Startup After Top-End Rebuild.

I hope to be ready soon, to fire it up with her fresh top-end.
The carbs should be close from last year, but I may need to synchronize and fine-tune them before putting the bike on the road...especially with the different head on the engine.

Is there a recommended time range to let these engines run when first started, like five minutes or something?
I will have a shop fan blowing air at the front end, so no issue there.


Thanks for the great suggestions you all give to each other, and guy's like me with limited mentanical capacity.

nope.....just make sure oil light turns off and take off. no break in period.

Talk about opening a can of worms.
Ask 25 people and you'll get 30 different opinions on it.
Since I'll be lighting off my fresh top end rebuild (see my drag strip trip thread)
later this week here's my game plan.

I'll fire it up let it run for a few minutes to bring it up to temp.
change the oil then go bust it's ass.
A lot of people may think I'm wrong but if the rings don't seat in the first few minutes
they're not gonna.

I disagree. Fire it up and let it heat up. Shut it down, then start it again. Drive it around using the engine for breaking as normal. By then you should know if there are any issues. Ride it like normal revving it but don't red line until at least 500 miles. The last thing you need is for a ring to Gaul a cylinder or it to deform a piston. It's worth the wait.
Steve

Enjoy!

www.kzrider.com/forum/2-engine/107927-we...rt=20#s5_scrolltotop

www.kzrider.com/forum/2-engine/161675-break-in#s5_scrolltotop

www.kzrider.com/forum/2-engine/203737-br...rings#s5_scrolltotop

www.kzrider.com/forum/2-engine/242119-to...stion#s5_scrolltotop

Good Fortune!

zukdave wrote: Talk about opening a can of worms.
Ask 25 people and you'll get 30 different opinions on it.
Since I'll be lighting off my fresh top end rebuild (see my drag strip trip thread)
later this week here's my game plan.

I'll fire it up let it run for a few minutes to bring it up to temp.
change the oil then go bust it's ass.
A lot of people may think I'm wrong but if the rings don't seat in the first few minutes
they're not gonna.

I'll try all 30. If it messes up, then no particular idea can be blamed, and we'll all still be friends.

Warm it up to full temp. That's when it will hold idle at normal RPM without choke. Good time to do idle mixture and carb sync. Shut it down and let it fully cooldown. Retorque head. Check exhaust nuts for tightness. Oilpan hardware for sealing and tighness wouldn't be out of order too. Check camchain tension. Go for a ride and don't go full acceleration but do put a load on the engine. Change the oil. Have fun.

LOL. I agree with multiple checking on torque. I prefer to rev to redline, but not under a huge load. It allows the rings to seat properly without glazing. Some prefer to rev the blazes out of it, maximum power, but I cannot agree. Nor can I agree with the gentle break in, just does not make sense. So I compromise.

swest wrote: I disagree. Fire it up and let it heat up. Shut it down, then start it again. Drive it around using the engine for breaking as normal. By then you should know if there are any issues. Ride it like normal revving it but don't red line until at least 500 miles. The last thing you need is for a ring to Gaul a cylinder or it to deform a piston. It's worth the wait.
Steve

Make sure to re torque the head bolts after the first hot-cold cycle. I also swap the oil but probably not mandatory.

It would depend on how sloppy the rebuild was.
Steve

So a race motor gets ran about 5 minutes on a dyno
then they do FULL POWER pull's to redline
but a rering on a 30 year old motor needs 500+ mile's ?

koolaid_kid wrote: LOL. I agree with multiple checking on torque. I prefer to rev to redline, but not under a huge load. It allows the rings to seat properly without glazing. Some prefer to rev the blazes out of it, maximum power, but I cannot agree. Nor can I agree with the gentle break in, just does not make sense. So I compromise.

I was advised to put a light film of oil on the threads and bottom of the head-nuts before installing them.
Is the correct (re-torque) method to break loose each nut before re-tightening? If so, would that be just after initial heat/cool cycle, or anytime thereafter as well?