I tore into my vm carbs...

[chuck hahn]

Take all the plugs out so your not fighting all the compression from the other cylinders too. Start at number 4 ..so youre on the same side as the crank nut...and look down the plug hole with a flashlight and just roll the crank over with youre wrench and get a feel or whats happening in there and youll figure it out pretty fast...you seem like a sharp guy. and always turn the engine clockwise at the crank.

[slyone]

Yea I read up a little on this around here, sounds easy enough/makes sense. I guess the worst is getting the shims quickly and then of course cleaning all this crap and gettin it ready for reinstallLOL! Well it was good talkin to ya Chuck and Thanks for the info..I'm gonna hit the hay so I can get crackin tomorrow

[chuck hahn]

Figure outn hwat ones you need and what bucket they gom in and then PM Ghostgs1 ( Ray ) at the shim club. He will send you what you need...you swap them out and send him back your used ones..and NEVER EVER turn that crank without a shim in all the buckets!!!!!!

[slyone]

plan on getting next up shim for those 3 correct?[/COLOR]

I just thought about this, I believe I'll need to get "next down..or a smaller/thinner shim" won't I ?

[chuck hahn]

If say...the clearance is at .08 MM, which is at the very highest limit, then youll need a shim thats .03MM THICKER than whats in that bucket. so...lets say that shim ( with a caliper ) measures 2.70. So you need another .03MM to get the clearance to the nominal .05. Thus that bucket will require a 2.73 MM shim. Follow the math?

EDIT...And yess youll need a thinner guage than that .05 so you can get a read as to what the real gap is. if you dont know a real starting gap you cant do the math to find out what the tighter valves actually need..make sense??

[btbarb]

Hey Slyone, not sure if you're searched/read any other posts yet about the .03-.08mm clearance range, but the high side of the range is perfectly fine, some even go to .10 mm.

Last year I targeted the middle of the range, this year I targeted .08-10mm to see the difference, little more noise but spins easier.

[exdirtbiker]

Back to the carbs....
If you have the rubber coated fuel tubes, make sure they are really snug when they go in !
Or you'll do what I did Wednesday.. spent all day rebuilding and re-installing, just to find out the fuel "T" has gotten a little loose, and leaks like a pig. So now they have to come back out of the bike ..... again !!!
AND wait 4 days for parts from Z1. $#*& !!!!!!!

[twotimeGSr]

SLYONE: I just went through this on my 79 850. A couple of notes..

Valves: You can rotate your crank with your kick starter... no need to wrench..


Carbs: My fuel rails/tees were the same sleeved ones as yours.. I put them back in and they fit snugly.. but they always leaked a bit after that. I purchased the new ones with o-rings... no sleeves. The o-rings that came with them had two that were too snug... maybe the channel was cut a bit shallow or maybe the oring was too fat... either way they would not go in... but the o-rings "F" from the kit were a bit smaller/thinner and they worked fine... So don't pitch the "F's" just yet...

tp

[exdirtbiker]

Thanks TP !!! Just pulled my "F"s back from the garbage can !

[chuck hahn]

BTBARB...the bigger the gap..as you suggest .10 is OK..will also make the valves open that small amount less and for a shorter duration in relation to the intake and exhaust strokes..thus mening deminished performance actually. Secondly, they need to be adjutsed at the optimal .05 so that the buckets arent getting beaten against the tops of the valve stems so violently..all these factors, and probably others, need to be taken in to consideration. Now will it run with a .10 gap?? Yes, but the engine is in no way tuned to its optimum potential at that range. If its clattering then it is wrong...now way around that fact.

[chuck hahn]

And a lttle oil or Vaseline on the "F" orings will help them slide into the fuel ports much easier..I would go with the tightest ones i can get away with if it was my carbs.

[twotimeGSr]

And a lttle oil or Vaseline on the "F" orings will help them slide into the fuel ports much easier..I would go with the tightest ones i can get away with if it was my carbs.

I totally agree... The tighter, the better... but it still has to go in the hole to work. I had mine lightly lubed and most went in snug and well... but a couple just would not go in.. they just deformed and rolled out... believe me, it wasn't meant to be. And the ones in the o-ring kit were still tight... and the kit is highly recommended as high quality material for this exact purpose, so I don't anticipate any issues swaping if needed.

[chuck hahn]

The bodies arent machined real smoothly as you can tell. Maybe a burr or divet in the hole. Roll up some fine ( 800 or so ) emory paper and polish the holes a bit to smooth the casting out...then retry.

[Steve]

Just take out the plugs and youll be able to see the valves..just position the doubled over zip tie between the valve and the valve seat then turn the crank from the BIG nut on the crank under the points cover. This traps the valve open and relieves the bucket so you can get to the shim. Have some tweezers or hemostats handy to help fish the shims out.

This might help you vizualize the process.


.

[chuck hahn]

Thing i was thinking when I was doing the zip tie method is this::: Why double over the tie and do all that engineering to it...why not just make one bend about 1/2 inch up from the buckle and use that.