2 Stroke Engine Parts

Home Up OEM Motor Parts
 

YAMAHA 2 STROKE MOTOR MODS
and
BIG BORE KITS

HIGH PERFORMANCE HEAD
for MM & SX
 

Our billet heads reduce detonation & greatly enhance cooling while increasing bottom and mid-range horsepower. Detonation is reduced while compression is increased by virtue of computer aided combustion chamber design. The result is more compression and a correct squish band; a feature that can’t be duplicated by milling your stock head. Each size combustion chamber is a unique design, not just a cut down version of some other size. Cooling is enhanced by increasing water contact with the combustion chamber by stair-stepping the chamber sides (something that can’t be duplicated in a cast head). Replaceable chambers are available in 1cc increments. All heads are polished & anodized for durability and continued great looks. The Head design features a 2 piece shell (top & bottom halves) and 3 replaceable domes. 

  • OEM MM/SXr chambers are 23.8cc's
  • Sizing recommendations: 
    • 0-2000ft 22cc
    • 2000-6000ft 21cc
    • 6000-10,000ft 20cc
    • Typically subtract 1cc for porting.

Use / reuse stock head gaskets (not included). The upper & lower halves use O-ring seals along with chamber inserts.

Click for Larger Image

Click for Larger Image

High Perf MM Heads with Replaceable Chambers
Specify Color xx = (Red=rd, Blue=bu and Titanium Splash Anodized = na)

US Dollars
 mhm-0100-xx   Complete Head with Replaceable Domes (spec chamber size)  $ 350
 mhm-0200  Replacement O-ring set $ 25
 mhm-0300  Replacement Dome (each) $ 50
 mhm-0303  Replacement Dome Set $ 100
 mgm-0101  OEM Head Gasket Set of 3 $ 80
 
 

VIPER & SRX BILLET HEAD EXTREME COOLING
Our billet heads reduce detonation & greatly enhance cooling while increasing bottom and mid-range horsepower. Detonation is reduced while compression is increased by virtue of computer aided combustion chamber design. The result is more compression and a correct squish band; a feature that can’t be duplicated by milling your stock head. Each size combustion chamber is a unique design, not just a cut down version of some other size. Cooling is enhanced by increasing water contact with the combustion chamber by stair-stepping the chamber sides (something that can’t be duplicated in a cast head). Replaceable chambers are available in 1cc increments for the Viper and 1.5cc increments for the SRX. All heads are polished & anodized for durability and continued great looks. The Viper comes with a separate water manifold. This new design improves water flow an enhances cylinder to cylinder cooling. The Viper & SRX heads are both compatible with DTS (Detonation Control System). SRX uses the OEM water manifold. 
  • Viper OEM chambers are 24cc PTO & 21cc Mag/Center. 
    SRX OEM Chambers are 26cc 
    Typically subtract 1 to 1.5cc for porting. 
  • Viper Chamber Sizing
    • 0-2000 ft  - 22cc (21cc high perf)
    • 2000-6000ft - 21cc (20cc high perf)
    • 6000-10000ft - 20cc (19cc high perf)
  • SRX Chamber Sizing
    • 0-2000 ft  - 24cc
    • 2000-6000ft - 24cc (22.5cc high perf)
    • 6000-10000ft - 22.5cc (21cc high perf)

Click for Larger Image

Click for Larger Image

VIPER HEAD with Replaceable Domes
Specify Color xx where (Red=rd, Blue Splash =bu and Titanium Splash  = sl) 

US Dollars
 mhv-0110-xx   Complete Viper Head with Replaceable Domes (spec cc)  $ 399
 mhv-0200  Replacement O-ring set $ 25
 mhv-0300  Replacement Dome (each) $ 50
 mhv-0303  Replacement Dome Set of 3 $ 100
SRX HEAD with Replaceable Domes
 mhs-0100-xx   Complete Head with Replaceable Domes (spec chamber size)  $ 375
 mhs-0200  Replacement O-ring set $ 25
 mhs-0300  Replacement Dome (each) $ 50
 mhs-0303  Replacement Dome Set of 3 $100
 
 

REED SPACER KIT FOR ALL YAMAHA TRIPLES
   
The reed cage on the MM/SX(r) blocks off the Intake port feeding the rear of the cylinder, resulting in restricted fuel flow. Spacing out the reed cages gives the air and fuel a much straighter path to this rear port. By smoothing out the fuel flow you gain 3hp at low/mid and 1hp top end, plus the steady slow speed burble at low end is nearly eliminated, resulting in improved throttle response. Kit comes complete with longer bolts, 6 OEM gaskets, and spacers. Works great with V-Force and Carbon Tech reeds.

Click for Larger Image
CLICK FOR
LARGER IMAGE

REED SPACER KIT

US Dollars
 mrr-0980   Reed Spacer Kit for All Yamaha Triples SALE $25
      
 
 

OEM CARB JETS & NOZZLES

MPI stocks a complete selection of jets for all Yamaha triples. All components are genuine Mikuni.

Note RX-1 also uses same main jets listed.

Main Jet Example (120, 121.3, 122.5, 123.8, 125, 126.3, 127, 128.8)

Click for Larger Image

OEM CARB JETS & NOZZLES
120 Main jet = mjm-1200 or 153.8 Main Jet = mjm-1538

US Dollars
 mjm-xxxx  Main Jets 120-160 by 2.50 (120, 122.5) $ 3.50
 mjm-xxxx  Main Jets 1/4 sizes (xx1.3, xx3.8, xx6.3, xx8.8) $ 6.50
 mjp-0xxx  Pilot Jets 45 to 65 by 2.5 (60 pilot = mjp-0600) $ 7.95
 mja-0xx0   Air Correction Jet 0.7 to 1.2 by 0.1 $ 5.00
 mjn-01x0   Nozzles P5 to Q8 (Q2 = mjn-0120) $ 24.70
  
  

OEM PARTS PAGE 
 CLICK HERE FOR OEM PARTS PAGE

Click here for OEM PARTS
  
  

Back Up Next