Decompression Cable Installation?

[Thatslyb]

Wondering if anyone has any sort of guide or info on installing a decompression cable? I have an XT350 and it doesnt talk about how to actually put one on. I know where it connects at the front and by the kickstarter but dont know how it should be run or what it actually connects to lol

[swhite836]

I havent got my xt any more but it was an automatic decompression on mine

[Thatslyb]

You mean it had no cable? this bike definately had a decompression cable.. it was just taken off since it was broken. i think up to 92 they had them atleast I believe there was no major change during that time period

[Qqqqqqqqqqqq]

Yeah .. to fit a decomp cable you need to check the valve clearances first . Make sure the valves are in spec , connect the cable and adjust the cable / decomp as per the manual . Or ... If you have the valve cover removed , adjust the decomp / cable so it barely opens the exhaust valve at TDC .

[jjktmrider]

The cable goes down to in front of the kicker shaft , there should be a spot that the cable slips into and the inner cable lead knob fits on a short lever that moves as the kicker is pushed down , it's about 2 inches forward of the kicker shaft . You adjusted the cable length via the coupler till there is 1/16" (2mm approx.) of movement before the decomp "cam" in the head starts to move. Fairly easy setup .

 

I know the Warrior had an auto comp setup , don't know what system used , so the e-start's shouldn't need the cable setup.

 

 

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Edited May 12, 2017 by jjktmrider

[William1]

Just pulled out the XT manual, 2~3mm play at the point where the cable is in the head, measured at the swage of the cable.

[Thatslyb]

12 hours ago, NEKOOHC said:

Yeah .. to fit a decomp cable you need to check the valve clearances first . Make sure the valves are in spec , connect the cable and adjust the cable / decomp as per the manual . Or ... If you have the valve cover removed , adjust the decomp / cable so it barely opens the exhaust valve at TDC .

So I have to remove the cover? I see the spot where the cable threads in, if I remove the cover there is it easy to find where it actually connects to inside? Im not very mechanical

[Thatslyb]

4 hours ago, William1 said:

Just pulled out the XT manual, 2~3mm play at the point where the cable is in the head, measured at the swage of the cable.

Yeah I see that in my clymer manual. Im more caught up on how the cable actually runs on the other side. I know it threads into the top of the valves, but dont know where the cable actually goes inside

[William1]

The cable at the head rotates a shaft that presses down on one of the exhaust valve buckets, holding it open, this reduces compression, which permit the engine to gain some momentum before the actuator snaps closed, full compression occurs and the engine fires. On the kick start side, it is a ratchet mechanism that pulls the cable, holds it about 75% of the stroke of the kick movement then releases the cable.

Part 25 is the cable, 20 is the shaft that it attaches to.

[Thatslyb]

55 minutes ago, William1 said:

The cable at the head rotates a shaft that presses down on one of the exhaust valve buckets, holding it open, this reduces compression, which permit the engine to gain some momentum before the actuator snaps closed, full compression occurs and the engine fires. On the kick start side, it is a ratchet mechanism that pulls the cable, holds it about 75% of the stroke of the kick movement then releases the cable.

Part 25 is the cable, 20 is the shaft that it attaches to.

Thank you for the help. that would be the shaft thats down by the kick lever, right? Im actually confused as to where the other end of the cable attaches to (the top part in the diagram). 

[William1]

9 hours ago, Thatslyb said:

Thank you for the help. that would be the shaft thats down by the kick lever, right? Im actually confused as to where the other end of the cable attaches to (the top part in the diagram). 

The cable end attaches to part #30 in the below. Just above the kick start.

Look at part #1, that lumpy square part is inside the cases, it is a sort of cam that acts on part #27. Look at the on line parts books.

[jjktmrider]

The cable doesn't go inside the case at all , there is the shaft that comes out of the case in front of the kicker shaft #27 in Williams schematic , the cable end hooks on to that outside of the case . There is an upside down T shaped metal bracket that holds the outer cable in place  and the inner cable comes out to hook to that #27 shaft .

 

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[Thatslyb]

On 5/13/2017 at 3:42 PM, jjktmrider said:

The cable doesn't go inside the case at all , there is the shaft that comes out of the case in front of the kicker shaft #27 in Williams schematic , the cable end hooks on to that outside of the case . There is an upside down T shaped metal bracket that holds the outer cable in place  and the inner cable comes out to hook to that #27 shaft .

 

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Edit: I made another reply after this one with pictures. I think I found both attachment points for cable ends but not where cable housing attaches. Also raised tqo more questions: What is the open hole for near the attachment arm? And what is the piece that is leaking oil on the top in the final pic?

 

Im sorry Im not sure why Im not getting this. I know about the lever it connects to  right by the kickstarter , but where does the other end of the cable go? When I got the bike the decomp cable was broken. The remnants of a cable was coming out of a threaded hole in the front top part of the engine (behind the front tire). The mechanic got rid of that and now there is just an empty hole there. maybe I should take a picture.

 

What I understand so far is the bottom of the cable connects to the little lever by the kickshaft that moves slightly when the kickstarter is pressed. Where the other end connects to though is where I seem to be incapable of understanding lol. does the cable not run up and over to the forward part of the engine? maybe theres a part missing for it.

 

 

I appreciate everyones help and patience I dont know why I am not getting it. Maybe I am wrong about the area I thought it connects or maybe something is missing

Edited May 16, 2017 by Thatslyb

[Thatslyb]

Edit: I made an edit but it disappeared so Im going to add it again and hope it doesnt mess it all up.

