cylinder no.1

[Anonymous]

hey guys hows it goin?

pretty much a rookie mechanically, but learning everyday. fixing up a '79 gs 750. got it LOOKING great, i just have an on going issue with cylinder no.1.

works fine for a few days, then plug fouls and cylinder won't fire. bike has been modified with K&N's and a vance and hince four into one.

when shes good, she's very good but the plug gobbling is getting me down.

works fine when i replace the plug.

sounds a bit rich at the bottom end but feels lean and holds back at the top in 4th or 5th.

i've never done carb work, but i'm willing to give it go with the right guidance. anybody out there feel like giving me some advice? any body encountered the same problem?

thanks gs'ers.

nigel

vancouver bc

 

[JJ]

If you haven't adjusted the idle mixture, and synched the carbs, you really should.....

 

[saaz]

And also it could be as simple as the plug cap. Just had a few go on me, worse when hot.

 

[Anonymous]

i replaced the plug caps a few months ago. its always the same cylinder though.

the carbs have been adjusted ( by a mechanic) a bunch of times and it really does run well for quite long periods.

i've never had the carbs off myself but i want to give adjusting them a go. can you explain "sinching the carbs" and also how to adjust idle mixture. i image sinching the carbs will involve adjusting them to get the most efficient sir/gas mixture, i just don't know where to start!!!

i think the idle adjustment is the large round bolt in the middle of between the carbs? it idles fine though. altough it always needs lots of choke to start.

could carb no.1 be adjusted out of sync with the rest of the carbs?

thanks for the responses

nigel

 

[scotty]

DID THIS ALWAYS HAPPEN?? DID YOU JUST GET THE BIKE?? Did it happen just after someone did any work on the engine??

Caps key?????

 

[Anonymous]

hey scotty, how's it goin'?

it's never run consitently well since the mods were done (k&n's/new exhaust). i've had the bike about 18 months, the modified version around six. you just get used to everything running smooth and all seems well then out of the blue she doesn't fire on all cylinders at starting. if i wind up the accelerator a ridiculous amount and hold the plug cap a couple of centimeters away from the plug the arc jumps and blasts the plug into action and cylinder one will fire (a couple of small shocks and one big electric shock later and i no longer like this method). and it's REALLY hard on the engine. i've just been carrying spare plugs around with me. if i change cylinder 1 plug it works fine, i'm just going through too many plugs (2 this week!!!) so i'd like to solve the problem once and for all instead of just band aid solution.

thanks for listening,

Nige

 

[snowbeard]

I have a similar problem, but it seems to go away as I run it longer. I almost question if I have such a high resistance due to a faulty wire that it has to really try hard before it can get firing, overcoming the initial lack of conductance. :roll:

perhaps you can just clean the plugs instead of always replacing them? I just sand a bit in between and check the gap... if the plug is really toasted after a foul then you probably have even more issues than you think...

good luck!

 

[Anonymous]

hey snowbloke! thanks for the reply.

yeah, i don't chuck the plug everytime but it is a right pain in the arse to keep taking it off every couple of hundred clicks. the problem seems to reoccur more quickly if i clean the plug rather than replace it.

is your problem with cylinder 1? have you had the carbs off?

Nige

 

[Anonymous]

is the plug wet when it's removed? have you had it rejetted after the mods? If it is wet, is it oil or gas? If it's oil, it sounds like a blow-by problem to me....but alas, I much like yourself, am a rookie at this as well, and could be just blowin' smoke up yer arse, but just thought i'd give my 2

steve

 

[snowbeard]

I had them off last fall when I first got the bike... mostly cleaned, at least enough to run pretty smoothly. but my plug cap is breaking up, with the rubber at the base turning freely, etc. hence my suspiscion (spelling changed to protect the innocent :wink: )

synching the carbs adjusts the vacuum pressure on each carb so there's equal suction on each, I haven't done it as the previous owner had recently, and it seemed to have taken. it could be related to your problem, but that's for better biker's than I to tell ya.