1994 vmax 600 oil pump cable free play

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walkert

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Feb 26, 2008
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Age
59
Location
Lyndhurst, Ontario, Canada
I'm trying to solve a sluggish vmax problem. It has been stored for the past 10 years. The sled has only 700km but is running very rich (oil I think).
I've had the carbs apart and cleaned and inspected. I installed new needle and seats in both, set the float level, checked the jet sizes, needle position in the slides, etc. It runs very rich in the mid range and is quite sluggish. I do notice substantial smoke and feel that the pump may be adjusted heavy.
What is the pump cable free play and the throttle cable free play for this sled?
 
Hold the throttle wide open and align the marks on the oil pump lever and housing...........
 
not sure of marks

I'm used to the oldies (80's) sleds and a little unfamiliar with what to look for.
I think I can see a line on the pump lever, but do I line it up with the casting post (front of the casting post?) or is there an actual line on the pump casing near the lever path?
 
The other way to do this is to just measure the free play on the cable. The lines are kind of useless because that is the factory setting for these sleds which is way rich. The free play on the cable should be about 27-29mm.

I have mine set at 30mm and I think my oil usuage is about spot on now.

Throttle cable free play should be about 2mm if I remember correctly.

I still have a very slight bog in the mid-range (30-35mph) when it is 20 degrees and warmer and will try moving the needle to the #1 position to see if that takes care of it, needle is currently set in the #2 spot.
 
For one oil is probably not all your issues here,vm's of that year were pig
rich on jetting,you say you had your carbs apart cleaning and inspecting
what is your jetting spec's?? so we can help you get it to where it needs
to be we need to know,you'll probably need to jet down in mid range.

oh and 1994 vm's don't have line up marks,you need to measure the gap
and that gap is 27 to 29mm, i would start with 29 and go from there..

here's how you adjust it,first you need to do these's other cable free
play adj. before you do oil.

Do these checks in this order;

1st- set idle to 16- 1,650 rpm's(@ operating temp)

2nd- set throttle end play to 2mm(adjustment for that is down at the carb rack)

3rd- set oil pump cable free play here and here to 27(richer)to 29(leaner)mm
 
Thanks for the direction

I'll make the adjustments tonight with the stock jets and see if there is any improvement.
What baffles me is that it must have worked better than this when new; and it still is, basically, new. What happened during that 10 year period of storage that caused it to be this way? Seals are good as well. I've taken it out and run it hard to hopefully clear out the crankcase of any residual oil and it is better, but far from useable. When I back off on it to be considered low speed to mid range, it seems like the choke is partially on(I've checked that too).
It will sit and idle and not quit but is definitley rich.
Who knows what the previous owner may have monkeyed with it prior to storing it. He may have just set the oil up richer, we'll see.
The plugs are still dark after the plug chop test on the lake but I can't rule out fuel as well as oil.

Thanks again, I'll be back with the jetting information tomorrow and go from there.
 
Look at the casting of the pump and you will see a raised area that the lever lines up with when you hold the throttle wide open there is a line in that cast area which it lines up with.

Oil consumption/volume that an engine requires is determined by the factory, adjusting your oil cable to what YOU THINK is OK oil consumption and what YOU THINK is OK by how much it smokes usually is not what the engine thinks is OK. I've replaced alot of cranks over the years that were blued from getting hot from lack of oil and when I give the sled back they always seem to complain their sled smokes more than it used to, that's because it is supposed to.............

Your loading up issue is a carb problem, adjust the oil pump cable correctly and then go after the fuel issues.
 
800,

on the 1994 vmax twins(5-600) there is no alining marks,you measure cable
free play,yamaha didn't start using the pump boss marks till 1995..

if a '94 has them the pump has been replaced...and NOT original.
 
Thanks "800"

I've always been a fan of too much oil than pressing apart the crank or trying to remove scuff marks.
I'll have a look at the whole oil adjustment issue; maybe take some pictures for judgements.
As I remember, the jetting is stock and the carbs are squeeky clean.
It's not as easy taking these down in comparison to the old VM mikuni's (takes a little longer) but I'm getting used to it. Possibly the neddle needs to drop a ring or two, but I'm still pretty leary of potential damage( coming out of high speed circuit to an air-rich midrange can make it squeak pretty quickly.

Thanks.
 
walkert said:
but I'm still pretty leary of potential damage( coming out of high speed circuit to an air-rich midrange can make it squeak pretty quickly.
Click to expand...
NOT if your doing plug checks in each range and keeping an eye on plug color/wash,this is not rocket science,can be accomplished very easily with
some patients..
 
All Mikuni oil pumps have a full stroke mark on them, no matter what make sled it is in. They give you a cable free play setting just to make it easier to do, My 94' has a mark on it, just hard to see. The end of the oil pump stroke and the end of the flipper/carb stroke are supposed to meet together.

The 94' 600's were just terrible on fuel down low and then they went lean in the middle, the problem was the needle, back in the day we actually made our own needles but thats way too much work. The best thing you can do on a 94 is just make sure everything is right in the carbs and keep a close eye on the clutches, because they are so sensitive, if you have a worn belt or clutch, it will just eat fuel when it over shifts. Make quite sure the secondary is in good order, that thing was a pain. The best thing you can do for that sled is to update the clutches, night and day all around performance. Find a 95-6 secondary
 
Jetting etc

Thanks for your replies and comments. I have no doubt that the 94 600's have their issues but what has to be remembered is that this sled only has 700 kms on it. It's seen more time under the cover than the light of day.
The clutch's haven't had much in the way of run time and probably don't need repair just yet. I will keep my eyes peeled for a newer year replacement.

I took it apart again last night and had a look at the jetting -->pilots = 53.5 and mains -->=155.3. The clip was in the center notch of the needle, float level was fine.
The pump and alignment marks are a bit on the rich side (according to the factory marks on the lever and casting) but nothing serious.
As mentioned previously, the plugs are dark, and if anything, I could start with a size smaller on the pilot; 53 or 52.5?.

Time's running out with rain expected on Monday, I might have to continue this next year !
 
stock that sled should have;

oil pump 29mm
m/j 156.3
p/j #52.5
p.a.j needle Q2.5(not a Q but circle with a line through it)
p/s 1-1/8 out
float height 20.3-24.3mm

so your already leaner on the mj and too fat on the pj,needle jet is too fat
too.

i would suggest dropping your needles to clip postition 1, it's been discussed before on these vm's that they run rich in mid,dropping the nj should help.
 
Thanks Daman

The mains could be 156.3, it's very hard to read the impressions on the top.
Are the old VM type Mikuni carb needles interchangable with the TMXflat slides on the Vmax 600?
I moved the clip up one position on the pin. I'll adjust the oil cable when I put it back together and give it a shot on the weekend.
 
Vmax 600 slugish

Well it has been a while and was finally able to get out and really test this thing. I took it on a trail ride and it was a ride from hell . .and at the same time fast and exciting. The end result is that it is NOT an oil problem or it can't be totally blamed on excess oil. I disconnected the oil pump cable and took it for a spin (carefully). It did the same thing. 3/4 to wide open throttle was great - anything less was a smokey pain. After I reconnected the pump cable, I went for a pretty decent ride. I barely made it to the pumps where others still had plenty of fuel. The carbs have been inspected by me and many other VERY experienced 'others' and it's being chocked up to jetting issues. Duh! We thought that initially but couldn't imagine a basically new sled being such a slug and getting to 700km that way. This season I will do some specific jetting to get it usable again.
Thanks for all of the suggestions!
 
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