I just finished the rejetting of the carbs and put a full Jardine system on my 09 GS500F yesterday. I rode for about an hour and noticed a couple issues:
There is a noticeable "ti ti ti ti" sound coming from the engine and I also think it's audible from the exhaust. I'm going to see if I can tighten the headers again today and hopefully that will fix the sound.
The right side of the engine seems to be getting a lot hotter than the left. I noticed it while I was driving down the road and when I would stop at a light, so it's fairly significant. This may also be due to the headers not being fully tightened, but I was wondering it could also have something to do with the one cylinder running a little lean.
Also when I would blip the throttle while downshifting, I noticed at least a few times where the engine would not react to the blip, almost like it was being bogged down, but at a standstill idle, I could blip the throttle and everything seemed OK. Any idea what would cause this? I hadn't noticed this before the rejet and exhaust.
I'm thinking the air screws may need some adjustment. What's the best way to tell if there needs to be some adjustment and what's the recommended way to adjust the air screws?
curious what jets you're running?
The ti ti ti noise could also be valves or cam shaft side drift. And yes you can have a exhaust leak ... but the general thing is, motor and mechanical noises are let through the exhaust unfiltered unlike the stock pipe which kills a lot of it. Worth checking, but dont go nuts, its likely it was always there, and you just hear it now. You may have to learn and get familiar with listening to it, then if it makes more noises later on you can pin point that its got stuff going on and work on it etc.
Ride side getting hotter - where are you measuring that ? Engine ? How exactly ... by touch ? I dunno what could be going on here, if this was an 89-00 I'd say your vacuum line is bad, cos the 89-00 has vacuum line to left carb only.
Blipping the throttle - here do this experiment for me. On an empty road get ~3-4K in 4th gear maybe and whack the throttle open. See what it does. Then same situation, open the throttle slowly - see what it does and post back.
Air screws - you should have done it when you had the carbs off - anyway if you dont have a huge difference in cold idle vs hot idle, you dont worry about them.
Cool.
Buddha.
I'm going to do a more thorough check regarding the engine noises this weekend and I'll also do your test by opening up the throttle in 4th. I'll post back when I do that.
The right side of the engine is getting hotter than the left. I can feel the heat from the motor on my right knee and I can feel it when I put my hand inside the fairing on the right side more than I can on the left. Not sure if this is a big issue but it did strike me as being unusual. I should also note that when I was riding yesterday the temperature was in the mid-80s; 15 degrees hotter than when I've ridden it previously. This may have something to do with it. Again, I'll test more thoroughly this weekend.
Also, I did turn out the air screws 3 turns on each carb, but I was just curious about how precise the screws really are. There may be small differences from one carb to the other, not sure if it would be noticeable though.
Jets are: 20 pilots, 132.5 mains, 1 washer, 65 mids. Stock air filter and Jardine full exhaust.
The Ti Ti Ti... are you hearing the NEW pipes expanding and contracting a bit as they break in? and cool down heat up?
Quote from: Fry on May 13, 2011, 08:53:14 AM
The Ti Ti Ti... are you hearing the NEW pipes expanding and contracting a bit as they break in? and cool down heat up?
my Vance and Hines made a similar noise and smelled awful until it went through a few heat cycles.
Its a bit noisier now, but the oil level seems fine and there are no flakes in my oil or anything. I think the GS just has a nosier than normal valve train.
Blipping the throttle can produce no reaction if the bike is too rich in that range ... or if the slide is rising too fast ... so run that test and get back to me, I am leaning toward a wee bit rich @ this point. Oh yea tighten the exhaust so its not leaking.
Cool.
Buddha.
The sound is definitely not because the pipes are new...
The only reason I say this is because the sound only occurs (noticeably at least) when I'm accelerating, and the volume and rhythm of the ti ti ti increasing as I increase the throttle.
I don't notice the sound when cruising or at idle. I'm going to try to tighten the headers and test it out again. I'm not sure I tightened them sufficiently because my allen wrench tool only fit in to the header bolts at an angle because of the frame being in the way.
Oh yea whatever fool decided that this frame gotta be that way and the exhaust ports right there ... awful.
Anyway ball tip allen sockets my friend, those are an absolute must.
Cool.
Buddha.
I bought a better allen wrench to tighten the headers now, but I have yet to take off the fairings and get to it, so I can't comment on the origin of the noise yet.
I did however test power in 4th gear (and other gears) by opening up the throttle at 3-4k rpm. It seems to react just fine; pulls along, doesn't get bogged down, doesn't feel particularly lean.
After further testing, here is what I noticed about blipping the throttle: throttle response seems perfectly normal while idling. When cruising along at speed and then coasting and clutching while downshifting and blipping the throttle, there seems to be little to no response from the engine. It doesn't happen every time though. Almost seems too lean, like the fuel from my throttle is being immediately evacuated through the exhaust. This is only for light, quick turns of the throttle, probably 10% throttle.
Is this possibly due to running lean? Any other symptoms of running lean?
Almost all throttle opening problems are likely to be rich condition. Lean condition usually acts up @ steady throttle. Lean surging, lean misfire any of those things are usually @ steady throttle. The 4th gear test elimiated the rich condition in that throttle range, you can be lean @ that throttle position still. Try steady throttle - and jetting is related to throttle position, not rpm. So convert your observations to throttle position and re test. Like mark the grip and the switch with little chalk or marker and refer to that when the bike acts up/works fine.
BTW as you blip the throttle, you do know you may not get a real change in the venturi velocity to produce a change in rpm right, especially since the rpm and the slide is dropping, you may just get it to drop a shade slower which you dont even notice.
Anyway get the exhaust leak sorted and see what it does, exhaust leak can cause an artificial lean condition especially down low.
Cool.
Buddha.
I'm still have an issue with blipping the throttle, particularly when downshifting. It seems to "putter" out fairly often when hitting the throttle. I seem to have to give it even more throttle than normal to get the engine to rev up, instead of just blipping.
It's a minor annoyance so I'll just live with it if it's not a sign of something more serious. Any ideas?
It sounds like a vacuum issue or to many turns on the mix/pilot screws.Only make one change at a time and test.This way you will know if the problem gets better or worse,and can make the corrections.Also,the header bolts are only torqued to 15-18 foot pounds of torque.New header gaskets don't cost much, if you suspect a header leak.