'85 700E jettet lean for emissions?

[t3rmin]

Was perusing the shop manual for my new 700 and there was a blurb about special jet size designations for emissions control. It had a little table showing one font for normal jets and an italicized font for the special emissions control jets. This is in reference to the size stamped on the jets. It warned not to use the non-emissions jets.

I'm guessing these emissions jets with their italic number stamps are probably slightly leaner/smaller versions of the "real" jets of the same number designation, no doubt to satisfy Uncle Sam's penchant for regulation. Is that correct?

It occurred to me that there may be a power increase to be had by replacing these jets with standard, non emission Mikuni ones, if in fact the bike is artificially lean to satisfy emission requirements.

It's cheap and easy to obtain and swap jets so it's an attractive proposition. Any thoughts?

 

[LeeGS550E]

I think since you got such a good deal on it, you should require yourself to buy a 4-1 and pods for the thing. I believe stock's in the range of 122 mains (IIRC). Might try bumping them up one size without changing anything. Right now I've got cheapo Emgo's, V&H 4-1 (gixxer parts=faster, right?), and I'm running 40 pilots, 135 mains, no move on the needles yet. Still havn't done alot of tuning on the top end, and to idle it needs three full turns on the screws, so I may want to jump another size on my pilot. Distraction628 can totally line you out on jetting that thing though. He could also line you out on using Keihin CR's :-D.

 

[t3rmin]

I wouldn't mind doing a 4-1 some day. And I've already got K&N pods in the garage. The stock exhaust is absolutely pristine though, and I do like the way it looks, so I'll probably stay stock for a while.

If the stock jets are, say 122 (as you mentioned), my shop manual would seem to indicate that's actually 122 (note italics). What that means I'm not sure, but I have a hunch it's actually slightly smaller than a "real" 122. If that's the case, I wonder if just throwing standard 122 jets in there would give a little power bump without further mods. The assumption being the bike is running on the lean side intentionally from the factory to pass emissions so I'm just *correcting* the lean condition.

Can anyone confirm or deny these assumptions?

 

[LeeGS550E]

When I pulled out my stock 122's, they looked like off-the-shelf Mikuni style jets. They did not have any indication (stamps, marks or otherwise) of being special "lean jets"....can't really confirm or deny, but I saw no indication that they were different.

 

[t3rmin]

When I pulled out my stock 122's, they looked like off-the-shelf Mikuni style jets. They did not have any indication (stamps, marks or otherwise) of being special "lean jets"....can't really confirm or deny, but I saw no indication that they were different.

You don't by any chance recall the font of the stamping on there? According to my manual it's the italic font that indicates the emissions jets.

 

[LeeGS550E]

I don't off-hand, but I can post a picture when I get home.

 

[t3rmin]

I don't off-hand, but I can post a picture when I get home.

No worries, I'll have my own off either today or tomorrow. Although I wouldn't mind a closeup of some definite "normal" Mikuni jet markings for comparison.

 

[LeeGS550E]

Ok, I tried to get the best shot possible with my camera set on macro...still a little blurry. I goofed around with the color on the photo too, but you can just barely make out the font on the jets. It doesn't look to me like the 122.5 is written in italics.

 

[distraction628]

My manual Say's that the EMISSION JETS where only on the CALI Model

 

[Mark whiz]

I believe ALL of the '85 models are listed with the italisized jets. All the Suzuki parts fiche call for the funky jets. If memory serves me correctly I believe my '85 does have them and it is definitely a 49 state model. Lee, do you have a '83 or an '85 - the '83 still had the "standard" type jets...............or maybe a PO already made the swap t3rmin is asking about.

I would like to know the same info, as I have contemplated the same move.

T3rmin, the first move you might want to consider is drilling out the plugs on the idle mixture screws and richening them up a bit - that should make it's cold-blooded starting behavior improve as well as its low speed behavior.

 

[t3rmin]

Well I was in the carbs last night for a quick cleaning and the jet fonts didn't look italic. Took pics but I don't have them with me now. Wonder if somebody put regular ones in already?

Mark: I hear you re: turning out the mixture screws. Was planning on doing that when I have a spare minute. It is cold blooded and a bit weak down low, although it is idling now!

I need to read that section of the manual a bit closer regarding the Cali thing...

 

[LeeGS550E]

ILee, do you have a '83 or an '85 - the '83 still had the "standard" type jets...............or maybe a PO already made the swap t3rmin is asking about.

