87’ should the throttle snap closed?

[Pasta Burner]

I feel like the throttle never “snapped” closed since I bought the bike last year.  But it did throttle down when rolled forward.  Through my tinkering and reading it seems there are four throttle cables.  What’s the easiest way to get at them and lube them?  They might need replacing but I’d like to try cleaning first.  It seems clear the left fairing needs to come off but where is the cruise housing located?  I think that’s where cables one and two turn into three and four.

 

also any tips on installing E clips to the carb linkage?  I bought a variety set from harbor freight but can’t get my fingers or tweezers in there without dropping or flying the clip.

[luvmy40]

I haven't had to do any carb work on my '86, but its' pretty tight in there. Maybe try a long locking hemostat? I haven't messed with the cables at all either, so I'm afraid I'm no help there.

Edited September 25, 2021 by luvmy40

[saddlebum]

If the throttle cable snaps shut on its own I would leave it. That's a good thing, means everything is free. most times if a throttle only rolls back because you rolled it back, the problem lies in rust build up on the handle bar which causes the plastic sleeve to bind, on the handlebar. Removing the entire throttle assembly including the white sleeve from the handle bar, cleaning away all the rust. after all the rust is gone paint he handle bar with a good quality rust proofing paint but not too thick the sleeve needs to move freely on the handle bar. When dry lubricate with a good light rust proofing lubricant like fluid film, then reassemble

 One trick to lube the cables is to fill a small plastic bag with oil stick the free end of the cable ( whichever end you can get at with the least amount of work ) into the bag with the outer sheath just past the opening. tie a string tightly around the bag and sheath using  a sack or millers knot (this is one time string is better than a zip tie) than hang it so oil can trickle from the bag down into the cable Leave over night or longer.

The throttle cable divider is on the left side it is a flat foot ball shaped plastic box with 2 cables from the throttle, 2 cables to the carb and one cable from the cruise control diaphragm and it sits behind the upper fairing about 3-4 inches back of the upper corner of the rad. you will have to remove the entire upper fairing to get at it. Unless there is a real issue with it which is rare its not worth al the work to get at it. If I remember there is a a white multi grooved wheel where the cables attache too.  This allows either the throttle cable or the cruise cable to  operate the carb cable by way of the shared plastic wheel inside the box. Odds of anything inside that box going wrong is very slim.

Edited September 25, 2021 by saddlebum

[saddlebum]

10 hours ago, Pasta Burner said:

also any tips on installing E clips to the carb linkage?  I bought a variety set from harbor freight but can’t get my fingers or tweezers in there without dropping or flying the clip.

The easiest way that I know of,  is to start the clips in the groove than with a good pair of needle nose pliers carefully  place one jaw tip against the shaft  and the other jaw tip against the back  of the clip at the center and carefully squeeze. Sometimes it may require bent needle nose. Come straight in from the end of the shaft not the side unless you have no other choice,

[Pasta Burner]

2 hours ago, saddlebum said:

The easiest way that I know of,  is to start the clips in the groove than with a good pair of needle nose pliers carefully  place one jaw tip against the shaft  and the other jaw tip against the back  of the clip at the center and carefully squeeze. Sometimes it may require bent needle nose. Come straight in from the end of the shaft not the side unless you have no other choice,

I’m going to go buy a new tweezer set to try and get in there. I’ve installed thousands of clips on electrical connectors throughout my career, but there seems to just be no easy access to get at the linkage.

 

go figure it’s the best riding weather of the year and I’m stuck in the garage.

Edited September 25, 2021 by Pasta Burner

[saddlebum]

On 9/25/2021 at 12:00 PM, Pasta Burner said:

I’m going to go buy a new tweezer set to try and get in there. I’ve installed thousands of clips on electrical connectors throughout my career, but there seems to just be no easy access to get at the linkage.

 

go figure it’s the best riding weather of the year and I’m stuck in the garage.

