Vibration 94 Suzuki intruder 1400. About 39000 miles. Engine is strong uses no oil. I love the bike, Lately it seems to vibrate a lot. Could the carbs need synchronized ? I do notice a tinny sound at high rev. before each shift.

Hi, it all depends on the type of riding you do. Mr Suzuki advises 4,000 miles between oil changes. This is OK if you do a lot of miles every time you ride. If you do a lot of short journey's then you need to to do more frequent oil changes. I normally do an oil change every 2,000 to 2,500 miles as I do a lot of short trips. One of my bikes has no cam shaft bearings and I do an oil change every 1,000 to 1,500 miles regardless.

Hope this helps.

Give the bike a thorough service. These engines are very strong, but as with any engine this can be compromised by bad or missed servicing. The vibration could be any number of things, but check the front wheel bearings and the fork mounts and also the chain and sprockets. if the chain is old it can cause a vibration which would seem as if it is coming from the engine. If you have to change the chain then do the sprockets at the same time. If you fit a new chain to old sprockets it will wear faster and cost more.

Sounds like the float is sticking in the carb on the rear cylinder,washing the cylinder with fuel,and possibly going into the crankcase oil. The carbs will need to be removed,cleaned,set-up,and synchronized.Be sure to change your oil as well. The gas has most likely mixed with the engine oil,and will cause you to spin a bearing or worse.
Good Luck!

possible not enough clutch free play
engine oil is not used in the clutch assembly
it is a special clutch/ transmission oil
wrong oil will cause the clutch plates to slip

During break in, everything breaks in. Valves need to be adjusted,bolts loosen(check your engine mounting bolts),steering neck bearings need to be adjusted,carbs need tuning,etc. 600 mile check ups often include changing the plugs along with the oil. You need to go over the whole bike with a fine tooth comb, it's probably a motor mount bolt.

i my advice to you is that everytime before you ride a bike you perform a service check..there have been many times that i have had seat bols vibrate loose the brake handle nut was hanging on by a thread when i checked before one ride and the rear caliper bolts vibrated loose once and the chain backup up locking nuts vibrated off. believe me it will never ever happen to me again because i spent two days at my work going out to the parking lot and little by little took axle pinch bolts main rear axle nuts adjustment nuts seat bolt nut oil drain nut oil filled dip stick radiator cap, and lockwired all the hose clamps ( because i race and this is a requirement) but im glad they made me do it...because now by just a glance you look and see wire and that means theyre tight no question about it. you dont have to hope they're tight. after sixteen (k) miles, change the plugs and air filter, and oil and filter and check wheel bearings for any play and check for proper tire wear and inflation. Might want to spray some throttle body on the carbs also.

You cannot see the oil level in the window? you may be looking through the oil and it is over filled i don't know witch side your oil lever inspection window is, best thing to do is have some one help you tilt the bike to the opposite side while you watch use a flashlight if needed until you can see the oil level line you may be loosing oil that is over filled. check the oil level with the bike up and level
Hope this helps you out.

Did you sync the two carbs? If not the rear may be getting all the gas from the rear carb and none to the front. Twist throttle engine off and see if front carb cable is pulling the carb open.
Also unscrew the spark plug boot from the front spark plug wire and trim 1/8th inch off the wire and screw the boot back in. The plug wire end may be corroded on that wire.

cables too tight , poor lubrication of choke and or throttle cable