• Don't overlook our Welcome Package, it contains many links to important and helpful information about functions at VHT like posting pictures and sending PMs (private messages), as well as finding the parts you need.

    AD

Clutch springs, 83 CB450 nighthawk

SeanDubh

SeanDubh

Well-known Member
Joined
Jul 26, 2023
Total Posts
95
Total likes
31
Location
Toronto, Ontario, Canada
Okay folks.

I have been trying lots of different things to try and get my bike running better. I rebuilt the clutch last year and that was good for a time, til it wasn't. I've redone the carbs a few times now and everything seems to be fine there. The only thing I've come across that could be a problem so far is thus:;the Barnett clutch springs I put in last year appear to be 1mm under spec. According to the service manual if they are less than 41mm they need to be replaced. These ones, brand new, read 40. Could this 1mm be enough to make my clutch slip and make bike run poorly? Am I replacing these with new ones or is it possible to shim them with a little washer?

I welcome any thoughts.

Cheers.
 
Slipping clutch doesn't really make the bike run poorly, it just doesn't transmit the full power of the engine to the driveline to make the bike perform to its maximum. 1mm difference in spring length isn't much, but it would reduce the overall spring tension a little bit. To gauge the level of slippage of your clutch, what gear does it slip most in? Does it slip in 3rd or 4th gear, or only 5th (or 6th if you have it)?
 
Right, not "run" poorly but not go so good. It feels like the there's power to be had but the clutch isn't grabbing it. I tried to show it in a video. It seems most obvious when accelerating from a standstill into 1st.
 
SeanDubh said:
Right, not "run" poorly but not go so good. It feels like the there's power to be had but the clutch isn't grabbing it. I tried to show it in a video. It seems most obvious when accelerating from a standstill into 1st.
Click to expand...
I guess I missed the video, is it in a different thread?
 
ancientdad said:
I guess I missed the video, is it in a different thread?
Click to expand...
Tis was in an old thread. I'll try and capture it in a new one when I'm able. Basically it seems like it's "bogging down" (which I know has more to do with the carbs) in that it that RPMs drop and it feels like the clutch is slow to engage.

Free play seems good, clutch discs and steels are good, oil is good.
 
Last edited by a moderator:
SeanDubh said:
Basically it seems like it's "bogging down"... ...in that it that RPMs drop and it feels like the clutch is slow to engage.
Click to expand...
That description doesn't sound like clutch slippage. Clutch slippage is when the plates don't fully "lock" together and the engine revs up more than it should for the gear you're in when you're accelerating.
 
Im not doing well trying to describe it but a few different people Ive had ride it have all felt it was something clutch related. This description of clutch slippage above sounds like what's happening. It just really feels like Ive got no power in trying to gain speed. I can get it up to speed eventually but right out of the gate its always a struggle.
 
SeanDubh said:
Honda GN4 10W-40
Click to expand...
Oil should be fine. Personally I don't like it since it seems to thin out too quickly but that's me.
I would take a look at the outer clutch basket fingers where the frictions engage it. The engagement surface should be smooth so any dents need to be filed down. The dents can cause the frictions to stick.
The springs being short is a definite problem. They can be shimmed by adding a spacer under the release bearing or under the spring at the inner hub, be careful of clearances.
I've been using the EBC CSK15 springs for years and never had a length problem. Another good source is KG Clutch Factory part number KGS-019 sold by Parts Unlimited and Tucker Rocky. Even the Vesrah springs have been in spec. SK-110
Looks like Tucker Rocky has been sold to Turn14 in Pennsylvania and not accepting orders at this time.
 
You could use a spark plug washer under each spring, I've done it more than a few times to increase tension just a bit.
 
Hmmm okay some things to consider. I've gone ahead an ordered some new springs and if that doesn't do it I'm out of ideas. I'll have a peek at the clutch basket fingers but I seem to remember them looking alright. I'd like to avoid taking the basket off again cause it's such a pain getting that locknut loose.
 
crazypj said:
Do you have an extra plate with the Barnett clutch plates?
You may need an extra steel plate?
Personally I've never liked Barnett clutches way too 'grabby' when they work 'properly' although I have heard the newer ones are less 'drag race'?
Click to expand...
The friction discs are EBC, the springs are Barnett
 
