83 750 maxim, gear disengages under heavy load

in gears 3-5 when i'm facing a heavy headwind or hill and i'll twist the throttle to compensate sometimes the gear will seem to disengage and the bike just revs higher. also what revs should i be shifting at? cruising at?

 

On mine I shift from 3 to 4K. 65 MPH gets about 4500 RPM. Can you shift it back into gear or is it your clutch slipping. I would suggest checking the clutch adjustment. There are several posts on the procedure on here, just do a search.

 

Suggest you add your bike to your profile so everyone knows what you are talking about. Some pics would be nice too.........

 

That would seem to indicate a slipping clutch to me. You can try adjusting your clutch cable, probably easiest to do it at the clutch lever first.

Of course, it could also mean that you're due for new friction plates in your clutch. A little more expensive than cranking the cable adjuster in a few turns but not the end of the world. It's also something you can do yourself with a few tools and some mechanical inclination.

Out of curiosity, what kind of oil are you using in your bike? I've never experienced it myself, but I've read that modern oils with "friction modifiers" can cause wet clutches to slip.

 

I don't know what kind of oil it's using, just got the bike a week ago. It's my first bike so I'm in the process of learning a lot.

If i let back on the throttle it will grab again, and i can down shift and let back on the throttle and it will grab again.

What gear should I be in at 65mph?

 

5th gear I hope. If you haven't changed the OIL, I would suggest you change the oil and filter before doing any thing other than checking the freeplay adjustment on the clutch. There is a lot of controvery on the subject, but I use Castrol 20w50 in all my bikes and haven't had any problems. And it doesn't cost $10 per quart like some of the synthetics do. Remember, your clutch runs in oil and its operation is based on friction, and some of the "superslick" additives will make it slip.

 

I'm going to back Bstig60 on his recommendation, change that oil and filter asap! Odds are pretty good the P.O. used the wrong oil in the bike. Your slipping problem should clear up. If it doesn't, your clutch is in need of replacement. Chacal has them in stock at reasonable prices.

 

so engine oil is also lubing clutch?

 

Almost all Japanese bikes run a wet clutch.
At your clutch lever, under a rubber boot, loosen the lock ring, and give the inner piece one complete turn clockwise, then it's Time to Ride.
See if that help.

 

That is correct Lisa. Most bikes built since the 60s use what is termed a "wet" clutch wherein the clutch and engine share a common sump. There are notable exceptions (Ducati for instance) but I'm not the expert on which they are.
The use of American Petroleum Institute (API) "energy conserving" oil will cause clutch slip in our motors. Your symptoms are classic so why not take the easy fix first. Not to mention you should always change all fluids upon reciept of a bike unless you are 100% certain the P.O. knew what he was doing and gave you evidence of the servicing.
Just look for the API badge on the oil container and make certain it does not say "energy conserving" and you should be fine. There are loads of oils out there that will fit the bill. Rotella, Castrol GTX (20/50 being my favorite), Spectrol (very expensive), Shell,...the list is endless and the discussions about which is best is just as long. Find what is readily available to you at a price within your budget and you should be fine. I would highly recommend you review the oil recommendations from Yamaha for your particular model, typically available in the owners manual. If you don't have that, a good maintenance manual will have similar information. Make your choice based upon the ambient temperatures you ride in and what type of riding you do (i.e. street, highway, touring, canyon, high speed, etc). The higher the temps and the harder you push the machine, the heavier the oil you use should be.
Good luck to you!

 

That is correct Lisa. Most bikes built since the 60s use what is termed a "wet" clutch wherein the clutch and engine share a common sump. There are notable exceptions (Ducati for instance) but I'm not the expert on which they are.
The use of American Petroleum Institute (API) "energy conserving" oil will cause clutch slip in our motors. Your symptoms are classic so why not take the easy fix first. Not to mention you should always change all fluids upon reciept of a bike unless you are 100% certain the P.O. knew what he was doing and gave you evidence of the servicing.
Just look for the API badge on the oil container and make certain it does not say "energy conserving" and you should be fine. There are loads of oils out there that will fit the bill. Rotella, Castrol GTX (20/50 being my favorite), Spectrol (very expensive), Shell,...the list is endless and the discussions about which is best is just as long. Find what is readily available to you at a price within your budget and you should be fine. I would highly recommend you review the oil recommendations from Yamaha for your particular model, typically available in the owners manual. If you don't have that, a good maintenance manual will have similar information. Make your choice based upon the ambient temperatures you ride in and what type of riding you do (i.e. street, highway, touring, canyon, high speed, etc). The higher the temps and the harder you push the machine, the heavier the oil you use should be.
Good luck to you!