Hi guys,  
I just bought a '88 Venture Royale with 35,000 miles for $1,100 
It runs on 2 with a third cylinder kicking in sometimes. It backfires some. 
The tach works at idle, then reads about half true RPM's, then drops to zero. 
I used 3 gallons driving it 100 miles home, so it's not dumping gas. 
Then I found 2 broken spark plugs, and ran propane down the intakes to verify that all 4 cylinders were/would fire. My compression tester won't fit the small holes. 
The temp gauge barely comes up even when I got it quite hot, fan doesn't work. 
In neutral, the clutch seems to make a different sound when pulled, or out. 
The clutch and shifting are great, almost buttery- - nice ! 
I almost feel at 55 that the front bearings are shot, or making a vibration thru the bars. 
It won't go over 55 unless a third cyl fires up, then maxes out at about 75.   
I'm going into the carbs today.   
Question, is there a sure-fire way to tell if the bike has 135,000 or 35,000 ?? Thanks.