1990s Yamaha Snowmobile – Anyone know how to test oil injection?

Guys, a 1991 Yamaha Venture snow machine wandered into my shop. I normally don’t touch these mechanical nightmares (by that I mean all snow machines), but this is an older fellow who wants to fire up his machine and join his sons up north on a fishing trip. According to him, nobody’s going to be driving on the lakes they fish anytime soon, so he dragged out the ol’ Venture from the back of the shed and wants to fish with the boys after new year. So I’m going to break my own rule and I told him I’d give it 2 hours.

It’s the old Yamaha 485 fan cooled in these things, I think this is the same motor from the Phazer of this era. Anyone know are these good motors? I seem to recall hearing these were really bulletproof but I guess I don’t know.

Anyway, to my question. This is the classic “ran when parked” situation. This poor old sled has sat in the back of Ed’s garage for at least 7 years or so and has not been started at all. However… Unbelievably, he seems to have done everything right as far as storage. He pumped all the gas out of the tank and fogged the cylinders.

But what he didn’t do is pump out the oil in the injection tank.

I’m very worried about starting this thing and having the oil system not work. What I’ve done in the past was to run oil injection outboards on premix until I could determine that the pumps are working on the OI system.

But on a snow machine, I have no idea how to tell if the pump is working. Anyone know what the procedure or test is to determine if the pump and system are working on an old Yamaha sled?

Thanks guys.

Grouse

Does this help?

And if it’s an electric pump, I’d probably try and jump/hotwire the connection and see if the pump turns on before you attempt to start the motor. Pull the line and see if it’s pushing oil.

So I have a older ski doo snowmobile and had to take the oil pump off to replace pull rope, and what I did after I got back together was mark the oil reservoir level, then did a tank of mix gas to make sure the machine was using it.

I had an older phazer growing up we dug out of the back of the shed . Same scenario . We didn’t even dump the old oil out . She’s still running to this day . That was 15-20 years ago . Never touched the oil pump . Pay attention when you tear the carbs appart the black plugs go in the right holes – had a hell of a time with that when we put them together wrong.

Check the air box for mice . I believe the throttle linkage runs the oil pump if you follow it .

I jumped that sled so much I thought it blew up one day . Hell of a racket under the hood . The head bolt nuts rattled loose and went through the fan . Tightened the head back up and good to go

I’d do what Gregory said. I would mix the tank 50:1 and track the oil level. Change the plugs once you get back to straight gas. That’s what I would do.

you shouldn’t have to do any thing to the oil injection at all. After a over hall I us a coat hanger and hook the the leaver for the oil pump with the motor running pull it up. If it smokes you out of the shop then you know its working.

That is a very good motor I have the neighbors in my garage now replacing the stator

fishingstar wrote:

you shouldn’t have to do any thing to the oil injection at all. After a over hall I us a coat hanger and hook the the leaver for the oil pump with the motor running pull it up. If it smokes you out of the shop then you know its working.

That’s the same thing I do. I’ve always heard that Yamaha engineered the pump so when it fails it does so at wide open so you’ll be using so much oil it will be noticable.

I don’t have experience with that era of Yamaha sleds but I saw that on my 2000 sxr700. It was using 3 qts of oil per tank of gas! Way too much. At that age and sitting, the clutches would my worry.

Check the hyfax on the rails as well . Check fan shroud for mouse nest . And lastly stock up on some BR9ES lol

That 485 was arguably the most bullet proof engine Yamaha put in a sled. Fishingstar probably provide the best test for the oil injection check. 2 hours doesn’t do a whole lot for maintenance, but a few easy things to do besides what’s been mentioned. Use some compressed air to blow out the clutches. If the belt isn’t riding near the outside of the secondary, it could probably use a new belt. Change out chain case lube? How many miles on it?

Good motor, and as others said premix the oil and watch the oil level. I would make sure it has a new spare belt. Sitting that long can deteriorate the drive belt. I had gotten an old 775 TNT back from the dead when I was a kid. Rode it around for a few miles making everything was working again as it should and when I decided to see what the old tanker had the belt blew and cords came through the vents by the clutch. I opened the hood and just strands of belt were left. I walked home and had my dad pick it up with the truck.

Thanks for the feedback guys. The owner is convinced that the oil injection isn’t a problem but I’ve convinced him to run some pre-mixed gas through it just to make sure.

Actually this thing is in pretty remarkable shape. Just over 2500 one owner miles. As is always the case the seed is dry rotted all the heck. The high facts look good but could probably use replacement at some point if he’s going to use it a lot this winter.

I should get a chance to do some testing on it this weekend and I’ll post my results. Kind of a fun project.

Should be able to find a seat cover on Dennis Kirk or eBay . Good luck In your wrenching. Them old girls could really scoot for how light weight they are !

Is this a model that the headlight turned with the handle bars ? Basically a snowmobile fairing ?

big_g wrote:

Is this a model that the headlight turned with the handle bars ? Basically a snowmobile fairing ?

No. The Venture was never like that. But the Phazer and Exciter of this vintage had that design. Which I always thought looked really cool. No idea what it was like while riding, but it just looked modern to me.

