The heads supposedly will bolt on, but you'll also lose midrange power with no appreciable top end increase. At least that is what was reported back a while when this mod was tried. The SV throttle bodies seem to be the limiting factor in the swapping as the TL gained midrange with the SV heads and did not lose anything on the top end...still using its' TB's.

The SV heads are said to flow really well as the TL's are supposed to actually be a bit too large. Our Mr Schmidt has reported good gains on the SV with decreased squish clearances....which makes sense. Have you tried modifying the STV's? They only decrease performance and I'm enjoying them lying on the table very much.

 

Stock heads, milled squish, and setting cam timing is worth big gains. Mid range is where it is at for the street. Then a bigger cam will really get you some more bang in the mid and up on top if that is what you need.
-MS

 

The cans will bolt on as the headers end with in an 1/8 in from stock sv. I think the header may be the issue....

 

So I'll keep my stock heads and try to get some TL cams.

Instead of milling the squish, thinner head gaskets are $100, which will be cheaper and easier.

But my stock pistons won't collide with the valves after thinner head gaskets and bigger cams?

 

How thick are the head gasket you are referring too? SV1000 has really large squish and the cylinders can be milled down quite a bit.

What year bike? Pistons are slightly different and the later 05 and up pistons are higher compression. Either way, I have been able to get well over 12.5:1 out of stock pistons by milling the deck height down and milling the head slightly too. As for cams, set the cam timing where you want it with slotted gears and start measuring to make sure all clearances are good. Even stock cams degreed on an otherwise stock motor makes a difference.

-MS

 

If you are looking for more mid-range, advancing the timing works pretty well. The 4 degree key http://www.factorypro.com/Prod_Pages/prods59,SV650,03.html#Ignition_Advance_Kit is a bit expensive...but worked great. Noticeably stronger in the mid-range.

Also, recently have been running with the STV's laying on the bench....and enjoying it. Needs more fuel running like this, but the motor pulls much better....especially in the desired mid-range where the STV's seem to be really slow opening.

 

Thanks for the feedback on the ignition advance... reading through the site, I've seen mention of it here and there.

I've also caught your favorable comments about the STVs (or lack thereof, lol) with interest and was thinking of pulling 'em out to see how the bike responds... I've already got a K&N panel installed, the snorkel pulled, and the front of the tank raised ~20mm so it seems like a logical "next step" to delete (or swisscheese) the valves.

Already have a TFI box installed, so it's easy to bump the fuel curve around as/where needed.

Have the capability/tools/interest here to dither with cam timing, too so I was intrigued by schmidt314's comment.

.

 

Just wondering if any of you guys have an A/F ratio gauge fitted to your bikes ? You might be surprised how lean or rich you really are. I just fitted one to my bike , and with some pretty serious airbox mods and Micron bolt on's the stock map is slightly rich most of the time at partial throttle openings.

About 3500 at low throttle opening the mix is lean , approaching 14.5-15:1.

Most everywhere else the mix is about 12 or 13:1 at part throttle, with it running about the same at wide open throttle until I get way up in the r's, and honestly I wasn't looking at the gauge then.

This is on my bike of course, and the temp was in the low 90's . Your mods and state of tune will affect the results, of course.


If you look at the dyno charts of stock SV's that have A/F ratio graphs on them, you can see the SV is rich more than it is lean.



..........................Blake

 

Been reading a lot on the TL's lately trying to figure out what it what with them. I'm thinking the injection IS the wild-card in this mix. They have two injectors, and also operate in two modes. Speed density (like the SV) at low rpm's, then switches over to Alpha-N at higher power settings. Very interesting stuff.

The intake tracts are much larger on the TL's, while their TB's are shorter....and their airbox setup much different with Ram Air and a tuning flap in the box. There is a LOT more involved here than just the valve sizes and cam timings. I tend to believe James's observations as, remember, he was switching jugs/heads on bikes while leaving their induction systems alone. The SV heads seem to flow well....the differences in output are elsewhere I'm thinking.

Taking the STV's out makes the effective length of the intake snorkel longer, and this seems to help the power output in the midrange and the engine really responds well even without giving it full throttle. Passing people from low speed yesterday up on the mountain was SO much easier as the engine wanted to just GO! The STV's can't do anything but restrict things...which was their purpose. If you like a more 'TL like' engine...removing them with attendant fuel mods cures one of the major differences as the TL's didn't have the nanny throttles.

Going to fab in an O2 sensor this winter to keep an eye on things. Seeing as my bike is very efficient with the fuel, I figured it was nice and lean. And got too lean at WOT with the STV's out by sagging/bogging. Richening it up until it pulls strongly should have it close enough to not do damage as lean running at light throttle won't hurt anything.

I'm also running the stock airbox setup complete with snorkel. It seems to pull better at low revs/light throttle with it in. Perhaps it is acting to richen things a bit? My faith is in the Suzuki Engineers giving us a good engine that was artificially hamstrung to satisfy the 'Regulators'. With judicious tinkering, getting it up close to TL levels with better mileage seems within reach.

 

Been reading a lot on the TL's lately trying to figure out what it what with them. I'm thinking the injection IS the wild-card in this mix. They have two injectors, and also operate in two modes. Speed density (like the SV) at low rpm's, then switches over to Alpha-N at higher power settings. Very interesting stuff.



Only the TLR has two injectors per TB, the TLS uses one per, like the SV. Pretty sure the SV does something similar to the "Speed density /Alpha-N" switch , too.

