ENG

MOUNTING GUIDE

CYLINDER MXS GP 90FOR:

DERBI EURO 2 Ref.: MXSGP002

DERBI EURO 3Ref.: MXSGP003

MINARELLI AM6Ref.: MXSGP006

MINARELLI HORIZ . LCRef.: MXSGP008

XX-MXS-EBAMXSGP90 11/2014

MAXISCOOT - B.P. 50040 - F-57601 - Forbach Cedex

MOUNTING GUIDE : CYLINDER GP90 E INTRODUCTION / MOTOR CONFIGURATION

1.1 PREREQUISITESTo ensure the full potential and durability of the GP90 MXS cylinder, the following requirements have to be met:

SYMBOL GEARED MOPED :Refers exclusively to Derbi Euro2 / 3 and AM6 engines

SYMBOL SCOOTER :Refers exclusively to Minarelli horizontal engines

2. RECOMMENDED ENGINE CONFIGURATIONCRANKSHAFT: MXS RacingEXHAUST: 90cc MXS RacingCARBURETOR: The minimum carburetor size is 30mm, to exploit full potential, a bore size of 38mm is recommended.

SPARK PLUG: NGK 105IGNITION: Stage6 R / T (PVL) or Bidalot (PVL)

GEARED MOPED: TRANSMISSION: BidalotCLUTCH: Minimum 5-disc clutch

SCOOTER : CVT GEARBOX: Overrange kit, Malossi, Stage6 or PoliniRECOMMENDED TRANSMISSION: Primary 14/42, Secondary 16/41 (Street) Secondary 14/41 (Run)

TABLE OF CONTENTS Page

1. Introduction 11.1 Prerequisites 1

2. Recommended engine configuration 1 3. Scope of delivery 2 4. Milling the engine case 3

5. Installing the MXS GP90 cylinder kit 5.1 Mounting the cylinder 4

5.2 Squish clearance 4 5.3 Installing the sealing plug 5 5.4 Installation of the cylinder head / combustion chamber 5 5.5 Position of cylinder head bolts 6

6. Water cooling 6

7. Ignition 6

8. Fuel 6

9. Running in the engine 6

10. Maintenance & Service 6

11. Tuning 6

12. Portmap 7

13. Replacement parts 7

Min horiz. LC

1. INTRODUCTIONThank you for purchasing the MXS Racing GP90 cylinder and for the confidence you thereby place in our company.

The GP90 is the latest development of the MXS team, and the result of two years of intensive work. The patented cylinder moun-ting replaces the traditional studs by socket screws and aluminum sealing plugs at the lower part of the cylinder. This system facilitates the design of new transfer and exhaust port layouts that a traditional construction would not allow of. This results in a higher peak power and torque!

WARRANTYThe warranty of the MXS RACING cylinder kit includes initial manufacturing defects that can be observed prior to installation. The warranty does not apply to damages caused by natural wear, exter-nal influences (faulty assembly or disassembly, faulty maintenance, improper use...) or by a modification of the product not intended or specified by the dealer. For more information, contact us at info@maxiscoot.com.

Euro 2 + 3, AM6

THE INSTALLATION INST-RUCTIONS MUST BE READ CAREFULLY TO AVOID ENGINE DAMAGE.

CHECK OUT ALL THE MXS GP 90 PRODUCTS ON THE LAST PAGE

01

1.1

1.5 1.6 1.7

1.111.10

2.1

1.2

1.12

2.2

1.3

1.9

2.3

1.4

1.8

2.4

4 x4 x4 x

4 x

4 x

2 x

8 x

Cylinder head cover

Combustion chamber

Screws M6 x 20 mm

Piston

O-ring cylinder head cover

O-ring combustion chamber to cylinder

Screws M6 x 25 mm

Piston ring

Water deflector

Washer Ø 5mm

Vent connections

Gudgeon pin

O-ring combustion cham-ber to cylinder head cover

Screws M5 x 25 mm

Washer Ø 6 mm

Gudgeon pin clip

EXPLODED VIEW CYLINDER HEAD

EXPLODED VIEW PISTON

EXPLODED VIEW CYLINDER

3.1

3.5

3.9

3.13

3.2

3.6

3.10

3.14

3.3

3.7

3.11

3.15

3.4

3.8

3.12

3.16

2 x

2 x

2 x 8 x 4 x

3 x

2 x

Cylinder MXS GP 90cc

Exhaust flange gasket

Screws M7 x 30 mm

Base gasket paper 0.2 mm

Water supply

Screws M7 x 25 mm

Base gasket aluminum 0.1 mm

Washer Ø 24 mm

O-rings sealing plugs

Spacer cylinder base 5mm

Screws M7 x 35 mm

Centering pin sealing plugs

Euro 2 + 3, AM6

Min horiz. LC

Min horiz. LC

3. SCOPE OF DELIVERY

Individual parts piston :

Individual parts cylinder head:

Individual parts cylinder :

MOUNTING GUIDE : CYLINDER GP90 SCOPE OF DELIVERY02

Sealing plug back rightSealing plug rear leftSealing plug right frontSealing plug front left

4. MILLING THE ENGINE CASE1. To avoid irreparable damages caused by an extreme perfor-

mance increase, engine block, gearbox and all bearings must be in perfect condition.

