69cc Thunder Thud

Grubee Inc


Sorry, this item is out of stock

Here's the real "Thunder Thud".   Made for racing > all out performance. 


    We're have done final development and dyno testing in China at the WoodPecker factory!    We are comparing the pros and cons of case reed valve to that of cylinder port reed valve positioning to determine who would win the race. 

  1. 69cc displacement;  47x40 mm bore & stroke.
  2. 3 hole Balanced crank;   smooth operation all the way up to 10,000 revs. 
  3. Ported and polished cylinder with cast iron piston sleeve.
  4. 6203 bottom in bearings.  ( standard engines have smaller 6202 bearings.)
  5. Special 10 roller wrist pin needle bearing. ( Std. engines have 9 rollers. )
  6. Reed valve induction.  
  7. Special Light wt. domed piston.   
  8. 6cc displacement head with thin copper gasket.
  9. Special Double Clutch.  ( Note: All Standard engines use a single clutch. ) 
  10. NGK BPR7 spark plug.
  11. FatBoy 4700 T magneto coil for HP external aftermarket TCI use. 
  12. High performance TCI ignition being developed in KCMO at this time.
  13. Wide 10T drive sprocket for 415 chain.
  14. Special jetted Mikuni knockoff Racing carb. with open bell intake.
  15. Motorized Oil Pump engine break in and live run tested in the USA.  
  16. Every engine must pass a performance run test before shipment. 
  17. Factory adjusted clutch for thumb turn drive sprockets when lever is pushed in. 
  18. Must use a Plenum Chamber or an Expansion Chamber exhaust system.
  19. Limited availability;  only 25 TT engines per year for US market.
  20. Engine only;  Not available in total installation kit form.  
  21. Only Sold to qualifying customers with proper mechanical abilities.
  22. No extended warranty on racing engines but Guaranteed to run when received.  Place your order early:   Write for details:  Watch this add for news as developments occur.   Price subject to change.