There's a possibility that the PO made the swap. My plugs were drilled out, so that may be a sign that tinkering had happened. If anyone finds those italicized jets, they should be worth good money as novelty items. :-D

 

[t3rmin]

Down with italicized jets!!! ;-)

 

[t3rmin]

After reviewing the pictures I took of my jets, they've got the same font as yours. After re-reading the Suzuki shop manual, the difference between the fonts isn't so much italics as it is rounded versus angular. The emissions jets have an angular/boxy font and the non-emissions jets are a more rounded natural font. Your jets and mine have the emissions font.

The shop manual claims these emissions jets are "machined to closer tolerances". Whether that actually means "closer" or "smaller", who knows...?

Interestingly I noticed from the specs in the manual the '83-up 750's actually had smaller main jets (don't remember the number). Must be part of the beefing up Suzuki did to make the 700 as potent as the 750.

 

[Nessism]

The shop manual claims these emissions jets are "machined to closer tolerances". Whether that actually means "closer" or "smaller", who knows...?

Interestingly I noticed from the specs in the manual the '83-up 750's actually had smaller main jets (don't remember the number). Must be part of the beefing up Suzuki did to make the 700 as potent as the 750.

The "machined to closer tolerances" makes sense to me; they need to assure the variation between different bikes is close since the emissions testing process involves testing batches of bikes, not just one - (at least it's that way for automobiles).

As far as beefing up the bike, are there differences between the 700 compared to the 750 other than the stroke? My memory seems to recall higher lift cams for the 700 to make up for displacement but I can't remember for sure. There is a killer nice 700ES on Craigslist here in LA. I'd love to buy it but the guy wants big money for it...and I already have two bikes.

 

[t3rmin]

From what I understand it's de-stroked, more aggressively cammed, and has domed pistons. Has LOTS of pep, that's for sure. They did really well with this powerplant. It's definitely lean down low, which I'm hoping can be corrected with just the mixture screws. And I don't think I've ridden anything more flickable. I just can't say enough about this bike.

I'll probably "leave well enough alone" with the jets...

 

[Nessism]

Long duration cams are known to trade low end power for high (they are also dirty from an emissions standpoint) thus the softness you feel in the powerband may not have anything to do with lean running.

How is the engine in terms of vibration smoothness? I used to have a ’87 VFR700 and that bike had plenty of getty-up for me, and the engine was wonderfully smooth. A short stroke 700 that likes to rev sounds like fun as long as the engine is smooth.

 

[t3rmin]

Well I can tell it's lean by the cold bloodedness and slight backfiring when warming up and hanging idle when blipped. I don't expect it to be as torquey as the 750 with cams like this, and I'm OK with that. High-revving power is a different kind of fun. ;-) Redline is 10k on the 700.

The motor still has some of the characteristic GS buzz, but it's much smoother than my 650 or 750. The buzz is really only there when accelerating, once you settle in at speed it's a non-issue. It cruises very comfortably at 80mph all day long, which is most definitely NOT the case with the 750.

Actually my buddy just bought a VFR750 on Sunday but I have yet to ride it. Says it's a really sweet bike so I'm itchin' to check it out.

 

[Guest]

A buddy of mine bought an '83 750 Interceptor the same week I got my ES. They (the VF) were a tiny bit smoother, one wasn't really faster than the other. Anouther guy I know got a VF700 the first year those came out, they were not as fast as the VF750's or, atleast that one wasn't.

 

[Mark whiz]

I still have the original test ride articles on the 700's from Cycle World & Motorcyclist at the house and I know they spell out the differences between the 700 & 750. I know it was de-stroked, final gear ratio changed, carb jetting changed, and a few minor differences on things like fork oil level and such. I'm not sure if they used higher lift cams or if they just adjusted the valve timing. I'll have to dig that out tonight and see what it is.

Either way, it is definitely a "cammy" engine. Below 4K rpm it is no "stump-puller" for sure, but once it gets on the cam around 4k, it'll move like a scalded dog. :shock: It has a really light flywheel effect which makes it rather rev-happy............which you have to watch cause I know when I've run mine up to 8K on the tach, it instantly jumped up to the redline of 10K - What a RUSH! :-D

Unfortunately, that rush starting around 4K brings with it more vibration - mine has always buzzed pretty good from that point on. I'm sure replacing the intake o-rings and sync'ing the carbs will help it some now, but it always buzzed pretty good above 4K ever since it came out of the box. So if the older models buzzed harder - that's scarey 8-[