Summary of BT49QT-21B1
Page 1
Bt49qt-21b1 model service manual.
Page 2
Bt49qt-21b1 model spare parts name： ： ： ：.
Page 3: Contents
Contents summary 1 chapter one maintenance of the motorcycle Ⅰ. Items of maintenance 2 Ⅱ. Periodic maintenance schedule and maintenance locations 2 Ⅲ. Maintenance specifications 5 Ⅳ. Throttle actuation inspection 6 Ⅴ. Air filter inspection and cleaning 7 Ⅵ . B r a k e b l o c k s i n s p e c t i o n...
Page 4: Summary
1 summary this 2-stroke scooter bt49qt-21b1 is with low weight, enough power, low oil consumption and good operating performance. This manual is for maintenance men to repair and maintain bt49qt-21b1 and it is also useful when maintain other models. This manual holds the latest technical information...
Page 5
2 chapter one maintenance of the motorcycle Ⅰ Ⅰ Ⅰ Ⅰ. Items of maintenance when the motorcycle is used, parts loose and mechanical wear inevitably occur to varied extents. Neglecting of timely maintenance not only reduces its mechanical function, economic performance, stability and durability, but al...
Page 6
3 1. Maintenance schedule maintenance schedule time item mileage 1000km 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 11000 12000 engine oil new r 300km r r r r r r r r r r r engine oil strainer c c gasoline strainer r gear oil note 4 new r 300km r r throttle play a a a a carburetor i i c air f...
Page 7
4 2. Maintenance locations.
Page 8
5 Ⅲ Ⅲ Ⅲ Ⅲ. Maintenance specifications the basic methods of motorcycle maintenance include inspection, adjustment, tightening, lubrication, cleaning, supplementing and replacement, which constitute the main elements of maintenance. 1. Inspection inspection refers to basic inspecting operations in acc...
Page 9
6 iv. Throttle actuation inspection inspect throttle grip for easy and smooth movement. Inspect throttle free travel. Free travel: 2-6mm the main adjusting position is beside the carburetor. Remove rear luggage box cover. Adjust by loosening the fastening nut and turning the adjusting nut. Fine adju...
Page 10
7 Ⅴ Ⅴ Ⅴ Ⅴ. Air filter inspection and cleaning after a certain mileage, dust and impurities will gather in air filter case and strainer, which will clog strainer pores and reduce inlet of air and thus lead to excessive concentration of mixed gas and reduce the performance of engine. That’s why the st...
Page 11
8 vii. Brake system inspection, adjustment and replacement 1. Front brake (disk brake) remove the bolts linking brake caliper and front shock absorber. Remove brake caliper. * do not pull brake lever when brake caliper is removed so as to prevent jamming of brake block. If brake block is jammed, pry...
Page 12
9 2. Rear brake inspect rear brake lever free travel. Free travel: 10-20mm turn adjusting nut to effect adjustment when free travel exceeds limit. Viii. Front and rear shock absorber inspection 1. Front shock absorber tighten front brake lever, press front shock absorber up and down and inspect actu...
Page 13
10 ix. Front wheel and rear wheel inspection wheel rim inspection: inspect wheel rim, remove rust stains and rubber chips. Deformation and fissures are causes of air leakage. Do not use wheel rims in the following cases: bruise of wheel rim face contacting tire bead ring exceeds 0.5mm in depth and 1...
Page 14
11 inspect if front wheel nut is loose. Inspect if rear wheel nut is loose. If loose, tighten them to specified torques. Torques: front wheel nut 60n·m rear wheel nut 120n·m x. Steering stem inspection swing handlebar right and left to see if there is interference such as wire or other things. Turn ...
Page 15
12 chapter two maintenance information i. Frame number and engine number location ii. Precautions in operation removed washers, 0-rings, elastic retaining rings and split pins must be replaced with new ones. When mounting bolts, nuts and screws, proceed from trial tightening, from larger diameters t...
Page 16
13 connectors must be inserted home. When connecting connectors with locks, confirm that their locks are fastened. Confirm that the wires are not loose. Confirm that connectors’ plastic sleeves completely cover the connectors without fail. Before connecting the connectors, confirm that their sleeves...
