- Location
- Lafayette,LA
I got art to taper and bore my single 44.....nice smooth delivery of power throughout the powerband snappy with instant throttle response, very pleased. does consume alittle more gas though...
Other poll : should I Bore carbs to larger size
- Thread starter yama-doo
- Start date
- Location
- marion ohio
Some people are just good planer and execute even better. Limitedslip7 has amazed me several times with things he's done 1st time trying. It seems the only time things don't work out perfect for him is when he takes my advise.
- Location
- the jetski grave yard
my bad for getting involved in this fuster cluck.i'll just shake my head and laugh. good fn luck. over n out!
Half flip95
Formerly pondracer95
- Location
- Lake Havasu City AZ
lol yeea we are all guilty of doing it... asking a question but reject legitimate responses because we have already made up our mind on what we want the answer to be. so why ask at all?
You go online and ask about the effects of boring your carb. To me, this is an immediate indicator that you don't know what you're doing. You have the skills/equipment to perform the modification, but you are unsure what the end result will be. It is a noble endeavor, but it could end up been costly and ineffective.
I would take a look at Group Ks Engine package for the GP1200. They suggest boring the carbs on most of their engine packages, but not on the GP1200.
You go online and ask about the effects of boring your carb. To me, this is an immediate indicator that you don't know what you're doing. You have the skills/equipment to perform the modification, but you are unsure what the end result will be. It is a noble endeavor, but it could end up been costly and ineffective.
I would take a look at Group Ks Engine package for the GP1200. They suggest boring the carbs on most of their engine packages, but not on the GP1200.
Nuklear6
I Dream 10' Surf!
yama-boo,
What are you going to do for a venturi (or "bomb site") after you bore them? Something has to deliver the fuel. Even straight through carbs like black jacks have a angular venturi around the circumference of the aftermarket "bell" pressed in the top of the carb. The other issue is; are you going to make your own throttle plate and shaft? If not id suggest going 48 mm as there are already plates and shafts on the market that could be bought. No one is questioning your machine ability. I have done a lot of machining on sbn carbs lately and all im saying is accurately making a bigger hole is def the easy part. By no means am i saying dont do it im just saying make sure you have a complete plan before just taking some hss to your carbs.
On the subject of boring just the bottom of the carbs...... That is a waist of time. Im not saying that some good tuners back in the day didnt make it work. But id attest that more to there superior tuning ability rather then the actual machine work making a difference. Even 46mm off the shelf mikunis are much smaller then 46mm at the reduction ring in the throat (something like 42mm but i think LESS).
What are you going to do for a venturi (or "bomb site") after you bore them? Something has to deliver the fuel. Even straight through carbs like black jacks have a angular venturi around the circumference of the aftermarket "bell" pressed in the top of the carb. The other issue is; are you going to make your own throttle plate and shaft? If not id suggest going 48 mm as there are already plates and shafts on the market that could be bought. No one is questioning your machine ability. I have done a lot of machining on sbn carbs lately and all im saying is accurately making a bigger hole is def the easy part. By no means am i saying dont do it im just saying make sure you have a complete plan before just taking some hss to your carbs.
On the subject of boring just the bottom of the carbs...... That is a waist of time. Im not saying that some good tuners back in the day didnt make it work. But id attest that more to there superior tuning ability rather then the actual machine work making a difference. Even 46mm off the shelf mikunis are much smaller then 46mm at the reduction ring in the throat (something like 42mm but i think LESS).
yama-doo
X-
- Location
- Port Saint Lucie Florida
I had not really made my mind up so any "Legitimate" answers either way ya or na was and/or is fine, and yes I am guilty I do like to ask even if I have a idea just to see what other peoples results where. different type of engines you general want different effects an modifying a 0-520 has completely different effects then a xl1200 jet ski engine and admittedly I have not played with or modded much of any jets skis for at least 15+ years besides a occasional engine swap so there are lots more knowledge people about how a mod will effect a jetski engine. I have read group K material as well , everyone is a little different but personally I like to hear for the average person to see there results vs companies selling products (companies have lots of good info but at times could be consider basis or at least that's how I look at it)
Actual the one post saying it would give bottom end but not top end has me leaning to not boring them as I feel this particular project ski should have plenty of bottom end as it is and with no top end increase it doesn't seem worth the effort for my project is how I am thinking right now
Maybe I came off wrong in my reply to him but he pissed me off going off topic to start questioning my abilities and talking about using a the dermal (maybe that's how he does it who knows) I tried to joke it off with the first post but ...anyway it just rubbed me the wrong way so I a said something , but its over and done now he wished me a color amount of luck and we moved on
Actual the one post saying it would give bottom end but not top end has me leaning to not boring them as I feel this particular project ski should have plenty of bottom end as it is and with no top end increase it doesn't seem worth the effort for my project is how I am thinking right now
Maybe I came off wrong in my reply to him but he pissed me off going off topic to start questioning my abilities and talking about using a the dermal (maybe that's how he does it who knows) I tried to joke it off with the first post but ...anyway it just rubbed me the wrong way so I a said something , but its over and done now he wished me a color amount of luck and we moved on
yama-doo
X-
- Location
- Port Saint Lucie Florida
nuke6,
ya I was just typing (I'm little slow on these computers) but lean towards not doing them if its just going to be bottom end
......... with that said you post does bring up some good discussion points....
