R26 engine break-in

[euro518]

Hello all. Does anyone have experience with breaking in an overhauled engine, aside from being gentle with reving etc.? When are the cylinder head bolts re-torqued? Thanks.

[euro518]

[Kurt in S.A.]

I've only recently done this on my R69S, but I plan on doing this on my R25/2 when I overhaul it sometime in the next year or so.

My approach would be to start the bike and get the RPMs up to say over 2500 and hold it for 30-45 seconds.  Then I would go for a ride immediately, constantly varying the throttle.  Try not to stop and idle.  Go for a 20-25 minute ride.  I would drain the engine oil after about 30-45 minutes and refill.  I like dino oil and I believe it is recommended on break-in as opposed to synthetic.  When cooled the next day, I would recheck the head torque and valve clearances.

At that point, I would repeat the drain/retorque/clearances at say 50, 100, 250, and 500 miles.  Maybe that's a bit much, maybe dropping one or more of them but getting a handle on things early is important and then monitoring as it goes.  If things are stable after 250 say, I might not recheck for a while.

Kurt in S.A.

[cledrera]

Hi euro518,
in the main I agree with Kurt in S.A..
But:
1. Change Oil often and early. At first after 30 Miles, second after 90 Miles, third after 185 Miles, fourth after 310 Miles.
2. Retorque the cylinder head-bolts the first time after 30 or 90 Miles.
3. Make a valve clearance after 30 Miles.
4. Speed: The Statement of Kurt in S.A. is good. Complementiv:
- Don`t drive Highspeed in the first 310 Miles; 25 % slower is maximum warp.
- After the first 310 Miles you have separatly breaking in the higher Speedarea. That`s no joke. Drive carefully quicker an quicker.

My new overhauled engine (R25/3; this year) runs 621,371192237 Miles (1.000 Kilometer  ) before breaking in is over.  Better save than sorry.

Good Luck an much fun

Clemens

[euro518]

Thanks to both of you. I doubt whether I will hit much past the 90 mile mark this year as the leaves are already starting to turn (although today will be 23 and sunny).

-Kevin

[Rütz]

I agree with Kurt and do it nearly the same, except one point:
Avoiding idle is ok, but i do stop extra often during the first run. Let's say after 2, 4, 8, 16, 32... km or miles (no need to count peanuts ).
I stop and let the engine cool down until every part can be touched longer without getting burned (-> below ~60°C).
'Cause, during break in, engines are prone to "heat congestion" (Hitzestau?).
Also this has a kind of "tempering effect" on new alloy parts, i.e. the piston.

Ruetz