Need help. about molkt 26mm carb.
I just purchased this carb to my sinnis stealth(Same engine as apache).
I dont know to start tuning, in this carb way different over mikuni vm22, starting with size, and screw's turns, its way too different.
Can anyone help at least how to start ?
So far i have 1turn out on mixture screw, but there is alot of exhaust smoke, and it bogs alot.
On minkuni i knew that mixture screw would be fine between 2 turn out to 3 turns out, and then ajusting idling, and it was that easy, but these one, i dont know... :(
Re: Need help. about molkt 26mm carb.
Well the problem with these larger carbs is that they are designed to be used with larger bore engines so a small adjustment makes a big difference, this is even worse if you have not fitted a big bore kit to make it a 150cc.
First of all screw the idle mixture screw in all the way (clokwise) and make very small adjustments to get the idle right. If you are unable to get it right then you probably need a smaller idle jet. I had trouble finding one my self so I would suggest that you look at your current one then fine one on eBay that looks the same.
As for the needle position I have mine on the middle position but you might need yours set one position lower.
I have a 120 main jet which actually runs a tad rich. If you don't have a big bore kit installed you probably need a size 110.
Could you send a link to the carb that you have bought?
Re: Need help. about molkt 26mm carb.
Quote:
Originally Posted by
spencer2004
Well the problem with these larger carbs is that they are designed to be used with larger bore engines so a small adjustment makes a big difference, this is even worse if you have not fitted a big bore kit to make it a 150cc.
First of all screw the idle mixture screw in all the way (clokwise) and make very small adjustments to get the idle right. If you are unable to get it right then you probably need a smaller idle jet. I had trouble finding one my self so I would suggest that you look at your current one then fine one on eBay that looks the same.
As for the needle position I have mine on the middle position but you might need yours set one position lower.
I have a 120 main jet which actually runs a tad rich. If you don't have a big bore kit installed you probably need a size 110.
Could you send a link to the carb that you have bought?
First of all, thank you for that fast reply :)
Well, let me see where i start to explain, this mess....
First, after 2 days, of trying to find how to get engine to start, i've found that sensor on side stand was not working properly , so i've passed it (remove) to "eleminate" that problem...
Then, i've found the intake manifold was cracked :O, then, i changed it for a good one, have managed to fireup the engine. (picked up used one for 25€ on local seller.)
But today, i was not able to turn on engine... I think there is another problem. I had spent all my time these days to find out, but with no luck.
So i took my bike to an local moto expert, to find out whats up now...
I'm affraid i choosed a bad time to start that carb "change" lol...
And now i see why last weeks, and last runs my bike was not running properly ... :\
its anything on eletrical system wich cause this malfunction.
One year ago, i was stuck on middle traffic because of stand sensor, it took 2 days for mechanics found what was the problem.
Lets see what is now.
Sorry for my english, i really understand, but its little hard to explain my self.
That is carb i have, http://www.ebay.co.uk/itm/1715232164...%3AMEBIDX%3AIT
Now i'm waiting for mechanics solve that "eletrical" problem, and tune carb.
Re: Need help. about molkt 26mm carb.
Ah I see.
That carb is different to the one I have but it is the one I want to switch to as my current 28mm one is shit.
I think that electrical problems with Chinese bikes are fairly common. I have had a problem with my tail light because of a broken connection in my wiring loom, I was luckily able to find the broken wire by pure luck.
As you have now sought professional help I guess that you don't need advice any more but I will give you a couple of tips none the less.
As the problem is suspected to be an electrical problem that narrows is down to an ignition problem. If it was me I'd first check if the ignition system is working by removing the spark plug and checking that there is a spark. If there is none then figure out which safety systems would cause the ignition to be disabled (i.e. side stand, kill switch, clutch position sensor) and disable them one by one to isolate the problem. If it isn't a problem in that area then it's a connection problem to the CDI, crank position sensor or spark plug or a problem with either of those parts them selves. Poking around with a multimeter and having a basic understanding of the ignition system should lead to you finding the problem.
Re: Need help. about molkt 26mm carb.
