CRM250 with clean carb but still won't start

CRMPete · Post by **CRMPete** » 05 Dec 2009, 18:22

Hi, brand new to this and having problems with bike. Have read the forums and found no answer. It was running fine and died whilst out on it. Wouldnt start so I dropped a bit of fuel in the spark plug then it started. Then died after it ran out of fuel again. It has a full tank of fuel and the oil is full too. I have just cleaned the carb twice and I can see down through all of the jets and blow through them with no problems. The carb is now back on and still it does not want to start. Not electrical I dont think as lights flash on when kicked over. Have tried leaning it at 45 degrees and emptying carb then starting with full choke. Nothing!

Any help from here would be very welcome!

The spark plug is sparkling clean everytime I check it like there is none or very very little fuel coming through to it. So with the carb clean and free what is the next thing to check for fuel to the spark plug. Have checked plug for spark and it is fine!

Thanks

Post by **delvey91** » 05 Dec 2009, 18:37

Is the fuel tap in the on position?

CRMPete · Post by **CRMPete** » 05 Dec 2009, 18:57

Fuel tap is on, even checked reserve on to. Wont go in either position!

Post by **SkidMark** » 05 Dec 2009, 19:14

welcome to the site!

regarding your fueling problem:

Personally I would be checking the fuel supply to the carb before ripping the carb off and disassembling it (maybe you did but didn't include that in your summary)

got through the system sequentially starting 'top level' ie easy to check.
fuel in the tank
fuel tap is on? (sure?

)
pull the hose from the tap outlet - does fuel flow? if not your tap has a problem (there is a coarse screen on the tap that can block up), if this is your problem then check the inside of your tank for rust or dirt.
if you have an inline fuel filter is it blocked?
pull the fuel hose off the carb inlet and turn fuel tap on - does fuel flow out? if it doesn't your hose maybe blocked or kinked

What exactly where you doing when the bike cut out originally?

that should get you started - report back your results and we will take it from there..

Regards

SkidMark

CRMPete · Post by **CRMPete** » 05 Dec 2009, 19:20

Hi Skidmark,

Checked that there was fuel from the tap to the carb (ie taking the fuel line off the carb) and it is running freely. There is no inline fuel filter to block up. Fuel is filling into the carb as when i took it off the second time it was full up!
Fuel tap def on as carb filling with fuel.
Getting spark from spark plug. Tried putting a little fuel in the spark plug hole again earlier but wouldnt start again.
Cheers

Post by **delvey91** » 05 Dec 2009, 19:34

Are you using any throttle when starting? If so try it with no throttle at all.

CRMPete · Post by **CRMPete** » 05 Dec 2009, 19:36

Tried with no throttle and choke on, throttle and choke on, choke off no throttle and choke off with throttle. Still nothing. I take the sparg plug out and make sure it clean everytime too. I am getting very good at taking the sparg plug out thats for sure!

CRMPete · Post by **CRMPete** » 05 Dec 2009, 20:46

Update - took spark plug out put a little fuel in and got it to fire up again - sounded good for 3 or 4 seconds then died again. If I disconnected the carb but left the hoses connected and kicked it over would I be able to see the fuel coming out of the carb? or is that not possible?

Im guessing my next step is to take off what ever is between the carb and the engine? I see 4 bolts there?

AlanH · Post by **AlanH** » 05 Dec 2009, 21:19

If the reeds are damaged (that's what's between the carbs and the engine) then that can make it hard to start.

Post by **knackeredMk1** » 05 Dec 2009, 22:32

Almost all 2 strokes are easy to flood if you don't treate them right and each is an individual.

1) I would be tempted to say that your fuel system has an intermittent fault. Most likely the fuel tap filter. This is causing the 'stopping'. To check this take the fuel tap off the tank. My betting is that the filter is full of crap and needs a good clean out. You can also clean the tap out at the same time as it should be able to turn to 'off' and 'res', but it is probably too full of corrosion.

