Monday, June 03, 2013

David's R69s

Please welcome David's R69s to Scottie's Workshop.

David reported poor idle and hard starting.  He tested the compression and found the left at 120 psi and the right at 70.   Ugh!

So David towed the bike all the way from Sonora, California, frowning all the way because he was anticipating a big repair bill.   Discussing significant repair expenses with a customer is always uncomfortable, however I feel it is best to discuss possibilities and expectations up front. I presented a best - case scenario and a worse case scenario for Dave. The best case scenario would have been that the valves needed adjustment and one or more valves were not closing all the way, or perhaps a bent pushrod. A worse case scenario would have been damage to the bores and/or pistons. This would have likely required new pistons, bore and hone, etc., which is expensive.

I will cut to the chase and say that I was so pleased to call Dave later that evening and give him some good news.  Here's the story:

Dave's very nice looking R69s with Ranger bags. 

After testing the compression, I began by checking the valve clearance. I retorqued the head bolts (they were not too loose or too tight.) I started on the right since it was the one with bad compression. I noticed right away that the intake valve was not closing - clearance was zero.  So the right intake valve was not closing all the way on the compression stroke. This could be the problem. I then also checked the left side and noticed the exhaust valve was 0.1mm.

Also, I noticed the right exhaust push rod was bent and so I  replaced it with a good used item.

After re torquing the head bolts and setting valves left and right, compression was rechecked and found to be 120 Left, and 120 Right.  YAY!

Examination revealed a broken advance unit stop limit spring. It was replaced with a new spring shown in the background. 

Examination revealed the front brake cable dangerously MISROUTED.  All  /2 owners should be mindful to route brake lines through the levers correctly.  This is a serious safety violation!

After this work was performed, a static timing check was performed to set the magneto position and check for differential timing.  D.T. was found to be 1/4" or so (surface of flywheel).  This is within spec and it was left uncorrected.  A strobe was used adjust the points. After timing, the carbs were balanced at idle and the air mixture set.  The cables were then balanced. 

The bike is now running pretty good.  

There is a bit of oil smoke coming from the tail pipe.  After the chassis service, I'll take it on a  good long test ride and see if it continues to smoke. 

Stay tuned for more updates on Dave's R69s.....

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