Quote:
Originally Posted by
spencer2004
Ah I see.
That carb is different to the one I have but it is the one I want to switch to as my current 28mm one is shit.
I think that electrical problems with Chinese bikes are fairly common. I have had a problem with my tail light because of a broken connection in my wiring loom, I was luckily able to find the broken wire by pure luck.
As you have now sought professional help I guess that you don't need advice any more but I will give you a couple of tips none the less.
As the problem is suspected to be an electrical problem that narrows is down to an ignition problem. If it was me I'd first check if the ignition system is working by removing the spark plug and checking that there is a spark. If there is none then figure out which safety systems would cause the ignition to be disabled (i.e. side stand, kill switch, clutch position sensor) and disable them one by one to isolate the problem. If it isn't a problem in that area then it's a connection problem to the CDI, crank position sensor or spark plug or a problem with either of those parts them selves. Poking around with a multimeter and having a basic understanding of the ignition system should lead to you finding the problem.
Why you tell 28mm is shit? I'm curious. XD
From what i saw, its very hard to find molkt 28mm and 30mm, at least on ebay. Maybe there is on taobao, etc..
I believe if the ignition was just good, i've some skills to tune carb. I done before one my mikuni.
Yes, you are right it very plausible about ignition problem, i just give up, after spending to much time to find it out :S, it could be most these options you told. but i i lost patience with it.
Despite options i tryed, cdi its just good(i tryed original one and no changes), i have one of these aftermarket with 4lines. I took the sparkplug of and start engine, to see if it sparks, i saw just sparks at beginning, than its seems to disapear or tending to be not powerfull as first spark....(it could indicate coil problem?)
It looks like an "intermittent" problem...
now i just have to wait and spend some cash on specialized working time... :\
Thanks for help :) i'm happy with this forum, i learned alot here .
Re: Need help. about molkt 26mm carb.
The particular 28mm one I have is shit because it's impossible to set the correct idle mixture without the RPMs going crazy, the idle circuit seems to get blocked really easily, there aren't any idle jets available for it and every now and then the float bowl will get stuck so it leaks petrol all over the floor.
Well hopefully the professionals will get it sorted for you and not charge you an arm and a leg. I forgot about the coil, it could be arcing inside or something.
Re: Need help. about molkt 26mm carb.
Quote:
Originally Posted by
spencer2004
The particular 28mm one I have is shit because it's impossible to set the correct idle mixture without the RPMs going crazy, the idle circuit seems to get blocked really easily, there aren't any idle jets available for it and every now and then the float bowl will get stuck so it leaks petrol all over the floor.
Well hopefully the professionals will get it sorted for you and not charge you an arm and a leg. I forgot about the coil, it could be arcing inside or something.
Did you try to sed needle position? i noticed that molkt carbs, work a bit different in that point over mikuni... its strange. Maybe down the needle a bit could help you.
Another thing i noticed was de hole to trottle cable. if it there is a leak, it could affect engine...
So, it look like ive made a good choice, without knowing.. lol
luckly, i didnt found that 28mm carb! You have to get 26mm one, now! maybe you are lucky to sell your easy, since its not an "common" one.
I hope so they not charge my arms/eyes/legs lol, i was very frustrated about my bike, last runs with friends, my bike seems to be died... lol and my friends noticed that, since my 125cc was the fastest of friends group!
In our rides, i used to be the guy who has to wait others...good times... hope it will repeat again, :( lol
On those good days, my bike achieved 115/120 kmg, on flat, very easy, and my friends was about 100/105km/h max... On last ride, mine was topping about 90km/h LOL XD
Re: Need help. about molkt 26mm carb.
Well... professionals discovered the prob... bike was valves "stuck", today they showed my bike running, but they say that molkt carb its a piece of shit.... LOL even professionalss cant tune molkt carb properly. :O
So i think, i wil stuck with mikuni carb... what a 55€ wasted.... :O
Another found, somehow my bike frame was breaked in 2 points, the only one accident i had, it all was "repaired", but now i see how good it was... :O
Or it ihas defect/bad welding.. (cloud be it too)