2) The reason, I think

, you are having trouble starting (if you are sure that the carb is working fine), is that the engine is flooded. Every time you are adding fuel in, by whatever means, is just prolonging the agony. Take the plug out and put a piece of rag/gauze over the plug hole, so as to let gases out. Then, with the ignition OFF, put the bike into 2nd/3rd gear and push the bike for at least 40 yards with the engine turning over. To be completely sure leave it standing for a few hours, put a new spark plug in and go through the starting procedure. Fuel on for at least 30 seconds - choke on - try to start the engine with minimal throttle. Once it fires twist the throttle a bit (1-2mm) more to get the revs up a bit. Keep it reving at low revs on the throttle and after about 20 seconds let it slowly go down to idle and take the choke off.

You may find that you need to play with the throttle to keep it going at low revs for some time after you take the throttle off, maybe 1-2 minutes until it will idle. It may not idle if you have changed the idle screw &/or the pilot air screw, but you should be able to get the engine warm and work from there to get it settled.

All engines are individuals and you may well find your final starting procedure differs from the above but this should get you out of the current hole

.

CRMPete · Post by **CRMPete** » 06 Dec 2009, 08:49

Im almost certain its not the fuel as if I disconnect the fuel hose from the carb it just keeps flowing freely. If I take the carb off the bowl is full of fuel. I have re checked the carb again and everything is whistle clean and I can see through every hole. Even had led torches through them all to check light coming through and it is spot on!

To check carb I left all pipes connected to the carb then tok it off the engine side of the bike to kick it over to see that the fuel was coming through - and to my suprise no fuel was coming out. I have consulted a friend about this and he said that the carb would not shoot fuel out unless connected to the engine side as this is what creates the vacuum to pull the fuel through from the carb.

So I put my hand over the rubber seal coming from the engine side, kicked the bike over and I can feel the suction - not sure how much suction there should be but there is definately suction.

So im assuming it must be the reeds - which I have no idea what they do or how I might fix them, or possibly the spark plug?
It is sparking but I was told sometimes they can be faulty. It has not caused a prob yet but its got to be worth a go for the price of a spark plug.

There are four bolts on the engine side after the carb, I am assuming then that this must be the reed. Anybody familiar with taking these off and fixing them?
Many thanks for help so far!

Post by **fallenmikethebike** » 06 Dec 2009, 12:01

Reeds, are a possibility,, but so is a weak spark, unfortunately, that can be more agro.
Take the spark plug cap off, then unscrew it from the lead,[ normally anti clockwise fro off], check for , verdigris,, this is greenish deposits, that would inhibit, a sound contact to the threaded brass section at the base of the H.T. lead entry.
I would recommend trimming back, about , 6mm off the lead, as long as that doesn't leave it too short to reconnect.
Have you checked the earth for the coil is sound.
From there, you are possibly looking at, coil, though it does'nt sound like a coil fault.
Magneto, lack of electrical generation on the ignition field coils/ pick up.
Absolute worst case, C.D.I. Box, though again, highly unlikely.
How's the compression?.

CRMPete · Post by **CRMPete** » 06 Dec 2009, 13:52

Could not believe it - changed the spark plug this morning and it started first kick! Checked the other spark plug and that is still sparking just wont start the bike. A friend said that it could be a faulty spark plug? Still thanks to everybody for the help - I have learnt quite a bit about the bike in a short space of time!

Post by **fallenmikethebike** » 06 Dec 2009, 16:41

CRMPete wrote:Could not believe it - changed the spark plug this morning and it started first kick! Checked the other spark plug and that is still sparking just wont start the bike. A friend said that it could be a faulty spark plug? Still thanks to everybody for the help - I have learnt quite a bit about the bike in a short space of time!

And you now have a squeaky clean carburation system

Mike

AlanH · Post by **AlanH** » 06 Dec 2009, 17:40

What oil are you using? I had issues with plugs giving up when running fully synthetic.

CRM250 with clean carb but still won't start

CRM250 with clean carb but still won't start

Re: CRM250 with clean carb but still won't start

Re: CRM250 with clean carb but still won't start

Re: CRM250 with clean carb but still won't start

Re: CRM250 with clean carb but still won't start

Re: CRM250 with clean carb but still won't start

Re: CRM250 with clean carb but still won't start

Re: CRM250 with clean carb but still won't start

Re: CRM250 with clean carb but still won't start

Re: CRM250 with clean carb but still won't start

Re: CRM250 with clean carb but still won't start

Re: CRM250 with clean carb but still won't start

Re: CRM250 with clean carb but still won't start

Re: CRM250 with clean carb but still won't start

Re: CRM250 with clean carb but still won't start