idle issues cont

[tom203]

A good bench sync will get you real close mechanically ...but it won?t tell you if one or more carbs have blocked idle circuit passages. Before you reclean them, try this... got any long downhills nearby? Accelerate down, repeatedly closing throttle to put vacuum on the tiny passages in idle circuits. This might suck out some gunk....sometimes you can get lucky.
P.S. your a good son

 

[Nessism]

You might want to read through the Newbie Mistakes and carb rebuild tutorials linked in my signature. Short cuts are long cuts when it comes to cleaning carbs and performing all the bikes maintenance. Consider this your warning...

 

[gustovh]

hi gustov so are you saying that after you finish sync that when your throttle is closed with 1/8" gap that is how you leave it set up for idle!yes were gonna check the valves my dad says their fine but i want to check them other wise i just feel like im going round in circles,i have replaced orings ,set floats cleaned carbs, gonna check the plug gaps too to make sure, like i said previous how do you know for sure every little passageway in carb is completly unblocked but i am going to pull them off again. cheers paul.

once all the butterfly’s are set, you remove the pin from #3 and the flys close. So leave the pin in #3 while adjusting the others. I also agree that short cuts aren’t.

V

 

[Guest]

hi tom well went round dads tonight to do compression test as no4 cylinder not firing and ive checked out leads, coil, cap etc they were ok. so not great compression no 4 was 100psi the others were around 90/95 . 123 cylinders are firing, so no4 the one with the most compression isnt,so im thinking it gotta be carb,were going to check valve clearencs too,im a bit concerned,dad reground the valves fitted new stem seals and told me he took a bit off the top off stems with a grinder!! he said when he set the gap he aired on the side of caution so they wouldnt be tight.all being said it starts up fine with choke obviously no 4 not firing but dad reckons it is at higher revs. it would be abit awkward fo me at the moment to take it to a hill, perhaps after a third clean i will try it,thanks for the compliment i try to be and i try not to show my frustration with this bike in front of him as i know he is frustrated himself and i think he regrets taking it on ,im more of a 2 stroke guy myself i race quads trx250rs ,but im being teached a lesson in multi cylinder 4 strokes at the mo lol,cheers paul

 

[Guest]

hi nessism yes i have followed the carb tutorial its good but he doesnt show not that i can see anyway,how he cleans the pilot circuits and how to ensure they are completely unblocked i have had carb cleaner coming out the hole in front of the butterflys and out of the 3 little holes just behind the butterflys ,but im going to take them off again and have another go at them,cheers paul

 

[Grimly]

yes were gonna check the valves my dad says their fine

This is where familiarity with older Brit bikes is of no use. Generally, OBBs would signal the valves need attention by getting noisier - the GS bikes don't. The GS bikes get quieter as the valves need adjusted. This could fool somebody with an ear for older engines to think there's nothing wrong with them.

 

[gustovh]

All your cylinders are LOW, check valve clearance...no guess work here, check the gap.

V

 

[Guest]

hi gustov i checked valves tonight they were o.o5 to 0.08 clearences so that seems to be in spec, i just thought! would i get better results with the slides up,as usually the test is done with throttle open but this is not possible with cv carbs unless you hold slides up.but yes they are low. im gonna take carbs of again and clean them and see if i can get no 4 cylinder to fire at idle, as 123 cylinders do so. cheers paul

 

[tom203]

?..usually the test is done with throttle open but this is not possible with cv carbs unless you hold slides up?

the slides won?t interfere with testing....just hold the throttle open - then the throttle plates won?t block the intakes

 

[Guest]

hi tom well had the carbs off again 3rd time in the bath put them back on bike fired up straight away with choke and idled fine, push choke in it struggles to idle but revs out okay and no hanging revs, revs come down sharply.but open up butterflies via idle screw to get it to idle then blip the throttle revs start to hang,it gets worse the more i increase the idle!is it doing it because im having to open up the butterflies to much to get it to idle!ive replaced orings, checked valves cant find air leak ,what next!!im gonna sync the carbs with gauges see if that helps.

 

[tom203]

From your description, I say your pilot circuits on one or more carbs is still blocked...and forcing you to fiddle with idle stop screw to compensate. What and how long is your ?bath? for these bad boys? Maybe you need to find a guy with a ultrasonic unit.

 

[Guest]

hi tom im pretty sure it is a uitrasonic bath that they have been in my dad has took them to a bike shop to be done i will double check thou,jf it is ultrsonic and they are still blocked i dont know what else to do,im gonna sync them see if that improves anything,its almost there just not quite idling,.i didnt try it last night tom but what if when i increase idle and blip throttle it hangs as described,but then when i turn engine off and restart it with no throttle it idles okay, but only hangs when throttle is blipped,ill double check this tommorrow but im sure this is the case to in the past, cheers paul