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Hi there i have a 1991 cbr 400rr gull-arm. I am absolutely stumped with this one i have tried most things but any advice will be greatly appreciated! So when i try to start the bike up she wants to go but then decieds not to in trying to start her up i flatten the battery most of the time i have checked sparks they seem fine i have ordered a new set just incase (current ones only 3 months old). I am stuck with this one guys i am desperate to get my baby back on the road so any advice will be received graciously

Thanks! :thumb:
 

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are you getting fuel through?

loopys was a pig to start when we first got it.... new plugs seamed to sort it out, but it quickly developed an intermitant fuel pump....
which, cos of its intermitant nature was a bastr'd to pin down:crap:
 

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Discussion Starter #3
There was a kink in the fuel hose so i replaced that to no avail!
the bike was running fine up until 4 weeks ago i sat it up in the garage while
i was on holiday! i didnt get someone to start it for me so i came home and tried to start her and this has been the story since!

I will replace plugs when i get them i cant see them as they are only 3 months old i cant see this being the problem any other ideas?
Thanks for your reply Sideshow Bob :thumb:
 

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There was a kink in the fuel hose so i replaced that to no avail!
the bike was running fine up until 4 weeks ago i sat it up in the garage while
i was on holiday!
i didnt get someone to start it for me so i came home and tried to start her and this has been the story since!

I will replace plugs when i get them nut as they are only 3 months old i cant see this being the problem any other ideas?
Thanks for your reply Sideshow Bob :thumb:
ah! that maybe the answer... they don't seam to like sitting for too long. after a couple of weeks(and the cold weather dont help) they don't wanna start ...

you tried jump leads?
 

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:welcome: Alcopopkid..

There's no point me adding to Sideshows comments as he helped me sort my Baby Blade out :thumb:
 

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Assuming all else is good, the 2 key items you need are good cranking speed and dry spark plugs. Your plugs could be brand new but if they get soaked for any amount of time, they are garbage.

Boost the bike if you must to get good cranking speed. Add choke as needed only. It's easier to add choke if needed, rather than get your plugs wet with too much choke.
 

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bike batterys aint the strongest things in the world.... I always hook it up to the van (not running) when struggling to get summut to fire...

you should get a good/strong crank that way and if that don't get her firing you can start looking for other reasons:D

 

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Discussion Starter #10
Thanks sideshow bob i will try hooking her up to the car tomorrow and give it a good crank and we shall she how we go! I will message back tomorrow and let you know how i get on :thumb:
 

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Oh one more thing do u think i would be best just hooking her straaight up to a car battery and cranking her?
Thanks
 

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Oh one more thing do u think i would be best just hooking her straaight up to a car battery and cranking her?
Thanks
yep..... and as Denzee said be careful with your choke.... I usualy crank it a bit, then give it a bit of choke if nothin happens
 

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Oh one more thing do u think i would be best just hooking her straaight up to a car battery and cranking her?
Thanks
You can do that but still have your bike battery charged and good dry plugs. Do not keep cranking the engine for extended periods because a car battery will crank a long time, possibly overheating connections and/or the starter itself causing damage. Don't worry about the backfire.

I notice you are from Falkirk. While visiting to Glasgow we went to see the Falkirk wheel, very cool indeed!
 

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Discussion Starter #17
So tried the car battery, cranked it a few times throught the day (as not to burn out starter) still no luck so i will wait for the new plugs and see how we get on.
Thanks again for your advice guys! :thumb:
 

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Am I correct in assuming that by saying "she wants to go but then decieds not to" you mean that you crank it and you hear some cylinders firing occasionally but the bike won't start. I think that's typical behavior for when you're not getting any/enough fuel. For example I'm getting it when I run out of fuel. When refuelling the carbs are empty and the fuel pump is wired so as to only provide fuel when the engine is turning over so you have to turn it over a bit before the carb bowls fill up and the engine can start. In the mean time the engine is running lean (as the level in the bowls is not high enough to provide adequate fuel) and it sputters like this.

The problem is that you haven't run out of fuel. The fact that the bike has been sitting for a few weeks though suggests that the jets inside the carbs have gummed up and can't provide enough fuel to start. If that is the case I don't know what to suggest other than taking the carbs apart for inspection and cleaning. Have you tried starting her with some throttle? How much depends so you need to fiddle with it slowly when cranking to see if it makes any difference. The thing is that your carbs have three seperate circuits through which they draw fuel, each with its own jet (a small hole, through which gasoline fumes are drawn) and if only the idling circuit jet is clogged say, you may be able to start her up by drawing fuel from the pilot or main jet. You "select" circuits with the throttle so it might be worth a try.

You should check your fuel pump as well. You can feel it by sticking your hand under your fuel tank from the right side but you need to know where it is. If it vibrates it's working, if not then it's either dead or your carbs are full so it doesn't need to pump fuel. That's an easy check but it probably won't tell you much. The other obvious way to test it is to disconnect the fuel line from the carbs and crank the bike to see if any (and how much) fuel comes out of it. You should be ready to catch it in some container of course as it might be quite a bit.

Sorry about the lengthy reply but I have a thing against unjustified advice. Hope you get her started. Even if you do though cleaning the carbs would probably be a good idea.
 

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Discussion Starter #19
Thanks for the advice dpapavas im still currently waiting on new sparks! so i got it going (just) two nights ago, it took a van and half a can of easy start lol but nah i see its just the cold weather thats cozing the problem. its been out in the garge for 2 weeks no in - whatever degrees so that must just be the problem so i will persevere and she how she goes i did replace the fuel hose because it was kinked so tht didnt help lol it was just the weather so thanks for all the advice guys! :thanks:
 
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