Nope. I am using a 40mm Mikuni off of a 650 single (susuki DR650) All I did was up the pilot and main jets! I works great! No starting or drive away issues!
KC, I could see myself possibly leaning that way in the future! Why the 40 mm, instead if the 36mm flat slide, that I've read so much about, on this forum, that guys seem to favor? Limestone
A carburetor is not a fuel injector. Air flow through the Venturi produces a slight boost in the vacuum, and that vacuum pulls fuel through the metering system and into the air stream. The carburetor doesn’t care how many cylinders are down stream from it just how much vacuum and air flow it is seeing through the Venturi. S So, long as the air flow volume going through it and the vacuum at that flow is the same, it will deliver the same amount fuel into that air stream. So, just about any carburetor designed for a 500 to 750cc engine is used, it will deliver the right amount of fuel for the amount of air flowing through it. MNost of the carbs on these smaller engines, have what is known as a variable Venturi, or Constant Vacuum Carburetor. There is a piston which slides up and down in response to teh manifold vacuum, and varies the size of the Venturi, based on that vacuum, and how far open the throttle plate is. Wide open throttle it will open up to allow more air through at the same air velocity, it had at idle. Typically there is a tapered metering rod attached to the bottom of the piston, which moves with it. That metering rod goes into the main metering jet of the carburetor and controls how much fuel goes into the air stream in proportion to how far the piston has moved. If you want to understand it there are literally whole books written on how carburetors work. Some at a pretty basic technician level, which say do this and get this result, and others which are aimed at teaching engineers how to design them, which include a whole lot of physics, and higher level math, (calculus and differential equations). I learned calculus trying to figure out how the carburetor on my first car worked. I checked out a book from the library in my high school, on carburetors. It had some mathematical equations in it with symbols I didn’t recognize in it. So, I asked my math teacher what they were. She was kind enough to hand me a Calculus text book, and spend the time to teach me one on one. She was responsible for me veering off from the jock Motörhead, taking shop classes track, and into the science and engineering direction. Computerized fuel injection is far easier to deal with than carbs. And, the knowledge of how to tune a carburetor is slowly disappearing. It gets harder as time goes by to find the books which explain carburetors. but if you look on eBay there are still some out there to be found.
The carb is a Constant Velocity Pumper I have always had issue with the wind Much better now though So you think if I go to the 33 Pumper I would gain torque?
Thanks All!!! Great thread, this was really helpful in getting my '98 Carry DD51T running!!! when I bought it the carb was missing completely. I found everything needed on Amazon to install a 660 rhino carburetor. Below are the items I used to hopefully help others. The whole install was around $120, much cheaper than an original style carburetor (which sound problematic as well). Carb- https://www.amazon.com/gp/product/B07MDYLKNX/ref=ppx_yo_dt_b_asin_title_o08_s00?ie=UTF8&psc=1 Intake boot for a Yamaha V-Star 1100- https://www.amazon.com/gp/product/B07MGRYCFX/ref=ppx_yo_dt_b_asin_title_o07_s01?ie=UTF8&psc=1 This includes a vacuum port and came in a two pack. I had to enlarge the ID slightly with a razor knife and drill the mounting holes out to 5/16", but fits nicely. The vacuum port allows all the original vacuum components to remain functional. I used a basic pull-style choke cable cut to length then used a small ball of JB Weld at the carb end to fit the choke valve. https://www.amazon.com/gp/product/B07S1M87HL/ref=ppx_yo_dt_b_asin_title_o07_s01?ie=UTF8&psc=1 I capped it off with a motorcycle style air cleaner for good air flow- 60mm air cleaner- https://www.amazon.com/gp/product/B07BFSXYKP/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1 The main jet that came with the carb is a 158. to resolve the hesitation off idle I put the needle clip in the 3rd grove from the top and also placed BOTH of the white plastic spacers below the clip. I added a couple additional shims as well made from 2.5mm washers. It runs and accelerates well, but I may try a 160 or 165 main jet when I get a chance. For the fuel supply side I used an electric fuel pump and regulator set to 2 lbs. EP42 pump- https://www.amazon.com/gp/product/B07HRMTM3L/ref=ppx_yo_dt_b_asin_title_o04_s01?ie=UTF8&psc=1 in-line regulator- https://www.amazon.com/gp/product/B07S3ZGDSR/ref=ppx_yo_dt_b_asin_title_o07_s00?ie=UTF8&psc=1 Photos with the bed removed-
backing up a few posts.... the 660 Rhino is NOT a 2 cylinder... its a 1 lunger! but as JIGs explained: a carb doesnt care how many cylinders are there. it just flows the air & mixes the fuel. WHY that carb? well i would of liked to claimed the "discovery" of it.. but it werent me. lots of guys i saw on the net had taken these old mini's & stuck that carb on there when theirs crapped out. i did search after search after search & always found guys using them. they were cheap, available & came from the same "size" motor 660cc.... that was probably the biggest reason the farmboys went with them. have read other guys using Honda carbs from 650 rincon's & so on..... no wrong way to do it if it works.
