- Location
- Coeur D' Alene, ID
Bottom and mid ran great, i trusted the person to gave them to me, and with them being taper bored its hard to tell from top down that they are that much smaller. Appreciate your valuable input to my thread.
Freestyle Fuel Starvation
- Thread starter Citizen
- Start date
Bottom and mid ran great, i trusted the person to gave them to me, and with them being taper bored its hard to tell from top down that they are that much smaller. Appreciate your valuable input to my thread.
@Citizen Depending on what you end up with carb wise I can help you with some jetting specs. Some carbs like reverse jetting some dont. I was more making a statement that I cant believe it ran . Plus most everyone had covered the differences in between carbs. But ill do it anyways.
3 bolts up top with an OEM intake manifold with no speed plate, one fuel pump with a master and a slave carb = OEM 38's
4 bolts up top is 44/46 SBN. Black 44's with curved fuel in and out fittings are OEM off a 760 And usually came with fuel pumps with 2 different angle of pulse fittings. 760 cases always had 2 pulse fittings one per side. OEM 44's always had 1 fuel pump per carb. OEM dual 44 intake manifolds had a factory speed plate as the SBN38 has a different bolting pattern.
Silver 44's and 46's have a different 90 degree in and out for the fuel lines and both pulse fittings carb side will match.
Anything that doesnt have a bolt on area for a flame arrestor probably has a bell pressed into it. Most of the time you can tell what it is and who makes it BUT always measure the underside to get the size of the carb. If you post a picture of somthing with a press in fuel bell most people on here can tell you what it is or what we think it is.
Personally i always run 1 fuel in line from the tank per carb, then I "Y" the return line. Depending if the AM carbs your running have the restrictors drilled out you have to run a main jet inside the return "Y" fitting. The 967 needs good consistent fuel flow. I have friends that have VERY good luck with OEM 46's. If you need an intake manifold pony up for the PHP manifold from @JetManiac Everyone has a preference, I prefer VF2's for reeds.
3 bolts up top with an OEM intake manifold with no speed plate, one fuel pump with a master and a slave carb = OEM 38's
4 bolts up top is 44/46 SBN. Black 44's with curved fuel in and out fittings are OEM off a 760 And usually came with fuel pumps with 2 different angle of pulse fittings. 760 cases always had 2 pulse fittings one per side. OEM 44's always had 1 fuel pump per carb. OEM dual 44 intake manifolds had a factory speed plate as the SBN38 has a different bolting pattern.
Silver 44's and 46's have a different 90 degree in and out for the fuel lines and both pulse fittings carb side will match.
Anything that doesnt have a bolt on area for a flame arrestor probably has a bell pressed into it. Most of the time you can tell what it is and who makes it BUT always measure the underside to get the size of the carb. If you post a picture of somthing with a press in fuel bell most people on here can tell you what it is or what we think it is.
Personally i always run 1 fuel in line from the tank per carb, then I "Y" the return line. Depending if the AM carbs your running have the restrictors drilled out you have to run a main jet inside the return "Y" fitting. The 967 needs good consistent fuel flow. I have friends that have VERY good luck with OEM 46's. If you need an intake manifold pony up for the PHP manifold from @JetManiac Everyone has a preference, I prefer VF2's for reeds.
- Location
- Coeur D' Alene, ID
I will have measurements and pics of the carbs tonight I will post up. Appreciate the help and info man, those 38's which i were told were 46's have been bullet proof for 6 years or so for me so carbs are not something i have much experience with. I believe these have a pulse on each carb as well.
Hoping they are 46's but sounds like i should get by fine with 44's considering how well the motor ran with the smaller 38's, at least in the low to mid range.
@Citizen looking at the pictures of the throat bore they cant be much bigger than 40's for what you have on there now. You would be supprised, 8MM doesnt sound like alot untill you hold the base gaskets up to eachother. Ill bet that little intake manifold doesnt have enough material to bore open that much either. Report back with the measurements.
