Ditto here.
For me, no throttle = no start.

 

Looks like I'm not alone here. The carbs on the 650 have a vacume operated slide that does not move until the motor is running so this piston slide acts like a choke as well. If you look at the carb break down, it is part #6.
(04-05-06 650 V-2)
650 V 2 Carb

 

I don't really think you have a clue about the carbs. I was playing with carbs with slides before you were born. The 650 V-Twin has a pair of carbs, bolted together to work as a single 2 throat carb. Other than it being a pair, the individual carbs is just a standard Keihin carb, with slide, enrichment system, etc, just like the carbs on a 250, 300, 400, 500 and 650 H-1. In fact the 650 carbs are identical to the 300's carb except for the parts to make them work together. So either know what you are talking about before you tell me I don't know. I make it my business to know, before I pass out advise.

 

Bear you have always been great when it comes to giving people advice or technical help on these forums and I have even pm'd other members and told them to ask you for your knowledge on AC quads but one thing I have also noticed is that anytime somone disagrees with you or has a different procedure than you, you turn into a grumpy ol' bass turd and you jump all over them and try to make them look stupid. Where do you get off telling me how to start my 650 and say,"I don't really think you have a clue about the carbs. I have owned the 04 and the 05 and I have had troubles starting these quads in single digit weather but I always got them started by cracking the throttle from 0 to 1/4 to get them to start. Once they are started I let them idle for several minutes to warm up. Theshonk and Chumley both said they have to use the same procedure. And what do you know about my knowledge of carbs. I have owned Arctic Cat snowmobiles for 25 years and I have always cleaned and rebuilt (when needed) my own carbs without any problems. I also know that the CV carbs on AC quads have a butterfly valve which is operated by the throttle cable and a vacume operated flat slide for the main needle jet. The main slide on a CV carb does not move until the motor creates a vacume.( Thats what I meant by the slide acting like a choke) The more vacume = the further the slide pulls the needle out of the main jet. Caburetors that are used on AC snowmobiles also use a slide but the main slide it operated by the throttle cable. There are two types of slide carbs, Round Slide and Flat Slide, the flat slide is now the most common in new sleds. You are WRONG when you say that the 300 has the same identical carb as the 650's. The 650 is a down draft carb with the float bowl located on the side of the carb and the 300 is a side draft with the float bowl on the bottom of the carb, They both work the same but they are far from identical. I also know the difference between a fuel enrichment system that dumps extra fuel into the motor when you pull the choke cable and there is a butterfly type choke that cuts the amount of air entering the carb so that the vacume created by the motor when it starts tuning over, pulls fuel from the float bowl. This thread was started by "shingle" because he was having problems starting his 650 in cold weather, I gave him one procedure that he should try because it works for me (Theshonk and Chumley and two of my fiends that have 650's as well) even though it defies all of the laws of physics. One more thing Bear, I did not know that slide carbs have been around for 42 years, I learn somthing new everyday. Someday I hope to know as much as you do but I know, I know that is impossible. Have a nice day!!

 

When you tell me the carbs on the 650 are different when they aren't, it burns my butt. I probably was less than tactful and for that I do apologize. But you are wrong about the carb. As to the slide being pulled open by more vacuum, not true, if the throttle valve is closed. The vacuum source for the slide is in front of the throttle valve and the slide can't move if the throttle valve is closed. The slide can't act as a choke because it does close off the throttle boreenough to do so. The enrichener system bleeds fuel into the engine behind the throttle vavle, so if you open the valve you lessen the vacuum signal to the enrichener and lessen the extra fuel supply for start up. These are facts that can't be changed. You are worried about constuction of the carb the throttle bore and venturis are identical in size and the placement of the float bowl etc are irelevent in how the carbs work, and the are the same size so must flow the same amount of air, the slides work the same way and been a vertical or horizontial throttle bore changes nothing. The Keihin carbs on AC quads have a throttle valve but they also have a slide. The again so does the 650s carbs or you wouldn't need a sychronisatiom screw because the slides are vacuum control and if the slides were used as the primary throttle valves, then all you would do is tie the vacuum chambers together. Like is done on the vacuum secondaries of daul 4 carb on car engines. What you think is a choke butterfly valve is the throttle valve. Slide carbs have been around longer than I have and I have 17 years on you.

