Clutch Issues

[rps1116]

Hi Guys.

I was out riding my 77 XS650 bobber yesterday and all was good until I got about 2 miles from home. I was down shifting and started to notice when I pulled my clutch in no matter what gear I was in the engine was revving really high. I don’t have a tachometer or speedometer so I can’t say where the rpm’s were but even in 5th it revved high with the clutch pulled in. I know there could be a number of reasons for this so before I open anything up I would like to hear from you guys on where I should start. I’m thinking of checking and possibly adjusting the screw on the opposite side to see if that helps. Any thoughts on this and what I need to do will help me a lot. Thanks

Rich

 

[JJames]

Not necessarily a clutch issue. You didn't leave the choke on by chance? Vacuum leak?

 

[rps1116]

Not necessarily a clutch issue. You didn't leave the choke on by chance? Vacuum leak?

No. I turned the choke off right after I started the bike. I have Mikuni VM34's and they're tuned pretty good so in the warmer weather I dont really need to use the choke, However I did use them on my first start of the day normally I would hear the difference whiole idling with them on. The bike was fine most of the day and like I said in my post I noticed it when I was down shifting with the clutch pulled in. I limped home with it in third and even when I went to put it in neutral I pulled the clutch and it started screaming. So i just shut if off in gear and the rolled it up my driveway. I am going to change the oil today in hopes that it will help fix the problem but I'm second guessing my self. I will also pull the clutch cable off to check and see if its frayed or kinked. Its really strange that its happening only when the clutch is pulled in. I will also check and see if I did leave the choke on and see if there is a possible vacuum leak. I appreciate any help you can give JJames thanks my man.

Rich

 

[JJames]

You say that the issue only happens when the clutch is pulled in. It seems to me that pulling the clutch, "disconects" the engine from resistance and lets it rev based on idle speed and mixture adjustments. How much was the bike riden recently and in its current configuration . Tell us more about your bike. Exhaust? Air box? Etc. We love pictures and they will encourage replies from others with more knowledge and experience. Have fun.

 

[gggGary]

I'd be checking throttle cables, maybe a loose cable allowed a ferrule to sit on the edge of it's receiver bucket not allowing the carbs to return to idle. How long you been a motorcyclist?

 

[rps1116]

That actually makes sense. I did change the main jets over the winter to a bigger jet. That could be a possibility. I have not put a lot of miles on it yet this year maybe 75 to 100. I have my air intake screws about 1 1/8 turned out. My idler screw are out to where it would be running rich not lean. I have pandemonium straight pipes and I'm using Uni air filters. Its just weird that it it wasnt doing it at all when I first took it out. I will definitly put smaller main jets in tonight. As for pictures give me a little bit to load them from my phone and I will try to post a video of it after work today. Thanks for heads up on the mixture adjustment Im thinking that the bigger jets might be the problem. I will keep you posted on this. Thanks again man.

Rich

 

[rps1116]

I'd be checking throttle cables, maybe a loose cable allowed a ferrule to sit on the edge of it's receiver bucket not allowing the carbs to return to idle. How long you been a motorcyclist?

Hi gggGary,

You helped me with an issue last year with my brake arm. Ive been riding most of my life with breaks here and there. I checked the throttle cable as soon as I got home and that wasnt the issue. I also checked to make sure the carbs were still in synch to the way I set them and thankfully they were. The throttle itself is snapping back nicely no drag at all. In my reply to JJJames I mentioned that I did put larger main jets in my carbs so I will start there later today and see if that changes anything for the better. I will keep everyone posted on any progress I make. Thanks again

Rich

 

[gggGary]

Confirm both slides are sitting on the idle stop screws?
Was just riffing on calling this a clutch issue??

 

[rps1116]

Here’s a few pics. Not sure if they will do any justice. I have a video I will post of it idling last summer before I changed the jets

 

[rps1116]

Confirm both slides are sitting on the idle stop screws?
Was just riffing on calling this a clutch issue??

Ill do that. I am assuming they are. I have two precision ground stainless rods that i use for bench synching and I put them in yesterday and both moved at the same time when i eased the throttle open. I also checked when I turned the screws in and out to make sure the screws were moving the slides and they were. I will check again though. I have a two into one throttle cable and maybe one side is sticking when im riding who knows. Ill let ya know. Thanks Man

Rich

 

[gggGary]

quick "tell" on idle screws;
if it is on the engine side of the slide it's a fuel flow control screw, out is rich
if it's on the intake side it's an air flow control screw, out is lean.
VM series screws are air screws.

 

[rps1116]

quick "tell" on idle screws;
if it is on the engine side of the slide it's a fuel flow control screw, out is rich
if it's on the intake side it's an air flow control screw, out is lean.
VM series screws are air screws.

Correct the VM is an air intake screw being that is on the intake side and turning it out is lean. I have them approx 1 1/8 turns out. That seems to be the sweet spot on mine.

 

[Wingedwheel]

I would probably fire it up and see what it does in the driveway. Could be anything from an intake boot leaking to sticking advance weights def not caused by the clutch and maybe not the carbs directly.

 

[Jim]

With VM carbs it's easy to swap left and right slides. When that happens they'll do all manner of odd stuff... like revving to the moon, when prior to swapping everything worked great.

Check and see if you swapped 'em when you last had the carbs out.

 

[rps1116]

I would probably fire it up and see what it does in the driveway. Could be anything from an intake boot leaking to sticking advance weights def not caused by the clutch and maybe not the carbs directly.

I'll start it up when I get home. I will try anything at this point to get this fixed.

With VM carbs it's easy to swap left and right slides. When that happens they'll do all manner of odd stuff... like revving to the moon, when prior to swapping everything worked great.

Check and see if you swapped 'em when you last had the carbs out.

 

[rps1116]

With VM carbs it's easy to swap left and right slides. When that happens they'll do all manner of odd stuff... like revving to the moon, when prior to swapping everything worked great.

Check and see if you swapped 'em when you last had the carbs out.

Thanks Jim. I’ll do that. I don’t usually take both off at the same time because of that reason but I definitely doesn’t hurt to check. Thanks man

Rich

 

[gggGary]

My idler screw are out to where it would be running rich not lean

moving the screws out makes it lean.
Turn em in and see if idle slows down?
Like the winger sez air leaks....
What iggynition are you using?

 

[rps1116]

moving the screws out makes it lean.
Turn em in and see if idle slows down?
Like the winger sez air leaks....
What iggynition are you using?

Its the Huges CDI System. It was installed before I bought the bike. I will definitely mess with the Idle and let you know. I have another 2 hours at work and then I'll get home and mess with this . Thank you all so much for all of this help I appreciate it and hope I can return the favors some day. I will keep you posted as soon as I have an answer to this

Rich

 

[rps1116]

I'd be checking throttle cables, maybe a loose cable allowed a ferrule to sit on the edge of it's receiver bucket not allowing the carbs to return to idle. How long you been a motorcyclist?

Hi Gary

So I’m sorry I haven’t responded to this thread in about a week I was a little under the weather but you were right about my clutch cable it popped out of the clip in my tunnel and it was ever so slightly putting pressure on my throttle cable on my left carb. So I pulled it out re lubed it and rerouted it and it’s not revving high when I pull the clutch. I did pop the adjustment screw cover off and adjusted it because it seemed way too loose so now it’s running pretty good. Thanks again Buddy for your advice and thanks to everyone who helped me out with this. I’m sure I’ll be posting another thread soon but in the meantime I’m riding again and hopefully I won’t have any issues.

Rich