G1 23hp Vanguard Install

[slonomo]

One thing I did run into was the Vegas Carts "dogbones" don't fit the Vanguards. Aaron told me it would, but as you can see in the pics the Vanguard has a raised up section on one side, and the bolt holes in the engine are smaller so the little alignment tabs won't fit. The bolt holes could be enlarged quite easily, but the raised up section isn't compatible. Too bad. So I just used the old bolt and washers setup. And yes, bolting the engine down is every bit of a 25 minute job....

[slonomo]

So I decided to ditch the stock 2 barrel carb in favor of a Mikuni 42 CV carb from a Yamaha Grizzly 660. As far as engine size, it's the closest I could find. The reasons for the swap are as follows:
1. Idle speed tuning, I would like to get 800 rpm idle speed
2. Main jet tunability, lots of jets available, and only 1 is required
3. Very forgiving with jetting due to the CV design
4. Parts availability, very easy to find jets, rebuild parts, etc
5. Better overall performance, these carbs are used for racing

I was having a heck of a time with the stock 2 barrel carb on my 23. When I got it, it fired right up and ran very smoothly, with the exception of an 1100-1200 idle speed, just couldn't get it any lower. That really interfered with shifting the cart into gear. At times it would rev higher, leading me to believe it was running lean. So I'd adjust it and it would be better for a few days then it would idle too low and stall.

So I'll update on my progress shortly.

[TheNewGuy]

I'm watching!

[raydhd]

If it were me I would have tried something like a mikuni VM 36 which would be fairly simple to tune. But I guess you have the carb laying around. The CV are a whole lot harder to tune as Sho found on his clone. The CV uses a vacuum chamber to control the throttle plate rather than just lifting the slide as the VM and TM series mikunis use. What are you going to do about a manifold? I have not seen where anyone sells a spout type manifold adapter for the vanguard besides the very expensive Black Death unit. P.S. I have a VM34 on the snowmobile powered Harley cart and VM38 on my Ironhead Harley chopper. I also have TM40 in case I needed more than the VM38 on the bike BUT it will pull 6500 rpms easily thru all 4 gears so I never installed the TM40. The 40 mm venturi is the max recommended for the 1000 cc Ironhead engine.

[slonomo]

The choice in carb is simply due to familiarity. I used to race atv's, the last one I raced was a Yamaha Raptor 660, which used two Mikuni CV carbs and a split manifold feeding a large 660 cc single cylinder 5 valve engine. It used dual Mikuni BSR 33's. So I'm just very comfortable tuning this type of carb because of experience. Very similar carb to this. This 42mm CV carb came from a Grizzly 660cc atv, same engine just setup a little different. I wanted a single carb. I chose the 660 Griz because of the engine size similarity and the CV design.

Blackwater Performance uses a 34mm single carb for their kit, but it's a the older VM flat slide style, not really a fan of those. They are very good at WOT type racing where high rpm is key, hence selling them for mud boats. Mud boats don't run at 2500 rpm very often, and they almost never sit and idle. VM carbs tend to be a little finicky and less forgiving when varying the throttle position. They are very responsive because the throttle cable is connected directly to the slide. The downside is they aren't as forgiving when the throttle position is varied quickly, and they don't deal with elevation changes as well. But overall still a good carb and very popular and easy to tune.

Knowing what I know about atv's and the conditions they ride and perform in, that's really what I'm going for. I use my cart for trail riding, yard work, towing trailers and mowers, the kids ride it around the yard. So the most important items on my list for the carb was easy starts, good idle, reliability, good performance in all rpm and conditions, and it had to be something I have had good experience with.

The Vanguard 23 is 627cc vs. 660cc on the Griz. The Vanguard uses a two barrel carb (26mm each) for a total of 52mm of venturi and the 660 Griz uses 42mm of venturi. The Vanguard uses a split manifold similar to the 660 Griz. So, the similarities are many. I figured it was a safe place to start. Plus the plan includes head work, cam change, valve springs and pushrods. I won't rev this thing past 5500, but I plan to use it in the 4000-5000 rpm range, which the 42mm should be able to handle without question.

There has and always will be a size and type debate for small engine and motorcycle carbs. I don't argue, I just use what I like.

[BIKERMIKEYBLACK]

I’m very envious of your setup there that’s definitely they way I would LIKE to go

[raydhd]

I didn't know Mikuni made a CV type carb. Maybe because I haven't ever been involved with ATV's. Some of the Harleys later than mine used Keihin produced CV carb that some owners switched over to mikuni flat sides. Maybe you have found a replacement for the Nikki set up on vanguards.

[slonomo]

Mikuni makes 3 types of carbs. VM Flat slide, CV, and BSR (also a CV).

[slonomo]

The plan was to use this intake adapter. I was trying to find a 45 degree mikuni adapter to fit the 42mm carb to the 2" briggs manifold adapter. I couldn't find one, still looking though. If any of you have a source where you can find one let me know.

[slonomo]

Here is the Mikuni CV 42mm carb from the 2003 Yamaha Grizzly 660. I have not checked the jet sizes as of yet. I did take it apart and clean it up. It was really dirty on the outside (common for an atv), and very very clean on the inside. So I washed it off and sprayed the jets and called it good for now.