unit_mx
Well-Known Member
Thanks for that mate, Really appreciate you detailed posts.
Molkt Carbiy, what's the go?
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themountain
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CACTUS...you´re the dood , boy!!
...I only like to stir the things up sometimes
@Unit : haha.. got one of this piaggio things myself ...cheap and awesome!!
...I only like to stir the things up sometimes@Unit : haha.. got one of this piaggio things myself ...cheap and awesome!!
Cactus Jack
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As an example of what I was saying ..... check out the jet sizes they supply with the VM 26 carb kit in this link ...... then check out what jet sizes Honda uses for their 175 / 185 / 250 / 350 engines ...... Now check out the Keihin to Mikuni jet conversion chart and see how ridiculously HUGE the jets are that come with the yank carb kits .... ..... I simply can't see jets that big working on a 160 four stroke over here ........
# Genuine Mikuni VM26mm Performance Carb
# Intake Kit
# Jet kit with 3 different sizes (Stock size is a #195 - Extra jets sizes of 155, 165 & 175)
Trail Bikes 160cc Bore Kit and Mikuni VM26mm Carb Performance Kit for KLX110 - Trail Bikes - Pit Bike Parts
Width "---- Keihin # -- DynoJets # -- Mikuni #
0.0720---- 185--------- 166--------- 155.6
0.0730---- 187.5------- 168--------- 157.5
0.0740---- 190--------- 170--------- 159.4
0.0750---- 192.5------- 172--------- 161.3
0.0760---- 195--------- 174--------- 163.1
0.0770---- 197.5------- 176--------- 165.0
0.0780---- 200--------- 178--------- 166.9
0.0790---- 202.5------- 180--------- 168.8
0.0800---- 205--------- 182--------- 170.6
0.0810---- 207.5------- 184--------- 172.5
0.0820---- 210--------- 186--------- 174.4
0.0830---- 212.5------- 188--------- 176.3
0.0840---- 215--------- 190--------- 178.1
0.0850---- 217.5------- 192--------- 180.0
0.0860---- 220--------- 194--------- 181.9
0.0870---- 222.5------- 196--------- 183.7
0.0880---- 225--------- 198--------- 185.6
0.0890---- 227.5------- 200--------- 187.5
..... I simply can't see jets that big working on a 160 four stroke over here ........ # Genuine Mikuni VM26mm Performance Carb
# Intake Kit
# Jet kit with 3 different sizes (Stock size is a #195 - Extra jets sizes of 155, 165 & 175)
Trail Bikes 160cc Bore Kit and Mikuni VM26mm Carb Performance Kit for KLX110 - Trail Bikes - Pit Bike Parts
Width "---- Keihin # -- DynoJets # -- Mikuni #
0.0720---- 185--------- 166--------- 155.6
0.0730---- 187.5------- 168--------- 157.5
0.0740---- 190--------- 170--------- 159.4
0.0750---- 192.5------- 172--------- 161.3
0.0760---- 195--------- 174--------- 163.1
0.0770---- 197.5------- 176--------- 165.0
0.0780---- 200--------- 178--------- 166.9
0.0790---- 202.5------- 180--------- 168.8
0.0800---- 205--------- 182--------- 170.6
0.0810---- 207.5------- 184--------- 172.5
0.0820---- 210--------- 186--------- 174.4
0.0830---- 212.5------- 188--------- 176.3
0.0840---- 215--------- 190--------- 178.1
0.0850---- 217.5------- 192--------- 180.0
0.0860---- 220--------- 194--------- 181.9
0.0870---- 222.5------- 196--------- 183.7
0.0880---- 225--------- 198--------- 185.6
0.0890---- 227.5------- 200--------- 187.5
Cactus Jack
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More info on useful jet kits to help with fine tuning carbs :
Mikuni VM-26 jet kit :
Pilot : Honda Trail Bikes
Main : Honda Trail Bikes
This jet kit for the Keihin PE-28 would work over here :
Main: Honda Trail Bikes
But this one wouldn't :
Main : Honda Trail Bikes
OKO 26 mm :
Pilot : Honda Trail Bikes
Main : Honda Trail Bikes
You'd just need to email them to find out what jets will fit flat slide OKO's , MOLKTS , MICONIS and the "25" and "30" Mikunis ......
