90cc. CR-3 3 speed Close ratio gear set Semi Auto race engine

90cc. CR-3  3 speed Close ratio gear set Semi Auto race engine
  • Click to enlarge

£310.00 ExVAT

Product Code: 5430

CR 90cc 3 speed Close ratio gear set Semi Auto race engine

We have found gear clusters to fit hence price reduction, so we don’t have to sabotage engines to get them!!

Limited edition close ratio tall first gear 30 mph

This is a really slick changing gear box where you can actually change down a gear without over revving the engine due to the sheer gap in the ratio! And it staying within its power range.

Can be use with standard C90 clutch cover

Spec 85cc
Gears N-1-2-3- UP

Ignition type Race VMR118 kit with Coil CDI and mini loom


1 Stock head and compression. 


2 Red TAG performance head, higher compression and altered valve timing

The above reworked allows the engine to hold the same power doesn’t build up excessive heat.


Option on carb Pre jetted PZ19 style 15mm slide ready to us with pod foam filter 35mm fitting.


Service info

Engine oil:            10/40 Mineral Oil

Capacity approx: 725mm

Valve clearance: 0.10mm inlet 0.12mm exhaust


Type: Single cylinder, horizontal, 4 stoke, air cooling, top cam

Size (L*W*H) mm* mm* mm:                  477*395*280

Net weight, kg:                                          22.5               

Bore, mm:                                                  47mm

Stroke, mm:                                               49mm

Compression ratio:                                  8.8:1 stock 9.3 tuned

Ignition advance angle at idle speed:    15 @ 1500RPM

Lubricating system:                                  Press splash

Valve clearance (cold state) mm:           0.03±0.01

Transmission type:                                   Constant engage, 2 grade, 3 gears

Clutch type:                                               Semi  wet multi-plate

Primary reduction ratio:                           1:3.722


Gear Ratios: 1St is a tall

Gear 1:     1 = 1:1.938

Gear 2:     2 = 1:1.350

Gear 3:     3 = 1:1.043

Product Code5430