engine revs rising..

DoggyX

DoggyX

DoggyX

Associate
Joined
21 Oct 2004
Posts
205
Location
West Yorkshire
.. when idle? After running for a while and when the engine gets warm the idle revs sometimes rise to nearly 3k!! usually sitting at around the 1k mark when no issue.

So far I've tightened the clamps around the carb (there was quite a bit of room to tighten aswell) cleaned the air filter and swapped the spark plug - though have kept the old one as I'm going to clean it up for a spare.

My dad suggested to put in some of that Revvit stuff from halfords to clean out any carbon deposits and I've done that but reckon the carb might need a good clean - as due to an injury the poor dear was just sitting idle over the back end of winter.

Would this fix the problem? I'm a little worried that the diaphragm has got pin holes in which would be annoying as I can only find complete carbs to buy and not replacment parts - accept the needle valve.

I'm a bit of a novice to bike mechanics but have a haynes and my dad is always on hand to help and give advice.

Thanks

Si

p.s. bikes a Suzuki GN125 '94 model, quite well looked after with 23kmiles on clock etc etc
 
Check for binding in the throttle cables and carb linkage. Also check there is adequate free play in the throttle cables and they are routed correctly (tight bends will cause the cables to pull).
 
i have the same problem with my z650 at the moment i just changed the exhaust to a harris race pipe without re jetting it,so think maybe a carb problem?maybe
 
sorry to revive my thread but just got a quick question, When using carb cleaner is it safe to just spray/pour it in the air intake and run it through or am I best stripping the carb and removing the rubber parts first? a lot of what I found from google searchs has left me puzzled as some say you can and others say it will damage the rubber parts.

Mainly wondering as I have a replacement air filter which is a dry one - standard one is a wet one in the air box. This - I believe - means taking off the standard air box and filter mount and attaching it straight to the carb?? either way I will be opening this end and meaning I will have easy access to the air intake valve.
 
I know this may seem a bit simple but have you simply left the choke ok and forgot about it?

Once by bike has warmed up with choke on revs rise to 3k

As for cleaning the carbs I'd personally take them apart. It will depend upon the product but if it is a participially corrosive one it has potential to damage plastic and rubber parts.

They're not that difficult to take off and clean although getting the airbox back on can be a pita.
 
nah, choke is deffinatley off, I did flood it once over winter by mistake which meant a good wait until I could start the bike again :(

If weather holds over this weekend I wil probable take it off and give it a good clean and check over. I know the mixture is running too rich as the spark plug end is blackened with 'powder'. And that was on a fairly new spark plug.

This is the air filter I've got: 39mm Off Set which I think just goes straight onto the carb bypassing the air box? I could be wrong. I also beleive its a dry filter so no need to oil? also could be wrong - haha still learning. Also got a hiflo oil filter to replace stock one and an iridium spark plug, all were cheap and mainly bought to prolong bike and keep good mpg. Probably do an oil change too if time permits.

Hoping the carbs ok or I'm going to have to fork out another £55 or so on new one, nevermind this is all still cheaper than the bus in the long run lol!
 
could be, have done as much as I can without taking the carb off the bike - afaik. Need to check the diaphragm and any seals, if there the problem then its most likely new carb time. I don't think its ever been placed which considering the bikes age is quite good (its not noted on any of the service history but then I doubt its 100% anyway).
Don't mind forking out just trying to eliminate all possibilities first :)
 
well, airbox off carb ready for new air filter and o yeah.. wrong size haha! the site claims its for a gn125 yet upon reading further no gn125 has a carb inlet size of 39mm, all are roughly 50mm. Nevermind live and learn, going to ring them up and organise an exchange if possible as they have a 52mm filter which they list for a GSXR750.

Looks like a week without the bike, gives me time for a thorough clean, oil change, yada yada, also got some lower handle bars to fit as I find with the front tyre being so thin and having very little of my body weight on it slow control is a bit hard and i wobble some.
 
You must log in or register to reply here.
Back
Top Bottom