Gsx1100ex a little modernisation.

[smirk]

So, I started with a set of mk1 1200 bandit carbs to fit. I then found a set of bsr36's from a 2002 750 tea pot - I don't know why but I chose these. Now all rebuilt with 20 pilots & 147 mains (never touched the little intermediate jet as 3 jets confuses me) needles on bottom groove / fuel screws at 3 turns. They went on with a bit more fuss - but OK, throttle cable a bit to short but original choke all bodged in. Running k&n pods on a v&h unbaffled with pingle tap. I've given the dyna s a full checking & given them a relay fed full 12v supply.... one day I must get rid of the cartridge fuse box. But now it's pissing down.

I spent ages bench balancing the carbs & it starts + runs / revs quite nice in garage... but still has a poppy farty session in the exhaust at idle. I'm hoping a proper balance will smooth its flatulence? Also I've never removed the exhaust & checked head gaskets..... any advice on my lumpy farty poppy idle ( it's probably not as bad as I make it sound) but I'm hoping I can get it gone.

[Toecutter]

Syncing the carbs might help your popping if they are still quite out after bench syncing. Might be worth checking valve clearances of you haven't already before syncing carbs. Do you mean the exhaust gaskets you haven't checked? Could cause popping if leaking a little. 

[smirk]

Yes valve clearances are after a quick balance check/adjust today.

I've not had exhaust off it - so I'm doubting the exhaust gaskets.

It was a little poppy farty before I started all the mods, but ran fine once off idle. May well be valves, as I've done a lot of changes & it's flatulence is still there. Or it's just a characteistic of an old v&h empty 4 into 1?

[TonyGee]

you do get a certain amount of popping in an exhaust on carb'd bikes on the over run, but its masked by the standard exhaust so its hard to here, but on a free flowing exhaust its more noticeable.  

[smirk]

It does it on over run which I'm quite happy with. But the idle erratic burbly farting (can't call it backfiring) & it's sometimes worse than other times, makes me think balance/valve clearance/ or leaks at exhaust to head? (Inlets are new).

I've just noticed my victory in fitting the bsr carbs has shallowed a bit, as the middle synch screw is pretty inaccessible, but I now have vac take offs on both the carbs & the intakes. Think in going for the intake ones first. But rain is stopping here now, so set balance & it's a little better. Going to ride it before any more tinkering. But new valve cover gasket & exhaust gaskets on order for next weekends fun. Pick up response it much improved over dinosaur carbs!

[Toecutter]

Ideally valve clearances are checked and set before carb sync is undertaken. Assuming you have no vacuum leaks at the boots and as you are using a pingle tap, all vacuum take off ports on the carbs should be plugged off too. Assuming everything is ok internally with the carbs and your jetting is very very close if not bang on, then popping on decel is normal. Any popping/farting at idle Could be air leak related and or carb sync. Is the idle smooth or does it flactuate when popping then drop off then rise then settle etc?

[smirk]

I only did the sync as it was quicker than the valves & it was cold in my garage.. all plugs are on vac ports - inlets are new & can't see any issues. Idle is a bit wooly up & down when it gets farty sometimes stops at nice rpm and then up a bit. I'm onto the valves next weekend.

 

[Reinhoud]

My GS1000 with 1247 big bore didn't want run properly on carbs from a 750, put carbs on it from an 1100 and it ran fine

[smirk]

Well.. I done valve clearances - lifted needles to one off bottom clip - re balanced & she still farts in the can!

The bsr 36 carbs run nice sitting - lovely pick up....but terrible flat spot about 3500 on the road. Thinks I gotta take them off again & do float heights & put needles up another clip! 

[TonyGee]

sounds like its still running lean, try wrapping the filters a small amount with tape and take it for a run and see if the flat spot at 3500.  if its better then its defo running lean. 

[smirk]

Yes... another job for next week! It does actually feel like a bit of fuel starvation though.

Masking tape round filters next. But I'm going on Eblag to see what mixture analysis device is available - I had a colourtune but hated it!

[smirk]

Question time - is a co meter any good for setting the air fuel? They seem pretty cheap these days.

I don't want to weld an o2 sensor plug into the system... can I dangle a sensor into the big hole of the many holes in the v&h can?

[Gixer1460]

A lambda sensor is useful for tuning but with carbs and unless done on a Dyno you won't know where the slide is when the stumble occurs - throttle position doesn't correspond to slide position.