20hp intake mod on a carbed Vec?

[Stubbs]

A properly tuned Vec is no joke, they will surprise a lot of people. The carbed 973 does feel a little soft compared to a fuelie, but they can both be made to run with the right bits and bites.

 

[74Nitro]

A properly tuned Vec is no joke, they will surprise a lot of people. The carbed 973 does feel a little soft compared to a fuelie, but they can both be made to run with the right bits and bites.

I knew a guy with an 06 rage that was top ending some 800's in that same age group on the lake.

 

[74Nitro]

This engine was about 120HP according to dynotech. There was an aftermarket header that added about 6 on the top.
I highly doubt this kit adds 20, I would think 5-10 is possible.

 

[Metallicat]

This engine was about 120HP according to dynotech. There was an aftermarket header that added about 6 on the top.
I highly doubt this kit adds 20, I would think 5-10 is possible.

Yeah, I have the header on mine, only because my stock exhaust tore itself in half years ago. My own fault for that one. Also have the green Holtzman carb springs and Ulmer clutching. The header added nothing, same with the carb springs. Ulmer clutching is the way to go, though. Spot on and waaay better than stock.

 

[pdiddy]

No, I am not at all interested in keeping up with 800s or other 150hp sleds. My Vector holds its own against the current 600 group I ride with. It trumps our 600 VES Edge, 600 cfi IQ, 600 cfi ProRide, and 600 Sabercat. The 600 Sabercat and I top out almost exactly the same, but I tend to jump out 2 sled lengths and just stay there. It is just that the throttle response is so sluggish, it seems like the 600 smokers will run circles around it, but line them up and the Vector takes them all.

Sounds like you are happy with overall performance of your 973. If you want more throttle response I'm not sure this kit you're considering is the best direction. You could drop the gear ratio for a lot less. Also consider selling it and buying a 2010 or later with the 1049 EFI. All the 2-smoke sleds you mention have EFI and so should you! Pure Yamaha EFI delivers instant throttle response. As a bonus fall startup will be a ton easier than the carb'd 973's which require severe resuscitation after storage.

 

[74Nitro]

Yeah, I have the header on mine, only because my stock exhaust tore itself in half years ago. My own fault for that one. Also have the green Holtzman carb springs and Ulmer clutching. The header added nothing, same with the carb springs. Ulmer clutching is the way to go, though. Spot on and waaay better than stock.

It certainly did at dynotech.

 

[STAIN]

The EFI is definitely an improvement on these motors BUT the carb versions are good runners and get better gas milage in my experience.

 

[Metallicat]

It certainly did at dynotech.

It does add hp, but only after about 7500rpm, and it is right around 7hp on top, which allows the engine to spin a few hundred rpm higher than stock. But low end power is softer. So spinning at 8800 to 8900 rpm now. Stock it was easily a 104 to 108 mph sled on the speedometer in good conditions. Still the same, saw no increase, but it is indeed slower off the line through mid range.

 

[Metallicat]

Sounds like you are happy with overall performance of your 973. If you want more throttle response I'm not sure this kit you're considering is the best direction. You could drop the gear ratio for a lot less. Also consider selling it and buying a 2010 or later with the 1049 EFI. All the 2-smoke sleds you mention have EFI and so should you! Pure Yamaha EFI delivers instant throttle response. As a bonus fall startup will be a ton easier than the carb'd 973's which require severe resuscitation after storage.

Yes, other than throttle response I am quite pleased with the performance. I did drop gearing down to 20/39 a few years back, but changed it back to stock gearing as I was trying different belts and wanted to establish a baseline that I was more familiar with. Ended up going back to the 8dn belt. I have 3 xs805 belts, purchased in different years, and they all have vastly different profiles. They kept changing their belt design so I could not properly clutch for one, and have the other run correctly. Had to reshim the secondary to run the spare. Crazy.

The throttle response is perhaps due to the way the cv carbs are tuned from the factory, or maybe that is just how cv carbs run. I am running slightly larger pilot jets in mine which did help a ton with cold start idle quality and greatly reduced pilot jet fouling after storage. I also tried the next size main jets, no difference that I noticed other than it seemed to use a bit more fuel perhaps. Went back to stock mains. Also drilled out the plugs which capped the fuel screws and adjusted them to 2005 specs. They were set lean from the factory and capped in 2008. Carbs are synced.

