Guest Posted July 20, 2008 Share Posted July 20, 2008 Hi folks, I have a suzuki GS125 that has recently had new carb and barrel, compression pressure is 130psi. Problem is when in 3rd gear, i can scream the guts out of the bike to get up to 50mph, as soon as 4th is selected there is no power and even less in 5th. so i am wondering if anyone has any ideas before i go down the route of replacing valves and camshaft. cheers in advance Quote Link to comment Share on other sites More sharing options...
Guest Posted July 20, 2008 Share Posted July 20, 2008 Hiya... I have no answer for u im afraid...but hello anyway 8) Quote Link to comment Share on other sites More sharing options...
Guest Posted July 23, 2008 Share Posted July 23, 2008 sounds like it could be your ht leads or coils breaking down, does your bike sound like its going to die if you open the throttle suddenly from tickover when idling ?, if so, give your ht leads a good clean with wd40 and then spray some ignition sealer on them if you have some, and see if it improves it ?, if it does, then its time for a new coil as i believe the ht leads are hard wired on that bike Quote Link to comment Share on other sites More sharing options...
Guest Posted July 23, 2008 Share Posted July 23, 2008 I will check but not to my knowledge. Once warmed up the bike idles lovely. It picks up well till about 30mph and then wont go any faster unless i drop back to 3rd when there is a pause before if suddenly picks up and will do 60mph at about 8000rpm. select 4th and 5th and the bike just drops back to 30ish as the revs wont come up above 3500. sparkplug is sooted indicating not enough air. so tried without air filter and does exactly the same. I have just cleaned the tank out and filter, replaced fuel hose and put new air filter in. yet still no different. I will check the coil however. cheers happy Quote Link to comment Share on other sites More sharing options...
Guest Posted July 23, 2008 Share Posted July 23, 2008 It could also be the coil breaking down, you need more power to get a decent spark under high loads, and running at low revs with the throttle fully open will highlight any HT lead or coil deficiencies, its symptoms are very similar to what you have described, you get up to a decent speed in a low gear because you are running at high revs which doesnt need a high power spark, but as soon as you load up the engine with full power at low revs, the spark decays and you slow down, and the only thing that will get your speed back up is dropping a gear and revving the nuts off of it !You also get sooting of the plugs, because the fuel isnt being burnt, which leads people to conclude that not enough air is getting into the mix, but in reality, theres plenty of air and fuel, but not enough spark to burn it all properlyhope that all makes sense Quote Link to comment Share on other sites More sharing options...
Guest Posted July 23, 2008 Share Posted July 23, 2008 Had a look at the coil and there is signs of rust which could be shorting or tracking slightly. However have ordered one if only to eliminate it. Cheers mosser for help, will see in a few days if it solves problem. Quote Link to comment Share on other sites More sharing options...
Guest Posted July 26, 2008 Share Posted July 26, 2008 Hi , new coil fitted and no change to previous symptoms. Quote Link to comment Share on other sites More sharing options...
Guest Posted July 26, 2008 Share Posted July 26, 2008 not sure if it is fitted but sounds similar to my old sr125 problem with the cdi unit as it was not advancing the timing for the higher revs.... changed that and away it went Quote Link to comment Share on other sites More sharing options...
Guest Posted November 1, 2008 Share Posted November 1, 2008 Cheers for all your help, went back to beginning and found that carb needle valve was wrong type even though it was a new carb. Anyway sorted now and the bike does 70 easily. Quote Link to comment Share on other sites More sharing options...
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