Do i need to retune Carby ? 125 to 140cc
- Thread starter lerroy
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AWESOME! Paid today and he probably wont know because I still cannot email him I just get some bullshit
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lerroy
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Ian Williams Tuning <[email protected]>
thats what im sending to works for me sent one today
i recieved both jets today as well not in the package says please ring me credit card didnt go through hahaha so he sent before payment i sorted him out today though via phone
its 08 83409288
thats what im sending to works for me sent one today
i recieved both jets today as well not in the package says please ring me credit card didnt go through hahaha so he sent before payment i sorted him out today though via phone
its 08 83409288
I know I just posted this in another thread but I'll put it here as well.
To get these 140 engines really going you must ditch the Pitpro and DHZ supplied exhausts or any other crap china pipe. I really can't believe the exhaust DHZ is running on his 140. I know this is probably one of the most expensive parts to add to your bike, but it does allow the whole thing to breath properly and can travel from bike to bike once you have one. If you can TIG weld your own out of stainless you are laughing, or know someone that will do it. Once you are running a big bore pipe then you will have to jet up to suit on the smaller carbs or upgrade to a bigger carb which may have suitable jetting right off the bat.
I just trialled the 28mm OKO, and the main is good but the low speed jet is too small. Easy fixed. The motor with a 28mm carb and exhaust in 28mm stepped to 32mm without any port matching or any other modification, was pulling way better and longer than a DHZ bike with port matched and smoothed intake, 30mm China Mikuni with correct jetting and running a big cam and a derestricted DHZ exhaust. The two things holding that bike back are the so called 30mm carb and shit flowing exhaust.
I was skeptical on the 28mm OKO with a stock engine but was surprised to find it very responsive and hard pulling. If you read the other thread I posted about this you will see I was surprised more than i would of liked...
The fact that this is a stroked 140 with a reasonable compression ratio obviously is allowing it suck and blow a lot harder than a 55mm stroke engine bored to 140.
To get these 140 engines really going you must ditch the Pitpro and DHZ supplied exhausts or any other crap china pipe. I really can't believe the exhaust DHZ is running on his 140. I know this is probably one of the most expensive parts to add to your bike, but it does allow the whole thing to breath properly and can travel from bike to bike once you have one. If you can TIG weld your own out of stainless you are laughing, or know someone that will do it. Once you are running a big bore pipe then you will have to jet up to suit on the smaller carbs or upgrade to a bigger carb which may have suitable jetting right off the bat.
I just trialled the 28mm OKO, and the main is good but the low speed jet is too small. Easy fixed. The motor with a 28mm carb and exhaust in 28mm stepped to 32mm without any port matching or any other modification, was pulling way better and longer than a DHZ bike with port matched and smoothed intake, 30mm China Mikuni with correct jetting and running a big cam and a derestricted DHZ exhaust. The two things holding that bike back are the so called 30mm carb and shit flowing exhaust.
I was skeptical on the 28mm OKO with a stock engine but was surprised to find it very responsive and hard pulling. If you read the other thread I posted about this you will see I was surprised more than i would of liked...
The fact that this is a stroked 140 with a reasonable compression ratio obviously is allowing it suck and blow a lot harder than a 55mm stroke engine bored to 140.
oko and vm mikuni
but isnt the 26mm vm mikuni and the 28mm oko, two stroke designed carbies??? and why are people using them on the four strokes i have heard there very hard to tune?? and i bought a oko 28mm but sent it back because mack told me it wasnt ideal its too big and so did cactus i wish people spoke from experience instead of hear say!! i mean i only comment if im positive on the advice im going to give..
but isnt the 26mm vm mikuni and the 28mm oko, two stroke designed carbies??? and why are people using them on the four strokes i have heard there very hard to tune?? and i bought a oko 28mm but sent it back because mack told me it wasnt ideal its too big and so did cactus i wish people spoke from experience instead of hear say!!
i mean i only comment if im positive on the advice im going to give..Well basic carbs aren't really designed one way or the other, some more suitable for one or the other, buy design, but basically they all have a choke size, deliver a metered ratio of fuel throughout the throttle range and have a mounting for manifold and filter. Carbs have been getting swapped and adapted from engine to engine through trial and error since time eternal.