FOR SCOOTER : 2. To allow the installation in scooter engines, the cylinder base

and the crankcase have to be milled by a professional mecha-nic to make everything fit. (Diagram 4.1a + 4.1b)

FOR GEAR SHIFT : 2. In Derbi engines the cylinder base seat of the engine case has

to be extended by 2mm. (Diagram 4.2a + 4.2b)3. All engines require an enlarged conrod recess (Diagram 4.3a +

4.3b)

4. Once the milling is completed, all bearings, oil seals and gas-kets have to be replaced. We recommend to use new gearbox bearings and to replace damaged gears and gear pairs with new parts.

5. After milling the entire engine case has to be cleaned meticu-lously!

Ø58

Milling scheme crankcase(only for Min. horiz. LC)

View of millings engine case(only for Euro 2 + 3)

Milling scheme conrod recess(for Euro 2 + 3, AM6, Min. horiz. LC)

Detailed view(only for Euro 2 + 3)

Detailed view(for Euro 2 + 3, AM6, Min. horiz. LC)

Milling scheme engine case (cylinder)(only for Min. horiz. LC)

2 mm

Depth

3 mm

Width

4 mm

Diagram 4.1a

Diagram 4.1b

Diagram 4.2a Diagram 4.2b

Euro 2 + 3

Euro 2 + 3, AM6

Min horiz. LC

Euro 2 + 3

Diagram 4.3a Diagram 4.3b

Euro 2 + 3, AM6 Min horiz. LC

Min horiz. LC

Min horiz. LC

+ 0

.1m

m

+ 0

.2m

m

ø 77

.3 m

m

MOUNTING GUIDE : CYLINDER GP90 MILLING THE ENGINE CASE03

5. INSTALL ING THE CYLINDER

5.1 MOUNTING THE CYLINDEROnce the milling is completed, the engine is thoroughly cleaned and equipped with new bearings and the MXS GP crankshaft is installed, we proceed with the mounting of the cylinder:

1. Lubricate the needle bearing and install the piston.2. Lubricate the cylinder bore.3. Use the 0.2mm paper gasket.

FOR SCOOTERS : 4. Only for Nitro scooters: Use the 5mm cylinder base spacer and

apply silicone sealant on both sides.5. Position cylinder on the engine case.6. Tighten the screws M7 with a torque of 20Nm. (Diagram 5.1a + b)

30 35

25

30

5.2 SQUISH CLEARANCE

1. Mount the cylinder head (without seals) and tighten the M6 screws (8pcs) with a torque of 12Nm.

2. Use 0.8mm tin-solder to measure the squish clearance. It needs to be 0.55mm. Use the paper joints to regulate the squish if needed.

If you do not know how this is done: please consult the online pdf tutorial http://www.maxiscoot.com/ma-gazine/tutoriaux-fiche-de-montage with the help of an online translation.

Diagram 5.1b

Diagram 5.1a

3.10 3.9

CUT

CUT

3.83.9

Sectional drawing of the cylinder with indication of screw positions (only for Min. horiz. LC)

Sectional drawing of the cylinder with indication of screw positions (only for Euro 2 + 3, AM6)

Sectional drawing squish clearance

Diagram 5.2

Min horiz. LC

Euro 2 + 3, AM6

3.9 3.103.8

2 x 2 x2 xScrews M7 x 30 mm Screws M7 x 25 mmScrews M7 x 35 mm

Euro 2 + 3, AM6 Min horz. LC

3.4

Spacer cylinder base 5mm

Min horz. LC

CUT

3.2 3.3

Base gasket paper 0.2 mm

Base gasket aluminum 0.1 mm

20 Nm 20 Nm 20 Nm

MOUNTING GUIDE : CYLINDER GP90 CYLINDER ASSEMBLY04

Parts used :

0.55 mm

MOUNTING GUIDE : CYLINDER GP90 CYLINDER ASSEMBLY

5.3. MOUNTING THE SEALING PLUGS

1. Once the squish clearance has been determined, remove the cylinder head and start installing the plugs.

2. Attention! Each plug has an allocated position (see diagram 5.3b).3. Locate the respective positions of the sealing plugs and pro-

ceed with the installation of their o-rings.4. Once mounted, a sufficient amount of silicone sealant has to

be applied on the plugs below the o-rings (see diagram 5.3a). Now you can insert the sealing plugs.