Oz mini 50's are the Australian distributors for trail bikes parts :
No title
Mikuni VM-26 jet kit :
Pilot : Honda Trail Bikes
Main : Honda Trail Bikes
This jet kit for the Keihin PE-28 would work over here :
Main: Honda Trail Bikes
But this one wouldn't :
Main : Honda Trail Bikes
OKO 26 mm :
Pilot : Honda Trail Bikes
Main : Honda Trail Bikes
You'd just need to email them to find out what jets will fit flat slide OKO's , MOLKTS , MICONIS and the "25" and "30" Mikunis ......
Oz mini 50's are the Australian distributors for trail bikes parts :
No title
I have a problem, it seems to happen when holding a steady throttle after accelerating. I can accelerate at any throttle opening but when I shut the throttle down to cruise thats when it starts jerking. I can't get rid of it with changing the needle clip. Would that mean it's my main jet? Hope so, just bought a jet kit, would it be worthwhile trying to buy another molkt or something else?
this is a bit of an odd one...
I'm sure you've posted details before, but i cant be buggered sifting through threads finding out what you have...
So engine, carb diameter, mods and jetting specs???
The first thing that comes to mind, is a: float bowl isnt adjusted correctly, and is borderline on the low side... meaning it's sucking through under acceleration, and filling as per usual... but when it settles down to run at a steady rev setting, it may be under then oversupplying... hence the surging... Do you run a 1/4 turn throttle? odd as it sounds, "clumsy" hands on the throttle, particularly with the 1/4 turn throttles can make them feel like it's surging...
First thing i would look at, would be float bowl height... then perhaps look at changing the actual needle itself for a slightly smaller one, thus richening up fuel mix through the mid.. i had the same issue with my widow... ran great on acceleration, but as soon as you sat at steady throttle settings, it started surging, popping etc etc... then you'd have to wind it on to get the fuel back where it should be...
in the end, we made a custom needle for it, which had a radically different taper just between pilot and needle overlap... and then another taper where it overlapped the needle to main jet operation... might be a bit extreme, but could be a solution if you have the tooling...
However, life shouldnt be that tricky for an engine with the technology of a tractor/boat anchor...
what size is your pilot??
think i read in the chat box you're running a #26 pilot??
might be too big, and causing the surging at light cruise throttle settings...
try a #20 or #22 pilot, and adjust fuel screw accordingly. Ideally it should be 1.5-2 turns out... if your fuel screw is around there, your jetting is ok... too far in, you need a smaller pilot... 3 or more turns out, you need a bigger pilot... Hmm... hate that one, pretty sure i have it the right way round...
CACTUS, help!!! have i got it right way round for pilot/fuel screw adjustment??
anyways, try a smaller pilot, see how you go... and check the float level...
I'm sure you've posted details before, but i cant be buggered sifting through threads finding out what you have...
So engine, carb diameter, mods and jetting specs???
The first thing that comes to mind, is a: float bowl isnt adjusted correctly, and is borderline on the low side... meaning it's sucking through under acceleration, and filling as per usual... but when it settles down to run at a steady rev setting, it may be under then oversupplying... hence the surging... Do you run a 1/4 turn throttle? odd as it sounds, "clumsy" hands on the throttle, particularly with the 1/4 turn throttles can make them feel like it's surging...
First thing i would look at, would be float bowl height... then perhaps look at changing the actual needle itself for a slightly smaller one, thus richening up fuel mix through the mid.. i had the same issue with my widow... ran great on acceleration, but as soon as you sat at steady throttle settings, it started surging, popping etc etc... then you'd have to wind it on to get the fuel back where it should be...
in the end, we made a custom needle for it, which had a radically different taper just between pilot and needle overlap... and then another taper where it overlapped the needle to main jet operation... might be a bit extreme, but could be a solution if you have the tooling...
However, life shouldnt be that tricky for an engine with the technology of a tractor/boat anchor...
what size is your pilot??
think i read in the chat box you're running a #26 pilot??
might be too big, and causing the surging at light cruise throttle settings...
try a #20 or #22 pilot, and adjust fuel screw accordingly. Ideally it should be 1.5-2 turns out... if your fuel screw is around there, your jetting is ok... too far in, you need a smaller pilot... 3 or more turns out, you need a bigger pilot... Hmm... hate that one, pretty sure i have it the right way round...
