'85 700E jettet lean for emissions?

[t3rmin]

I've ridden a 78 GS750, 81 GS650, 80 GS 750 (16v), and 82 GS1100 (8v). All were buzzier than the 700. The 700 is only slightly more buzzy than modern inline-4 sport bikes I've ridden (ZRX, CBR 600F2). It's not a problem at all.

So I adjusted the mixture screws yesterday. All were around 3 turns out already. I think I've got them around 3.5 turns out now for highest idle. Morning starting is improved (less fussy about choke, starts with fewer cranks, almost zero backfiring), off-idle response is a bit better, and idle is improved. Still takes a while to warm up before it'll hold a low idle.

I've never had to turn the mixture screws out that far on my other GSs. I can only assume I'm having to compensate for something else being lean. Pilot jet? Float levels? What do you think?

 

[slugsride]

I've ridden a 78 GS750, 81 GS650, 80 GS 750 (16v), and 82 GS1100 (8v). All were buzzier than the 700. The 700 is only slightly more buzzy than modern inline-4 sport bikes I've ridden (ZRX, CBR 600F2). It's not a problem at all.

So I adjusted the mixture screws yesterday. All were around 3 turns out already. I think I've got them around 3.5 turns out now for highest idle. Morning starting is improved (less fussy about choke, starts with fewer cranks, almost zero backfiring), off-idle response is a bit better, and idle is improved. Still takes a while to warm up before it'll hold a low idle.

I've never had to turn the mixture screws out that far on my other GSs. I can only assume I'm having to compensate for something else being lean. Pilot jet? Float levels? What do you think?

Did the idle hanging when you blipped the throttle go away? I've had mine since new (leftover-bought in 88), the cold-bloodedness is normal but the backfiring and not holding low idle is not. Mentioned the boot o-rings on your "pics" post because yours has the same mileage as mine, and now I'm doing a top-end job as a result of them leaking.
My idle screws (which still had the caps on) were all between 2 1/2 and 2 7/8 turns.

 

[t3rmin]

Did the idle hanging when you blipped the throttle go away? I've had mine since new (leftover-bought in 88), the cold-bloodedness is normal but the backfiring and not holding low idle is not. Mentioned the boot o-rings on your "pics" post because yours has the same mileage as mine, and now I'm doing a top-end job as a result of them leaking.
My idle screws (which still had the caps on) were all between 2 1/2 and 2 7/8 turns.

Throttle blip and return to idle doesn't seem quite as snappy as the 750, but it is improved. Actually it's hard to tell because this darn electronic tach is glitchy down low (and up high).

It'll hold a low idle fine once it's totally warmed up (5-10 minutes on choke). I had to significantly turn down the idle screw as adjusting the mixture screws raised the idle quite a bit, and I found a definite "sweet spot" on each cylinder where idle was best, so I'm fairly confident the mixture screws are correctly set, all else being equal.

Backfiring is almost non-existent now. Heard just a few pops on full choke right after starting up, but none after running for a few seconds. Before there was a fairly steady pop every few seconds while on choke during first few minutes of warm up.

Note I still haven't checked the valves. I'm hoping to find time tomorrow.

Intake o-rings are still an unknown. I've got them on order from Mr. Robert Barr and will probably replace them. Intake boots themselves look great. I'm not seeing any extreme intake leak symptoms, the bike runs fantastic, oil temp is fine, and headers aren't blueing, so I doubt I'm in any kind of dangerous lean scenario.

 

[slugsride]

Throttle blip and return to idle doesn't seem quite as snappy as the 750, but it is improved. Actually it's hard to tell because this darn electronic tach is glitchy down low (and up high).

***Do a search on that problem--when I was trying to find out what was wrong with mine I read a post about a 700 that had idle problems, his eventual fix was a ignition module and he said that also fixed his glitchy tach! Mine never had that symptom.

It'll hold a low idle fine once it's totally warmed up (5-10 minutes on choke). I had to significantly turn down the idle screw as adjusting the mixture screws raised the idle quite a bit, and I found a definite "sweet spot" on each cylinder where idle was best, so I'm fairly confident the mixture screws are correctly set, all else being equal.

Backfiring is almost non-existent now. Heard just a few pops on full choke right after starting up, but none after running for a few seconds. Before there was a fairly steady pop every few seconds while on choke during first few minutes of warm up.

Note I still haven't checked the valves. I'm hoping to find time tomorrow.

Intake o-rings are still an unknown. I've got them on order from Mr. Robert Barr and will probably replace them. Intake boots themselves look great. I'm not seeing any extreme intake leak symptoms, the bike runs fantastic, oil temp is fine, and headers aren't blueing, so I doubt I'm in any kind of dangerous lean scenario.

My boots looked good too (amazing at 22 years!). Getting the bolts out is a real PITA, had the best luck using the bit from my impact in a 5/16 socket and a ratchet, still had to Dremel slot a couple. My o-rings didn't look as bad as Mr. Barr's picture, but they were all hard and flat. When mine started acting up the two center pipes were turning a gold color near the head.

 

[QuaiChangKane]

I'm late jumping into this party, but I'll share what I know...


Versus the 750, the 700 had longer rods, taller pistons, slightly different cam lift/duration/timing, and different gearing for better acceleration (sacrificing a smidge of top end). In fact, it was only a couple of tenths shy of the '83 750E in the quarter.

