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03-10-2002, 11:01 PM
DUNCAN RACING INTERNATIONAL INC. - TECHNICAL INFORMATION

4 STROKE ENGINE BREAK-IN

After your engine has been completely installed in the chassis. Be sure all fluids have been filled (oil, coolant etc.). Before starting a freshly rebuilt engine it is strongly recommended to make sure that the carburetor has been thoroughly cleaned and fuel tank has been flushed clean. Fresh fuel should always be used. Air box should be cleaned and a new or freshly serviced air filter should be installed. Once the above steps have been completed, you should be ready to start your engine and follow the engine break-in instructions below.

IMPORTANT RECOMMENDATION: Upon initial start up of a fresh engine, make sure that the engine is getting oil to the top end (valve train). Most OEM service manuals will cover the necessary procedure to check this for your specific model machine.

PART I (3-Idle periods, 3-Cool down periods)

IDLE: Start engine and let idle with a fan blowing on the front of the engine, to simulate Tiding type
conditions without a load on the engine. Let engine idle for exactly 10 minutes.
COOL DOWN: Shut engine off after 10 minutes of running and let machine cool down for a minimum
of 30 minutes. Let fan continue to blow on engine.
IDLE: Repeat first step
COOL DOWN: Repeat second step.
IDLE: Repeat first step.
COOL DOWN: Repeat second step.

PART 11 (6-Riding periods, 6-Cool down periods)

RIDE: Ride machine for 10 minutes. Make sure to vary your RPM range. Ride machine at 50% of your normal riding pace. Be careful not to put any unnecessary strain on the motor during break-in. COOL DOWN: After 10 minutes of riding, shut machine off and let machine cool down for a minimum of 30 minutes. RIDE: Repeat initial riding period. But ride for 10 minutes at 60% of your normal pace. COOL DOWN: Shut machine off and let machine cool down for a minimum of 30 minutes. RIDE: Repeat initial riding period. But ride for 10 minutes at 70% of your normal pace. COOL DOWN: Shut machine off and let machine cool down for a minimum of 30 minutes. RIDE: Repeat initial riding period. But ride for 10 minutes at 80% of your normal pace. COOL DOWN: Shut machine off and let machine cool down for a minimum of 30 minutes. RIDE: Repeat initial riding period. But ride for 10 minutes at 90% of your normal pace. COOL DOWN: Shut machine off and let machine cool down for a minimum of 30 minutes. RIDE: Repeat initial riding period. But ride for 10 minutes at 100% of your normal pace. COOL DOWN: Shut machine off and let machine cool down for a minimum of 30 minutes.

Break-in should now be complete. Confirm that carburetion settings are correct and give your machine a complete safety check before continuing your riding.

TIPS FOR A SMOOTHER BREAK-IN

- Do not use paddle tires. Stay away from deep sand dunes, mud etc. Until break-in is complete.

- Check that all fluid levels are correct.

- Check carburetion jetting periodically during break-in.

- Check all engine mount and chassis bolts are secure during coold down periods.

- Check all oil or coolant lines are secure and free from oil leaks.

- Make sure exhaust system remains secure. Snug at cylinder head with engine warm.

- Valve clearance should be checked after approximately 5 hours of initial running time.

- Re-adjust cam chain tension when applicable.

- Keep drive chain in adjustment.

Leo
03-11-2002, 04:38 AM
let the engine idle....

?!?!?

not mine, not during break in..

Leo

MOFO
03-11-2002, 05:22 AM
Same here. Looks to me like Duncan is looking for more business....if you know what I mean.



Eric

beerock
03-11-2002, 11:09 AM
"Make sure to vary your RPM range."

thats the only thing that made sense....

Honda Guy
03-11-2002, 01:51 PM
I always thought you just ride no more than 1/2 throttle for the first 10 hrs. and vary the throttle then. Do the same for another 10 hours with no more than3/4 throttle. Am I wrong?

03-11-2002, 04:46 PM
2 good things bout used ones, can come wit upgrades, and broken it.

MOFO
03-12-2002, 06:56 AM
Originally posted by 440
2 good things bout used ones, can come wit upgrades, and broken it.



All depends if the guy who bought it new "broke" it in or if he followed those crazy directions posted above. Personally, I'll take new any day and know how its been treated from day one. Just my opinion though....


Eric

03-12-2002, 11:22 AM
i followed duncans tech and my quads runing fine. no smoking and it has good compression