Honda CX 500 Forum banner
1 - 20 of 35 Posts

·
Registered
Joined
·
64 Posts
Discussion Starter · #1 ·
I'm getting there as far as tearing the 79 cx500 down, but after removing the radiator and themstat and assorted hoses and pipes, I unscrewed the fan bolt and notice the fan is loose on the metal collar in the middle, as if it got worn out. However, i can't seem to get the collar (for lack of a better term) to budge so I can remove the fan. I'm tearing down the motor to determine why the valves aren't moving when I manually turn the crank. Any suggestions?
 

·
Registered
Joined
·
8,423 Posts
On one engine I made a couple of Wooden chisels out of some old broom handle and whacked them either side of the fan at the small gap between it and the tacho drive unit to move it off the cam shaft after a soaking with penetrating oil/WD40 type stuff



HTH
 

·
Registered
Joined
·
5,563 Posts
I'm getting there as far as tearing the 79 cx500 down, but after removing the radiator and themstat and assorted hoses and pipes, I unscrewed the fan bolt and notice the fan is loose on the metal collar in the middle, as if it got worn out. However, i can't seem to get the collar (for lack of a better term) to budge so I can remove the fan. I'm tearing down the motor to determine why the valves aren't moving when I manually turn the crank. Any suggestions?
buy this bolt,Fan puller bolt.

M14 x 1.5 about 2 inches long.

it goes into the fan centre hole,bites on the shaft and your fan will pop right off[or what left of it]

 

·
Registered
Joined
·
64 Posts
Discussion Starter · #4 ·
Great ideas. Thanks! I have cb550/750 engines down to a science, but this cx motor is a different ball game altogether. One day maybe I'll be the master of all types of Honda motors...
 

·
Registered
Joined
·
595 Posts
This is a controversial thing to say, but if you have a spare axle laying around, it should thread into the fan and pop it right off. Some axles aren't threaded to the fan hub, so YMMV, and you may ruin threads on one or the other. However, I can say that my spare axle screwed into the fan hub on my spare engine very smoothly with no binding ,and once it was hand tight, I put a crescent wrench on it, and tapped it lightly with a mallet. The fan came right off.
 

·
Registered
Joined
·
5,563 Posts
Great ideas. Thanks! I have cb550/750 engines down to a science, but this cx motor is a different ball game altogether. One day maybe I'll be the master of all types of Honda motors...
good to have you on board.if you decide to buy the correct bolt for a couple of bucks,paint the head green......its now a tool


if your happy working on the cb range,these will be a walk in the park
 

·
Registered
Joined
·
7,223 Posts
Are you going to replace the fan or maybe put on an electric one? If the plastic blades are loose on the hub it sure sounds like that fan is toast and should be replaced. These fan do have a tendency to crack and shatter, usually taking the rad with it.
 

·
Registered
Joined
·
595 Posts
One of the problems is that the centre hubs of the fans are made of,"Monkey" metal and the threads have the tensile strength of cottage cheese


Yeah, which is why it's a controversial thing to mention using the axle.



Personally, I didn't mind using it because I'm too lazy to head out to the hardware store and grab the proper bolt when I want to get something done "now" and I'm gonna go to an electric fan anyhow. It's nice to have a spare, but if it breaks it breaks.
 

·
Registered
Joined
·
3,999 Posts
Some axles aren't threaded to the fan hub, so YMMV, and you may ruin threads on one or the other.


It's not because the threads don't match that you may have a problem using the axle.



The problem is because the front axle is tapered on the end. When you thread it into the fan hub the first few threads on the axle will not fully engage the threads in the fan hub so you might strip the threads if the fan is stubborn and does not pop off easily. A normal bolt is the same size all the way to the end so you will have all the threads engage.



You can probably use the axle,,but if you have to use a lot of torque,,you could strip the threads.

 

·
Registered
Joined
·
5,563 Posts
nice drawing Allan,speaks a thousnd words.never seen that before




Sture in Swedon quoted 2 years ago.........whoever wrote in the honda manual that it is ok to use the front axel......should be shot.
 

·
Registered
Joined
·
4,035 Posts
nice drawing Allan,speaks a thousnd words.never seen that before




Sture in Swedon quoted 2 years ago.........whoever wrote in the honda manual that it is ok to use the front axel......should be shot.


Agree! However, you missed the taper on the shaft and fan hub! LoL!






Is the taper needed on the end of the axle to put it through it's holes? If not, one could grind a bit of it off to allow more threads to engage.
 