CACTUS, help!!! have i got it right way round for pilot/fuel screw adjustment??
anyways, try a smaller pilot, see how you go... and check the float level...
nah no quarter turn throttle, I don't think it's got anything to do with my throttle control. I've tried playing with float heights to no avail. I can hold steady throttle and have no bogging, it's only when I come back down from a higher throttle opening it does it.
The pilot has no number on it, the main is a 102 though. clockwise is richer on my air screw. I currently have it 1 turn it, it varies from 3/4 turns to 1 1/2 turns depending on float height. I think my carb is just buggered, it cuts out when doing wheelies also
It only does it at high rpm, low throttle openings though. Come to think of it, if I decelerate on any throttle opening except for closed it'll buck.
Acceleration. no probs.
I have seriously played with everything I could think of, changed spark plug for a new one too.
I even tried mixing methanol in with my fuel to lean it out as I couldn't change jets.
I bought some jets from dhz but they were the wrong ones, so if anyone needs a 25 pilot and 97.5 mikuni let me know.
I have a 22.5 pilot and this jet kit coming Honda Trail Bikes
hope that will fix it. I have a feeling it's nothing I'm doing though and that the carb is whacked..
I did read on a mikuni manual that one way to test if you're running rich is to go full throttle and then suddenly back off to half throttle, if it bogs main jet is rich. Sounds like what I'm having?
The pilot has no number on it, the main is a 102 though. clockwise is richer on my air screw. I currently have it 1 turn it, it varies from 3/4 turns to 1 1/2 turns depending on float height. I think my carb is just buggered, it cuts out when doing wheelies also
It only does it at high rpm, low throttle openings though. Come to think of it, if I decelerate on any throttle opening except for closed it'll buck.
Acceleration. no probs.
I have seriously played with everything I could think of, changed spark plug for a new one too.
I even tried mixing methanol in with my fuel to lean it out as I couldn't change jets.
I bought some jets from dhz but they were the wrong ones, so if anyone needs a 25 pilot and 97.5 mikuni let me know.
I have a 22.5 pilot and this jet kit coming Honda Trail Bikes
hope that will fix it. I have a feeling it's nothing I'm doing though and that the carb is whacked..
I did read on a mikuni manual that one way to test if you're running rich is to go full throttle and then suddenly back off to half throttle, if it bogs main jet is rich. Sounds like what I'm having?
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tormentandglory
Well-Known Member
I've been playing with a mikuni 28mm flatslide off an old kr250. I've fitted it on a fairly hot lifan 150. After much tooling about, I've found that its the needle taper that has been causing me trouble. Moving it up and down won't help to much if its the wrong shape! Try polishing the needle down with some emery paper and spinning it in a cordless drill.
Might not be a good idea to fiddle to much if you're not entirely sure what you're up to, or make sure you have a spare needle if you ruin the original.
Jet drills are ace! You can buy a set off egay very cheaply. My set was less than $30 and it has all sizes from 0.3mm up to 1.6mm in 0.05mm increments. And you can use them to gauge the size of the china jets that have no markings. And they're small enough to measure/drill pilot jets to One of my molkt 26mm carbs has some ridiculous thread on the jets, jap ones don't fit. Drilling is the only option.
Might not be a good idea to fiddle to much if you're not entirely sure what you're up to, or make sure you have a spare needle if you ruin the original.
Jet drills are ace! You can buy a set off egay very cheaply. My set was less than $30 and it has all sizes from 0.3mm up to 1.6mm in 0.05mm increments. And you can use them to gauge the size of the china jets that have no markings. And they're small enough to measure/drill pilot jets to
One of my molkt 26mm carbs has some ridiculous thread on the jets, jap ones don't fit. Drilling is the only option.
tormentandglory
Well-Known Member
And as for the leaky needle and seat, don't give up on them. The rubber tip on the needle is quite often not perfectly concentric with the needle body. Carefully grip the needle with a pair of pliers and twist/push it into the hole in the carb. That'll squish the rubber back into shape and it should work fine. I've tried this on oko's and on molkts and it works well
nah no quarter turn throttle, I don't think it's got anything to do with my throttle control. I've tried playing with float heights to no avail. I can hold steady throttle and have no bogging, it's only when I come back down from a higher throttle opening it does it.
