Clutch slipping after stop and go traffic?
 

Hi guys,

Just got a superhawk and today was the first day hot enough to ride it to work... well, I had to drive through the city since I've only got my permit (no interstates) and after I got out of it the bike was pretty warm (fine temperature wise, but the oil was definitely hot)

I went to rip on second gear and I got the dreaded "BBRRRrRRRRRRrrrrR" with no power being transferred :banghead:

So my clutch is definitely slipping. I have a lot of mechanical experience, because I own shitty old BMWs, and have experienced these same symptoms from failing car clutches... it is quite clear what is happening.

Is it absolutely the clutch? I do leak some oil, does lower oil cause problems like this?

Another thing to mention is shifting into first from neutral results in a small lurch forward and an audible mechanical clunking, but I've always had that on every bike, so I'm not worried.. my 1st to 2nd gear shift feels a little iffy, but grabs easy.

Not familiar with the worn clutch on the SuperHawk yet, but just curious, how many miles do you have on it?

And welcome to the forum!

21k on the clock... 2 owners, owned by a girl for 200mi, and a bike mechanic for the rest.. I've put almost 200 on it myself

And thank you!

I'd start with bleeding and replacing the hydraulic fluid. Good chance that's all it needs if the fluid is old or you have air in the system, exasperated by the heat. Also, how old and what kind of oil do you have in the bike?

The lurch from neutral to first is pretty standard, nothing to worry about.

What kind of motor oil You have in there.
It's a wet clutch and it takes only certain types of oil,this could be a cause too.
Look into this and when you find oil You happy with.use it for every change.

The oil is probably old. The people I bought it from didn't really know anything about the bike, and I didn't get an owner's manual or anything.

How many qts of oil does it take, and what's the best oil to use?
Is there a DIY for the hydraulic fluid flush?

http://www.superhawk996.net/Honda_VT...ice_Manual.pdf


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So, is it generally the oil that is the problem? I'm going to take it down the street and see if it slips now, just to see if it makes any difference when its cooled off..

Update: Clutch does not slip at all after the bike has cooled off. This leads me to believe that I may be running too thin of an oil, based on what others are saying. Thoughts?

mobil1 synthetic v-twin motorcycle oil
rotel,not sure which model oil
there is a oil thread that has the different oils you could use safely in the bike.
it is a full 4quarts with filter change.

You are experiencing symptoms of a worn clutch. But, it could also be a combination of things such as previously mentioned in this thread. I had some light occasional clutch slippage years ago soon after I put this Hawk on the road. It had about 12k miles at the time. I found some good reports online about oil in motorcycles and decided to go with Rotella 15W40. After the first change the slippage never occurred again. Tranny was smoother too.

I am not positive, but I THINK the first oil I had in it was Honda?

IME, a worn clutch slips regardless of current operating temperature. It grips hard and swiftly with no problems after I let the bike cool down a bit.. Its gotta be the oil or hydraulic fluid

i would change and bleed the clutch lines and change motor oil.
mine had little problem like that,it was little,but i noticed.
i changed oil to mobil1 synthetic v-twin oil.not a problem since.
while you are at it,change all the brake fluids too and bleed them.get it all done at once.

walmart or the local auto part store will have what you need.

+1 Beerhunter
The clutches on VTR's are exceptionally durable. Rotella dino 15W40 (with Triple Protection!) from Walmart is a good cheap oil. It could be an easy fix.

https://www.superhawkforum.com/forum...-thread-26779/
https://www.superhawkforum.com/forum...erencing-7884/

Rotella 15W40 is what I run in my BMW M3. It really is a good oil!

because its a wet clutch,it cant have any energy conserving ingredients in it.
if you are carefull,you will find plenty of different choices of oit that will be good for the hawk.
and find a good filter for it.there is a link with the cross reference in my other post.

Also when you bleed it it would be an good idea to dissasemble the cluch slave cylinder and check for wear/grime... That's not too uncommon unfortunately...

Update: I changed the oil to 20w-50 mobil1 vtwin motorcycle oil as recommended. I thought it fixed the problem.

Drove to chipotle for lunch today, all was well, but when I was leaving I noticed the bike was particularly hard to engage the clutch. I had to slip it to get it to move for an unreasonable amount of time. I almost got rear ended because I couldn't gain any speed. It got slightly better as I was moving but still, its nearly undrivable.

One thing I noticed was my clutch fluid reservoir is 100% empty. I am assuming this is what is causing my problem. Is it typical for the clutch to slip / not engage fully when the fluid is empty? My guess is yes.. but looking for a confirmation.