·
Registered
Joined
·
64 Posts
Discussion Starter · #13 ·
Oh my Gawd! I bought the 14 mm bolt, turned it a couple of times and the fan popped right off! It was soooo easy. I love you guys. I also popped off the starter. Next problem: At the backside of the engine - sort of across from the fan shaft, I removed all of the bolts for the water pump but the cover will not budge. Is there a trick. After that, I should be able to remove the whole back cover off and see what the heck is going on with the lack of valve movement when I turn the crank. I bet its a broken cam chain....
 

·
Registered
Joined
·
2,282 Posts
No real trick to getting the cover off. There are two locating dowels on the cover, so you can't rotate it to break it loose. Just try tapping with a block of wood and a hammer to jar the seal loose. Once you have it loose, then you can carefully pry the cover up and off with a gentle screwdriver.
 

·
Registered
Joined
·
7,223 Posts
yea, you got to love that bolt trick




I got mine off by gentle tapping an "olfa knife blade" (the really wide blades that you can break bits off of) into the gasket area between the two surfaces. Since the blade it thin, it wont "gouge" the mating surfaces like a screwdriver blade, and due to the severe acute angle on the blade edge, it can never even touch the mating surfaces (IF tapped in straight in line with the gasket). Do this in a few places and the force exerted by the blade thickness will pos loose the gasket. You can then try "carefully" prying the cover off, near the large bolt holes (thats where the dowel pins are), preferably with a wood chisle (a LOT pointier than a screwdriver, and it can be gently wigled without maring the mating surfaces.
 

·
Registered
Joined
·
64 Posts
Discussion Starter · #16 ·
Thanks, Fox. There are some similarities with cb engines. I remember dowels on the left side cover of the 750.
 

·
Registered
Joined
·
595 Posts
Time for me to eat my words. I had plans on pulling my old, already broken, fan off of my engine today. Handed the axle to my father who helped me remove my fan off of my spare engine and said "Here, you know how to do it, pop this out while I grab us some drinks." I come out to witness him vigorously shaking it up and down. Sigh. Bye bye threads. Considering that the fan was bad anyhow, do you guys have any...alternate ideas to removing it? There may be a few threads left, so maybe I'll grab myself a bolt and give it a shot. Ugh. If I would have done it maybe it would've been fine lol.



Also of note, it was EXTREMELY difficult to remove the bolt, and it had evidence of locktite in the threads as well as rounding on the edges.



I'm going to an e-fan anyhow, so if I end up having to grind everything off then I won't really care lol.
 

·
Registered
Joined
·
5,563 Posts
Agree! However, you missed the taper on the shaft and fan hub! LoL!






Is the taper needed on the end of the axle to put it through it's holes? If not, one could grind a bit of it off to allow more threads to engage.
Dan,no taper needed at all,just a simple arris[chamfer]
 

·
Registered
Joined
·
5,563 Posts
Time for me to eat my words. I had plans on pulling my old, already broken, fan off of my engine today. Handed the axle to my father who helped me remove my fan off of my spare engine and said "Here, you know how to do it, pop this out while I grab us some drinks." I come out to witness him vigorously shaking it up and down. Sigh. Bye bye threads. Considering that the fan was bad anyhow, do you guys have any...alternate ideas to removing it? There may be a few threads left, so maybe I'll grab myself a bolt and give it a shot. Ugh. If I would have done it maybe it would've been fine lol.



Also of note, it was EXTREMELY difficult to remove the bolt, and it had evidence of locktite in the threads as well as rounding on the edges.



I'm going to an e-fan anyhow, so if I end up having to grind everything off then I won't really care lol.
cut 2 wooden wedges,tap them in behind the fan body,tap equally and it should pop off.a wooden broom handle makes a nice wedge when cut up
 

·
Registered
Joined
·
595 Posts
I'll grab my old wire brush and give it a shot, thanks bandit
.



In the mean time, I went to autozone to find a bolt. They have a wheel stud that looks a lot like a somewhat expensive fan puller I saw linked in another thread. This one only costs 2 bucks, only difference is the "handle' isn't as ergo-dynamic. I screwed it in, hoping it'd pop the fan off. No dice. It's in there so tight, that it's turning the engine with the fan now o.0. The fan just doesn't want to budge Once I had it hand tight, I put vice grips on it and whacked it with a mallet as I did with my other fan, and I did the last time I removed this very fan. Ugh.



It's in there very tight. No wobble. It does look slightly crossthreaded though, probably thanks to the damage my dad did with the axle >,>. It's angled slightly to the right. The engine is indeed in gear too. I'm going to try and whack it a few times while trying to keep the fan still and if that doesn't work I'm going to use my old wire brush's handle as a chisel.
 
1 - 20 of 35 Posts
Top