Struggling to keep a low idle

Weird; it's just the photo. In person I cannot even see these "cracks." There is very faint surface dirt and such, but that's all. I reduced the photo size by 80% in photo shop and saved as a jpeg. The lossy format and dramatic size reduction probably created the effect.

That's good, I thought it might just be the photo but thought I had better point it out anyway. This is one of those times that I am glad I was wrong, especially for your sake.
 
test your coils.

hook red wire from ohmeter to red/white and black wire from ohmeter to orange wire. set ohm meter at 200... should get reading around 2.7

try cold and warm test
 
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On the "cracks",they are surface imperfections,as if they were serious cracks they would extend through the plug holes. As was mentioned,lack of good ground in the spark plugs could be a problem. Cleaning with a dremel wire brush can help by allowing a clean surface for grounding,and using anti-sieze compound on the plug threads can help corrosion. I use anti-sieze on all plugs,as aluminum is soft and the threads can easily get destroyed while removing them too hot. lha
 
test your coils.

hook red wire from ohmeter to red/white and black wire from ohmeter to orange wire. set ohm meter at 200... should get reading around 2.7

try cold and warm test

I tested my coils last season and they were out of spec. The bike seemed to run fine, but I think I just wasn't as perceptive as I am now. This is only my second season of riding.
 
I tested my coils for fun and they both read 3.3

My friend has a busted up xs850( came coils) and hes read 3.3 aswell

Weird the book says 2.7
 
3.3 is close enough to spec for the primary resistance. My Hayne's says 4.0 ohms +/- 10% at 20 degrees Celsius. So, a "normal" range is about 3.6 to 4.4 ohms depending on temperature.
 
Update:

New coils, wires, and bp7es plugs.
35+ mile ride.
No change in performance; intermittent miss at idle still occurs; the right side pops on decel more and more as the bike warms up.

See photos for plugs.

The right side is lean as hell. The left doesn't look bad at all. The right is very white on the tip and the metal around the insulator is completely clean. The left side has a slightly darkened tip, the face is brown, and the metal surrounding the insulator is brown as well.

The plan? Keep the bp7es on the left and run a bp8es on the right.

Commencing test ride..... NOW.
 

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Sorry for the delay; I had a date :D

The photos are in!

60 miles ridden
left cylinder was a bp7es (same plug as last time)
right cylinder was changed to a bp8es

The photos compare the right cylinder with the previous bp7es and the new bp8es.
The photos then compare the left cylinder (bp7es) with the right cylinder (new bp8es).

The change is distinct, but they still look quite lean to me.

I am looking into replacement exhaust systems; an exhaust leak was suggested to me and I tend to agree it is quite possible due to my muffler installation method.

I am also ordering new plug caps, but I am a little confused on what to order. I took a closer look at my existing caps; both at labeled as NGK, but only one of them has a model number printed on it. The cap with the model number printed on it is a 5k ohm type. The other cap has nothing to indicate what kind it is.

Should I be getting a non-resistor cap for my points ignition with non-resistor plugs (bp7es or bp8es)?
 

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I tightened all of my exhaust hardware and put a bead of silicone around the right muffler and the popping on decel was pretty much eliminated.

At this time I only get the occasional backfire. Upon coming to a stop the rpms drop below idle. Cracking the throttle very slightly upon decel prevents this. She is a bit sluggish off the line as well.

It looks like I am clearly too rich on the main/needle position now.

I will be bumping the mains down to 145 (currently 150) and giving her another go tomorrow afternoon. It looks like I did have an exhaust leak and it was creating lean symptoms mixed with rich symptoms (hard to diagnose). Now that I have taken care of the exhaust leak the symptoms are clear.
 
bead of silicone will not affect jetting :)


pods and headers probably only just next size up 125 too 130 example at best.

Jet kits are bull... like a skinner needle would help its all bull. best to set stock needle to middle grove and at best lift needle one grove.

after 1/4 throttle its only the main jets thats working and not alot of HP down there
 
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I just did 50 miles with the 145 main jets:

The diving rpms at idle when coming to a stop has not changed. She feels a little less sluggish off the line, but I am still too rich at low rpms.

The rpms also dive below idle if I rev the engine to 6,000 or so in neutral.

Interestingly I am now too lean at WOT above 6,500 rpms. She is not pulling hard anymore at that range.

The plan is to go back up to 147.5 or 150 mains and lowering the needle(raising clip position) a notch. I am hoping this will do the trick.
 
whats the stock size jet?

I had issues with a old bike once... it was flooding and sometimes overflowing carbs, even with new float valves... valve seat o ring was letting alittle gas threw, messed up a good running motor because it was putting gas in base.

just a thought good luck.

25c part :)

Little o ring was dried up http://www.ebay.ca/itm/YAMAHA-CARBU...rcycles_Parts_Accessories&hash=item4cf7b0f737

After taking off check nut... and pulling it out... place alittle oil on it... and slide back in... if loose thats your issue.

Need to place alittle oil to slide new o rings in aswell
 
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Yes... get skinny ones that are tight to get on... buy a size or 2 there cheap.

motor was a nice running 88gsxr1100 :(
 
My carb internals, all gaskets and brass pieces, are brand new.

Stock mains are 137.5, or at least that is what I pulled out of the bike originally. My replacement kit came with 132.5 mains, however. So, I am not actually sure.

Update:

I tried something radical; I lowered the main jet needle a notch (raised clip) and I lowered the main jet 3 sizes (down to 142.5) and she pulls much, much harder above 6,500 rpms.

The blasted dying at idle did not get any better. I tried lowering the float height 1 mm (26 mm to 27 mm) and it got even worse!

I have a theory though: I think the float needle is not opening far enough and therefore choking the engine as it waits for the bowls to fill. I intentionally adjusted the float needles in the past to only open a minimal amount; it's time to crank those puppies open a bit more.

Unfortunately there will be no more testing tonight; it's a weekday and my exhaust is quite loud...
 
Try going all the way back to stock needle and buy stock over sized main jets(5$each).

if you need bigger jets go to jetsrus and get serial of bigger jet and give to dealer(only way they can find it in system)
 
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