Maybe I'm missing something, but I like the fact that my clutch engages high (far from the bar). It makes shifting so much quicker. A little preemptive toe pressure, a blip of the throttle, a tap of the lever and there she goes.

 

Got the Hawk up to 35mph, shifted up to 6th and rolled on the throttle. No slip at all. Only had the bike for four months and just really been able to ride it the last two. Must just be the way it's set up. I have to say that it makes shifting very quick... Thanks for all the input.

 

my clutch is the same engages almost all the way out been talking with the guys who ride at work and one has a ZXR1300 Ninja I let him ride my SH and he said its normal for a sportbike clutch to be that way makes for smoother shifts as long as it doesn't slip

 

My hawk also releases near the end of the travel. I chaulk it up to a 'Hawk trait, just like some ford trucks release near the firewall, and most Jeeps release near the end of the travel.

 

Same clutch action on my hawk.

 

i thought i read on this site were somebody put a shim ( or extra gasket ) behind the clutch slave cylinder to get it to engage closer to the bar ?

tim

 

I pulled a search before hitting the panic button and I'm glad I did. My son and I have been having this disagreement that the Superhawk is slipping clutch.

He says it's because it releases so late in the travel and I tell him that's bullshit - well, at least that's not the case when I ride it.

When I'm shifting on the push I want that 3/4" response. It's also more comfortable for me at a stop. I have some flex before I hit the pressure point of release with the feet.

He says his CBR released in the middle of the travel. I didn't say it but CBR's are for squids and VTR's are for old drag racers. I think he is getting back to the throttle too soon for doing a shift up through the pattern. Especially if he's thinking he has to do the full travel clutch lever movement.

I shift like the member RPV-Hawk - a little toe pressure and when it breaks we're on it hard again. I can easily keep very light pressure on the front of the bike because if your accelerating that hard there is very little steering pressure. NONE! hehehe! This is straight line stuff only.

I think it's just a matter of timing that he hasn't had enough miles to get coordinated.

My mechanic says to go to hi-temp race fluid. Says it's good up to 5-600F.

It is true that Chas rides the bike longer and harder than I do. He has reported that the longer he rides the worse it gets.

Have any of you guys used this stuff?

 

I think you need to let your son know that his CBR has a cable operated clutch and can be adjusted to release whenever it's wanted to and that you're limited with what you can try on a hydraulic actuated clutch. Comparing the two means absolutely nothing. For (useless) reference, and being someone that owns one of each, it's the same way for me.

As for your assumption about his co-ordination - for the most part I agree (see below why I don't). If I switch between the two bikes immediately without really paying attention then i'll screw something up. Wether I stall it or leave the line humping the tank ..... it's all about co-ordination and watching what you're doing.

Now, about the time thing ..... yeah, if i've been riding for 3 or 4 hours and the engine/transmission is good and "heat soaked" (emphasizing several heat "cycles" - rad fan on/off) then the "problem" (which is not a clutch engaging problem) is worse ..... but that clutch ain't slippin'.

Honestly, I really believe it has something to do with the fluid in the clutch actuation system getting really hot (starting at the engine end, so the slave cylinder) and altering the fluid's compression characteristics some way. Just a theory. The engine oil itself, i'm not sure how much I believe that (not enough experience under my belt). I say this because if I ride for an hour I don't notice a change in clutch actualtion. If I ride for 3 or 4 hours THEN I notice a change.

What's the difference between the two scenarios? Simple - the engine/transmission oil has a cooling system and is temperature-regulated, the clutch actuation system does not.

That's my story and i'm stickin' to it.

 

Thanks, Slim! He came into the office later last evening and I let him read the entire thread. We talked and talked and now what we think is that he's slipping the back tire and not the clutch. He said while easy cruising if he really gets on the wrist the clutch breaks loose. After our discussion we now think it's the back tire.

This is a much stronger bike than his CBR and he's still feeling out the liter class.

I appreciate everyone's comments. I hate these mechanical witch-hunts - especially if the issue is a phantom. Thank God for the search function.

 

Make sure you do not have air trapped near the upper banjo bolt, pretty common on the SuperChicken's Brake and clutch lines as the Banjo bolt is one of the highest points. YOu may need to cover all body parts on the bike and bleed carefully loosen the banjo bolts while the lever is pulled to bleed any air that may be trapped there.

Another trick that works on brakes is the night before you go riding pull the brake lever all the way to the grip and secure it there over night with a zip tie or some other manner. This will auto bleed the line.

It works, try it.

 

Thanks Thumper, I've done that successfully with the brakes too!

New development: I took the Superhawk out for a ride this afternoon and rode well and hard for 45 minutes. Was cruising past one of my customer's homes and they were out stringing Christmas lights. We yacked for a while - great folks.

I get about leaving and the bike is not holding gear. It's slipping someplace really badly! As I get it back on the road and get some air around it things get better but only marginally.

Got back to the shop and sat down with the kid and he reports the same behavior. Ride hard out of the barn ok - for me it was 45 min - for him it was 1.5 hours. Stop for a little bit - get going again and it's slipping all over the place - I mean sloppy - stay in the slow lane so you make sure you can keep up - sloppy.

We've been through the ritual before - we bleed it we're good - for a while - this is the second time the bike has done this. It's almost like I have an air leak into the system. Is that possible? Does it occur at the upper banjo?

I got no puddles under the bike and it's always in the same spot.

 

Air leak into the system IS possible... unlikely but possible... I had a bad crushshim at the top banjo... I guess it was re-used once to often...