TheFamousGrouse wrote:

<div class=”d4p-bbt-quote-title”>big_g wrote:</div>
Is this a model that the headlight turned with the handle bars ? Basically a snowmobile fairing ?

No. The Venture was never like that. But the Phazer and Exciter of this vintage had that design. Which I always thought looked really cool. No idea what it was like while riding, but it just looked modern to me.

A buddy had an PhazerII around 1990… it had it. It was great until he was in the woods on a tight iced trail, he would turn, the headlight would turn, but the sled might not … he said it was kinda freaky at night !

Update just in case anyone’s interested.

The 1991 Venture got dropped off tonight and you guys should see this thing. It’s a pristine time machine. Unbelievable condition considering how badly treated most sleds get when they get to this age. I’ll shoot some pics tomorrow in the daylight.

We pulled it off the trailer and of course, the owner wanted to see if would at least fire but, as he put it, the electric start “isn’t working very well”. And by that he meant, like, not at all.

I had about a quart of mixed gas ready, so I put some gas in. I pulled the rope over slowly about 5 times to prime her a little.

“Well, here goes nothing.” Choke on, ignition hot, kill on.

One pull! Off she went. The last he can remember using it was 7 or 8 years ago, but then the owner and his son were going back and forth and recalled using it on Christmas of 2013, so it’s more than 8 years ago its been mothballed.

Judging by the sheer volume of smoke, she’s oiling plenty from the injection system. He had a container of Yamaha oil that he brought and the oil tank is half full. I pulled a sample and it looks just fine, so I’m going to test drive it as much as my yard allows and if she seems good, I’m going to let her ride. She’s lived this long…

Anyway, he wants it gone through, chain case oil changed, plugs changed, and see if I can figure out why the electric start doesn’t work.

So after dinner I went out and pulled the battery out. I think I found the electric start problem.

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Can we get a pic of this sweet machine?

Ripjiggen wrote:

Can we get a pic of this sweet machine?

Yeah, as I said I’ll shoot some pictures tomorrow in the daylight. Right after I get back with the new battery because I don’t think there’s any saving the old one.

That’s now a 10v battery…

1990s sweet vintage Yammi.

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Gotta love that pogo suspension!

isu22andy wrote:

Gotta love that pogo suspension!

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Yes, it looks like Yamaha was on the pogo-stick all through the 80s and 90s. Interesting setup, don’t know that much about them.

So after over 8 years in the back of the garage, all I needed to do was:
– Added fresh non-ox gas.
– Changed plugs even though they really didn’t look like they needed it.
– Changed chain case oil.
– New battery
– Checked hyfax (very little wear, I assume they have been changed before), bave the undercarriage and track a good look over, no bad bogies or bearings that I could see.
– The owner would like a new seat cover installed and he has ordered one, so I’ll keep it until that arrives.

My takeaway from this rather interesting little adventure: Proper storage WORKS.

By pumping out the tank with a $5 hand pump and fogging the cylinders, the owner saved what would have certainly been a big hassle and $$ getting the thing going again. I can’t imagine the mess (well, actually I can) if that gas tank had been left full of sh!tty ethanol pump gas. Surely the carbs would have been trashed and every fuel line in the sled probably as well.

That thing is in amazing shape Grouse.

Not sure which non-oxy you’re running but the ONLY flavor around the twin cities I’ve ever seen is 91 or 93 non-oxy. These sleds are not high compression engines and will start a lot simpler in the cold if you can find non-oxy 87. The new kwik Trip in Prescott sells it.

You aren’t hurting anything on 91 or 93 non-oxy, but if you can locate N87 and use that instead it would be ideal.

I run a 96′ Vmax 600XT as my backup sled. Love the pogo stick Yamahas. Fuel pump is a real PITA if that goes, since there’s no rebuild kit available for these old Taiyogiken pumps. I found a used pump on ebay, if it ever goes again I’ll re-plumb it using a mikuni off a polaris. And maybe locate it in a better spot.

I’ll add more since I just noticed your pogostick comment.

The pogo sticks have those “control arms”, upper and lower. Every pivot point has a bushing, these bushings tend to corrode and basically fuse into the aluminum arms. Suggest taking it all apart end of season and checking those. Quick check in your driveway would be to pick up one ski at a time and drop it, noting for travel in those arms. If they are frozen solid you’re in for a frustrating job when you go to repair those bushing. if they move good news, you just take them apart and grease all of them at end of season.

Do those steel skis have skins underneath? They came with plastic skins from the factory. A much, much better option would be to replace with a whole plastic ski. My 96′ handles beautifully and shed about 30 lbs up front by running 2 plastic skis.

Runs a lot better on amsoil 2 stroke. I use the cheapest amsoil flavor, blue jug labelled for snowmobile and marine. Amsoil Interceptor is great but I hate burning all my $$$. Runs very smoky on cheap oils but it’s tough to kill these yamahas.

Lots and lots of parts available for these on ebay at fairly decent prices. Look around if you need something you’re sure to find it. The pogosticks are very cool but also the most irritating feature for those of us in salt country IMO, because those control arms hate salt.