Author Topic: CB350F clutch issues. (Read 6610 times)

camshaft1991 · « **on:** July 05, 2018, 01:11:41 AM »

Alright so my clutch is unresponsive and stiff. I'm not on good terms with the last person who worked on my clutch so talking to him is out of the question. I rebuilt my clutch a few years back with new plates and springs. The springs are Barnet springs that I purchased from 4into1 and they were noted to be a little stiffer than OEM springs. Since the rebuild I put about 900 miles on the bike. The bike has been worked on several times since I have had it and the clutch has been disassembled twice and rebuilt once.

My clutch was stiffer after it was worked on by my former mechanic. I adjusted the play to help deal with the stiffness and the clutch stopped working. I then tried remove all play in the clutch and still nothing. The clutch lever at the handle bars feels like it's 50lbs and it does not free up the back wheel from the transmission.

I removed my clutch cover and clutch and found nothing out of the ordinary. All plates and friction plates are accounted for. I haven't checked for warpage yet, but the clutch was rebuilt a few years ago and I have put less than 1000 miles since it was rebuilt. The one problem I had was loosening the clutch spring plate. I felt like I was about to break my arm trying to loosen the 4 bolts to the plate that held in the clutch springs. I do not remember it being that difficult when I first removed them.

Assuming nothing is worn, what could have been done wrong upon assembly that would make the clutch behave this way? Or could the clutch lever in the right crank case cover be bad?

camshaft1991 · « **Reply #1 on:** July 05, 2018, 08:30:47 PM »

I found something. I thought originally 4into1 sold me the wrong springs but for some reason the spring kit came with 5 springs and my clutch assembly only needed 4. The minimum requirements for the spring lengths uncompressed is 34mm. The springs I took out of my clutch are around 34.17mm uncompressed. That’s pretty damn close. My old springs measured at 35.5mm and guess what my 5th Barnet spring measured at, ~35.5mm. Those are both at assembly standard. Unless the current springs are going to stretch I think I’ll be inclined to use my old springs.

Here’s another issue. What do I torque my springs to? If the current 4 Barnet springs are shorter than the 5th matching Barnet spring, then the clutch was overtorqued upon assembly. Right? I mean why would my original springs and a Barnet spring be the same length uncompressed while the other matching 4 Barnet springs that were in my clutch be a whole millimeter shorter uncompressed? I don’t have something telling me the exact torque specs for the clutch springs with exception of the Clutch Spring Preload which is 25.0/19.3-20.7kg(kg/cm). Is that what they need to be torqued to? does it mean a height of 25mm at 19.3-20.7kg/cm of force? If so I have no idea how to measure the springs while they are inside the assembly. This is from my OEM Honda manual. My Clymer manual states the clutch center is 400-450kg/cm, which I have no clue what the clutch center refers to. Clymer also clumps the 350f, 400f, 500f, and 550f together for the clutch center.

When I first reinstalled them I didn’t use a torque wrench and I didn’t have an OEM Honda manual at the time.

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camshaft1991 · « **Reply #2 on:** July 05, 2018, 10:09:23 PM »

A post on torquing a CB550F mentioned 7lbs of torque, which is not much. Before I found out water got into my digital torque wrench it had a minimum read out of 7.5lbs of torque. I guess I should just torque them with a mini socket wrench until it feels relatively tight. It's not like the bolts need lock washers to secure the bolts when there are springs exerting force against them. I did it once with out a torque wrench so I guess I can do it again.

Quote from: MCRider on April 09, 2012, 06:08:31 AM

Quote from: ajracer on November 13, 2009, 03:42:01 PM
My book says 29 to 32 foot lbs. does it mean inch lbs. I just snapped a bolt and the others seemed to keep turning after it started to get tight. really don't want to strip out my clutch.
29 to 32 ft lbs is more than a cyl head nut, which is hardened 8mm. Very suspicious. No plain 6mm bolt can stand that.