Page 17
14 standard torques: designations torques: n·m bolt, nut m5 5 bolt, nut m6 10 bolt, nutm8 21.5 bolt, nut m10 35 bolt, nut m12 55 screw m5 4 screw m6 9 flange bolt, nut m6 12 flange bolt, nut m8 27 flange bolt, nut m10 40
Page 18
15 chapter three body troubleshooting section one body common troubles and trouble detection body part common troubles and possible causes are as follows: troubles causes details (reference) over tightening of handlebar adjusting nut handlebar rotation not easy (strenuous turning or unstable tightne...
Page 19
16 chart continued troubles causes details (reference) inadequate liquid contaminated brake block and brake disc bent or deformed brake disc contaminated brake caliper worn seal ring of brake caliper piston viscous or worn brake caliper piston inability of brake caliper normal sliding worn main cyli...
Page 20
17 chart continued troubles causes details (reference) hardened brake block surface or dusty block uneven or slotted brake block surface serious wear of brake block lining abnormal braking sound serious slots inside brake drum refer to “rear brake service” steering stem rotation not easy refer to “f...
Page 21
18 section two detailed description of body parts malfunction precautions in operation: forced mounting or dismounting of body cover parts will cause damage to claws and slots of corresponding hoods. When mounting body cover parts, be sure to align the corresponding parts of hoods. When mounting bod...
Page 22
19 axle bending inspection place axle on a v-seat and measure with a dial gauge. The dial gauge indicates a 1/2 bending value. Limit of use: replace if >0.2mm. Wheel rim oscillation inspection measure oscillation value on a correcting bench. Limit of use: replace if >2.0mm. Traverse direction: repla...
Page 23
20 front wheel bearing replacement dismounting: remove front wheel bearing by means of a bearing remover, take out spacer. Mounting: apply grease to the bearing. Drive in left bearings. Mount spacer. Drive in right bearings. Bearings must be driven in parallel. Dust cover must be driven in with the ...
Page 24
21 brake oil replenishing lock exhaust valve. Replenish oil reservoir with specified brake oil. ·it is not necessary to fill the oil reservoir to the full capacity. ·brake oil for replenishing should be the same as original. The specification of brake oil is indicated on the reservoir cover. Place d...
Page 25
22 exhaust brake oil from front brake system. Pull out brake switch plug from main cable. Remove bracket bolts from handlebar, remove main cylinder. Remove brake oil pipe from main cylinder. · prevent brake oil from splashing to rubber, plastic or painted surfaces. Cover the above-mentioned parts wi...
Page 26
23 Ⅲ Ⅲ Ⅲ Ⅲ. Front shock absorber service dismounting remove front body covering parts. Remove front brake calliper. Remove front wheel. Remove front fender mounting bolts and front fender mounting bracket. Remove front fender. Remove 2 pieces of bolts on the upper part of front shock absorber. Remov...
Page 27
24 remove front wheel and front shock absorber together with front fender and steering stem from head tube. The removing of the bottom bearing cup, bearing top and bearing set is the same as the removing of the upper series. Do not damage steering stem when removing bearing cup and bearing top. Clea...
Page 28
25 pass steering stem through head tube. Apply grease to top bearing cup and bearing top. Mount in order upper bearing cup, bearing ball set and upper bearing top on the upper part of steering stem and fasten them. Torque: 15 n·m turn front fork right and left to effect close contact of bearing ball...
Page 29
26 ·when removing left grip and throttle grip, remove contamination and grease from contacting face. Mounting mount handlebar on steering stem guide tube, fit bush, setting bolt and nut. Torque: 45 n·m mount left brake lever and fasten bolts. Torque: 9 n·m mount front brake main cylinder. Apply grea...
Page 30
27 mounting mount rear wheel and fasten rear axle nut. Torque: 120n·m mount exhaust muffler. Fasten exhaust muffler connecting nuts and bolts. Torque: exhaust muffler connecting nut: 12n·m exhaust muffler mounting bolt: 35n·m Ⅶ Ⅶ Ⅶ Ⅶ. Rear brake service remove exhaust muffler. Remove rear wheel. Ins...
Page 31
28 do not apply grease to parts not specified. Superfluous grease flows into brake friction linings of brake drum shall reduce braking effect. Mount brake cam. Mount brake swing arm on brake cam. Notch on brake swing arm should be aligned with the cut-off of brake cam. Mount brake swing arm setting ...
Page 32
29 inspection inspect rear shock absorber oil seal for oil leakage, inspect buffer bar and spring for deformation and other parts for damage and loosening. Mounting mount rear shock absorber. Torque: upper mounting bolt: 40n·m bottom mounting bolt: 25n·m mount air filter. Mount motorcycle body cover...