LongDistanceRider said:
Oil should be fine. Personally I don't like it since it seems to thin out too quickly but that's me.
I would take a look at the outer clutch basket fingers where the frictions engage it. The engagement surface should be smooth so any dents need to be filed down. The dents can cause the frictions to stick.
The springs being short is a definite problem. They can be shimmed by adding a spacer under the release bearing or under the spring at the inner hub, be careful of clearances.
I've been using the EBC CSK15 springs for years and never had a length problem. Another good source is KG Clutch Factory part number KGS-019 sold by Parts Unlimited and Tucker Rocky. Even the Vesrah springs have been in spec. SK-110
Looks like Tucker Rocky has been sold to Turn14 in Pennsylvania and not accepting orders at this time.
Click to expand...
Okay I think I'm going to try filing down the fingers, like you say, and also try a few spark plug washers, like Ancientdad suggested. I also heard of using a medium grit sandpaper to scuff up the steels so might try that. Then I'll double check everything and if it STILL doesn't work I will take it in.

The grooves thing (and the springs) seems to make the most sense to me because it still feels slow to engage after releasing the clutch, as though the springs aren't doing their job and/or the frictions are getting hung up.
 
SeanDubh said:
Yes, I should clarify and say one per spring. Does it matter which side of the spring, bike side or outer?
Click to expand...
It's far easier to put the plug washer on the post first, under the spring. It would be nearly impossible to keep the large inner diameter plug washer in position to go over the post if you put it on top of the spring, since the flat washer on the bolt doesn't contact the end of the post (with the proper diameter for the plug washer) until the bolt is tight and you'd have to keep the washer centered until the bolt was tight to be sure it went over the end of the post.
 
I had clutch slip on my 450 nighthawk that only showed up in 4/5 gear and when I would try and hit the gas hard. Otherwise it performed ok.

Curious, I didn't see it mentioned, but when you redid your clutch previously did you make sure to put the clutch plates in correct order? I think one is thinner than the rest and needs to be farthest out from the engine... maybe that's the issue and it just took time to surface?
 
Okay so this is interesting. I tried the sparkplug washer trick and it actually made the problem worse so now the clutch doesn't engage at all when I let it out.

Thoughts?
 
Okay I'm back.

Today was going to be my final attempt before throwing in the towel. I took the shim washers out and pulled the basket one last time to inspect everything. I decided to file down the basket fingers, scuff up the steels and just double check everything to make sure something wasn't missing or in the wrong order.

SUCCESS!! The clutch is grabbing so well now. I almost feel like I have to relearn to ride this bike because it's so much more feisty. I really think it had a lot to do with filing down the fingers. It didn't look that bad initially but when I looked closer there were some pretty deep ruts.

Now, there are probably going to be some things I'll need to adjust (throttle free play) to accommodate how sensitive the clutch has become. One new thing has arisen and it is has become pretty difficult to put it in neutral, where as that used to be no problem. Could this be a freeplay adjustment??
 
SeanDubh said:
SUCCESS!! The clutch is grabbing so well now. I almost feel like I have to relearn to ride this bike because it's so much more feisty. I really think it had a lot to do with filing down the fingers. It didn't look that bad initially but when I looked closer there were some pretty deep ruts.
Click to expand...
Glad you got it figured out.
SeanDubh said:
Now, there are probably going to be some things I'll need to adjust (throttle free play) to accommodate how sensitive the clutch has become. One new thing has arisen and it is has become pretty difficult to put it in neutral, where as that used to be no problem. Could this be a freeplay adjustment??
Click to expand...
Yes, if you have too much free movement at the lever the clutch will not disengage enough.
 
What are the chances that this is only a temporary solution and that these grooves will reappear before too long? Is it worth trying to find a replacement in better condition?
 
SeanDubh said:
What are the chances that this is only a temporary solution and that these grooves will reappear before too long? Is it worth trying to find a replacement in better condition?
Click to expand...
I'd suspect it took a long time for those grooves to build up to the point where they were a problem, so it's likely you won't encounter that again for quite a while. Keep in mind that many of these bikes were very poorly maintained over the decades and lots of areas weren't attended to, very possibly since the bike was new.
 
Eventually the notches will reappear, probably looking at 20K miles or more. Even if you replaced with new they will appear just as fast.
Hard finding neutral is a clutch adjustment issue. I set the clutch lever freeplay at @2mm and then adjust the bar lever to suit my taste.
 
You must log in or register to reply here.
Back
Top Bottom