No reason these need more than a regular 6mm. The 6 to 8 ft lbs mentioned by many is plenty.

http://forums.sohc4.net/index.php?topic=61447.0

Little_Phil · « **Reply #3 on:** July 06, 2018, 01:27:16 AM »

I don't know the 350 clutch but on 500/550s the torque setting for the clutch bolts is 7.2-10.1 ft ilbs. (I'd stick with the lower end value) And the setting is to ensure that the bolts are secure. The torque setting will not really affect clutch operation as the spring compression is set by the length of the bosses on the clutch inner drum and washers on the bolts. Put a spring on the drum location and assemble without any plates to show yourself.

dave500 · « **Reply #4 on:** July 06, 2018, 03:23:36 AM »

if you feel like your gonna break your arm on those pissy 6mm threads to undo them your a limp wristed pussy,theyll shear off so #$%*ing easy man!you have changed a flat tire on a car I hope?

camshaft1991 · « **Reply #5 on:** July 06, 2018, 08:41:47 AM »

I hear you Dave,
I originally tried to use two socket wrenches: one for each clutch bolt and another on the little drive sprocket to the engine. I then try to make them come together as if I was the Incredible Hulk. It took me a little while to find a better alternative and use a regular 17mm wrench to brace the sprocket against the crankcase. Then I was able to put my full body against the clutch bolts with relatively more ease. Don’t know how they didn’t shear off, but they got to go.

Phil, what my book said about 25/19.03-20.7kg/cm with the spring length and torque value, would you say by torquing them down without plates I would be able to see their lengths after reaching their torque values?

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Bodi · « **Reply #6 on:** July 06, 2018, 12:18:28 PM »

The torque does not affect spring length, the bolts just hold them against the cylindrical bosses the bolts go into. Odd that you got 5 springs though. You can compare the spring strengths by stacking them in a vise, the weaker one will compress first.
As to pull, this is pretty much always cable related: you can't change the clutch pack pressure without changing springs. Any odd bends in the clutch cable can make an unbelievable difference in pull, and the cable has to be kept nicely lubed or pull goes way high.
Adjustment is pretty simple, the engine adjuster should be set for a bit of free play in the actuating lever before getting stiff - this ensures the throwout bearing isn't engaged with clutch engaged so it doesn't wear out prematurely.
Whatever your problem is, I doubt it's a mm or so spring length causing it.
If someone used Barnett plates, they can stick together very hard when unused for a while.

dave500 · « **Reply #7 on:** July 06, 2018, 03:26:20 PM »

next time you tighten or loosen those bolts have a piece of heavy rag wedged between the primary drive gears.

camshaft1991 · « **Reply #8 on:** July 06, 2018, 04:04:07 PM »

I have a motion pro gear stopper for that gear in particular but I destroyed it when I used it to remove my primary drive sprocket. I just need to buy another one, but I'll ball up rag into a knot in the mean time.

Do sticky plates cause any issues? The bike went over a year without use. I noticed that they were a little sticky when I pulled them apart. I measured the friction plates for thickness and clutch plates for warping but they all checked out.

I found my old invoice from 4into1. My plates, and springs are actually EBC. I do not know why I thought they were Barnet. I replaced the cable with the clutch rebuild, but I threw out my old cable because the cable sleeve was stiff, brittle and breaking. The thing is the cable I have now is like a sealed unit almost. My old cable could be pulled completely out of the sleeve and lubed. The new cable can be lubed but the sleeve won't allow much of anything to go in and removing the cable is impossible unless I break off the metal ends of the sleeve that help seal the cable. If removed and held out vertically, with one hand I can feel decent resistance when I pull and push the cable. The resistance is even greater with each bend made in order to fit it in. The more turns the cable has to make, the more resistance. I get that. I wish I saved my old cable but the sleeve to it would leak lubricant and let in dirt and other things in.

The issue I had with adjustment was that the clutch stopped working when I gave myself more play. I tried to set the play to how it was before. I remember spending an entire day and night trying different amounts of play. I guess replacing the cable will eliminate one possible issue. My original springs are not only softer, but their uncompressed lengths are at factory standard. So I might just reuse them instead. I'll check the EBC springs' uncompressed length next week to see if they reverted back to the factory standard length. I only have one EBC spring that is at the uncompressed factory standard, 35.5mm. As for putting the springs in a vice, would I compare my used EBC springs together or compare them to my 5th EBC spring? Or do you mean actually stack them on top of each other in the vice?