Yes it can cause the problem...... The one time mine got low I also had the slipping issues.

You might want to remove the slave cylinder and check to make sure it is not leaking while you are at it. ;)

+1
at this point,you have to take slave off and clean it out thoroughly,clean all around the area very good.take apart the slave cylinder and look for any damage,scoring,gunk,clean it all out.
once its back together,fill with fluid,bleed properly.after its all done.keep a eye on it for leaks.constantly check from the cup,all the way down to the slave cylinder.
on the sprocket cover,you can feel it if its leaking.there is a little hole on the bottom that it would come out of.
this should get you back on track,but there could be a leak,so you might have to get a rebuild kit.good luck.

An a note on the car filter cross reference, open the box an make sure its black or a dark color...mine ended up being white an sticks out lika sore thumb lol

I'm almost certain the slave cylinder is leaking, as there's always a puddle of something underneath the bike and it's definitely not oil.

Generally if you have air in your clutch system it'll not dissengage the clutch. It won't cause slippage issues being the fluid opens the clutch, not holds it closed. The exception to this would be if the return ports in the master cylinder are plugged it might not let the fluid return properly and could cause some slippage issues.

Well it's just another case of you can believe me or not....it really doesn't matter.

On this bike if you are low on fluid in the clutch system it can cause slipping.

It may be counter intuitive but it does happen.

So like I recommended, pull the slave cylinder and disassemble it. Check for scoring in the bore. If it is FUBARed then you are looking at around a little over $100 for a new assembly.

If it is good or at least decent you can replace pos #9 Honda, ATV Parts, Scooter Parts, Motorcycle Parts,CRF,CR,MX Parts, Goldwing parts

and see if that fixes the issue.

Or you might get lucky and a good cleaning will rectify the issue.

Its not just low, it is entirely empty. I also believe it is leaking and that's why the slipping has gotten progressively worse. I will take a look at it this weekend.

While you're at it, check the fitting at the the end of your clutch line to insure that it is tight and has the washers installed on both sides of the fitting. If your clutch fluid is low you will now have to bleed the system when you refill. There are a number of ways to get all the air bubbles out or past the upper banjo fitting.

Look below your slave cylinder and if it is clutch fluid leaking it'll stip your paint where it's leaking from so you'll know it's clutch fluid.

Generally if you fill the resivoir you can just flick the lever back and forth and it'll work the air out. The only exception is the banjo is higher than the orfice in the master cylinder so you'll likely need to bleed it at the banjo bolt as well. If you want to keep from spilling fluid while bleeding the banjo you can also take the master cylinder off the bar and tilt it so the banjo bolt isn't the highest spot in the system and pump/flick the lever and let it snap back to finish bleeding it.

Bumping this thread to ask a question...

I changed the oil to Mobil1 VTWIN motorcycle oil and saw no change in slippage

I opened the bleed nut on the slave and pulled the clutch lever -- fluid shot out, but the slave reservoir level did not change and was totally unaffected. Is that normal?

The master did lose some fluid

The clutch slave cylinder does not have a reservoir, so not sure what you are saying.

You mean to tell me that the reservoir on the clutch side of the handlebars that has lines that go to the slave cylinder is unrelated to the slave cylinder?

you have to bleed it like youre doing brakes,take your time,it is a slow procedure,but once any air in there is out.it will start to flow.

No, what he meant is that your terminology is screwed up...

The part on the handelbar is the MASTER cylinder, and it has a reservoar... The part on the side of the engine is the SLAVE cylinder, and it does not have a reservoar... When you operate the MASTER, it affects the SLAVE...

Now, common sense says that since you have bought the bike used form people that might not know a whole lot, you should change the fluids... So trying to diagnose this with an unknown fluid in there is pointless... Go get a bottle of clutch/brake fluid (DOT 4 or 5.1, don't mix it with DOT 5, they are not the same) and clean out the old, and bleed with new...

Then come back and we will figure this out...

+1 on checking the clutch slave and replacing seals, check the bore as grit can get in and score the surface making the seal ineffective. (sometimes a bit of fine wet'n'dry and polish can restore it, but you can replace the clutch slave with one from a Blackbird or Pan Euro)

When bleeding make sure you fill the reservoir little and often, as it has a smaller capacity than the front brake reservoir. A handy trick if you have a friend is to use a large syringe to suck fluid through the system while your mate keeps it topped up.