- Location
- Coeur D' Alene, ID
Been trying to find more info on carbs, but from what I am finding there isn't anything between a 38 and a 44 for yamaha?
no theres not. Kawasaki and Seadoo Had the 38 and 40mm mikuni i body carbs which were very similar to SBN and share the same rebuild kits and jets but different bolt pattern all together. Wetjets were a 61x based single carb and some of them had 46mm carbs from the factory as well.
- Location
- Coeur D' Alene, ID
Lucked out, they are 46's on a a r&d mani that looks port matched, both looked super clean. Doesn't look like the returns were drilled out. Took lots of pics and will upload tomorrow. Swapped my n/s and jetting across, will install on Thursday.
the ones from his bud with bells on top
- Location
- Coeur D' Alene, ID
DAG
Yes, my balls tickled from that landing
- Location
- Charlotte, NC
I'm curious about the inner venture. Is it pulling fuel from 2 circuits with the arm going all the way across like that. And are there 2 rings of holes around the middle?
FlyinRyan324
High on Helium
- Location
- Lake Wylie, North Carolina
I'd just buy someone's used full specs for $800-1000. It sounds like a lot of money, because it is. However, you may or may not have realized this when making the jump to a big motor, but in order for that "package" to work correctly, you need the supplemental parts.
If someone gave you a brand new 1200cc motor for FREE, that's amazing! But you better plan on spending some money on all the other parts to make it work.
I hate to watch you try to "make it work" to save money in the short term. But then down the road, your most expensive part blows up because it had cheap carbs.
Just my 2¢. Luckily I've had smart people around me who've watched this stuff happen to them or other people and force me into spending 4x my planned budget, instead of cheaping out. That sounds a bit harsh, but it's the wisdom that I've learned in this big motor world
If someone gave you a brand new 1200cc motor for FREE, that's amazing! But you better plan on spending some money on all the other parts to make it work.
I hate to watch you try to "make it work" to save money in the short term. But then down the road, your most expensive part blows up because it had cheap carbs.
Just my 2¢. Luckily I've had smart people around me who've watched this stuff happen to them or other people and force me into spending 4x my planned budget, instead of cheaping out. That sounds a bit harsh, but it's the wisdom that I've learned in this big motor world
DAG
Yes, my balls tickled from that landing
- Location
- Charlotte, NC
So not full specs then..
- Location
- Charlotte NC
- Location
- Coeur D' Alene, ID
Totally get what you are saying Ryan and can't disagree. However, Full spec's just are not in the cards for me at the moment. There seem to be quite a few people running 46's on bigger motors and my specific motor without issues. Not saying it is ideal, but I don't think it is going to cause engine failure. My plan is full spec's next spring, and TL the following most likely.
Carbs should be measured at the butterfly or throttle valve not the bottom or top.
That's what I meant....kinda should have specified I shove my calipers all the way to the butterfly from the bottom
mike b
Michael "Mayhem" Bevacqua aka MikeyChan
- Location
- California
Hell if you made due with the 38s and didn't damage the motor the 46s will for sure be better. Listen to Ryan on having to run the right stuff, all about package the builder says. This is how some people get turned off on a good motor because of user error/small pockets, not trying to be harsh on you but buying two or three carbs you will be over the FS budget. Hope the 46s work for you and that motor is okay. I understand the budget thing but I was talked into the right bolt ons by engine builder early on because he knew what I would have done otherwise lol. Good luck
- Location
- Coeur D' Alene, ID
Thanks a lot for chiming in Mike. I may have a line on some 48fs with php mani and will sell the dual 46's to recoup some of the cost. Deciding factor at this point is if my reeds and cages on an r&d 46mm manifold will work on the php. If it does i will pull the trigger, but if i have to spend another 250 on reeds i will be divorced lol. To avoid that, I will just make due with the 46's.
Do you think the FS carbs will really make that much of a power difference? I am not familiar on what changes are made to the carbs to make them a FS.
Do you think the FS carbs will really make that much of a power difference? I am not familiar on what changes are made to the carbs to make them a FS.