I thought I was sold a spring set for a 500f/550f because of that 5th spring but they were too long uncompressed for those two bikes.Turns out it came with 6 springs but I do not know what happened to the 6th spring. I followed a link to the springs I bought and saw they were meant to fit over a dozen other bikes as well. I don't have my book with me because I live in another city from where I work on my bike but I believe 500f and 550f have shorter springs. Their uncompressed minimum is around 30mm as opposed to 34mm for the 350f/400f.
The following is my 4into1 order from 2015 and the two EBC springs
(unused on the left used on the right)

dave500 · « **Reply #9 on:** July 07, 2018, 02:33:16 AM »

the Honda springs are best,any after market super duty ones are just bull#$%*,they aint no better in fact they could be softer?ive been thrashing the #$%* out of a david silvers clutch kit for years in a 550,never been re adjusted,it comes with genuine springs,i had some super wank springs I could actually compress between my thumb and forefinger once,i complained and explained but could only get store credit so swapped em for spark plugs,the stock clutch is pretty bloody good and has heaps of reserve,the 350s torque might flip an egg but I doubt itll fry clutches?

camshaft1991 · « **Reply #10 on:** July 10, 2018, 04:19:58 PM »

I found my 6th EBC spring. I was going to use it as a control for an experiment but I think I got it confused with my 5th spring. I compressed an EBC spring against an original spring

I experimented with ~25mm twice; however, I believe I compressed both EBC springs on
each test. So I have no control or reference to how it was before. I was distracted. Anyways the ends of the spring are now downward which looks like to show that it has been compressed. The OEM spring coil is more narrow and more coiled but there is a significant difference in force each spring exerts. I can partially compress OEM springs with two fingers and I can hardly even make the EBC spring compress noticeably with two fingers.
My conclusion with EBC springs is that they don’t retain their elasticity as much as OEM springs. They also look like completely different springs.

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camshaft1991 · « **Reply #11 on:** July 11, 2018, 04:13:21 PM »

The following are the uncompressed measurements of an OEM spring and an EBC spring

A millimeter really isn’t that much but there are other things to consider, time and usage. The OEM spring has been the bike for over 40 years and has 9k miles of usage. The EBC spring has been in there for less than two years and has been used for less than a thousand miles. The fact they were sold as a one spring fits over two dozen models is enough to say it’s not specialized for a few models.
https://4into1.com/ebc-clutch-spring-set-csk10-cb350f-cb750k-gl1000/
(15% stiffer my ass)
Anyways, I’m waiting on a new clutch cable and with a new clutch cable and OEM springs, I believe my clutch problem will be solved.
(I also left a review for people for fair warning)

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jonda500 · « **Reply #12 on:** July 11, 2018, 05:13:47 PM »

For the test Bodi mentioned to compare spring strengths to work, they need to be stacked on TOP of each other in the vice then measured - not side by side in the vice!
John

camshaft1991 · « **Reply #13 on:** July 11, 2018, 05:55:01 PM »

Thanks for the confirmation I’ll try that. Can I do two at a time or do I need to stack all 4? The EBC springs almost look lop sided. I just don’t want a spring to shoot out from my vice lol.

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camshaft1991 · « **Reply #14 on:** July 11, 2018, 06:07:58 PM »

This is why I ask

I can’t even stack them uncompressed. To the right is OEM springs. They’re leaning a bit to but I didn’t take time to rearrange them.

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camshaft1991 · « **Reply #15 on:** July 11, 2018, 06:14:21 PM »

And 4 of them in a vice was indeed a bad idea

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jonda500 · « **Reply #16 on:** July 11, 2018, 06:30:14 PM »

Yeah, I would only do two at a time - i.e. compare the strength of one to another - to help you can put something flat between the two springs - which will make it easier to measure too...
John

carnivorous chicken · « **Reply #17 on:** July 11, 2018, 06:57:58 PM »

For the cable, motion pro (IIRC) makes a little tool that looks like a clamp with one end open and the other end not. The cable end goes in the clamp, with the housing side in the part that is more open, the clamp closes down on the housing and around the exposed cable, and there is a hole for shooting lube in there from a spray can with a straw. I use mine all the time for old cables if/when they get sluggish so it's worth having.

camshaft1991 · « **Reply #18 on:** July 11, 2018, 10:04:03 PM »

Quote from: carnivorous chicken on July 11, 2018, 06:57:58 PM

For the cable, motion pro (IIRC) makes a little tool that looks like a clamp with one end open and the other end not. The cable end goes in the clamp, with the housing side in the part that is more open, the clamp closes down on the housing and around the exposed cable, and there is a hole for shooting lube in there from a spray can with a straw. I use mine all the time for old cables if/when they get sluggish so it's worth having.