The pilot has no number on it, the main is a 102 though. clockwise is richer on my air screw. I currently have it 1 turn it, it varies from 3/4 turns to 1 1/2 turns depending on float height. I think my carb is just buggered, it cuts out when doing wheelies also
It only does it at high rpm, low throttle openings though. Come to think of it, if I decelerate on any throttle opening except for closed it'll buck.
Acceleration. no probs.
I have seriously played with everything I could think of, changed spark plug for a new one too.
I even tried mixing methanol in with my fuel to lean it out as I couldn't change jets.
I bought some jets from dhz but they were the wrong ones, so if anyone needs a 25 pilot and 97.5 mikuni let me know.
I have a 22.5 pilot and this jet kit coming Honda Trail Bikes
hope that will fix it. I have a feeling it's nothing I'm doing though and that the carb is whacked..
I did read on a mikuni manual that one way to test if you're running rich is to go full throttle and then suddenly back off to half throttle, if it bogs main jet is rich. Sounds like what I'm having?
When you say it's "bucking" when you back off, i'm wondering if it's running on... ie, the carb isnt closing as quickly as you are shutting off the throttle... problem that used to plague 500cc 2-strokes... have you removed your slide, and given it a going over with very fine emery paper to smooth it off? might be worth a try...
MrBrnz can you post up all your bike specs in here, that way we can get a better idea of what jetting you should be running...
By the sounds of it, your jetting isnt far off, if your 1 turn out on the fuel screw, and it's pulling fine at all throttle openings... starting to think it's a mechanical issue with the carby, not jetting... is the cable lubed and operating smoothly??
Process of elimination my friend..
it's an atomik nitrous with yx150 daytona style,molkt 26mm, ngk cr7hsa new plug, 102 slotted hex main jet, unknown pilot. I've taken this carb apart maybe 40-50 times now, the slide seems to move ok, I was also thinking that maybe the needle wasn't dropping fast enough along with the slide as the clip only works when moving up and not down?
by "bucking" I mean it'll shut off then come back full power, shut off again, rinse repeat, unless I open throttle more or shut the throttle completely.
I can get the same thing happening on acceleration if I pull the choke which is what makes me think it's running rich on decel.
It's bloody annoying though. I never hadd such carb problems on my cbr250rr and I never played with the carbs even once lol.
by "bucking" I mean it'll shut off then come back full power, shut off again, rinse repeat, unless I open throttle more or shut the throttle completely.
I can get the same thing happening on acceleration if I pull the choke which is what makes me think it's running rich on decel.
It's bloody annoying though. I never hadd such carb problems on my cbr250rr and I never played with the carbs even once lol.
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might be a long shot, but is the needle perfectly straight??
there should be a weird clip thingy on top of the needle, where it sits in the slide... which itself is held in place also by the throttle spring...
If this clip is missing, it may be contributing to the issue.
there should be a weird clip thingy on top of the needle, where it sits in the slide... which itself is held in place also by the throttle spring...
If this clip is missing, it may be contributing to the issue.
ARGHHH i FIXED IT, after I bought 200 bucks worth of parts from ebay, lol..
turns out I had my needle placed wrong, i'm such a noob, I had it on top of the bronze circle thing instead of below, thus raising the needle and not pushing the needle down when letting off the throttle either, causing it to run rich on decel...
i'm such a carb NOOB
so you were right thump140, effectively the round thing on top of the needle was missing, because it waas under the needle
turns out I had my needle placed wrong, i'm such a noob, I had it on top of the bronze circle thing instead of below, thus raising the needle and not pushing the needle down when letting off the throttle either, causing it to run rich on decel...
i'm such a carb NOOB
so you were right thump140, effectively the round thing on top of the needle was missing, because it waas under the needle
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oh deary deary. Epic Fail!!! ha ha ha!! Dont worry about it mate, we've all done similar things... I rejetted my Blitz twice, before i figured out i had the choke operation the wrong way around... lol... seems up was choke on... heh heh... whoops..