personally I would not go over 48mm as I feel the walls would not be any more then a paper shells, but everyone is different and has different opinions about that. yes mikuni design uses a forced reduction to create turbulence around the ventri and beleive you are correct if it being roughly 2mm of reduction , you could bore the top and bottom of the barrel on the lathe but personally I would leave the ventruri in place then set the carb up on the mill and work the reduction ring down to roughly about the same percentage ratio (barrel to reduction) it is now. Also with staying with 46 or 48 the plates and shafts like you said they are readily available and it would have been just plain easier to order them vs fabricating some, though it would not be hard just time consuming plus the cost of stock
ya I was just typing (I'm little slow on these computers) but lean towards not doing them if its just going to be bottom end
......... with that said you post does bring up some good discussion points....
personally I would not go over 48mm as I feel the walls would not be any more then a paper shells, but everyone is different and has different opinions about that. yes mikuni design uses a forced reduction to create turbulence around the ventri and beleive you are correct if it being roughly 2mm of reduction , you could bore the top and bottom of the barrel on the lathe but personally I would leave the ventruri in place then set the carb up on the mill and work the reduction ring down to roughly about the same percentage ratio (barrel to reduction) it is now. Also with staying with 46 or 48 the plates and shafts like you said they are readily available and it would have been just plain easier to order them vs fabricating some, though it would not be hard just time consuming plus the cost of stock
- Location
- Houston/Galveston
Yama-doo, what carbs are you going to bore?? OEM 44's?? I say go for it. I even have a junk pair you can have to set up and practice on if you would like them. I say they are junk because I cant even get the metering block out its so corroded in. I have bead blasted them on both sides but not in the bore.
Lathe work, easy as pie, you can do it. 4 jaw chuck, indicate part in and set your feed. Rock n roll. People who cant machine are skeeerd.
Lathe work, easy as pie, you can do it. 4 jaw chuck, indicate part in and set your feed. Rock n roll. People who cant machine are skeeerd.
yama-doo
X-
- Location
- Port Saint Lucie Florida
ya my stuff is stock oem 44's
I used to use glass beads and some other media stuff for the blasting cabinet doing Ac cases, carbs ,cylinders etc and had the same kind off issue I finial just went to a straight out side sand blaster ........ its messier but it well clean everything! after you clean them either soak them in the parts washer over night OR heat them in the oven and all you stuff will come out of those carbs . I use anti seize on anything that will touch aluminum to prevent that problem in the future
I used to use glass beads and some other media stuff for the blasting cabinet doing Ac cases, carbs ,cylinders etc and had the same kind off issue I finial just went to a straight out side sand blaster ........ its messier but it well clean everything! after you clean them either soak them in the parts washer over night OR heat them in the oven and all you stuff will come out of those carbs . I use anti seize on anything that will touch aluminum to prevent that problem in the future
- Location
- Houston/Galveston
Yama doo.. what are you talking about?? The glass beads did not mess the carbs up. I wouldnt even think about sand blasting carbs, your doing it wrong. Soaking them in parts washer over night wont help these carbs either. I have soaked these things in penetrating oil for a week and nada. You should go ask the previous owner of the carbs why he let the carbs fill with water for so long. Thanks for the advise, but its all Caption obvious advise. lol.
yama-doo
X-
- Location
- Port Saint Lucie Florida
I was just refereeing to what I found has worked though it may not be the commonly accepted methods thinking maybe you could save your carbs.
glass bead media is recommend for aluminum materials such as an aircraft case or a jet ski carb basically anything made form aluminum because the glass beads are not as aggressive of a media against the soft aluminum materials and they do clean nicely But I found more aggressive medias to work better eating corrosive areas. Sand used to be commonly used but modern methods discourage the use of sand as a media. Granted everything has its down side but I have heard a lot of younger guys say oh you can't use sand..lol. normally this is enough to free up enough of the corrosive area as you where talking about but if not I tend to soak in parts washer it seems to soften the corrosion and make easier to break lose again this may not be a accepted method but works for me The issue your fighting is when you have a different metal material such as bronze,brass, stainless steel etc touch aluminum directly you get that corrosive build up and on a internal area makes it harder to deal with and being around salt water makes it even worse . short of freeing it up you would need to drill out the out parts and replace what needs replacing
glass bead media is recommend for aluminum materials such as an aircraft case or a jet ski carb basically anything made form aluminum because the glass beads are not as aggressive of a media against the soft aluminum materials and they do clean nicely But I found more aggressive medias to work better eating corrosive areas. Sand used to be commonly used but modern methods discourage the use of sand as a media. Granted everything has its down side but I have heard a lot of younger guys say oh you can't use sand..lol. normally this is enough to free up enough of the corrosive area as you where talking about but if not I tend to soak in parts washer it seems to soften the corrosion and make easier to break lose again this may not be a accepted method but works for me The issue your fighting is when you have a different metal material such as bronze,brass, stainless steel etc touch aluminum directly you get that corrosive build up and on a internal area makes it harder to deal with and being around salt water makes it even worse . short of freeing it up you would need to drill out the out parts and replace what needs replacing
Philip Clemmons
Owner, P&P Performance
- Location
- Richmond, Va
The Venturi was designed around the bore of the carb (they work together). To change one component without the other is asking for trouble. The larger bore can potentially slow airflow down through the carb, which reduces signal strength at the Venturi. This leads to a poor working (metering) carb. The pros (such as Full Spec) flow each carb and adjust to verify proper/consistent signal at the Venturi and jetting circuits.
Your efforts are best focused elsewhere.
Your efforts are best focused elsewhere.
- Location
- Houston/Galveston
These carbs are beyond saving. I have just been saving them to practice powder coating on carbs. I made plastic plugs to cap off all the openings to aid in the ease of glass & sand blasting to keep from hitting anything that I dont want blasted. INSTEAD of using TAPE.