5. After inserting the plugs, all silicone residues have to be remo-ved from the cylinder.

6. Mount the cylinder head and all its gaskets.

To avoid irreparable damages to the engi-ne, caused by coolant, the installation of the sealing plugs has to be executed with utmost care! Deburr the drill holes if necessary!

3.13 3.14

3.15 3.16

1.11.3

Diagram 5.3a

Diagram 5.3b

Diagram 5.4a

Parts used :

Diagram 5.4b

3.13 3.14 3.15 3.16

Sealing plug back rightSealing plug rear leftSealing plug right frontSealing plug front left

3.11 3.12

3.12 3.12

3.123.12

8 x 4 xO-rings sealing plugs Centering pin sealing

plugs

1.1 1.51.2 1.61.3 1.4

1.4 1.4

1.4 1.4

Cylinder head cover Combustion chamberO-ring cylinder head cover O-ring combustion chamber to cylinder

Water deflector O-ring combustion cham-ber to cylinder head cover

5.4 INSTALLING THE CYLINDER HEAD COVER AND COMBUSTION CHAMBER1. Make sure the water deflector is mounted correctly (Diagram 5.4a)

2. When inserting the combustion chamber, pay attention to the recess of its anti rotation lock. (Diagram 5.4b)

1.51.1

Position water deflector Position combustion chamber

05

56.7

0

56.7

0

61.7

0

61.7

0

MOUNTING GUIDE : CYLINDER GP90 CYLINDER ASSEMBLY

6. WATER COOLING1. Attach all coolant tubes to the cylinder.2. Connect the two venting ports of the cylinder head with the original

4 mm tubes.3. Fill the cooling circuit with coolant.4. Disconnect the tubes from the two venting ports until no more air

emerges. Reconnect the tubes to the ports after venting.

To ensure a constant operating temperature of 50°, the original radiator should be replaced by a larger model (or two serial models). The mini-mum operating temperature is 45°. The maximum operating tempera-ture of 60 ° must not be exceeded.

7. IGNITIONWe strongly recommend the use of a digital inner rotor ignition. To fully exploit the potential of the MXS GP90 cylinder, chose an ignition timing Stage6 R/T PVL ignition between 4.2 mm and 4.7 mm before TDC for gearshifter and 4 mm and 4.5 mm before TDC for scooters.

Min Horiz. LC: S6-4516600AM6: S6-4518800Derbi E2 / E3: S6-4519200

8. FUELTo avoid the risk of detonation use fuel of at least 100 octane (RON). Do not use any E10/E85 fuel since it is not compatible with commercial 2stroke oils. Make sure to use high quality oil. We recommend Castrol A747 or Motul 800GP. Remove the original oil pump and use a 2% fuel/oil-premix.

9. RUNNING-IN THE ENGINEBefore the first start of the engine, make sure the carburation is set on too „rich“. Once this is ensured you can start the engine. Check if the cooling system has been vented properly. Let the engine run at idle speed for about 20-30 minutes until it reaches an operating temperature of 65-70°. Then turn off the engine and allow it to cool for approximately 10 minutes. Repeat this procedure 2 more times and you can consider the engine to be run-in. Now you can start with adjustment (carburetor, ignition, transmission ...).

10. MAINTENANCE ADVICETo guarantee a consistent performance and durability, you should test the compression of the engine after it has been run in, remember this value and verify it every 1.5-2 operating hours. If the compression is too low, the piston ring or the piston itself has to be replaced. To avoid engi-ne damage, you should also adjust the mixture preparation regularly/ at a change of weather.

11. TUNINGIf you require more power, we recommend the use of the combustion chamber «Competition», which is available for all versions of the MXS GP90. If that is still not enough, please contact the Maxiscoot competiti-on-center at mxscustom@maxiscoot.com.

5.5 MOUNTING THE CYLINDER HEAD1. Mount the cylinder head and tighten the eight M6 screws with 12Nm

of torque and the four M5 screws with 6Nm of torque.

Do not forget to place the washers! (see diagram 5.5)

1.11 1.11

1.11 1.11

1.12

1.12

1.12

1.12

1.9

1.9 1.9

1.91.10

1.10 1.10

1.10

1.8 1.8

1.8

1.8

1.8 1.8

1.7 1.7

1.11 1.121.91.8 1.71.10

4 x 4 x4 x8 x 4 x 2 x6 Nm 12 Nm 12 Nm 10 Nm

Screws M6 x 20 mm Screws M6 x 25 mmWasher Ø 5 mm Vent connectionsScrews M5 x 25 mmWasher Ø 6 mm

Diagram 5.5

Parts used:

06

Ignition Timing MXS 90GP Version « Base » Exhaust : 192° Transfer ports A: 130°, B:128°, C:124°

