Breaking in a Rebuilt Engine

[gardengirl]

Hi there, brand new to all this so please go easy on me. I have a 1972 XS650 and recently had my engine rebuilt...so far 110 miles on the break in and the vibration on the bike is intense...so much so that I had to stop driving after 40 miles today as my hands and arms were numb and when I took off my helment my ears were ringing...any suggestions on how to get rid of some of this or reason why it is vibrating so bad...Thanks in advance

 

[angus67]

check the timing. Check all motor mounts are tite. wear ear plugs?

 

[retiredgentleman]

I'm not familiar with the 1972 year, but my 78 SE has rubber mounting of the handlebars. Does your bike have rubber mounting between the handlebars and the triple trees?

You should synchronize the carbs if you have not done that.

Perhaps you should try to buy handlebar grips that have thicker padding built into the grips.

Edit: Yes, these bikes do vibrate, but it should not be so extreme that you can only ride 40 miles. My 78 SE has only moderate vibration. I have no problem riding 400 kms in a day.

 

[blue900]

the vibs get very tolerable if the bike is in tune and in good shape-proper timing, jetting, and having the carbs synced.
Wheels balanced and good chain and sprockets are important also. Good tires and proper inflation.
the more perfect all these systems are the better the bike will ride.
I'm sure i missed some other stuff

 

[fredintoon]

Hi there, brand new to all this so please go easy on me. I have a 1972 XS650 and recently had my engine rebuilt...so far 110 miles on the break in and the vibration on the bike is intense...so much so that I had to stop driving after 40 miles today as my hands and arms were numb and when I took off my helment my ears were ringing...any suggestions on how to get rid of some of this or reason why it is vibrating so bad...Thanks in advance

Hi gardengirl and welcome,
any 360º vertical twin has the same balance problem as a big single, it's gotta shake because it's impossible to balance it (unless it's got additional balance shafts or other complicated add-ons.)
Did it shake that badly before the rebuild or has it gotten worse since the rebuilt engine was put back in the bike?
Worse than usual vibration could be loose engine bolts, unbalanced carbs, solid risers, or any combination.
Did the pre-rebuild riding cause tinnitis or is that a new thing too?
Like they said, earplugs. You should use them anyway.

 

[gardengirl]

Thanks, this is great! Wonderful to have people to share ideas with. Before the rebuild there was very little vibration, none that I even noticed to be honest. I am a new rider, only a year in so I don't know much else besides the older bikes as this is what I gravitate towards. I will make sure all the goods are tightened and the timing is correct. The engine is running great so far, but clearly the vibration is too much. The noise isn't bad at all, I have a great helmet. I will also look into the rubber mounts.

 

[Brew]

I just switched from stock 17/34 gearing to 18/32 and it helped out a bunch. cheap and easy to do.