eel .Pi vot i ng r ear ar m i n r ubber bushi ngs.

f r ont : 3. 0OX 21" wi t h mot o .cr oss t yr e.Rear : 4. 0Oxl S" wi t h mot o- cr oss t yr e f or 2504. SOX18" wi t h mot o- cr oss t yr e f or 400&501

Wheels:

Fr ont f or k:

400 - l 3T f r o nt - 52!rear250 - 11T f r ont - 52T rear501 - l 3T f r o nt - 52T r ear400 - l 3T f r o nt - 5 9T rear250 - 11T f r ont - 59T rear

501 - l 3T f r ont-

59T rear

;earbox:

Seven di sc mot e- cr oss t ype cl ut ch.Pr i mar y t r ans mi s s i on by dual r ow pr i mar yc hai n 1 9T x 39r ( 1 . 86 t o 1)

Secondar y t r ansmi ssi on by chai n dr i ve5/8" x 114ft). 12 teeth on gearbox sprocket

] n d 5 3 t e et h o n r e ar wh ee l .

" S I I Tr ans mi ss i on

T" Transmission

Transmission 4- Speed Heavy Dut y"Til "S"

Br akes:

1s t2nd3r d4t h

Mot a Cr oss1. 9 9 t o 11. 52

1. 23

1. 0

Cr oss Count r y2. 78 t o 11. 791. 291. 0

r ear : di am. 160x30 mm ( 6 5/ 1611x l 3 / 16 " )f r ont : di am. 14Ox30 mm ( 5 1/ 2"xl 3/ 16" )

Saddl e:

Oi l capaci t y: 1 quar t;11 r ecommendat i on: Tr ansmi ssi on oi l SAE 40wt .

f or 2S0, SAE 90wt . gearoi l f or 400 & 501.

Mot o- cr oss t ype.

Foot r est s:

FOl di ng f oot r est s at a 45 angl e.

; arhur et t or : 250 400 501

Mot o- er oss t ype wi t h paper el ement .

~i r f i l t er :

l i s t en & Fl ywheel dat a:

Wheel base: 54" ( 1315 1mI)Saddl e hei ght : 31. 5" ( SOO rrrn)Gr ound cl ear ance: 7" ( 180 mm)Dr y we i g ht : 2 50c c : 10 2 k g ( 2 24 l b . )

4 00c C: 10 5 k g ( 2 31 l b. )50 l c c : 10 7 k g ( 2 39 l b. )

Fi ber gl ass f uel t ankCapaci t y: 7 l i t er ( 1 . 9 Gal s)

r uel t ank:

Di mens i on s :

18035

2803

1 1/ 2

18535

2853

11/2

1/ 36/ 101180

35

2803

1 1/ 2

J i ng:Mai n j et :. dl i ng j et :l eedl e j et :l eedl e posi t i on:

Ai r scr ew openi ng:

Fl ywheel assembl y. S i de p l ay of connect i ngr od shal l be . 019- . 020. Repl ace . 023 or; r eat er .l i st ance acr oss f l ywheel s out si de t o out si de

2. 475. Ref er ence onl y.Run out when suppor t ed on bear i ng ar ea , easur ed at ext r eme end of magnet o t aper. hal l not exceed . 002 i nch

' i mi ng si de bear i ng - up & down pl ay . 010 nch max. s t o n r i ng e nd gap - . 0 03 p e r i nc h o f i amet er .l i d l t l i d 013

Scr ewed j oi nt s:

Nut f or magnet o: 10 l b. f t . ( 1. 7kpm)Nut f or out put chai nspr ocket : 50 I b. f t . ( 7kpm)Nut s whi ch hol d t he cyl i nder head t o t hecyl i nder : 15 l b. f t . ( 2. 5kpm) f or 250 & 400;25 l b. f t . 13. 5kpm) f or 501Engi ne mount i ng bol t s: 25 l b. f t . {3. Skpm) Bmm bol t s35 l b. f t . ( 5. 2kpm) f or 10m bol t sNut s whi ch hol d t he bear i ng bol t s f or t he r earwheel pi vot ar m: 25 I b. f t . ( 3. 5kpm)Cl ut c h nut 3 0 f o ot l b s .

maico-mc 250 400 501 square barrel-68 71-service manual engine

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