Busted carb slide...AGAIN



18 replies to this topic
  • Scott

Posted February 23, 2001 - 08:32 PM

#1

I can't believe this!! Looks like I have ANOTHER busted carb slide! It seems like I just replaced the f!*#ing thing. Hell, I bet I've only put a 100 miles on since it was replaced. The first one was just cracked. This one is missing a good size piece of metal from the side! I searched in the archives and read to look in the rubber boot for it. What if the metal piece isn't there? At first I was pissed about having to buy another slide, but I'm really more concerned about where the hell that broken piece is!?! Any suggestions on what to do....

Thanks in advance.


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99WR,WR timing,throttle stop removed,Uni filter,E-Series pipe,carbon air box,Pro Tapers,lights removed,YZ tank,13 tooth sprocket

  • Bruce_in_Phoenix

Posted February 23, 2001 - 09:21 PM

#2

Put your throttle stop back in so it doesn't slam the top of the carb every time you wack the throttle open.

  • JamesD

Posted February 24, 2001 - 07:13 AM

#3

I think all of us that have throttle stops that are too short but haven't experienced problems should take note of this.

The newer models ignitions may not get confused with a short throttle stop but the carb slide may still be taking abuse. Personally, buying a YZ throttle stop as a replacement is a lot more attractive than a top end rebuild.

  • MN_Kevin

Posted February 24, 2001 - 07:17 AM

#4

Unless something changed, the OEM 99 YZ throttle stop is not available from Yamaha. I do not know about Sudco or anywhere else.

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'99 WZ with all YZ mods, FMF PowerBomb header, Stroker SX-1 silencer, SS front brake line, forked over by Pro-Action, OEM YZ tank and IMS seat.

  • Scott

Posted February 24, 2001 - 07:19 AM

#5

YZ throttle stop will be purchased today.

But what should I do as far as the missing piece if I can't find it? Start the bike and hope that it doesn't funk up the engine? Take it to the shop and have the motor torn apart? What kind of devastation can that piece cause if it is floating around? Would it be smarter to have the engine torn apart by a shop to find the piece in hopes that that cost would be less than a new engine?

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99WR,WR timing,throttle stop removed,Uni filter,E-Series pipe,carbon air box,Pro Tapers,lights removed,YZ tank,13 tooth sprocket

  • Rich_in_Orlando

Posted February 24, 2001 - 07:45 AM

#6

Scott,

How big is(are) the missing piece(s)? I'm trying to visualize here where it(they) could have gone. It seems like there are 2 choices: in or out. In, as in into the cylinder, or out, back towards the filter. I suppose you already checked the air boot, so it's got to be in the cylinder or somewhere on the way towards it. I don't know how it could get past your cylinder and into the crankcase.

If we assume it hasn't made it into the crankcase, it shouldn't be too hard to fix it yourself. You don't have to take the engine out to take off the cylinder head. Draining and taking off the radiators takes 10 minutes, then remove the engine brackets off the top, take off the valve cover, then the camshafts and then the head. Maybe a 1-2 hour job at the most. Then take the garbage out and put it back together. You shouldn't have to touch the cylinder itself. If you have a manual, it's easy. I'm not kidding. You'd probably pay $250 or more if you got the work done at a shop. (Don't forget about a new head gasket.)

Good luck, I feel for you. I just got my bike up and running again after a month in the shop while the crankcase assembly was replaced. Now THAT was a job I didn't want to tackle.

Rich

  • Guest_Guest_*

Posted February 24, 2001 - 12:21 PM

#7

How big is the piece?

When did it happen?

Why did you notice it?

The engine didn't make any funny noises during your last ride?

If it went through without damaging anything then you are real lucky.

If you don't want to take off the head, I would at least do a compression check.

If the compression is as good as stock then it really didn't damage anything seriously and I guess I might just ride it (if I had the time and was 'into it' I might take the head off anyway).

