This page lists some of the differences between the TRX250R model year engines and associated electrical systems. Bold type indicates upgraded/changed part. NOTE: Some of these part numbers may have changed. This chart is most useful to determine the model year parts were upgraded. For the 1986 - 1989 TRX250R microfiche click here.
|
|
|
|
|
|
|
Water Pump |
||||
|
Impeller, water pump |
|
|
||
|
Cover, water pump |
|
|
||
|
Shaft, water pump |
|
|
||
|
Nut, cap, 6mm |
|
|
||
|
Washer, sealing, 6mm |
|
|
||
|
Washer, 8 x 13 |
|
|
||
|
Washer, 7.2 x 13 x 1.2 |
|
|
||
|
Bolt, Flange, 6 x 25 |
|
|
|
|
|
Bolt, Flange, 6 x 32 |
|
|
|
|
|
Here the impeller style is changed along with the shaft. It changed to a threaded impeller. |
||||
|
Cylinder / Head |
|
|
|
|
|
Cylinder Comp. A (for piston A) |
|
|
|
|
|
Cylinder Comp. B (for piston B) |
|
|
|
|
|
Head Comp., Cylinder |
|
|
|
|
|
Gasket, Cylinder Head |
|
|
|
|
|
Valve Assy, Reed |
|
|
|
|
|
Gasket A., Reed Valve |
|
|||
|
Gasket B., Reed Valve |
|
|
||
|
Insulator, Carburetor |
|
|
||
|
Spark Plug - NGK |
|
|||
|
Spark Plug - NGK |
|
|
||
|
The cylinder was changed after 1986 to make use of a longer (+5mm) connecting rod. The 1987 cylinder features a bridged intake port, revised exhaust port timing and a greater arc to the main transfers. The 1988/89 cylinders feature improved arc to the rear transfer ports as well. Over the years the heads dome (radius) was smaller as the squish area was made wider. The squish area was still too loose to be of much help. The carburetor mounting boot received an update to the O-ring style after 1986 too. It's interesting that Honda doesn't specify the BR8ES spark plug for the 1989 model year. |
||||
|
Right Crankcase Cover |
|
|
|
|
|
Cover, Comp., Right Crankcase |
|
|
||
|
Besides the color change, the right case received a built in spacer to keep the kick starter gear in place. Both cases feature slightly different mounting boss designs. |
||||
|
Clutch |
|
|
|
|
|
Gear, Balancer Drive (37T) |
|
|
||
|
Gear, Primary Drive (23T) |
|
|
||
|
Plate, Clutch Pressure |
|
|
||
|
Piece, Clutch Lifter |
|
|
|
|
|
Spring, Clutch |
|
|
||
|
Rod, Clutch Lifter |
|
|
|
|
|
Clip, Lifter Rod (7.5) |
|
|
|
|
|
Bearing, Needle (12mm) |
|
|
||
|
Bolt-Washer, 6 x 20 |
|
|
|
|
|
Ball, Steel, #9 (9/32) |
|
|
||
|
Ball, Steel, #4 |
|
|
|
|
|
Updating to the 1989 model year needle bearing pressure plate helps clutch feel a lot. The clutch rod lifter for 1986 is used in the 1989 set up. |
||||
|
Left Crankcase Cover |
|
|
|
|
|
Generator Assy, Flywheel Type |
|
|
|
|
|
Flywheel Comp |
|
|
||
|
Stator Comp |
|
|
||
|
Crankcase |
|
|
|
|
|
Crankcase Assy., R |
|
|
|
|
|
Crankcase Assy., L |
|
|
||
|
Crankcase, R |
|
|||
|
Crankcase, L - to #8105333 |
|
|||
|
Crankcase, L - from #8105334 |
|
|
||
|
Bearing, Radial Ball, 63/28 |
|
|
||
|
Bolt, Stud 10 x 70 |
|
|
||
|
Bolt, Stud 10 x 45 |
|
|
||
|
|
|
|
|
|
|
Piston A for Cylinder A (STD) |
|
|
|
|
|
Piston B for Cylinder B (STD) |
|
|
|
|
|
Pin, Piston |
|
|
||
|
Crankshaft Comp |
|
|
|
|
|
Weight Comp., Balancer |
|
|
||
|
The piston changes each year but the crankshaft doesn't change after 1988. |
||||
|
Transmission |
|
|
|
|
|
Mainshaft (14T) |
|
|
||
|
Countershaft |
|
|
||
|
Gear, Mainshaft Fifth (24T) |
|
|
||
|
Gear, Mainshaft Fifth (23T) |
|
|
||
|
Gear, Countershaft Fifth (26T) |
|
|
||
|
Gear, Countershaft Fifth (25T) |
|
|
||
|
Gear, Mainshaft Top (26T) |
|
|
||
|
Gear, Mainshaft Top (25T) |
|
|
|
|
|
Gear, Countershaft Top (23T) |
|
|
||
|
Collar, Mainshaft Top |
|
|
||
|
Washer, Thrust, 25.2 x 33 |
|
|
||
|
Here's the differences in the TRX gearbox. The lower gears stay the same. |
||||
|
Gearshift Drum |
|
|
|
|
|
Drum, Gearshift |
|
|
||
|
Collar, Shifter Gear Side |
|
|
||
|
Bolt, Gearshift Drum Stopper |
|
|
||
|
Bolt, Flange 6 x 16 |
|
|
||
|
Kick Starter Spindle |
|
|
|
|
|
Pinion, Kick Starter Only (44T) |
|
|
||
|
Spindle, Kick Starter |
|
|
||
|
Bolt, Hex., 6 x 16 |
|
|
||
|
Wire Harness |
|
|
|
|
|
Cushion, C.D.I.Unit |
|
|
||
|
Cushion, Regulator |
|
|
||
|
C.D.I. Unit |
|
|
||
|
Regulator Comp., A.C. |
|
3141-HB5-671 from frame # HK105359 |
|
|
|
Harness, Wire |
|
|
|
|
|
TRX250R Serial Numbers |
|
|
|
|
|
Engine Numbers |
|
|
|
|
|
Frame Numbers |
|
|
|
|