From my experience 28mm IS or can be problematic to tune on engines which are not flowing well. Hence I have recommended the average joe stick to 26mm and below. The trial of the above carb on a stock engine I would not normally even attempt but as it turned out I did cause I had nothing else at the time on hand. Also I still wouldn't recommend it unless you use a really good flowing pipe which most don't have. Trial and error as mentioned, is probably the main system used by every engine builder in the world, and this is where you should report your results isn't it?
From my experience 28mm IS or can be problematic to tune on engines which are not flowing well. Hence I have recommended the average joe stick to 26mm and below. The trial of the above carb on a stock engine I would not normally even attempt but as it turned out I did cause I had nothing else at the time on hand. Also I still wouldn't recommend it unless you use a really good flowing pipe which most don't have. Trial and error as mentioned, is probably the main system used by every engine builder in the world, and this is where you should report your results isn't it?
error
yes point taken, but im in an awkward position as i got a new motor and a new carbie now how am i going to run it in the correct way if im spending the precious running in time tuning the carbie?? by the time i tune this carbie there will be no more roughness in the bore to seat my rings well????
yes point taken, but im in an awkward position as i got a new motor and a new carbie now how am i going to run it in the correct way if im spending the precious running in time tuning the carbie?? by the time i tune this carbie there will be no more roughness in the bore to seat my rings well????
Cactus Jack
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Monty Python And The Holy Grail
Yes , some people are looking for hen's teeth , unicorns horns and the "Holy Grail" . They wanna go fast without being an expert tuner !
1 : The carb kit you bought was for a CRF50 - the Lifan 140 is based off a Honda NICE motor NOT a CRF/XR50 motor with a RACE head !
2 : You're going to have to use the long 26 mm LIFAN intake manifold - NOT the stock 90 degree junk that has "ZR" cast on the side . The manifold you got with that Mikuni kit is too low - the turn is too tight and kills velocity !
3: Read this :
Sudco - Mikuni Carburetors
4: Your exhaust pipe I/D needs to be larger than the bore of the inlet manifold and carb to make everything work . What goes in - MUST be allowed to go out - otherwise you get a traffic jam just the same as when two lanes of a freeway go into 1 lane .
5: If you read that ebay listing for the velocity stack correctly - you'll realise that the guy is saying that carbs with the air mixture screw underneath at the REAR are the 2 stroke carbs (ie "25" "26" and "30" mm Mikuni carbs supplied stock on every pit bike sold in OZ) . Proper VM26 Mikunis have an air/fuel mixture screw on the side near the inlet of the carb and that type of carb works better on a 4 stroke !
6: You can't expect to just buy a carb , plonk it on and - Hey Presto - crisp fuel injection type power and throttle response .
7: If you read back over my posts I said that the 24 mm OKO kit would be the absolute best carb to use on a stock Lifan 140 due to the fact that the inlet valve throat is only 23 mm in diameter .........and I can now also add that the stock exhaust header pipe is only 25 I/D so that explains why the 24 carb would work OK !
Yes , some people are looking for hen's teeth , unicorns horns and the "Holy Grail" . They wanna go fast without being an expert tuner !
1 : The carb kit you bought was for a CRF50 - the Lifan 140 is based off a Honda NICE motor NOT a CRF/XR50 motor with a RACE head !
2 : You're going to have to use the long 26 mm LIFAN intake manifold - NOT the stock 90 degree junk that has "ZR" cast on the side . The manifold you got with that Mikuni kit is too low - the turn is too tight and kills velocity !
3: Read this :
Sudco - Mikuni Carburetors
4: Your exhaust pipe I/D needs to be larger than the bore of the inlet manifold and carb to make everything work . What goes in - MUST be allowed to go out - otherwise you get a traffic jam just the same as when two lanes of a freeway go into 1 lane .