It is a scary thought.

  • Scott

Posted February 24, 2001 - 04:41 PM

#8

How big was the broken piece? If you think of the piece as two parts, one being the the inner circle and the other piece being the "frame" of the circle.. The missing piece is teh whole bottom left corner of the outer "frame". Pretty big piece.

I was riding on a motocross track and noticed my throttle was kind of sticking. It felt like my throttle cable had frayed and it was snagging. The engine started revving due to the "stuck" throttle, so I killed it and walked it back to the truck. Other than the revving, there was NO strange engine noise.

When you say, doa compression check, what does that mean. I got the kickstarter to TDC and could not kick it down without using the compression lever if that's what you mean..



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99WR,WR timing,throttle stop removed,Uni filter,E-Series pipe,carbon air box,Pro Tapers,lights removed,YZ tank,13 tooth sprocket

  • Scott

Posted February 24, 2001 - 07:38 PM

#9

OK, things are getting worse instead of better. Forget about the missing piece for a minute and listen to this...

As I'm messing around with my carb I put the "valve assembly" back in the carb. (That's what HLSM calls it - part # 10) http://216.37.204.20...e=13&A=142&B=35

When I try to manually lift it up and down, it barely moves!!! It's like it gets stuck about half way up. NOW WHAT?? It doesn't look damaged in any way, so maybe it's the inside of the carb?...

I'm thinking I'll take it over to the shop and see if they won't put a new assembly in just to see if that's the problem. Pfff, if it is, it's like $230.00 PLUS the valve (carb slide). If it isn't, who knows how much this is gonna cost!

AND CHANCES ARE, I STILL HAVE THAT BUSTED PIECE FLOATING AROUND SOMEWHERE!

AARRRGGGGGG!



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99WR,WR timing,throttle stop removed,Uni filter,E-Series pipe,carbon air box,Pro Tapers,lights removed,YZ tank,13 tooth sprocket

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  • Taffy

Posted February 25, 2001 - 02:48 AM

#10

only you can really tell what's binding.

all these breakages are down to fluttering.

if you get your tickover wrong on the blue monster you can hear the poor slide valve fluttering away like the clappers.

it sounds to me (with my std 'zorst) like whan we used to make popcorn as a kid. you can hear a muffled popping noise.

try changing the idle up or down a coupla hundred revs.

try & buy a new rubber ring to go with the plate if you don't get a new one each time.

try a little plastacine splodged in the back plate. what your trying to do is kill the 'fluttering' that's what is causing the breakages.

Taffy

  • AhamayWR426

Posted February 26, 2001 - 06:14 AM

#11

Scott, I may have had the same problem.
The accel pump adjustment screw seems to have a level that limits the throttle cable pulley from rotating back to closed position. I had to lift the lever up while sliding the valve assembly down. then I had to line the needle up with the hole in the bottom to get the assembly to close completely.

I hope the note above helps.

On a worse note. you could look in your exausht pipe for the broken piece. if you have a spark arrestor in it should not have left the system.

  • Scott

Posted February 26, 2001 - 01:30 PM

#12

UPDATE: After talking to Sudco, I realized that there is a f!@$ing seal that goes in between the vacuum plate (as they call it) and the valve assembly (slide). Geeze, who knew?! :) Certainly would have been nice had I known that. My bad!!



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99WR,WR timing,throttle stop removed,Uni filter,E-Series pipe,carbon air box,Pro Tapers,lights removed,YZ tank,13 tooth sprocket

  • Damian

Posted February 26, 2001 - 09:04 PM

#13

Another thing to be carefull of is to make sure the engine is not backfiring back through the carb (eg running lean and you close the throttle on a long downhill).
First sign I had of a failed slide (my first broken slide-I caught the second as it was just a crack, but this occurred after only 200km)was the revs would not drop back fully as I closed the throttle into a corner. I suppose a piece went miissing that made the bike run lean. When I restarted the bike a minute later, it must have sucked that broken bit into the head as you could hear it bouncing between the piston and valves. Anyway, off with its head and I removed the schrapnel. Luckily no bore damage. But I'm still pissed off that these slides break in the first place.