Wish I knew that existed lol. Post a pic I still don’t know what to look for on their website

I was able to put my OEM springs together

But they too started to give in the middle but a little more gracefully.
John, once I put two springs in a vice with something dividing them and compress them what do I measure? So my book said something about about ~19.3-20.3 kg/cm at 25mm. I guess when I compress two springs I would double that and add the thickness of the divider too. Do I measure the gaps in the spring coils and compare measurements? I’m eventually going to get a new torque wrench and maybe I can do it that way with new bolts. I’m nervous about torque, not because of breaking bolts but because of stripping my clutch holder.

Two of them are partially stripped and one can’t thread a bolt. If I fix this and torque them down, to 7lbs from what someone mentioned, then I’m going to need a pretty sensitive torque wrench. My last one would barely register 7.5lbs but that’s another discussion I need to get back to on the forum.

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camshaft1991 · « **Reply #19 on:** July 11, 2018, 10:39:53 PM »

Here’s something else I noticed

I didn’t clean anything. Does this mean anything? Aside from my clutch not working this does seem strange.

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camshaft1991 · « **Reply #20 on:** July 12, 2018, 12:01:23 AM »

Also, gasket remover overspray. Will a little bit of gasket remover be bad for my engine? I stuffed a blue shop towel in the side but I made sure not to stuff it too tight and have some blue shop towel bits rip and get lodged somewhere

The problem is I can’t tuck anything near or underneath this sprocket. I know how I’m going prevent over spray on the outside but I can’t prevent overspray on the inside. I had to spray my clutch cover 3 times with gasket remover before I could scrape it all off.

So should I go ahead with how i have it, or should I consider removing that sprocket?

It’s CRC gasket remover and it kind of adheres so it has to be wiped off.

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dave500 · « **Reply #21 on:** July 12, 2018, 12:19:23 AM »

cant you shimmy some cardboard around that gear and fold it over it?

carnivorous chicken · « **Reply #22 on:** July 12, 2018, 01:44:01 AM »

Quote from: camshaft1991 on July 11, 2018, 10:04:03 PM

Quote from: carnivorous chicken on July 11, 2018, 06:57:58 PM
For the cable, motion pro (IIRC) makes a little tool that looks like a clamp with one end open and the other end not. The cable end goes in the clamp, with the housing side in the part that is more open, the clamp closes down on the housing and around the exposed cable, and there is a hole for shooting lube in there from a spray can with a straw. I use mine all the time for old cables if/when they get sluggish so it's worth having.
Wish I knew that existed lol. Post a pic I still don’t know what to look for on their website

https://www.amazon.com/Motion-Pro-Cable-Lube-Luber/dp/B00U1LJLCG

camshaft1991 · « **Reply #23 on:** July 12, 2018, 02:13:25 PM »

Thanks Carnivorous chicken.

I think if I stuffed cardboard around the sprocket the cardboard might tare or flake when I pull it out later. I think I'm going to use card stock or notecards. Everything will get a little overspray eventually once everything is soaked, but I wont have overspray deep inside engine. There are not any gaskets in the middle of the engine, but the starter clutch does have some rubber components. I do not know wether the rubber dampers of the starter clutch is made of Buna-N Nitrile or FKM Viton. The properties of the two are very different. I know I'm being very OCD about this, but I don't event want stray fibers. I made sure not tuck the blue shop towel too tight because after it is soaked it will likely tare when removed. Assuming those components are Buna-N, could I clean off whatever is left with Seafoam's Deep Creep? I know WD-40 is potentially harmful to Buna-N but could I spray the inside of the crankcase case with Seafoam?

glenncal1 · « **Reply #24 on:** July 12, 2018, 03:42:35 PM »

Cam- how smooth is the clutch center, could the clutch plats be hanging up on the basket?

News:

Author Topic: CB350F clutch issues. (Read 6610 times)