Bandit 1200

[fish91]

Well carrying on from the last forum. Having a few problems with my motor popping loads on the overrun. I've removed the pair valves totally and blanked them off with no issues and it's still doing it. Also fuel or oil appears to be leaking all over the generator and around the part of the engine. Perhaps this is an air leak coming from the rubbers that need addressing? 
  

[kokolis]

Which valves?

Oil or fuel?

[Mc Nasty]

Well carrying on from the last forum. Having a few problems with my motor popping loads on the overrun. I've removed the pair valves totally and blanked them off with no issues and it's still doing it. Also fuel or oil appears to be leaking all over the generator and around the part of the engine. Perhaps this is an air leak coming from the rubbers that need addressing? 
  

Did you block the hole in the airbox where the Pair feeds into?

[Guest YoshiJohnny]

float needle valves

 

[fish91]

Yea I put a blank on the airbox hole. The airbox was filling with fuel from spitting back so now I leave the drain plug out so it doesn't collect leading me to the suspicion it's fuel on the engine. 
    The bike is using a bit of oil but the headgasket has recently started leaking aswell on the front left corner. I re-torqued that yesterday so that's hopefully done the trick.  

In regards to the needle valve presumably it wears out (thinner) and thus letting more fuel in? Fairly easy to replace by the looks of it? I took the bike to be dynoed at steve jordan and the mixture was bang on even tho I did mention the mixture screws are all over the place the bike generally runs ok. Say two of the carbs are 4-5turns out, If i make it 2turns it runs rich and dies.

Edited August 16, 2015 by fish91

[Guest YoshiJohnny]

Tips of the float needle valves are rubber, they wear and CAN fill the gearbox with fuel if you leave the tap in the PRI position..

Replace them before doing anything else, notorious Bandit 1200 problem and can wash the bores and trash an engine. Use genuine if you can as well, pattern replacements are rubbish.

Were the head nuts loose? 

 

YJ

[fish91]

Ah ok cheers, I'll order some tomorrow and see if these make a difference. The nuts wern't loose unfortunately, but thought i'd try a re-torque before buying a new HG. Problem after problem so far in ownership.

My friend is trying to encourage my to buy gsxr1100? 36mm carbs off him but but i quite like the fuel efficiency and having it as a potential tourer.

[Gixer1460]

If its a Mk1 1200 - you have 36mm carbs! they are virtually identical excluding the jetting!

[fish91]

Should've specified it's a mk2 

[Captain Chaos]

then the GSX-R carbs will no fit

[jamie k]

Defo second the float valves if this doesn't work it could be any of the o rings in the carbs this seems to be a more and more common problem ( maybe new fuel additive etc who knows) 

Ps  change your engine oil if you get it sorted to play it safe maybe your new leaking head is due to thinned oil from petrol already being In there , give it a sniff through the filler cap

[fish91]

 Hi guys, opened up the carbs, removed the jets and gave it all a good blow through and clean. The float needles looked like new, no cracked rubber, the emulsion tubes looked ok tho I suspect two look a bit bigger than the other two..... anyway while I was there I thought i'd try squeeze some more power out, recommended the ivans jet kit, 117.5  mains, new needles and a drilled air box with stock filter. Apparently a good plug and play kit.

    Stupid making another problem without solving the first but seeing as the bike generally performed ok I thought why not! Anyway this kit came with settings which i've tried. 2nd clip down on this new thinner  tapered needle and 3-4turns out on the M/screw. Bike wanted to wheelie like a good'un but won't run between 2-5K Literally will die. Will run smooth with choke, running lean?
    I then tried 3rd clip down, same again, definate improvement, but seems slower top end now and won't power wheelie as well. 

These needles are massively tapered from stock. Either way this setup doesn't work, perhaps it is my emulsion tubes but regardless I want to use this bike this weekend. 
    Was going to put the stock needles back in the bike and run them with the modified airbox and 117.5 main and play with the mixture. Has anyone done a simple tune like this before and know if it works? If not will put it back to stock tomorrow.

Cheers

Edited August 27, 2015 by fish91

[fish91]

[quote author=Fish91 link=topic=76775.msg732726#msg732726 date=1440754731]
Some progress this morning, put the stock needles in at stock 3rd clip down. Drilled airbox and removed snorkle, 117.5 main. 2.5turns out.

The bike goes like shit off a shovel full throttle, wheelie machine! Tiny bit rough still through 2-5K however it will happily sit and cruise at the speed without dying or missing like it was with ivans kit.

Here is the plug colour, bit sooty as you can see, the white i'm a bit confused about can't be lean? Might raise the needle 1clip, does the needle affect full throttle?

[img width=358 height=480]http://i43.photobucket.com/albums/e359/muhuha/Mobile Uploads/image_zpsycpn70kz.jpg

[Gixer1460]

As the needle never completely leaves the tube it will have an effect - the MJ basically governs overall fuel flow whilst the needle regulates throughout the range. Do a plug chop whilst riding where is roughest to give a steer on whether fat or lean

[fish91]

Ok nice one, well I did a proper plug chop, it's a very light choc brown. Bit light for my liking however I've restricted the airbox a bit (rubber snorkle) and adjusted the mixture screws to suit. This will do until my new emulsion tubes arrive!

Cheers

[colinworth79]

when messing about with jetting on an engine you need some way of monitoring the air fuel ratio (AFR) . An engine will run even if the AFR is out a bit but you will not get the best performance / smoothness . If its a stock bike leave the stock jets in . Checking plug colour is a load of old rubbish . Also there shouldn't be much fuel in the air box . You should be able to leave the fuel tap on for say an afternoon and the carbs not flood . My turbo charged bandit pops quite badly on the overrun but is set up spot on . Many hours have been spent running round with data logging equipment attached to the bike checking the air fuel ratio .

[fish91]

Well it was a stock bandit, fuel tap appears to be working ok and starts up after sitting for a week or two no problem. Was dynoed/AFR checked and like yours spot on, maybe the popping and banging is just part of the fun. 
    I purchased this ivans jetting kit after wanting a tad more power. Apparently pretty good stuff, doesn't seem to work well with my bike and now i'm thinking I should've just done it the normal way and jet it properly with a K&N and throw my wideband sensor on rather than wasting 100quid on a jet and needle kit.

I purchased some replacement fuel tubes from NRP carbs, they've turned up and they're the wrong bloody ones. The mk2 b12 has a 6hex shaped emulsion tube with a o-ring and a male thread which screws into the body of the carb?

Edited September 1, 2015 by fish91