predator 670 carb

[1 Hombre]

Hello. FNG here. I have a 93 cc ds carryall that I installed a predator 670 in. Not happy with the stock carb and linkage. Requesting recommendations for a replacement carb that runs smooth with easy adjustments. I have some mechanical ability but short on knowledge of parts. TIA

[raydhd]

Performance 670 sells a manifold adapter to use a mikuni type carb along with the whole set up if you want to spend that amount of $'s. BUT the manifold adapter itself is really pretty cheap for what is does. IF I were building a 670 I would get the adapter and work from there.

[slonomo]

I've used the Performance 670 mikuni adapter, good piece. The price has come down too. If you do the Mikuni, make sure you use the one rec by them, 34mm I think. I dont think they publish their jetting, you might have to call them to figure you're starting poins far a starting point.

As far as carb replacement goes, that's gonna be your best bet. I suppose you could use a Keihin.

The easiest will be the VM22 style mikuni. Its direct connect from pedal to carb. The CV style carbs use a vacuum diaphragm to level out the throttle based on engine vacuum. Still good carb thought.

[1 Hombre]

Thanks for the recommendations raydhd and slonomo.

[sho305]

I had problems getting top end out of my CV carb even after modding it to open more it was so so. However it ran like a top and started great, it was a pumper model 32mm. I think on a stock engine it would be very nice. Now I have a 30mm pumper slide carb and top end is better but this 420 has a cam in it too. Once in a while it bogs at low rpm just a little, otherwise its great. I may put the CV on a stock 420, it ran really nice, very smooth, started quick, very nice to drive around. Maybe the 420 didn't have enough signal to make the CV work well I don't know, 32mm is pretty big. The cam is just a cheater cam but it does have 1.3 rockers also. It would get up to 5500rpm or so, now it goes higher not sure but speed is higher.

[BigBlock904]

Just wondering have you tried tuning the stock carb? I put a 12 volt fuel pump on mine and adjusted it a bit and the motor runs great. There's a set of screws that affect the idle jet and really help starting/take off. Fuel pump is wired into the ignition key with a relay. I can start mine within a second on cold starts now and it never bogs down. Also, have you looked at getting a catch can for the case breather?
**Not the actu idle jet. But the idle/low speed system.

[slonomo]

Originally Posted by BigBlock904

Just wondering have you tried tuning the stock carb? I put a 12 volt fuel pump on mine and adjusted it a bit and the motor runs great. There's a set of screws that affect the idle jet and really help starting/take off. Fuel pump is wired into the ignition key with a relay. I can start mine within a second on cold starts now and it never bogs down. Also, have you looked at getting a catch can for the case breather?
**Not the actu idle jet. But the idle/low speed system.

You're talking about the pilot jets. Those 2 barrel carbs are very similar to the Briggs version. I've heard you can get them tuned pretty good. Patience, experience, and knowledge are all helpful when tuning carbs. Many people don't have all 3.

Also I have heard that the fuel pumps on the Predator 670 has been problematic. I've seen people upgrade them to Briggs units. What you've done with the electric pump is also a fine idea.

[BigBlock904]

Originally Posted by slonomo

You're talking about the pilot jets. Those 2 barrel carbs are very similar to the Briggs version. I've heard you can get them tuned pretty good. Patience, experience, and knowledge are all helpful when tuning carbs. Many people don't have all 3.

Also I have heard that the fuel pumps on the Predator 670 has been problematic. I've seen people upgrade them to Briggs units. What you've done with the electric pump is also a fine idea.

Yep a bit of all 3 (more of the patience), and a buddy who's a great mechanic! The pump took 10 min to install, maybe $12, and makes a world of a difference. Do you know of a similar system for the main jet, maybe location?
Op, search this on Amazon, $12 "JDMSPEED Universal 12V Heavy Duty Electric Fuel Pump Metal Solid Petrol 12 Volts" just worth a try maybe.

[BigBlock904]

I don't mind taking pictures and helping if youd like Hombre.