  • Taffy

Posted February 27, 2001 - 01:11 AM

#14

scott

i don't want to add to your misery but how long had you been looking at that seal in that picture you posted up?

guess i don't get the credit for telling you about it hey!

well let's just say that i've returned your favour at last!!!

Taffy

  • Dougie

Posted February 27, 2001 - 01:30 PM

#15

Scott,

So does that mean the missing rubber ring is your slide problem with the assembly? Do you know if it was missing before the plate cracked or after? I'm assuming this is root of all your problems. If so, it is good info to have.

  • Scott

Posted February 27, 2001 - 02:59 PM

#16

Yup, I think the lack of seal WAS the root of all my problems. Undoubtedly, that caused the excessive vibration resluting in the broken valve.
I know I didn't install it when I replaced the first valve, and thinking back, there was NO seal behind that valve either! Does the bike come stock with the seal? I bought the bike used.

I fixed the assembly last night by simply resting it on its side and pressing down to make sure the wheels were seated properly. I heard a pop which was a wheel being reset into the bearing. It now fits fine! Pheww!

So, I ordered the valve AND seal from Sudco and now "all" I have to worry about is the missing broken piece.

Considering I rode the bike for a while with WOT and I didn't hear any noises, I'm hoping that the piece exited the bike. I think I'm gonna simply start the bike after I replace the valve, listen and cross my fingers. :)

Thanks for the replies fellas!

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99WR,WR timing,throttle stop removed,Uni filter,E-Series pipe,carbon air box,Pro Tapers,lights removed,YZ tank,13 tooth sprocket

  • Ynahg

Posted February 28, 2001 - 06:36 AM

#17

Originally posted by Scott:
Yup, I think the lack of seal WAS the root of all my problems. Undoubtedly, that caused the excessive vibration resluting in the broken valve.
I know I didn't install it when I replaced the first valve, and thinking back, there was NO seal behind that valve either! Does the bike come stock with the seal? I bought the bike used.

I fixed the assembly last night by simply resting it on its side and pressing down to make sure the wheels were seated properly. I heard a pop which was a wheel being reset into the bearing. It now fits fine! Pheww!

So, I ordered the valve AND seal from Sudco and now "all" I have to worry about is the missing broken piece.

Considering I rode the bike for a while with WOT and I didn't hear any noises, I'm hoping that the piece exited the bike. I think I'm gonna simply start the bike after I replace the valve, listen and cross my fingers. :)

Thanks for the replies fellas!



  • Ynahg

Posted February 28, 2001 - 07:00 AM

#18

Originally posted by Scott:
Yup, I think the lack of seal WAS the root of all my problems. Undoubtedly, that caused the excessive vibration resluting in the broken valve.
I know I didn't install it when I replaced the first valve, and thinking back, there was NO seal behind that valve either! Does the bike come stock with the seal? I bought the bike used.

I fixed the assembly last night by simply resting it on its side and pressing down to make sure the wheels were seated properly. I heard a pop which was a wheel being reset into the bearing. It now fits fine! Pheww!

So, I ordered the valve AND seal from Sudco and now "all" I have to worry about is the missing broken piece.

Considering I rode the bike for a while with WOT and I didn't hear any noises, I'm hoping that the piece exited the bike. I think I'm gonna simply start the bike after I replace the valve, listen and cross my fingers. :)

Thanks for the replies fellas!




[This message has been edited by Ynahg (edited 02-28-2001).]

  • Ynahg

Posted February 28, 2001 - 07:04 AM

#19

Scott

Yust want you to know your not the only broken vacuum plate victim.

In Belgium we pay this 190$ !!!!!

Good luck.




 
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