What did you use for a primer? I'm thinking I may need to try that....I just can't get my choke to work right! Thanks, J
Hi KCCats! Cool, thanks for the quick response...... So to the novice, the primer was separate from the Mikuni pumper? What / where did you get it? I'm guessing the snowmobile choke was a choke cable you mean? any type/part in specific. (I'm good at copying...not so good at figurin ) Thanks!!
Do you still have the stock carburetor? If so, go the G&R imports site, and read their tech article on troubleshooting problems with the carb. 90% of carb issues are something else. If you go back a page there is a good posting on what parts you need to mount the motorcycle/atv carbs, and the parts you need, complete with links to Amazon to buy them.
Thanks Jigs, Yeah, I still have the stocker...haven't been able to successfully fix my stock choke issue.... was thinking if after I look at it a supplementary primer if it is not too invasive might be a work-around. (I know not the RIGHT way but if not invasive I can eventually someday figure out that right way ) I have seen that list but don't recall seeing a primer in it, will go back through it at lunch. Thanks again!! J
man this thread has a life of its own!! still glad it has helped a lot of people find another way from the junky factory carb!
that stock is JUNK! The Mikuni is a way better carb! Im at 147 main 40 pilot I used a standard Mikuni universal snowmobile choke cable as it has 2 stages and will stay at half or full choke. As for the Primer yes again a universal snowmobile Primer kit, comes with 1/4 X 1/8 T and some 1/8 line. I don't start my truck every day and it does go for months without starting, the Primer gives it a initial mouth full to get it all going! I have smooth drive away and full power almost immediately! I have almost half again the hp as well!
The stock carb has an acelerator pump. Pump the throttle full cycle a few time before trying to start. This is not fuel injection. You need to pump the throttle at least once to engage the choke, and a few shots to prime things is normally necessary unless the engine is fully warmed up. When it is down below 0-F I have to pump four times, and then ad a few pumps as it try’s to start. Once things fire off, it idles just fine, warms up, and comes off the high idle. Adding a primer to a stock carb would be pointless. And, the majority of problems I’ve read about with these carbs seems to be that they run too rich. My guess is that the needle and seat need replaced, or the vapor canister is blocked, pressurizing the fuel tank and return line, resulting in too high of fuel pressure, because with the fuel return line blocked, the internal relief valve on the stock fuel pump can’t work. Mine had a problem with that, which I solved with the installation of an electric fuel pump and a regulator set to 2-psi. The stock carb, at least on my Hijet is a very good carb. The only issue I had was that it is very different than most carbs. I hav never seen a constant velocity carb with an accelerator pump before. Or the wax motor driven choke system. It took me a bunch of twiddling with it, and shooting carb cleaner into it while disassembled to map out what nipples did what, and how the internal passages routed. And, I wish I could source jets for it, I’m still a little rich running at 4000 to 5000-feet, and would like to go down a couple of jet sizes. The Mikuni and other motorcycle carbs have good availability of parts and spares. And, they can make the trucks run, but I’m still not convinced that if we could get rebuild/tuning parts for the stock carbs, the motorcycle/atv/utv carbs are actually any better on a daily driver.
Just installd the new carb and right when I start it the carb revs to 5,000 RPMS instantly. I backed out the idle screw all the way and still it revs very high
Any idea of how to get it back to normal? Thanks Jig and KC, I did not have an air leak but my throttle cable housing was too long and was causing the cable to be pre pulled and not rest on the idle screw. Everything is back to normal except now the engine steams/ out of one OEM tube after a few minutes of running. I am not sure If I am supposed to cap the old Coolant ports on the engine or not. Ill add a photo of the tube but in the mean time the Tube is the thickest one that comes from the top of the engine near where all the small vacuum lines came on the diaphragm carb. The truck runs but deff want to fix it because I plow my driveway with this guy everyday
The cooling system is supposed to be pressurized to about 12-psi. So you definitely need to block, or loop the coolant lines which ran to the old carb. I would recommend looping them through a new run of hose, connected between the two ports the old coolant lines ran from/to. And, you may have to vent to coolant ports at the top of the head if the top of the radiator is lower then the top of the head. And, please go up to the blue field, follow the dark blue link, and add the information on your truck to your signature. It makes it lots easier for folks to give good advice.
Thanks, Yesterday I looped the coolant lines back to their counterparts (in to out, out to in line) and now I am at a Draw. Two Nights ago the truck was running but now all of yesterday and this morning it wont turn over. Also it started fine without the Choke on day 1 I have tried: Connecting to external power source while starting checked the plugs (look new) started without plugs plugs are now in and I turned our garage heat to 65 degrees Choke will be installed today but to mimic the choke in the meantime I would put my hand over the air intake and let a little air in. Unplugged drain line to see if the fuel pump was working and it is. I have not tried: Check the timing Install Choke But the biggest things is why did it start the night before??
You are refering to the Rhino carb correct? With out the choke plunger in it will not pull fuel but have a Direct air leak. Or does the Rhino have a butterfly choke?
I am also using the Rhino carb on my hijet, do any of you guys have a picture of your vaccum setup with that carb installed?
My one vac port on manifold pointing at carb goes to my Vac adv The other vac port opposite side does the Vac front dif There are the PCV vac port as well as the Brake booster Thats all I got
Thanks! No diff for me, I need to find a Carry diagram now, Im guessing you guys dont have a vaccum "stem" aka TVSV?
