Starting problems and petcock leaking cb400 SF project big 1

[bureklton]

Very strange, just out of curiosity, does the green fluid smell like petrol and being a bit of a pyromaniac will it ignite with a match?. Good to hear your petcock is working and you've parts on the way. I wouldn't worry about the fumes from the cylinder igniting when you are testing the spark, I have literally take a plug out of a flood engine (2 stroke) and tested for spark without any BOOM. Hopefully your plugs are good and with clean fuel in your system the bike will fire. If not it might be time to open and clean your carbs.

unless anyone else has a better suggestion my next step would be cleaning the carbs, it is possible the old petrol has gummed up your jets stopping fuel flow from the carbs to the cylinders. Although not a massive job it can be time consuming. When you are taking them out disconnect the airbox first and push it back (will only go about an 2 inchs or so) this will give you more wiggle room. From memory it is easiest to take them out on the right side of the bike.

[mykel49]

Ok so bright green fluid most definitely petrol, nearly burnt my house down thanks to bureklton lol !!!!

Ok so will try the spark test later in week, should I test all four? I wont be able to try start up until I get my new petcock from CHINA!!!! which may take some time.

[Superjack44]

If you do have to remove the carbs as has been said the airbox must be loosened off and pulled back as far as it will go to give some room to remove the carbs , the inlet manifold rubbers circular clips must be loosened as well and remember this they are all that actually holds the carbs in place and are usually stuck so have to be prised apart BE CAREFUL where you put the lever in order to prise them apart, try moving them up and down first to try and break the hold they have on the rubbers the mixture screws under the carbs are particularly prone to damage ( I know all about it) if you do slip and hit it it will definitely break off.

[mykel49]

Thanks for the advice. I think it will be some time before I try to fire her up as I'm waiting for a replacement petcock from China. Whats the best way to clean carbs, and should I just spray some carb cleaner in or completely strip down, what else should I check when I have the carbs out?

[Superjack44]

Thanks for the advice. I think it will be some time before I try to fire her up as I'm waiting for a replacement petcock from China. Whats the best way to clean carbs, and should I just spray some carb cleaner in or completely strip down, what else should I check when I have the carbs out?

Do not remove them yet, wait until you have solved your fuel leak problem first .
If you do have to take them off just remove the float bowls first (one at a time in order to make sure they go back onto the original carb) you now have access to the main jets carb cleaner and compressed air should be enough to ensure cleanliness .
Unless you have a good working knowledge and understanding of the workings of the carbs do not separate the four carbs .

[mykel49]

Thanks for the brilliant advice so far. Do you have any idea why the petrol sitting in the carbs would have turned this lime green colour, is this normal for fuel that has sat for a number of years?

[bureklton]

ha sorry about that mykel49, I hope you still have eyebrows. Regarding the colour change, no petrol doesn't change colour if it sits for a while. The reason you are told to put new fuel in a bike after its been sitting is that the old petrol has lost a lot of its potency and won't ignite and burn as well, making starting the bike difficult. If, like you said, the previous owner was clueless it is not impossible that they put fuel meant for a 2 stroke bike, which is mixed with oil giving it the same colour as the oil (blue or red or green depending on what colour the oil was), into it.

Also some great advice from the other guys regarding carb removal, be patient and get good lever points, although the boots (rubber connectors) are rubber petrol and sun light has a degrading effect on rubber and tends to make it stiff and hard.

[mykel49]

Ok guys, I a little update. I got new plugs today and tried the spark test, ie put the new plug in lead and held against casing , and there was no spark. I then tried every ht lead with the new spark plug and not a spark from any. So I have maybe narrowed the non start down to the ignition.

So my question now is,WTF do I do now !!!! ?

HELP

[mykel49]

Ok so another update, took all the leads off and connectors from the small black box that the HT leads go into and cleaned and sprayed with WD40, and now I'm getting a spark from all four. So forget the last post, sorry guys I was a bit premature with the last post. So anyway still waiting for petcock from China before I can see if the small jobs have work before I attempt the carb removal and cleaning- fingers crossed. Mike

[mykel49]

Here's a few pics of the new bike, hope you like, just hope I can get her running lol