 

[Redbeard]

It's interesting to read the feedback everyone has on the 973 carb engine. Everything from low end bog, pre-season woes, jetting trouble, etc.

I have owned a 2008 Vector LTX since new. Maybe it's dumb luck, but I have never once had to remove the carbs and clean them. This sled has always started right up when cold, and there is no low-end bog. Now, out-of-the-hole throttle response isn't like a 1049 efi, but this sled has always been strong from low end to the top.

All I have ever done at the end of the season, is completely drain all fuel from the gas tank and float bowls. At the start of the season, I remove one fuel line from one fuel pump, and insert a small funnel. I then use a small cup to pour in gasoline to fill the float bowls (6-8 oz). It will fill all three because the two separate fuel lines tee at the carbs. The sled lights instantly every fall.

I do own a Motion Pro carb sync tool, and I perform that procedure every other year. Other than that, I've done nothing else to this sled. I wonder why I've had good luck with everything, and others do not?

There is just shy of 15,000 miles on the clock. I run 21/39 gearing and still see 96 mph on the lake (probably actually 90).

 

[Fast Lane]

I only had dirty carbs when I bought it. The sled was sitting for quiet some time (many years). I have no bog. Great throttle response. I do start it up once every couple of months in the summer. Last year I forgot to start it up during summer and it was a bit of a pain to get started. I think the 973 has great power plus great fuel economy. I get the best mpg out of my group of friends that ride with plus I have a good size fuel tank. Everyone else will run out of gas before me.

Carbs don't compensate for air density very well so starting in the cold can be a pain. It fired up at -32C this winter but I have to reach for the idle screw and turn it up. Once the sled has some heat in it then I turn it back to normal. Tors is too sensitive. Idle has to be set perfectly or I get a hanging idle.

Outside of exhaust donuts and a chain case rear jackshaft seal leak, the sled has been great.

I love my sled. In the grand scheme it cost me very little for the smiles it has delivered over the years. This is why I'm interested in this carb upgrade.

 

[Metallicat]

It's interesting to read the feedback everyone has on the 973 carb engine. Everything from low end bog, pre-season woes, jetting trouble, etc.

I have owned a 2008 Vector LTX since new. Maybe it's dumb luck, but I have never once had to remove the carbs and clean them. This sled has always started right up when cold, and there is no low-end bog. Now, out-of-the-hole throttle response isn't like a 1049 efi, but this sled has always been strong from low end to the top.

All I have ever done at the end of the season, is completely drain all fuel from the gas tank and float bowls. At the start of the season, I remove one fuel line from one fuel pump, and insert a small funnel. I then use a small cup to pour in gasoline to fill the float bowls (6-8 oz). It will fill all three because the two separate fuel lines tee at the carbs. The sled lights instantly every fall.

I do own a Motion Pro carb sync tool, and I perform that procedure every other year. Other than that, I've done nothing else to this sled. I wonder why I've had good luck with everything, and others do not?

There is just shy of 15,000 miles on the clock. I run 21/39 gearing and still see 96 mph on the lake (probably actually 90).

You obviously take the right precautions at the end of the season to prevent pilot jets from gumming up due to stale fuel in the off season. I keep fuel in mine so I sometimes have had to clean the pilots after storage, but using a good fuel treatment plus non ethanol fuel has all but eliminated this requirement for me.

The sluggish throttle response comment is compared to newer 2 strokes with efi. They simply rev up and backshift quicker. It seems like my sled takes a moment or 2 to respond to quick throttle inputs. Been that way from day 1. So I have to plan ahead a bit more if I want to lift the skis up in preparation for a small jump, for example. Similar feeling to a ZR700 from the 90s. It just isn't as "zippy."

 

[Redbeard]

I think the 973 has great power plus great fuel economy. I get the best mpg out of my group of friends that ride with plus I have a good size fuel tank.

Absolutely. My 973 has always been great on fuel!

And yes, the costs of owning and operating this machine have been very cost worthy. This sled has been my favorite trail sled out of any I've ever owned. I'm not an aggressive rider, but I keep a descent pace. This sled is perfect for that.