My luck with tweezers has not been the best when ever I think tweezers would be great they usually end up flipping whatever I am holding further away than if I just tried with my fingers.

Edited September 27, 2021 by saddlebum

[Pasta Burner]

Ok so no luck getting the E clips in place so alligator clips it is for the mean time.  
 

good news soaking the cables overnight and grinding out a little more of the switch housing has the throttle snapping closed like it should.

fluid film is becoming my new best friend too  

The idle is still slow to calm down I’m not sure what is causing that,  the cables and linkage react immediately.

yet to test ride, probably to work tomorrow.

[larrydr]

I like my throttle so that when or if I let go of the throttle twist grip to close instantly ....It is best to maintain the throttle linkage and cables and if there is any question as to condition of the cables replace them  ...Out here in Manitoba we call that a dead mans throttle when it does not work as it should ..I bought a used bike that had a tumble when cruise control would not release , that is one reason I do not use a cruise control ...There times when you are out on the road when split seconds count ....

[luvmy40]

18 minutes ago, Pasta Burner said:

Ok so no luck getting the E clips in place so alligator clips it is for the mean time.  
 

good news soaking the cables overnight and grinding out a little more of the switch housing has the throttle snapping closed like it should.

fluid film is becoming my new best friend too  

The idle is still slow to calm down I’m not sure what is causing that,  the cables and linkage react immediately.

yet to test ride, probably to work tomorrow.

A hanging throttle is most likely a synchronization issue. I suppose it could also be a bad coast diaphragm, but I have no first hand experience with that particular problem.

[saddlebum]

12 hours ago, luvmy40 said:

A hanging throttle is most likely a synchronization issue. I suppose it could also be a bad coast diaphragm, but I have no first hand experience with that particular problem.

Also a vacuum leak between the bottom of the carb and the head can sometimes cause a slow return idle.

[Pasta Burner]

On 9/26/2021 at 6:50 PM, luvmy40 said:

A hanging throttle is most likely a synchronization issue. I suppose it could also be a bad coast diaphragm, but I have no first hand experience with that particular problem.

Coast diaphragm?

11 hours ago, saddlebum said:

Also a vacuum leak between the bottom of the carb and the head can sometimes cause a slow return idle.

I know for a fact there is a vacuum leak between the lower carb boot and head.  Would that also cause the high rpm?  Today’s test ride after work proved that warming up it was fine, then it reved about 2500 3 k between shifts and at a stop.  Once at a stop three to four flicks of the throttle caused it to drop back to 1k

[luvmy40]

1 hour ago, Pasta Burner said:

Coast diaphragm?

...

https://www.partzilla.com/product/yamaha/3LD-1490H-00-00?ref=82769654b20450c9f29fa9ce0c0e1ec6f5f4c930

https://www.partzilla.com/catalog/yamaha/motorcycle/1987/xvz13t/carburetor Assy(Part)#13

[Pasta Burner]

1 hour ago, luvmy40 said:

https://www.partzilla.com/product/yamaha/3LD-1490H-00-00?ref=82769654b20450c9f29fa9ce0c0e1ec6f5f4c930

https://www.partzilla.com/catalog/yamaha/motorcycle/1987/xvz13t/carburetor Assy(Part)#13

Looks like something I’ll have to pull the carb bank to do.

[saddlebum]

18 hours ago, Pasta Burner said:

Coast diaphragm?

I know for a fact there is a vacuum leak between the lower carb boot and head.  Would that also cause the high rpm?

It can, Back in 76 I had it happen to me coming of the highway I went around the ramp so fast I thought my knees were going to scrape. To this day I still do not know how it was I did not wipe out specially since the bike had trials tires on it. That was with my 1975 Canam 250 TNT. The carb mounting boot had a split in it.

