A friend just asked me about his 120" with approx 1K on the clock.When his reaches operating temps it starts losing power,and making a funny sound.I know it is not much to go on,I have not seen it.Just trying to get an idea of what we could look for.He says the motor only has 1 vent hose,that by itself does not sound right.Grasping for straws!!!

 

What chassis is it in? "Funny sound" is a little vague, Is it a grinding, a squeaking or what. How is the oil pressure? Where does the noise appear to be comming from? How is his compression? Take the plugs ou and torn the motor over by hand, how does it feel? See if you can get a little more input.

 

Have to drive 1 1/2 hrs to his house to see motor.He says the plugs look great,oil pressure was normal,noise seems to be coming from front cylinder.other than that he is afraid to go any deeper.

 

Where is he located??

 

Vassalboro.

 

Is that in Maine??

 

Could be a broken ring or maybe a wrist pin. He may have gotten it too hot on initial break in and scored a cylinder. Take a look in the cylinder with a light and see if you can see anything. If not maybe something in the rocker boxes. Hope this helps.

 

Vassalboro,Maine is above Augusta.Talking to my friend,he says letting the bike set a very short time it starts and runs great.When it gets hot it starts the problem over again.This problem he is having just started happening.It sounds to me without physically seeing,hearing the motor,like maybe the pistons are starting to seaze when it gets hot.Unless I hear otherwize a topend teardown is in order.

 

Piston slap!!! The 120" Ultima is notorious for piston slap and it usually occurs between 1000 and 3000K. Check the compression and check the oil. I'm sure there will be metal flaked oil.