RIP Clutch?

I have an '82 XJ 650 Maxim. I think the clutch is starting to slip under medium to heavy load at about 5k - 7k RPMs. I think this because when the bike reaches around 5k, the motor revs (how do I say this) to 7k in about a half second. Once it started doing that I would shift right away. It only does this in 3-5 gear but I don't rev it very high in the two lower gears because I know they're primarily for getting the bike moving just like a car. I've never dealt with a clutch before and I'm wondering, do I need a whole new clutch? Or do I just need springs? If I need a whole new clutch, what's the best aftermarket brand to buy? Lend me the benefit of your experience oh great congress of XJ riders.

 

I'm going to assume that you have
A: not done anything to the clutch since purchased
and B: have owned it for less than a year.

That being said, there are a few things that will cause the clutch to slip in mid-RPM range:

Incorrect oil choice- needs to be motorcycle oil, not auto oil
Thinned oil- that's why we don't add anything to the crankcase in a wet clutch system
Weak clutch springs
Worn friction plates

If you have fresh motorcycle oil in the crankcase, with nothing added, then you can put the bike on the side stand to change the clutch plates. If not, then plan on changing it.

If it's a lower mileage bike then you probably just need to change the friction plates and the springs. The solid plates should be ok, but you won't know for sure until you tear it apart.

If it has correct oil, then your clutch springs are starting to go. Once the springs go, the friction plates aren't usually very far behind. So it's a good idea to just go ahead and change them all at the same time.

A couple things to remember when installing the new components:
Soak ALL of the friction plates VERY WELL with fresh oil before installing.
You really don't need to go with heavy duty springs.
As far as manufacturer, EBC is probably the standard go-to company for most people.

 

Remember, clutch friction plates are nothing more than a collection of tiny brake pads glued to a disc. Sitting in oil. For 29 years. They don't always age well.

Quite often, clutch friction plates will need to be replaced due to sheer AGE rather than wearing out. They aren't completely submerged in oil when the bike is sitting, and they dry out/become petrified; and although within spec thickness-wise, will not have their proper "grippiness" any more.

A basic clutch rebuild consists of friction plates and springs; as long as your plain plates aren't scored, warped, or burnt blue, they can be cleaned up and re-used.

Clutch basics: http://xjbikes.com/Forums/viewtopic/t=29541.html

 

@tskaz I just changed the oil actually. I put 20w50 Castol synthetic blend in it. Could this be the cause of my clutch issues? I wanted to put some good oil in it but the only thing I could see that was "motorcycle oil" was castrol regular 4 stroke motorcycle oil. It sounded like mini-bike lube so I didn't go for it. mistake?

 

It could be your oil. Regular oil is best for these bikes, made according to old standards so they don't have any "friction modifiers" (chemicals that adhere to surfaces in an engine, reducing friction even in the absence of oil).

Servicing your clutch might still be a good idea, for the reasons mentioned, in addition to the oil issue. Chacal can get you what you need.

Also, first gear is just to get moving, second will GET YOU MOVING! It's the only way to legally take your bike to redline on the street . And when your tach goes from 7-9k rpm in a half second...that won't be your clutch slipping.

 

first gear is just to get moving"

when im feeling abit carefree and lose my head,and i love it , 1st gear on my 650 goes to 80km(50miles) an hour, give or take, but 2nd is my favourite gear. but its getting close to 11000 rpm ,but its well maintained ,strong and handles it well, what a bike, ya cant beat the old Hiroshima Screamer.

 

FWIW,
When I tried the Castrol 4T synthetic my starter started slipping.

 

You used CAR oil? Change it immediately; it can adversely affect more than just the clutch, like your starter clutch.

Castrol makes semi-synthetic 4T Motorcycle oil; I'm evaluating it in my '83 XJ550 right now. But it's "motorcycle specific." You can't use modern automotive oils; they (now) ALL contain fuel-economy improving friction modifiers.

 

I've tried Castrol GTX with friction reducing additives. Not good.
So I changed the clutch friction plates and gave it some stronger springs. Good idea anyway, the turbo where born with too week springs.
Nowadays i use Castrol 4T GPS 15W50, with no problems.

 

If you used car oil your clutch will probably slip. If you used synthetic or synthetic blend car oil your clutch will definitely slip!

Syn blend, I'm surprised that it waits till 5,00 to start slipping. Gotta change the oil AND the filter again, immediately.

Just write it off as an expensive lesson learned. If you really think you need to use syn oil then buy synthetic motorcycle oil, but plain old motorcycle oil works just fine.

 

indeed, my clutch works great. put half a quart of car oil in it once upon a time just to top it up and the clutch started slipping within half an hour. Full change using MC oil fixed it right up.

 

While you guys are on this topic, what's the BEST motor oil I can use in my XJ750 Maxim? I've been using Valvoline 10w 30 non synthetic, is this bad? The bike says use 10w 30 or 20w 40 right under the left panel so I figured use 30, I live in Cali, I'll probably be riding in the tripple digits.

Honestly have only ever used 10w 30 car oil, and so did the previous owner, so if there's a type of oil that will make the clutch perform better, I'm all for it.

 

The oil should be marked for use in motorcycles. Automotive oil is OK in bikes with the transmission and clutch separate from the engine.

 

Here's the situation: Automotive oil standards have CHANGED over the last couple of years; vitrually ALL automotive oil now contains friction modifiers as it's part of the new Service Standards. (Those "codes" on all oil.) Motorcycle oil doesn't.

I used good old Castrol GTX for over 40 years; but had to switch. Even Castrol themselves admit it's not the same anymore and not the best thing for motorcycles. Technologies have changed.

 

Thanks guys, I hope I haven't ruined the clutch. The bike has 46k on it and I wouldn't be surprised to know the clutch was original but this bike was someone's garage baby. No rust or pitting, the paint took a wax job and you can shave using your reflection in it. I'd post pics if I could figure out how.

 

Is there a specific brand and type of motorcycle oil any of you guys swear by? I dont mind completely flushing out the current oil to try it out even tho i did just change the oil and filter 340 miles ago.

 

sirbuick, you probably haven't ruined the clutch...yet. But you will if you don't get that oil changed.

unknown, brand and type of motorcycle oil is rider's choice, but weight of the oil is a different story.

Oil viscosity above 32*F is the second number when you look at the jug. 10-30 is 30 weight oil above freezing, 10-40 is 40 weight above freezing, etc.

50 is thicker than 40, 40 is thicker than 30. The importance of this in our bikes isn't really the lubricating factor, slippery is slippery and none of the weights will lubricate any better, but they definitely have an effect on the cooling of the motor.

The warmer the climate, the hotter the engine runs, the thicker you need the oil. That's why Yamaha recommends 10-30 for cold weather and 20-40 for warmer weather. A lot of guys use 20-50 in their bikes, and that's fine for hot weather.

If it's 110* in the shade where you live, and your sitting at a stop light, thicker is better. Even going down the road, thicker is better. Because, on our air cooled bikes, the fins only cool the two outer cylinders, the oil takes care of cooling the center cylinders. That's why we have the oil channels in the front of the motor, to help cool the oil.

I use 10-30 in February, March, and April.
I use 10-40 the rest of the year, and the bike is parked Nov, Dec, and Jan (for the most part).

But if I lived in Texas, I'd probably use 10-30 in the winter, and 20-50 in the summer.

 

I live here in Michigan as well; I run 20W40 when it's cooler out, and 20W50 in the brutal heat of the summer, especially when commuting in stop-n-go traffic. Otherwise just 20W40 all the time.

But then again, I won't ride when it's anything below about 39*F.