noob & new fizzer - engine trouble - couple of questions

thanks for that, very helpful.

now makes me think that there are possibly problems with the needle? i might try moving the clip up, firstly i will check the float levels, and then balance the carbs.

keep you posted

 

hey im thinking of trying to tune the bike myself, but ive been warned about making it too lean cause ill burn out the engine! i guess im keen to try and fix the problem myself, but dont want her to die in the process! can anyone give me advice on tuning and steps to take to unsure the safety of the engine, can i really do damage?

 

checked the float levels, they are way past the line on the bowls, they are up to the point that the bowl angles off (about 175mm higher)

 

lol i meant 17.5 mm

 

ok ive lowered the float bowls, syncd the carbs, reset the exup, and altered the idle mix, the bikes performance is definately better, sure its slightly higher pitched and doesnt sound like a 400, but i think formula one type noise is good enough <!-- s --><img src="{SMILIES_PATH}/icon_biggrin.gif" alt="" title="Very Happy" /><!-- s --> haha

now the only thing i have to do is try and get the bike to run more reliably. it now isnt a matter of hot or cold, up hill or downhill, it just seems to be running out of fuel! my father took the bike for a test spin to check it out, and most of the time it ran fine but after a while (the bike was hot before he took it out) it just started to die, couldnt get it started again, waited 5 mins and it went, for about 2 mins, when it died again... he checked the fuel filter and it was empty! (there is 3/4 of a tank of fuel) we did some basic diagnostics, ie running fuel out from various stages, and there was a nice gush from the tank hose, and anything after the fuel switch it was only trickling... i think that the bike must have been asking for more fuel than it could get! i have taken the switch apart and it seemed to be fairly clean, so im not quite sure what the go is, the hoses are clean too... do you guys get less fuel pressure after the switch? if i cant get enough pressure im thinking fuel pump...

 

the bike didnt have a pump on it, so i have stolen an old fuel pump off a fiat x1/9 thats sitting under the house, it doesnt turn itself off automatically so i set up a little switch with a metal plate that the screws for the fuel tap hold in place (quite nifty!) but really i just need to get an adaptor and plug it into the socket...

am going to take the bike for a spin tomorow and see how she holds up, two thoughts - just noticed in a post that most bikes arent tuned for premium fuel, i wouldnt have realised this could cause a detrimental affect! i have been putting bp ultimate in the bike assuming it would perform better... we have tuned it for ultimate, should i keep it running on ultimate or just normal petrol? also when i checked the jet sizes the pilot jets are all 30's! the rest of the jets are standard, should i change these? as i think a consequence the idle mix is nowhere near 3 turns out... the engine runs great at the moment now, very very responsive, and doest bog down... but when you roll off the throttle it makes a constant burble on the way down, which i am told means the idle mix is too rich... yet its nearly as lean as i can get it with the screws! does the pilot jet affect this?

also i took the fuel cap off (unscrewed it) to check that the pressure valve thing was unblocked and working, the metal tube is alowing air to freely flow but by the way the cap selas the tank it looks as though air may not be getting through... also there is a missing screw under the fuel cap which makes me wonder if there is a mechanism missing... would anyone beable to send me a photo of the fuel cap when it has been popped?

 

hooray!

i think weve made some definate progress, took the bike for a good long run, and it ran beautiful the whole time! still need to work on the idle mix (mega burbles on the way down) (ie 'uncool' burbles ) and the rear suspension has started squeaking (checked out the how to - will attempt soon) but at least i can ride it and know im gonna get home!