Mine was on the brakeline so I can't account for symptoms, apart from that I bled it over and over again, and still found air in the system, no puddles... Until i took it completely apart and did SS lines and new bolts and such...

BTW the leak was very small, just enough that I figured it out, after riding one day there was just enough brake fluid on the top banjo for me to see it and feel it... but that was it... not enough for a puddle...

 

Thanks, Tweety! This went from "assumed" kid induced problem to major malfunction and I'm glad I rolled the bike out this afternoon. I had been out on the Interceptor all morning and had a great ride. This was to be just a shake down and alas - it was! He and I have talked - we're both scratching our heads. Maybe time for a new clutch line. Blow all new fluid at the time. If it were the clutch plates they would slip all the time - this only slips when it's warm. I think there is an air bubble that is expanding with temperature and holding the slave cylinder rod in just slightly when hot.

 

That's possible... In my case it was just enough of a leak to gain air slowly into the system, a small amount every time I pressed the handle... But not really loose any large amounts of fluid... A small tiny leak at fully applied brakes... Small enough that i couldn't figure it out... And I bled the brakes probably 5-6 times... And still after about an hour of riding I would be pumping air... Also since the banjo is a highpoint, all the air that came in stayed there...

 

Well, I am definitely going back after this one Tweety! I'm pissed now! An aging clutch doesn't work really well for an hour and a half and take **** after a Coke break. I was at Ed & Clair's for maybe a half hour. Flawless before the stop - barely make it home stuff afterwards. It did get better once it had some air over it but not much and never did hold the whole nine miles back to the shop.

 

Definitely make sure that you bleed the banjo fitting at the clutch master cylinder as some residual air will remain in the fitting. Wrap the bolt and fitting with a rag and have someone pump the lever, crack the bolt enough to get the fluid to ooze out around the crush washers and then tighten.

Continue the bleeding process until you feel all air has been evacuated from the line.

This same procedure should be used when bleeding the front and rear brake lines as well.

 

1: The zip tie trick does not work well on the SH, UNLESS you do what would work on normal bleeding procedures,, and that is get the master at the needed angle. You can tie back the lever on the SH for a week, and that air bubble will sit at the high point all week...LOL.. Now if you remove the master or turn the bars and lean the bike over so things are level.. that air bubble will bleed out though the reservoir as you pump the lever a dozen times (or tie the ever back and leave it)

As for an air bubble expanding when it gets hot and causing the clutch to slip... In life anything is possible, but in a lot of years of riding, racing and wrenching I've not seen that happen... that I know of.

I just do not believe the expansion rate of air as it warms from ambient temp to even say 500deg could be enough to actuate the slave cylinder and release the clutch.

I'd sooner suggest that the clutch has been abused, the plates are glazed, and as they heat up enough you are feeling them slip. Or,, it's just a rider induced slip by the way the clutch is being used.

Tell ya what Doug,, I’ll test ride it in about 40 days…. We can bench race about it then.

 

Chicken, when I had my brake problem, I did bleed that bubble out, several times, getting things level and pumping... But in my case it was a definete leak as I then found the small dab of brake fluid... this was 3-4 days after I last had the banjo loosened (and I did clean it of)...

I'm not in any way saying that this is causing Dougs problem, I'm saying that even tho it is unlikely the fact is, it can happen, there can be a leak into the system...

So a starting point for me if having to deal with this probably would be atleast taking it apart, cleaning all mating surfaces and replacing the crush washers... and with an ageing stock line, it's a perfect time to put on a new one when you already are taking it completely apart...

As for air expanding how much at what temps...?! Dunno... Beats me, I have no idea.. So that I leave to someone else...

The glazed plates feels like a plausible explanation, I probably would start with the above, taking the clutch apart is more work... but again on the theme of doing the dismanteling only once, it could be an idea to have a look in there at the same time...

Smart people probably would... I'm lazy, so I usually get to take stuff apart more than once... I learn more that way to...

That's my excuse and I'm sticking to it...

 

I really wanted to have it close to ready so we could ride em! The long range forecast came out today and we are to be milder and about average for rainfall over the next 90 days! Yippee! We get to ride in air conditioning all winter!

I'm going to bleed it again and may even do a complete fluid changeout as my mechanic suggests to the hi-temp stuff. May also do an unscheduled oil change just to make sure.

 

What type of brake fluid are using? Is it DOT5 or DOT3
If the clutch is slipping after the bike sits after a good hot soak then the fluid will expand about 10 to 20% or the master cylinder has a resticted residual check valve . This will cause the slave cylinder not to release the pressure correctly .Just a thought.

 

Thanks for the input MMRed! When I did my build last winter I think everything got flushed with new DOT 4. What you describe is exactly what I experience. Thanks again for the tips. This will shake out soon.

 

Hopefully he did not use DOT 5, which is silicone based and not compatible with DOT 3, 4, or 5.1 You can use DOT5, but all components must be complete cleaned free of all traces of the glycol based fluid. The best method is to replace all rubber parts that have come in contact with the non DOT5 fluid, clean all metal or plastic parts prior to switching fluid types. Mixing DOT 5 and anything else makes a nasty mess.

DOT 5.1 is a good choice, though not as widely available as DOT4. I think I have written all this and more in reference to a brake fluid question, The information is all the same when used for clutch master cylinder

 

I went down to the shop to check for sure and it's synthetic dot4. It also says that it's good to 500F so no more talk about the hi-perf stuff. Chas and I will try to bleed it again this afternoon. I'm also going to bleed the upper banjo. I'll post back after we get it done. Thanks for all the help!