long term idle issue solved! but still vibrating - gsx600f

[taz4626]

hi guys i have a gsx600f 1992 which i love riding and its good fun. however i have had the same issue since i bought the bike in april, the revs when dropping down with the clutch in will hover at around 3k but if i drag the clutch to drop it lower it will then sit at around 1200 rpm. while it is idling at 1200 rpm i have the lights on if i turn them off the revs go up again to about the 3k mark. i have sprayed with wd40 for any vacuum leaks and it is completely sealed i have balanced the carbs about 3 times but doesnt change the issue.

the only thing that will drag the revs down without it hovering is if i put the idle screw further down but then the bike stalls? would it be worth changing my diaphrams? or any other ideas as to why its doing this?

as a separate issue i have quite a harsh vibration when the revs drop through 7k and only at 7k it seems to come from the inside of my right leg which is clutch side, as of yet i havent taken the clutch cover off but was wondering if it would be worth while taking a peak.? or any ideas what might be causing it?

many thanks for any advice - rob

[gearboxkart]

i had very similar engine probs on my xj600f few weeks ago, if i set tickover to 1200ish when warm, once on the road the revs sat at 2-3000rpm for a good few secs after i came off the gas so not good trying to go round round abouts etc lol ! i checked the diaphrams they were all on, what my problem was was the pilot jets full of crap, stripped the carbs blew them all out with carb cleaner and air line and once put back together all was fine i also had bad vibes thru the bars so initially i thought it could of been a siezed engine mounting bolt that goes thru the rubber mounts as they are sposed to be well greased up so the motor can actually move within the rubber mounts and engine bolt if its siezed it will vibrate, did this on mine still vibrated next i got the carbs balanced which more or less has got rid of the vibes now, i dont have vac guages so i got them done at a local bike shop for £30.

[Frost]

Things to check:

Spark plugs
Multimeter the coils
Multimeter the battery when running to see if its charging correctly
New battery
Carb mixture settings and balance
Check the clutch adjustment. Dragging or sticking plates can hurt tickover and make going into gear very harsh

[taz4626]

i thought carbs to start with but i have stripped the carbs completely about three times now and although it did get slightly better its not cured it. which one in particular is the pilot jet? just to make sure i have been cleaning all of them.

as for the vibration i have balanced the carbs 3 times now after stripping the carbs etc and still the same at 7k

[taz4626]

[Frost]

Mixture screws will be on the under sides of the carbs. A manual will show you where they are and what they should be set to. They are screwed all the way in, then given a number of turns out. People often fiddle with them to try to make a bike go faster but usually have the opposite effect.

Coils are tested for resistance using a multimeter across them, again the manual will say what they should be on.

Get the back wheel off the ground somehow and try putting it into gear with the clutch held in. If the back wheel turns very slowly, your okay. If it picks up speed quickly then the clutch is biking when it shouldn't and needs adjusting.

[taz4626]

[taz4626]

just checked the back wheel and when i engage 1st gear the back wheel starts to spin but the comes to a stop and only spins again when i rev the bike? im guessing thats the initial sticktion of the clutch then the plates starting to slip and therefore it stopping

[taz4626]

i have checked the coils and to start with they are wider than original coils as the dont line up to the bolt holes but anyways

the resistances should be 2-4 ohms primary coil and 30,000 - 40,000 on sthe secondary what im getting is 5 ohms on the primaries and 40,500 on the secondary although one of the ht leads needs a wiggle at the coil end to get the resistance so im guessing that will need reseating

im guessing having the wrong coils fitting with higher resistances (which by my servicing manual would be correct resistances for an 1100cc) would give me my idle issues?

[taz4626]

have finally found my idle issue needed to blow the pilot jet channels out in the carbs with compressed air after soaking the carbs for a fair few hours so one issue solved.

however i do still have the vibration between 5-7k revs, just on a side note it seems to bog down slightly at about 6k revs when accelerating in 3rd gear and above would this indicate another rebalance of the carbs? or something else?

also how would i start looking for the cause of a vibration i can tell its comeing from the rhs of the bike but thats about it at the moment

[Casper]

Coils getting wet is a common problem if this is the MK1 600F. Also the 750. The rain will run under the tank and soak the coils. Do you still have the rubber mat covering them? Not that this was any good. Get them tested as one can be on the way out. If you do need new ones when you fit them get bathroom sealant or something similar and coat where the HT leads go into the coil and get the rubber mat that should be there if yours is missing.

Oh, it does not have to be raining to get this problem as the damage could already be done.

[Casper]

Just read your last post. Try and swap coils over and see if vibration moves. If it does you have a buggered coil if not yer left foot has a twitch