 

Ok I went ahead and took some pictures. Sorry for the dirt the bike needs a wash. And the oil spots which is just from spraying lithium on some stuff yesterday. I think I now see what you are talking about. When looking at it though it raised a couple different questions, and one unrelated one. Numver one being that I dont see anywhere for the cable housing to attach to. Tell me if these two pieces are correct in pic 1 and 2. If so, what is the threaded hole for in pic 3 near the arm? And lastly I noticed the piece on the very top of the black section appears to be leaking. What is that part and why would it be leaking?

Edited May 16, 2017 by Thatslyb
Adding stuff

[Thatslyb]

Looking at a picture in the Clymer manual, it appears the "decompression cable mounting bracket" is missing by the kickstarter. Is that correct? that is unfortunate as I dont see any on ebay besides one that is gone that was sold with the cable.

[jjktmrider]

Yep the bracket is gone that holds the cable end , both ends need them .

#18 in the cylinder head schematic  http://www.partzilla.com/parts/search/Yamaha/Motorcycle/1989/XT350W/CYLINDER+HEAD/parts.html

#14 in the crankcase cover schematic  http://www.partzilla.com/parts/search/Yamaha/Motorcycle/1989/XT350W/CRANKCASE+COVER/parts.html

you may need to wait and watch ebay for them to come up unfortunately since they're not available new .

 

Here's the head bracket , http://www.ebay.com/itm/86-YAMAHA-TT350-TT-350-S-OEM-DECOMP-DECOMPRESSION-BRACKET-HOLDER-GUIDE-C-/131442865886?hash=item1e9a9af6de:g:W78AAOSwqu9U5kIn&vxp=mtr

and the one for the crankcase , though a bit ridiculously priced , http://www.ebay.com/itm/86-87-YAMAHA-TT350-TT-350-OEM-DECOMPRESSION-CABLE-BRACKET-AND-LEVER-ACTUATOR-/382078073141?hash=item58f5a0b935:g:nJIAAOSwONBZEzXj&vxp=mtr

This ones a little cheaper , but verify that it the correct one  http://www.ebay.com/itm/81-YAMAHA-XT250-XT-250-H-OEM-DECOMPRESSION-DECOMP-CABLE-GUIDE-HOLDER-BRACKET-B-/131484548192?hash=item1e9d16fc60:g:oPYAAOSwstxVJW5U&vxp=mtr

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Edited May 16, 2017 by jjktmrider

[Thatslyb]

12 hours ago, jjktmrider said:

Yep the bracket is gone that holds the cable end , both ends need them .

#18 in the cylinder head schematic  http://www.partzilla.com/parts/search/Yamaha/Motorcycle/1989/XT350W/CYLINDER+HEAD/parts.html

#14 in the crankcase cover schematic  http://www.partzilla.com/parts/search/Yamaha/Motorcycle/1989/XT350W/CRANKCASE+COVER/parts.html

you may need to wait and watch ebay for them to come up unfortunately since they're not available new .

 

Here's the head bracket , http://www.ebay.com/itm/86-YAMAHA-TT350-TT-350-S-OEM-DECOMP-DECOMPRESSION-BRACKET-HOLDER-GUIDE-C-/131442865886?hash=item1e9a9af6de:g:W78AAOSwqu9U5kIn&vxp=mtr

and the one for the crankcase , though a bit ridiculously priced , http://www.ebay.com/itm/86-87-YAMAHA-TT350-TT-350-OEM-DECOMPRESSION-CABLE-BRACKET-AND-LEVER-ACTUATOR-/382078073141?hash=item58f5a0b935:g:nJIAAOSwONBZEzXj&vxp=mtr

This ones a little cheaper , but verify that it the correct one  http://www.ebay.com/itm/81-YAMAHA-XT250-XT-250-H-OEM-DECOMPRESSION-DECOMP-CABLE-GUIDE-HOLDER-BRACKET-B-/131484548192?hash=item1e9d16fc60:g:oPYAAOSwstxVJW5U&vxp=mtr

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Thank you for the help. I must be using ebay wrong cause I found nothing when I looked lol. This patt is interchangeable between XT350 and TT350? Also Is that what the threaded hole in pic 3 is for? To attach that bracket? Should I cover that hole with tape for the time being? Can dust get into the case through there?

 

Last question, what exactly is the part on the very top in pic 4 that seems to be covered in oil?

Edited May 16, 2017 by Thatslyb

[jjktmrider]

I don't think that hole goes all the way through , there would be oil coming out . Wouldn't hurt to find a 6mm bolt to fill it in  , you'll need one for the bracket anyways . The bolt will be pretty short , 10mm (3/8") long roughly . Many parts are the same between TT's and XT's , they're the same bike except a few spots here and there .  The one bracket is also used on the 250's .

 

 

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[Thatslyb]

3 hours ago, jjktmrider said:

I don't think that hole goes all the way through , there would be oil coming out . Wouldn't hurt to find a 6mm bolt to fill it in  , you'll need one for the bracket anyways . The bolt will be pretty short , 10mm (3/8") long roughly . Many parts are the same between TT's and XT's , they're the same bike except a few spots here and there .  The one bracket is also used on the 250's .

 

 

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Thanks for the help. Could you tell me what the thing is called in thr last picture? There is 4 of them on the very top of the enginr. I think I actually have two of those things leaking oil. Hope its an easy fix. Cant find them mentioned in the manual

[Tooooold]

Members had much patience with this guy  some people want you to help breathe for them!