After changing oil feel like clutch are slipping didn't do it until i chang my oil ?

Yes it will wreck your clutch plates and you will need to replace them and flush the engine clean of the car oil as the anti friction additives in the oil attack the plates and they break down into little bits

can you get it out of gear?
can you change gear
does the clutch drag ( shifts are difficult )
the clutch plates are froze/ stuck together, remove clutch, check plates for rust clean soak in fresh oil replace any that are rusty..

Not too good. The least expensive change you can make is the oil. Go to a Mr Lube and have them do a hot change and put an additive into it. The new oil will help the clutches to grab and the additiv e will free up the valve body to shift properly. If that doesn't work you either need to rebuild it or replace it with a used one. Sometimes you can get lucky and find factory GM rebuild at the wrecker that will give you years of good use. The key is fresh oil and change it after the first 20k, then it's probably good for 60 more.

Nick:
I read two contradictory things here. One the clutch is slipping and the other is it's dragging. Ok. here's something to check. Check your throwout bearing on the right side of the bike. Drain the tranny and take the clutch release cover off the transmission. The throwout beaing is a small wafer bearing about a half inch in diameter. It's held on by a miniture clip that is notorious for coming off. If during the engine swap you pull the clutch release rod outwards just a bit, the bearing could have fallen off. check this and replace if necessary.

Now if you have a stock clutch, loose the cable really loose. Break the lock nut loose in the center of the clutch assembly and turn the screw inwards until you feel the resistance. This is done AFTER you put the right side of the tranny back together. Do not force the screw. Do it several times until you get the feel of it. Once you feel the resistance, back the screw off about 1/2 turn and lock the lock nut. Adjust the cable adjuster outwards until you have 1/8" free play at the lever.

Do not overfill the primary with oil. the oil level should not be any higher than the lowest part of the clutch spring. Too much oil will cause the clutch to feel like it dragging an won't allow you to find neutral with the engine running.

Try that and see what happens. But, I'm going to tell you now, that the stock clutch is probably NOT going to hold that 127 inch engine. You're are probably going to need to beef up the clutch as well.

Good luck
Steve

I don't think your clutch is bad, if it doesn't slip when hot. I would be blaming the pull on the lever not enough, or the gears are worn in the tranny. You can adjust the lever and you can try bleeding off the clutch, The engine oil usually cools the clutch, I'm not sure where your filter is, mine is underneath like a car. My tranny clunks and grinds when revving too much, have to wait for the revs to go down before shifting into first. It used to slip on hot days. Hasn't done it but a couple times. I never took out the clutch basket, but it seems fairly easy. If the oil change doesn't do it, and the bleeding of the slave, I would have to dig deeper into complaints about your bike, before I blame the clutch. You might not have to touch it, but you might be looking at something else. Check it out.

Drain fluid out of clutch cylinder. Clean out cylinder then look at bottom and you will see 2 small holes.Stick a small pin or wire into the hole that has a little check ball inside. Once you can push that ball in with the pin you will see some fluid come into the reservoir. That lets you know it was clogged. Now refill with dot 4 and bleed system. Clutch will not slip now. I just had the same problem and changed clutch spring, plates, etc and nothing worked until I did this.

Wave washer on the face of the clutch basket may have lost its tension, clutch friction plates may be wearing thin as she's an old girl. Some automotive (car) oils not specifically designed for wet clutches when used in a bike will cause the clutch to slip as they are designed to leave a deposit on friction areas. This will require a thorough flush and a few oil changes in quick succession.
Check the return function of the clutch release arm on the crankcase, they can bunch up the rubber shroud and not return fully. Good luck and Cheers.

it does seem to be low klm to be clutch wear,you may need to change your oil as if somebody put in a friction modified oil in at last oil change this can make the clutch slip,go to your bike shop and ask for your best oil match for your bike.try this first.it could also be as simple as clutch adjustment.hope this helps

if it is cable operated you want to adjust at the clutch perch (where the lever is mounted on) to where you have about an 8th inch of play before you feel the tension of the clutch in the lever. if that dosent do it change your oil if you havent done so already and if that dosent do it then the clutch is probably toast.

try adjusting clutch first.if it still slips in 4th and 5th.then you have to change clutch pressure plate and clutch release bearing and check condition of fork.