Clutch Fluid; DOT4 only or DOT3 ok?
 

I just finished replacing the oil and filter on the hawk. Went to warm it up so oil will fill the oil filter and let it warm up. Bike is on stands so I wanted to run it through the gears to get the new oil circulating everywhere.

However, when I pulled the clutch lever in I found it very difficult to shift into first. I pushed down pretty hard and heard a bit of grinding but got first to engage. Was able to go into second fairly easy when I noticed the wheel would not stop spinning when the clutch lever was pulled in, just kept on spinning like it's completely engaged.

I figure the fluid is old and needs replacing. Manual states DOT4 brake fluid and nothing else as others are not compatible. Can anyone chime in on this? Should DOT3 be avoided??? I bought the bike used, atleast two previous owners, not clue as to what's in there right now. TIA.

Correct DOT 3/4 should not be used emplace of the other. Technically they can be mixed with no ill effects, but they do not have the same capabilities .

DOT 5.1 can be used in replacement of either 3 or 4

Just buy yourself a new sealed container of the 4 and do it as Honda requests.

Thanks for the info E.Marquez.

What do you suggest I do Wolverine? I don't know what's in there right now. Is it safe to drain all the system and then refill with DOT4 or should I clean the lines/master cylinder/slave cylinder with alcohol first? TIA

Draw all the the contents of the res out with a suction devise. I use one of these, pick one and go.
http://interstatesbrandstore.com/files/CPB00005/269.jpg

Then refill with fresh and bleed about 2 res worth through the system. Should do the trick, easy peazy
https://s3.amazonaws.com/images.weal...10_cropped.jpg

Worth the read.

http://www.sector111.com/images/prod...ke%20Fluid.pdf

Thanks for the clarification Wolverine, picked up Prestone DOT4 tonight and will bleed the clutch tomorrow.

Good link for educational info xeris, but I didn't find anything there on what happens if DOT3 and 4 get mixed, or how to clean lines if that's even necessary.

As of now, I will bleed two maybe three reservoir worth and probably do the brakes as well.

Ok, here's the deal. I replaced all the clutch fluid at least 4 res full. No bubbles, clutch handle is firm. However, when the bike is on a rear stand with the rear wheel in the air, it is still spinning in each gear with the clutch lever pulled in all the way to the bar (I even extended the leverage to full range even though my hands are on the smaller side). I don't remember this phenomenon happening before. I took it for a quick spin around the block and it feels and shifts fine, idles fine as well. Any ideas? or is this normal?

PS
The oil I used now was conventional 10w40 motorcycle specific oil, not car oil. The oil that was in it before was also motorcycle specific oil 10w40 but synthetic. Could that affect it?

You're good to go. That's normal (tire spinning).

Wheel spinning - perfectectly normal

Have you changed it to semi synthetic? As some owners report clutch slip using fully synthetic...

Full synthetic DOES NOT cause clutch slip... This should only be reported as personal experience. I've used full syn in my VTR for 10 years... NO slip.
I work at a motorcycle shop as the only mechanic. I pour full syn regularly, never had complaint of slip...

As a rule all brake/clutch fluid should be changed every 24 months. Brake is very, very hygroscopic and the fluid starts absorbing moisture from the air as soon as you open the can. So what does this do?
1. Brake fluid gets hot, when it does the O2 part of H2O gets released, now you have spongy brakes, they need to be bleed.
2. The H2O is a an corrosive/oxidizer bad for your master and slave cylinders
3. H2O drops the boiling point of your brake fluid. The higher the boiling point of a fluid the more firm your lever will feel and the easier it is to modulate your braking.
4. Caveat, super high boiling point DOT4 fluids used in racing give amazing feel and lever firmness, but they absorb moisture at a higher rate than standard DOT 4 fluids and so need changing more regularly...

No clutch slip for me either I have been using full synthetic in my road and race bike since 1983. As a matter a fact after a break in of 200 miles all my race bike were slick 50 treated in with the synthetic oil, still never a problem. I always have used OEM clutch pack...

Nothing happens, its not incompatibility at issue, its different capabilities.

Just look at the two fluid general specs.
DOT 3 used in a system designed around the qualities and specs of DOT 4 will see fluid, and thus system failure.
DOT 4 "added" to a system with DOT 3 will not see any increase in fluid performance as the two are now mixed. Flush the DOT completely from the system and fill with DOT4 or 5.1 and you will see a fluid performance increase.

DOT 5 is silicone based and is not compatible with any other type ..they do not mix at all, or in any case separate. DOT5 is more compressible that DOT3, 4, 5.1 And is more effected by heat. It is not hygroscopic (it does not absorb moisture) thats good and bad,,the fluid retains its boiling point as it is not "wet" the bad, its allows the moisture that DOES get in the system to pool and cause corrosion.

Thanks for all the responses. E.Marquez, I did read the whole article you provided and understood it, but as I'm not a chemical or component engineer did not assume anything about the differences in properties and how they react to each other (Except or the silicone base stuff, that was pretty clear).

Since there was so much fluid left and the longer this stuff sits in an open container the less usable it becomes, I flushed both front and rear brakes to boot. Now all I have to do is flush the cooling system and she'll be like new again :)

Any consensus about using the Honda car 50/50 Type 2 Coolant? Have left over from my radiator change and thought it'll go to good use in the hawk. TIA.

If it is designed for a modern car and aluminum radiator it will be fine