[Pasta Burner]

4 hours ago, saddlebum said:

It can, Back in 76 I had it happen to me coming of the highway I went around the ramp so fast I thought my knees were going to scrape. To this day I still do not know how it was I did not wipe out specially since the bike had trials tires on it. That was with my 1975 Canam 250 TNT. The carb mounting boot had a split in it.

Well Jeez!  Glad you made it through that.  I’ve just been dependent to feathering the clutch.  Too much time messing with this lately has the wife pointing out the house list getting behind.  
My thought process is if it has the capability of idling correct and the high RPM is intermittent there must be a bind in the cable somewhere.  There is no room for adjustment at the grip, so I’m gonna work from the carb up.

[RDawson]

When troubleshooting always start by fixing any known problems first. Quite often two mild symptoms can combine to throw your thinking way off. 

[Pasta Burner]

34 minutes ago, RDawson said:

When troubleshooting always start by fixing any known problems first. Quite often two mild symptoms can combine to throw your thinking way off. 

Yes, I concur.  My hesitation at addressing the known vacuum leak is that it hasn’t been an issue before and I need to pull the carb bank to do it.  However I’m not riding anyway till I get this identified and fixed.

so new question…if I’m going to pull the carbs to inspect/replace the gaskets and inspect the coast diaphragm.  What else should I be looking at, replacing, inspecting, while I’m at it?

[saddlebum]

With all the issues you have been having and considering the PITA it is to R&I the carb I would do a complete tear down and total overhaul. At this point there is no point in picking away at it and constantly retracing your steps. In the end you will be glad you did.

Edited September 29, 2021 by saddlebum

[Pasta Burner]

Thanks all for the advice and to @saddlebum and @RDawson for pushing me to remove the carbs.  Honestly only took about 20min to get the carb bank out including the learning curve, not difficult at all like I’ve read about.

one boot had a half gasket and I’m pretty sure none of the gaskets are correct.  Got the OEM on order from my dealer coming in next week.

got all but one e-clip installed in place of the alligator clips.  
 

new slides and diaphragm should be here midweek too.  
 

might get lucky to have it back together for next weekend ride.

 

[Pasta Burner]

Oh!  I forgot to mention / ask…is it normal to have oil coming out of the lower boot holes?…front left and rear right?  First pic above where I reinstalled screws to stop the oil.

[saddlebum]

Not normally

[saddlebum]

You might want to check and see if your oil level is not too high. the air cleaner is dirty or the crankcase breather tube is not plugged (this is the small hose goes from the engine to the bottom of the air cleaner housing. Hopefully it is not a sign of bad oil control rings on the pistons.

[Pasta Burner]

On 10/3/2021 at 10:24 PM, saddlebum said:

You might want to check and see if your oil level is not too high. the air cleaner is dirty or the crankcase breather tube is not plugged (this is the small hose goes from the engine to the bottom of the air cleaner housing. Hopefully it is not a sign of bad oil control rings on the pistons.

Oil level was too high causing a leak out the breather, it’s now borderline too low getting an intermittent warning on the dash.  I know I hook up that hose but haven’t checked to make sure nothing got in there, will do that.  I did notice looking through the parts fiche that those two bolts are a different part number from the rest…not sure why yet though.

[saddlebum]

Length and thread pitch would be the main concerns. Too long could bottom out in a blind hole, too short can tear threads. Also make sure there is no oil or other fluid in blind holes. The hydraulic pressure of tightening a bolt can crack even cast iron blocks.

[Pasta Burner]

14 hours ago, saddlebum said:

Length and thread pitch would be the main concerns. Too long could bottom out in a blind hole, too short can tear threads. Also make sure there is no oil or other fluid in blind holes. The hydraulic pressure of tightening a bolt can crack even cast iron blocks.

Stopped by the dealer today to compare the screws I took out against what is listed in the parts fiche.  The difference in screws is length.  20mm for six and 16mm for the front left and rear right.  All mine were 20mm so my guess is the driving force of the longer screws wrongly installed, punctured into oil flow cavities.  It is what it is at this point.