Engine break in.

TheDude · Posted: July 18, 2008, 5:32 pm Post subject: Engine break in.

Anybody have any tips for properly breaking in an engine?

I rebuild my top end and instilled Mike's 750cc kit. I have 50mi. on it so far, and it smokes when I start it up. Is that normal?

I have already needed to retorque the head and adjust the valves. The valve lash had opened and begun to create quite a racket. After readjusting them, they seem to be getting noisier again. Anyone else have that experience?

Thanks

xsjohn · Posted: July 18, 2008, 5:48 pm Post subject: Re: Engine break in.

Would guess the smoke is the rings trying to seat and fit the cylinders......my other guess is that you did change the valve seals......keeping it from getting hot and ride it.......some throttle ocassionally.......xsjohn

TheDude · Posted: July 18, 2008, 5:56 pm Post subject: Re: Engine break in.

I changed the valve seals, got a three angle valve job, changed the cam chain, replaced the cylinders and pistons, added mac pipes and Emgo reverse cone mufflers (bigger main and pilot jets), and added a Boyer ignition.

it was quite costly, and it doesn't seem to run or sound as good as it did before I did the work.

xsjohn · Posted: July 18, 2008, 6:26 pm Post subject: Re: Engine break in.

Well since you have changed about everything it will all have to be dialed in.............as long as it is not lean it will be easier to tune after it breaks in.......you said bigger mains.....how much bigger and what year carbs.....xsjohn

Cooltouch · Posted: July 18, 2008, 11:15 pm Post subject: Re: Engine break in.

After only 50 miles, I think it's fair to say that your rings have not fully seated yet, so your compression will be down some and your bike will smoke a bit. If you haven't changed your carb jetting, this could be a big reason for the softer performance you're experiencing. You've increased the flow substantially by installing the 750cc kit and the low restriction exhaust.

How's your coil (or coils, depending on year)? If you're running the old stock coil, this could be another reason. Plug wires too.

Best,

ichael

TheDude · Posted: July 18, 2008, 11:50 pm Post subject: Re: Engine break in.

I was hoping the rings were just seating.

on this '78 (BS38 carbs), I increased the main jets to 142.5 (3 sizes over stock) and the pilots to #30 ( one size over). it may be a tad rich. the plugs are dark tan ( haven't done a formal throttle chop). The bike used to have good torque off idle. Now it stalls unless I give a bit of gas. It is also hard to start and often takes several kicks to get it started.

After the rebuild, I found my advance unit was not working properly. Rather than monkey with it, i used the last bit of money left over from the sale of my RZ350 and purchased the Boyer electronic ignition complete with coils, wires, etc. Just looking at the spark, it doesn't look any stronger than stock. Should it?

Frankly, I have not opened it up because I am still breaking it in.

jayel · Posted: July 19, 2008, 4:20 am Post subject: Re: Engine break in.

I was hoping the rings were just seating. on this '78 (BS38 carbs),

well there's the problem the rings were supposed to go on the pistons Rolling Eyes

as this chart clearly shows it's a chart, and here's a pic of my pride and joy, hang in there dude it'll straighten out

xsjohn · Posted: July 19, 2008, 4:49 am Post subject: Re: Engine break in.

What do the plugs look like.................xsjohn

TheDude · Posted: July 19, 2008, 11:25 am Post subject: Re: Engine break in.

As far as I can tell, the plugs look good. Maybe a little dark. I snapped a crappy picture, and don't have time to retake it.

Cooltouch · Posted: July 19, 2008, 2:16 pm Post subject: Re: Engine break in.

It does looks a tad rich. I'm not enough of a carb expert to opine, though.

I assume you've adjusted the cam chain, then the valves, and then the ignition timing on your Boyer? What sort of air filters are you running?

Best,

ichael

xsjohn · Posted: July 19, 2008, 2:29 pm Post subject: Re: Engine break in.

Plugs will remain somewhat dark if correct until the engine reaches full operating temperatures for a few minutes to clean them off.....since you are breaking it in and are probably wisely reluctant to bring it to full operating temps it may be good.........after 500 miles or so they also may lighten when the engine breaks in some more......a black art for sure......xsjohn

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