All-Road 250cc -> Carb Rejet -> Bogging Down -> Shu

[IronFist]

Originally Posted by TeamCheap

If the spark plug is black, sooty black then it is running to rich and you'll need to lean it out.

try a main jet in the 110-115 range.
You may want to try a smaller pilot jet as well.

Is there much of a difference whether the choke is open or closed on how it starts ?

Ditto.

[puush]

I have to full choke and use starter fluid to get it started and then go to half then no choke when its warmed up. Then it will bog down and quit.

[phil]

you are running out of gas your running too lean thus choke + starting fluid to crank and some choke to run the question is what is reducing fuel supply if there is a drain at the bottom of the float bowl turn on the gas and open the screw if fuel flows well then you have mostly ruled out float tank and the lines then all thats left is the jets :wink: or a little dirt in one

[puush]

well, when I have taken the carb off before to check it out fuel would pour out of it so I dont think its a float/bowl problem.

I am gonna shorten the fuel line from my gas tank to carb and take out fuel filter. Is this good idea?

I am gonna try to cover air filter opening on carb also to see if this might blow out any stuff in the jets.

I am purchasing a xmoto 250cc chines bike tommorrow. I hope I dont have lots of problems like with the DB-27. Honda wouldn't give me financing for a CRF dirt bike. oh well. The xmoto 250cc cost $3000 less!!!

I wont be free until I get the DB-27 to run again. Thanks for all your helps dudes.



Michael A

[phil]

you dont have too if it runs out when the line is unhooked from the carb its good i really really think you have a little something in a jet. this is easy you have to take the air filter off no short cuts rev the engine up not crazy high and put the palm of your hand over where the filter hose was what happens then is the engine that was sucking all that air now trys to pull it form somewhere else (jets gas line etc) i always do this to the new bikes and i have done it to a little 50 that i just rebuilt with new jets and it run much better it just cleans real good what you would miss with your eye it gets it wont get the mean stuff and use common sense it wont suck you in but you can feel it do this a couple of times and let me know shame you dont live closer

[TeamCheap]

If you have to use starting fluid it is either very VERY cold where you are or the thing is so far out of wack that it will need a very close looking over in several area's.

OK so how well does the fuel flow from the fuel tank to the carb???
(no thinking, no assuming, no guessing its fine, just do a simple fuel flow check)

shut the fuel off
pull the fuel line off the carb
put the hose into a CLEAN glass jar(so you can watch whats happening and reuse the fuel also)
turn the fuel on
let it run for a minute or so
if it slows down then look for the cause of blockage(fuel petcock or fuel cap vent)

If you want to go the super super easy way then just use "the magic chant of cuss words on it" no it wont help but neither will side stepping the process of elimination.

Three basic things to get an engine to run
fuel (gas and air mixture)
a spark (to light the fuel/air mixture)
and compression (to make use of the fuel/air mixture explosion)

after those three are there its pretty much a matter of tuning

[puush]

I will definately try to clear the jets with my hand covering carb air hole. And as far as the fuel line, I did take it of and let it run into a jug and fuel did flow without any problems. So I guess I can eliminate that. Its possible that jets might be obstructed with miniscule somethings. When I received the nw Mikuni 30mm Carb a couple months ago some idiot packed it in a box with a bunch of Styrofoam Packing peanuts and bits got all over inside. I assume I had cleaned it thoroughly but maybe I didn't.

Some history. Before I put the new Mikuni Carb on I had first put on a straight thru Air Cone Filter and a FMF PowerCore 4 exhaust. At first I didn't rejet my carb with the the FMF exhaust and air cone filter but the bike ran fine for couple hundred miles. I rode it wide open alot on a 20 fire trail mountain road. Then the last time it ran it just started bogging down and quot and then wouldn't start.

I replaced carb with Mikuni and rejetted and now I am where I am at.

Thanks for all the help mang...



Michael A

[katoranger]

You may also want to replace that spark plug too.

[puush]

where can I order a spark plug online? Also, I need a large nut that goes on top of my triple clamp that goes on top of the forks. Any suggestions? You guys rock.


Michael A

[katoranger]

Take the one you have to a parts store and have them match it up with on NGK. Should be less than $5.

Allen

[puush]

Well, i blew out the jets as best as I could and got bike running for a couple minutes with choke off but as bike warmed up and i revved engine it bogs out and dies. Also< i had to kick start bike to start it. And bike absolutely will not start without starter fluid. I bought new battery but trying to start runs battery dead and now its seems like battery doesn't want to charge. i am charging battery now. I don't know what to do. this is driving me insane. Thanks for all your help dudes.


Michael A

[katoranger]

Did you get a new plug? I am wondering if you have a weak spark.

Do you have another bike you could swap the coil and/or CDI box from?

I am thinking coil. The starting fluid is highly volatile and the weak spark is able to ignite it and the bike will stay running at idle speeds.

I have seen this happen with the wrong sparkplug installed too.

Allen

[Cal25]

I think Katoranger is on the right track again.

[katoranger]

I have been thinking about the black plug and the need for starting fluid to get it going.

If he was running rich the starting fluid would only make it worse and it really seems that he has checked the fuel system thoroughly.

Time for the next step.

Allen

[puush]

I will get a new spark plug. Why is new battery dieing you think? Thanks guys


Michael a