I don't recall anything about carburetion changes or valving changes. It seems that swapping the cams (or whole head) and pistons into a 750 motor while keeping the 750 rods will give a nice little bump in compression (plus a few cc's) and slightly more aggressive cams. I'd imagine that a copper head gasket might help a bit here, too...

It stands to reason that the carburetion would be the same on the 700 as it was on the California 750 - same engine, essentially - but CA was at least as strict in 1983 as the Fed was for 1985 as far as emissions go.


I picked up some 700 pistons last year, and am looking for some cams or a complete 700 head. I'll document this if I ever get the parts together. I'm also in the process of rebuilding a set of 34mm flatslides I got from a friend (free rocks!) that were in need of some TLC - my money says that that will be the hot mod. I'll try to do each mod separately so I can share the results for each one individually.

On a side note, I'm also looking at swapping out for a 700 tail, too - no performance gain, but I think it looks far better than the 750 tail with the additional sculpting along the bottom line. The 700 gas tank looks worse, though, even though I think the 750 tank is ugly on its own.

I'm also looking for an 1150 rear wheel (3.5" - PM ME IF YA GOT ONE!!), and am going to try the RaceTech cartridge emulators from a GS1100E in the 750's forks (and sell my first-born for an Ohlins shock ). SS brake and oil cooler lines, plus an aftermarket (larger) oil cooler just about wrap up the mods I've got planned. Well, maybe aftermarket guages, too - but I'm trying to limit my dreaming to a Thou at a time.... :-D




Sorry for the rambling - If you'd like, I can scan some of the GS700 articles I have for the first ride tests of the 1985 model year.



-Q!

 

[QuaiChangKane]

Forgot to mention....



My bike was very cold-blooded and cranky down low even after warmed. It turned out to be cracked o-rings on the fuel rails that couple the carbs together, causing the bike to run lean. YMMV, but this is apparently a common problem.

Check your intake boots as well, and check for poor connection on your airbox boots.



-Q!

 

[t3rmin]

Long overdue follow-up, but I bumped up the main and pilot jets one step. Warms up better, idles better, and power delivery is smoother all through the revs (especially the transition at 6k). Better gas mileage too. Highly recommended.

 

[Griffin]

Long overdue follow-up, but I bumped up the main and pilot jets one step. Warms up better, idles better, and power delivery is smoother all through the revs (especially the transition at 6k). Better gas mileage too. Highly recommended.

What size jets did you install?

 

[t3rmin]

Lessee, 122.5 to 125 main and 37.5 to 40 pilot if I recall correctly. Got 'em from z1enterprises.com.

Also I found out the stock pilots do NOT have the little holes on the side (VM style), which means I got the wrong ones (BS style). Luckily I also found out it doesn't matter as long as your carbs have the little rubber plugs over the pilot jet tubes. ;-)

I also installed a UNI brand drop-in filter at the same time. Dunno how much flow difference that is, but if you want to duplicate my results, I'd do the filter too (they're cheap).

 

[Hugh]

My bike was very cold-blooded and cranky down low even after warmed. It turned out to be cracked o-rings on the fuel rails that couple the carbs together, causing the bike to run lean. YMMV, but this is apparently a common problem.
-Q!

Is it possible that bad o-rings in the fuel rails would actually prevent the bike from starting altogether? My carbs have been off numerous times for cleaning and I still can't get the bike to start - even though they are spotless. I wonder if I buy the "Mikuni CV BS series carb O-ring kit" from Mr Barr (http://www.cycleorings.com/) if my bike would start and run again. Everything from his site for our bike would run a total of $22.09 so it's not that much money for what you get, but I hate to throw money at a problem if it won't fix it.

Here is what I am thinking about ordering - is this the right stuff for the 700?

Mikuni CV BS series carb O-ring kit, U.S. Shipping - $12.67 USD
Mikuni CV carb bowl drain O-ring set - $0.01 USD
20mm Stainless Steel fastener set, w/kit - $5.50 USD
Viton Intake O-ring set, large - $3.91 USD
Subtotal: - $22.09 USD

Hugh

 

[t3rmin]

Here is what I am thinking about ordering - is this the right stuff for the 700?

Mikuni CV BS series carb O-ring kit, U.S. Shipping - $12.67 USD
Mikuni CV carb bowl drain O-ring set - $0.01 USD
20mm Stainless Steel fastener set, w/kit - $5.50 USD
Viton Intake O-ring set, large - $3.91 USD
Subtotal: - $22.09 USD

Hugh

Do it. Mr Barr's kits are top notch and cheaper than snot. Once installed, it's less stuff to worry about as the possible problem.

 

[bigs_gs]

Where do you live where they do emissions. In TX they just put a sticker on it.

 

[dig dug mx6]

Mine was horribly cold blooded until... 4 to 1 drop in K&N and K&N stage 1 Jet. I followed the instuctions and set the cards just as they stated in the manual it came with. Now it minorly cold blooded. I may turn out the mixtures another 1/4 since I get some popping on decelleration.

 

[takepic]

Hello,,, Does anyone happen to know the correct jetting for a 1985 gs700es with the V&H 4:1 exhaust? Thanks,