Ignition Timing MXS 90GP Version « Competition » Exhaust : 194° Transfer ports A: 132°, B: 130°, C: 126°

All parts of the MXS Racing GP90 serie are available in our onlineshop :www.maxiscoot.com

Ignition Timing MXS 90GP Version « Base » Exhaust : 194° Transfer ports A: 130°, B: 127°, C: 124°

Ignition Timing MXS 90GP Version « Competition » Exhaust : 196° Transfer ports A: 132°, B: 129°, C: 126°

Cylinder head coverMXS120906-04 Cylinder head cover MXS GP90 AM6 / Derbi Euro3MXS120906-03 Cylinder head cover MXS GP90 Derbi Euro2MXS120906-02 Cylinder head cover MXS GP90 Min. horiz. LC

Combustion chamberMXS46GPBASE Combustion chamber MXS GP90 Base AM6 / DerbiMXS45GPBASE Combustion chamber MXS GP90 Base Min. horiz. LCMXSGP46COMP Combustion chamber MXS GP90 Comp. AM6 / DerbiMXSGP45COMP Combustion chamber MXS GP90 Comp. Min. horiz. LC

Sealing plug setMXS120906-1 Kit sealing plugs alu MXS GP90 AM6 / Derbi Euro3MXS120906-2 Kit sealing plugs alu MXS GP90 Derbi Euro2MXS120906-3 Kit sealing plugs alu MXS GP90 Min. horiz. LC

Centering pins sealing plugsMXSNRA2X63G2 centering pins sealing plugs, universel

Piston completeMXS06139050A Piston complete MXS GP90 cote AMXS06139050B Piston complete MXS GP90 cote BMXS06139050C Piston complete MXS GP90 cote C

Piston ringMXS11139050 Piston ring MXS GP90 universel

Casket & o-ring setMXS14139050 Casket & o-ring set MXS GP90 AM6MXS14089750 Casket & o-ring set MXS GP90 Derbi Euro2MXS14089850 Casket & o-ring set MXS GP90 Derbi Euro3MXS14074050 Casket & o-ring set MXS GP90 Min. horiz. LC

Washer setMXS15139050 Washer set MXS GP90 universel

Screws M7MXSGPM735 2 x Screws M7 35mmMXSGPM730 2 x Screws M7 30mmMXSGPM725 2 x Screws M7 25mm

Cylinder kitMXSGP006 Cylinder MXS GP90 travel 46mm AM6MXSGP002 Cylinder MXS GP90 travel 46mm Derbi Euro2 MXSGP003 Cylinder MXS GP90 travel 46mm Derbi Euro3MXSGP008 Cylinder MXS GP90 travel 45mm Min. horiz. LC

CrankshaftMXS64690 Crankshaft MXS GP90 AM6MXS24690 Crankshaft MXS GP90 Derbi Euro2MXS34690 Crankshaft MXS GP90 Derbi Euro3MXS84590 Crankshaft MXS GP90 Min. horiz. LC

ExhaustMXS385 Exhaust MXS GP90 AM6 / DerbiMXS365 Exhaust MXS GP90 Min. horiz. LC

Pack cylinder crankshaft MXSGP006P1 Pack cylinder crankshaft MXS GP90 course 46mm AM6MXSGP002P1 Pack cylinder crankshaft MXS GP90 course 46mm Derbi Euro2MXSGP003P1 Pack cylinder crankshaft MXS GP90 course 46mm Derbi Euro3MXSGP008P1 Pack cylinder crankshaft MXS GP90 course 45mm Min. horiz. LC

Pack cylinder crankshaft exhaustMXSGP006P2 Pack cylinder crankshaft exhaust MXS GP90 course 46mm AM6MXSGP002P2 Pack cylinder crankshaft exhaust MXS GP90 course 46mm Derbi Euro2MXSGP003P2 Pack cylinder crankshaft exhaust MXS GP90 course 46mm Derbi Euro3MXSGP008P2 Pack cylinder crankshaft exhaust MXS GP90 course 45mm Min. horiz. LC

Diagram 6 b

Diagram 6 a

Euro 2 + 3, AM6

Min horiz. LC

38

38

Com

busti

on ch

ambe

r(Com

p.)

Com

busti

on ch

ambe

r(Com

p.)

Com

busti

on ch

ambe

r (Ba

se)

Com

busti

on ch

ambe

r (Ba

se)

74.8

074

.50

(AM

6)73

.85

(Der

bi E

uro

2-3)

A B C

A B C

SPARE PARTS

MXS GP90 SERIE:

MOUNTING GUIDE : CYLINDER GP90 PORTMAP / SPARE PARTS07

38.4

0 26.3

0

26.6

0

38.8

1 3.10

2.20

2.60

3.40

38.4

0

26.3

0

26.6

0

38.8

1