 

Apology accepted. I do not claim to be an expert on carbs but I do know how they work. The vacume that controls the slide does not come from the air passing through the carb barrel, it's source comes through a seperate vacume line from the motor going to a small piston on the side of the carb of the 650 and on the top of the carbs on a 300,400 and 500. I understand what you are telling me about the butterfly valve being closed so there is not a strong enough vacume to open the slide since the butterfly vave is on the intake side and the slide is on the filter side. All the CV carbs work the same and have basically the same parts but the carbs on the 650 are the only carb I've ever seen with side mounted float bowls. Thats what I mean by different than the carb on the 300. Same parts,same function, different design and far from identical. Truce

 

Truce accepted, But where you hang the parts does not change anything. I've seen carb with the float bowl on top of the carb throttle bores on stilts. I have a 1967 100hp outboard with an inline 4 barrel front draft carb with the float bowls on the side, one for each throttle bores. I have seen a 2 barrel diaphram carbs without float bowls at all, the V-4 race motor had 4 of them. The only way the slide can know how far to open is sense the vacuum signal on the intake side of the carb, just like the vacuum secondaries on a Holley carb has to sense manifold vacuum to know how much throttle opening the engine can use, othewise it can't work. That's what is so slick about the slide carbs, after about a 1/4 throttle the slide controls how fat the throttle is open regardless of where the butterfly is. That's when these carb adapt to alitutde changes so well. I normally run from sea level to just under 3000 feet. But have run as high as 5500 feet for days and have been as high as 7000 feet without a jet change. If I lived there I change jets, but for a day trip, no. The only draw back is a lot more parts than a standard carb has, more things to go wrong. i've been thinking about this start problem with the V-Twins and I have some major experience with multi-carb engines (outboards, both 2 and 4 stroke with up to 6 carbs) and during set up, the first step is to alway check to make sure the throttle valves are in sync, clear closed at idle and start opening at the same time. Seen a lot of start and off idle problems solved by syncing the throttle valves.

 

New topic

Does the V2 650 have a wet clutch? I ask this question to confirm the correct oil to use.

Shonk

 

Bear, what brand of outboard motors did you race with? I have seen some very funky looking carbs on Mercury outboards that I would not attempt to disasemble. The carbs you describe sound very sophisticated but very interesting. No wonder you know so much about carbs.

Theshonk
The V-2 does not have a wet clutch. Myself and two of my friends that own 650 twins use Mobil 1 10w-30 Fully Synthetic oil. We can purchase a 5 qt. jug at Wal-Mart for $19.95. I can get Napa gold (Wix) filters for $6.95 part#1358. The 5 qt. jug will do two oil changes.
This subject will stir the pot as well because so many people think that you have to run oil with a "SG" rating, but the SG rating is way outdated and was designed for wet clutches. As long as the oil does not have Moly, it is safe for wet cluthes. I used Penzoil 10w-40 in my 98 500 becuase it had a SG rating a few years ago. I kept using it after it was tagged with a SL and SJ rating and I never had any problems. When I sold it to a good freind two years ago, it had 4,000 miles on it and by now it has close to 5,000.

 

I raced both Mercury in-line 6's and V-6's and V-4 Johnsons, all carbed. My super hot rod in-line 6 motor (basicly a hot rodded factory Super Stock motor) with 6 very big Tilliston carbs and turned 7800 to 8000 rpm. The 2.0 liter V-6 Champ motor with 3X2 throats turned 8300 rpms at 132 mph. My Johnson 100 CID V-4 would also rev to close to 8000 with the 4X2 throats (these were the diaphram carbs without the float bowls) and about 7500 with the dual 2 throats. I set 3 speed records with a Mercury factory 1500SX motor and won 2 National Championships. Best I did in the V-6 Champ class was 2nd in the National High point Championship (a lot tougher class to win in).

The oil thing for the clutches only applies to the manuals with their wet clutches. Of course Arctic Cat uses the same oil in both auto and manual to keep it simple.