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XT 600 1989 sticky throttle with new cable

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Morning!

I purchased a 1989 XT 600 at the beginning of the summer and I have been reading here and learning about these bikes.

It goes quite well (except for the few times it wouldn't start... kick start isn't the easiest on cold mornings) but the throttle doesn't snap back all the way all the time.

If I go to full throttle and let it go it will likely go back to idle but if I am part throttle it will just return slowly partway...

I have lubed the cables, that didn't help.  I installed new ones last night, still no better...

I am wondering if the routing is supposed to remain on the right hand side of the frame or go left, manuals seem conflicting.  Any tips?

Thanks!IMG_9520.JPG.39aaad9c0139b3b0a63ed5cb8e2b18d8.JPG

David

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Hi, sorry I took a while... long days at work. The cables run through the right hand side hole behind the tach, through the steering and in the cable clip on the right side of the frame. It then goes under the tank, through the engine mounting triangle bracket and to the carb. IMG_0105.JPG

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Cable clipIMG_0108.JPG

CarbIMG_0107.JPG

It is also now really hard to start... I suppose it’s time for a tune up...

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I’m thinking it may be caused by the steering riser. Maybe the cable gets a bit tight. I’ll remove the riser and see

 

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I had the tank off and forgot to take pictures...but I took these:

I'm not sure that mine routing is correct but it's not binding or making changes in the rpm with the bars in either direction.

The bad looking arrows are just pointing out things that the cables are behind.

Let me know if you want another view or picture.

 

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20200103_145508s.jpg

20200103_145525s.jpg

20200103_145546s.jpg

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Looks about right. Its all about keeping kinks to a minimum.

Have you verified that its the cables, and not the carb itself? You could try to disconnect the cables from the carbs, and see if you have a smooth action. This will also let you actuate the carbs without the cables attached.

 

Make sure everything is assembled right at the grips, and without burs ect on the throttle tube, handlebar ect.

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Possibilities:

Is there a little bit of throttle cable free play once it's all put back together? In other words, can you rotate the throttle grip a few millimeters before the cable starts to open the throttle? No free play can cause this.

Is the plastic part the cables attach to (the grip is glued to it, too), known as the throttle tube, in good condition, without cracks or damage? Is the end broken, allowing the grip to rub against the handlebar?

If the switch assembly/throttle housing is clamped to the handlebar too far to the left, it will result in the right side of the throttle tube/grip rubbing against the end of the handlebar. You should be able to slide the throttle tube/grip left-to-right a millimeter or two easily.

When the bike was new, there was a thin piece of plastic or nylon-type material that was positioned on the throttle tube, slid onto the throttle tube before the grip was installed onto the throttle tube. It looked like a plastic washer with a large outside diameter, and the parts catalogue for your XT600W calls it "ring". This would keep the big flange of the rubber grip from rubbing against the metal switch/throttle housing, causing drag.

Is the contact area of throttle tube/handlebar clean and without friction-causing spooge under there? On my bikes, I clean the inside of the throttle tube spotless, clean the handlebar surface spotless, and apply a thin coat of thin lubricant like the product called Pro Honda White Lithium Grease which comes in a handy aerosol can (they actually recommend this product for this very purpose in their Service Manuals and Setup instructions, so it's not just me recommending this stuff). Do not use chain lube or anything that gets thick and gooey. It doesn't take much of it to do the job, and don't put any lubricant where the switch/throttle housing contacts the handlebar.

All-in-all, there has to be no source of drag or friction at the throttle grip.

Also, please keep us posted once you find the problem and correct it. Giving advice and never reading the outcome is a drag, metaphorically speaking, just as the drag on your throttle grip is not good for you or your bike. This happens waaaaaaay too often, and I like to learn from these experiences, too.

Edited by YZEtc

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The best thing to lube the throttle tube with is that spray silicone lubricant that dries. Once dry, it's slick and wont gum up anything. I had a customer bring me his bike that he'd lube the throttle tube with Maxima Chain wax...Not good.

Also, check that little divider in the throttle housing itself. If its not just so, it'll hang on the cables. It can be a pain to get right if you've never done it before.

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Thanks guys!!  I noticed one difference in my routing, mine is going outside the triangular top engine mount pieces so that may cause additional drag. 
i have a bit of play in the throttle but I will try to give it a little bit more once I adjust the routing. I have cleaned up the grip surface and used thin lube on there and my plastic ring (washer) is still in place. Hopefully I get this right soon :)  not that it’s riding season up here but there will be nice days and I’ll want to take the bike out!!

I’ll report back!  
other thing I must do is respoke my back wheel. 

5804BD5B-5F83-46F5-83E5-8748E6CC7DBB.jpeg

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I think I may have found the culprit!

The secondary throttle lever is the only one attached to the carb throttle return spring and the primary throttle lever has an adjuster.  The manual says it must be touching and mine is not...  I'll readjust the carb as per the manual and check again!  Hopefully that is it!

Thanks for the help, I'll let you know once I have done the adjustment!  For now I have to un-cease my rear shock adjuster so I can lower it a bit but it appears to be proper stuck, maybe the PO tried to adjust the preload too high and drove the big nut out of the thread and it cross-threaded itself.

David

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well that wasn't it...  the secondary lever actually comes back regardless if it is adjusted properly.  Oh well.

I think maybe I have a bit too much resistance in my primary barrel actuator so I will be taking that apart and maybe using a polish to clean it up.

Also, when I did the carb synchronizing as per the manual (set so the secondary actuator just touches with 5mm opening on the primary), then at full throttle the secondary butterfly is past the horizontal position and the manual says it has to be horizontal,  Which is the most important?  Touch at 5mm opening or horizontal at FOT?
 

Thanks for the help again!

David

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Finally found it!  I was looking at pictures online of the carbs in case I missed something. After making sure that the linkage was fee and there was no binding it was still as if the throttle return spring was too loose... 

So looking at a picture I noticed the return spring was hooked to the other bolt post giving it pre-tension!!  Mine was attached to the back bolt post where it goes easily when reassembling but means the spring is more « relaxed » at idle and barely applying return torque!  
here is a picture of where it was hooked before!

727246FF-2368-427D-B25F-9A31F17C81CE.jpeg

And here is where it is hooked now giving it some pre-tension and therefore applying more return torque!  
 

C96BFC0D-86B9-4608-8F58-B5797C65025A.jpeg

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Thank you all for the help!  And taking pictures and all for me!  Now I have confidence my cables are routed the right way and problem solved!  (this problem anyway)🙂

 

Now maybe I can pass safety and go riding safely

Edited by Roby466

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