hi guys ,first of i was ment to take bike to dyno to be sorted out,but due to snow/ice garage recommend i give it a miss on trying to get there , so afew weeks ago i put bike on dyno as it ran very bad at higher revs 6k and above but idle and under 6k peferct ,but dyno results come back has 39.09hp and running extremely lean , so after taking carbs apart it was missing a main jet on 3rd carb so replaced jets (100 size) and orings put bike back togher it fired up fine also noticed idle screws were all over the place so put them back to 1.5 but now iv got new problems i cant get it to idle ,when its cold after choke use its idle low/stalling out when bike is warm idle comes up to 4k ,when riding bike at low revs you can only use 1/4 of throttle or it bogs ,mid/high revs is hit or miss really ,odd occasion it takes of like a rocket most of the time it still feels to lean hesitation etc what is wrong ? help please anyone iv read so many threads now and im confusing myself ,also can needle height be adjusted without removing carbs just wondering as you could on the old 2stroke stuff

Hey,
They are a nightmare are`nt they.... My 76a(the mrs) runs 2x turns out on the mixture,thats the only way i can get it to tick over (hot or cold) and the carbs have new mains/o-rings/pilots,basically they want for nothing the only thing i can put it down to is wear so every set is different. The basic settings are a good guide line but not guaranteed to work spot on with your bike. Try lifting the needles one clip to cure the lean problem you have(have you checked the plugs are they running hot?) and you can lift the carb tops insitu so a clip change is possible i think.....
Hope that helps mate,
Andy

hi andy thanks for reply iv just come out of shed and your right iv been slowly adjusting idle mixtures it probs about 2.5 turns out now and idle is smooth and if you blib throttle it returns to idle without hovering or dipping below so thats improved but yes i belive your right about needle hight ,i probs should have done that first but its very difficult without bike idling to test stuff so bike is back togher (kinda)going to take it for a ride and report back on how it goes

dsr91 wrote:hi andy thanks for reply iv just come out of shed and your right iv been slowly adjusting idle mixtures it probs about 2.5 turns out now and idle is smooth and if you blib throttle it returns to idle without hovering or dipping below so thats improved but yes i belive your right about needle hight ,i probs should have done that first but its very difficult without bike idling to test stuff so bike is back togher (kinda)going to take it for a ride and report back on how it goes

i forgot to add , the bike normally runs very cold to the point i dont like taking it to redline ,but with even cold weather iv made a radiator cover so now temp gauge says just under half but may change once its on road instead of shed

back from test ride (it was very cold awaiting feeling in my thumbs and fingers haha)well first good news idles fine its risen alittle so thats easy to take care of and revs between 12k-14k pull like a train but bad news is still from pull away upto 12k it still hesitates alot which to me means andy is right about needle hight for mid revs but low revs i could be wrong well hope im wrong but would that mean float height is wrong ?

dsr91 wrote:back from test ride (it was very cold awaiting feeling in my thumbs and fingers haha)well first good news idles fine its risen alittle so thats easy to take care of and revs between 12k-14k pull like a train but bad news is still from pull away upto 12k it still hesitates alot which to me means andy is right about needle hight for mid revs but low revs i could be wrong well hope im wrong but would that mean float height is wrong ?

Hey,
Lift the needles first then worry about float heights,chances are it will be fine after the needle adjustment.
Andy

Andy wrote:

dsr91 wrote:back from test ride (it was very cold awaiting feeling in my thumbs and fingers haha)well first good news idles fine its risen alittle so thats easy to take care of and revs between 12k-14k pull like a train but bad news is still from pull away upto 12k it still hesitates alot which to me means andy is right about needle hight for mid revs but low revs i could be wrong well hope im wrong but would that mean float height is wrong ?

Hey,
Lift the needles first then worry about float heights,chances are it will be fine after the needle adjustment.
Andy

Well I've raised the needles and now bike is unridable , anything below 8k it just sounds like it misfiring badly so going to have a look for air leaks , o yeah it doesn't idle any more I had to mess up my settings to try to get it to idle oops , from one extreme to the other

right there was a big air leak ,one of carbs didnt seal ,the rubber bit moved under the cap and i didnt see it ,but thanks andy you were spot on with moving the needle 1 , so out of the 5 clip points its now a 3rd down ,its snowing now here so cant go for test ride but sat in shed revving it ,it seems smooth from tick over to high revs full throttle with out a problem,

dsr91 wrote:right there was a big air leak ,one of carbs didnt seal ,the rubber bit moved under the cap and i didnt see it ,but thanks andy you were spot on with moving the needle 1 , so out of the 5 clip points its now a 3rd down ,its snowing now here so cant go for test ride but sat in shed revving it ,it seems smooth from tick over to high revs full throttle with out a problem,

Glad it helped bud i know how depressing the f*cking carbs can be. I`ve spent what seems like a lifetime messing with them but i think i now have the upper hand well until the next time!!
Andy

Im sure 3rd clip down on the needle is stock for the normal 76a and may be 4th from top on SP model.