5: If you read that ebay listing for the velocity stack correctly - you'll realise that the guy is saying that carbs with the air mixture screw underneath at the REAR are the 2 stroke carbs (ie "25" "26" and "30" mm Mikuni carbs supplied stock on every pit bike sold in OZ) . Proper VM26 Mikunis have an air/fuel mixture screw on the side near the inlet of the carb and that type of carb works better on a 4 stroke !
6: You can't expect to just buy a carb , plonk it on and - Hey Presto - crisp fuel injection type power and throttle response .
7: If you read back over my posts I said that the 24 mm OKO kit would be the absolute best carb to use on a stock Lifan 140 due to the fact that the inlet valve throat is only 23 mm in diameter .........and I can now also add that the stock exhaust header pipe is only 25 I/D so that explains why the 24 carb would work OK !
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Cactus Jack
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You can run it in with the carb off your old motor on it ! I ran a MOJO Lifan 120 monster motor in with a 15 mm early DHZ 120 carb on it without any problems ! You should bed your engine in using short bursts anyway - making it pull hard in taller gears without letting it rev - then let it cool and repeat .
What you REALLY need to do is make sure that pipe you're using ain't a 23 mm I/D junker because THAT will cook the hell out of your new 140 !
big bore
no i got a big bore exaust, its the bike you commented on as being sik the black monkey bike is mine?? and stop effing saying that i expect to bang on the carbie and hey presto dont try to make a fool out of me ffs!!! why the eff do you think i have been researching this forum for ages for , but its all in vien when you jump on and try to make me look like an idiot!!!
no i got a big bore exaust, its the bike you commented on as being sik the black monkey bike is mine?? and stop effing saying that i expect to bang on the carbie and hey presto dont try to make a fool out of me ffs!!! why the eff do you think i have been researching this forum for ages for , but its all in vien when you jump on and try to make me look like an idiot!!!
For what ever its worth (two cents) If i was running in the motor (just ran one in two days ago) i do this. Most carbs will come reasonably jetted to at least run fairly well. Don't worry about trying to tune it while running in cause the way it runs will change as it runs in. I run a carb i know is jetted fairly well for similar size engine. If using an unfamiliar carb, look on the net for commonly run mainjet sizes for that carb/engine combo. In your case planet mini would be a good place to search vm 26 jetting as a heap of guys run them with 146 kits. I then drop the needle clip to richen it a little and go for it. I don't muck around with running in. I start it with a screwdriver handy incase the idle screw is obviously way off, but if she runs clean enough first up thats it. I let the oil pump up with the oil return hose loose so she'll leak and i can be sure the lines are flowing, tighten her up quickly then i pretty much give her a good rap around a little flat track we have accellerating hard to about 2/3 rds throttle through second and third gear for about 5 mins finishing with a few really good revs and a hard steady run back to the shed and do a plug chop. Then straight on the bike stand, dump the oil for fresh to limit the castings and filings from spreading to far into every nook and cranny, have a look at the plug and make any changes to the carb settings if obviously running way off. If it ran fine and the plug isn't showing any obvious bad signs I don't worry any further for now. Straight back on and I pretty much get on the throttle and give her a bit. After about 15 mins of this, I dump that lot of oil and if all is still well and nothing is giving me warning bells, I go at it again now for as long as I like and really like to relax with it and see what shes got. After this run, or really, throughout this run I start to do a few plug chops and run through a few tuning seqences to start sorting it. Often I'm always setting the play in cables as well as checking other things at this time as well. I like to have fun scaring myself while I'm at it too. Thats the only reason I'm into it. I'm one finger typing right now cause of that. You guys now how much of a pain it is to put in capitals with one hand. If you think some of my sentances are too long, thats why. I know i'll have to do a capital next...
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sixeven
Well-Known Member
I think you guys should talk on the telephone. Heard of one? fark these posts are soooooooo bloody long its boring me and sending me to sleep.