The intake tracts are much larger on the TL's, while their TB's are shorter....and their airbox setup much different with Ram Air and a tuning flap in the box. There is a LOT more involved here than just the valve sizes and cam timings. I tend to believe James's observations as, remember, he was switching jugs/heads on bikes while leaving their induction systems alone. The SV heads seem to flow well....the differences in output are elsewhere I'm thinking.


Sure , I agree with that. There are many differences in the intake tract of the bikes. However, generally speaking a shorter intake tract is tuned more for top end power, so with the TLR's bigger lift/duration cams and valves , and the SV's shorter intake tract, how did the SV not gain on the big end when using all the pieces that supposedly allow for more top end/high rpm power ?

Taking the STV's out makes the effective length of the intake snorkel longer, and this seems to help the power output in the midrange and the engine really responds well even without giving it full throttle. Passing people from low speed yesterday up on the mountain was SO much easier as the engine wanted to just GO! The STV's can't do anything but restrict things...which was their purpose. If you like a more 'TL like' engine...removing them with attendant fuel mods cures one of the major differences as the TL's didn't have the nanny throttles.


Instead of removing them, I'm gonna try and put them in the "full open" position and mechanically disconnect them from the servo motor.I am currently using intake tract plates , and the fully open STV plates will just extend the intake tract plates. I'll post back after I try this out.

Going to fab in an O2 sensor this winter to keep an eye on things. Seeing as my bike is very efficient with the fuel, I figured it was nice and lean. And got too lean at WOT with the STV's out by sagging/bogging. Richening it up until it pulls strongly should have it close enough to not do damage as lean running at light throttle won't hurt anything.

I'm also running the stock airbox setup complete with snorkel. It seems to pull better at low revs/light throttle with it in. Perhaps it is acting to richen things a bit?


The stock airbox/snorkel is keeping the airspeed up, or giving higher velocity air intake, however you want to look at it.

My faith is in the Suzuki Engineers giving us a good engine that was artificially hamstrung to satisfy the 'Regulators'. With judicious tinkering, getting it up close to TL levels with better mileage seems within reach.

I think the factory SV ECM has a major part to play in the dumbing down of the SV's peak power. Ignition Timing , STV's position or something has to be at play here.





....................................Blake

 

Found some info from the past

http://www.sv-portal.com/forums/showthread.php?t=39629

http://www.sv-portal.com/forums/showthread.php?t=41190&highlight=cam+timing&page=2

ejh2854, the second one includes some info on setting the cam centerlines for best performance.

 

Calling out lobe centers is okay here as long as we're talking about different settings for the same grind, but the IO IC EO EC timing points at 0.040" (or 0.050") are more useful (to me, at least) for calculating other pieces of the puzzle (overlap relative to TDC, EO relative to BDC on the power stroke, etc). Not all lobes/ramps are symmetrical, another wildcard.

That said, can relate to 106/108ish combinations... have worked quite a bit with varying cam timing in the four-valve, I-4 GSXR engines and they're typically pretty happy in that general range too.

Based on what you've seen- where are the SV centerlines as-delivered?

.

 

I'm believing the stock airbox setup creates a tuned pulsing/resonating environment for the intake which aids the box filling. At light throttle, I'm not seeing anything having much velocity in the intake tract like it would at WOT....so the benefits seem to help you run with less throttle opening. At least that is how mine feels with back to back snorkel in/out runs. It pulls harder easier down low with the snorkel. And is quieter! But still honks pretty loud when the throttles open.

I'm thinking your plan of opening the STV's is going to run into a computer glitch. The servo motor runs one plate, but the sensor is on the other one. How are you going to fool the ECU into thinking it is still hooked up? Something tells me you might get a limp mode situation if it doesn't see the sensor moving or rig up some kind of electronic gizmo to fool it. Looks like I'll be investing in one over the winter when I remove all the STV stuff as I'm a 'remover' now.

 

I'm thinking your plan of opening the STV's is going to run into a computer glitch. The servo motor runs one plate, but the sensor is on the other one. How are you going to fool the ECU into thinking it is still hooked up? Something tells me you might get a limp mode situation if it doesn't see the sensor moving or rig up some kind of electronic gizmo to fool it. Looks like I'll be investing in one over the winter when I remove all the STV stuff as I'm a 'remover' now.

I have two STV removal boxes that allow the shafts to be removed and not cause errors(most of the time). One of my set of throttle bodies has no STV shafts and plugs inserted and polished and matched on the inside for smooth flow. They also have a modified main throttle shaft to increase flow. You cut half the shaft out along the rod axis and then mount he screws through to the plate instead of between the two halves of the shaft. I forget the actual area increase, but it was significant. Kind of like how the STV plates mount currently.

Leaving the STV plates in and holding them in the wide open position could be of help, because they do act somewhat as an air foil in high flow situation. I actually some time ago build a set of foils that mount to the shafts, but never really tried them.

-MS

 

IDK, hadn't thought about that. Perhaps use the servo motor to drive the STV sensor directly ?

Maybe buy the STV eliminator box that is sold (forget who makes it) by that one guy . I think his name has a "Z" in it.


What did you do, just remove the plates and leave the motor and sensor hooked up ?


................................Blake

 

Pulled the STV blades outta mine just a bit ago... took longer to get the seat off :msn-wink:

.

 

Report back on this thread and let us know what you think, por favour.




................................Blake

 

Got in a short hop before some rain showers rumbled through... enough to get the engine up to temp and make a few runs through the gearbox, but will have to test low-speed "grunt" manners another time.

From what I've felt so far, though- I'm definitely pleased with the change (improvement) in throttle response, particularly the upper-midrange punch which feels noticeably livelier.

Pull from ~3k revs to ~5k feels about like it did before, perhaps slightly softer... I've got a TFI box on the bike:

http://www.holeshot.com/dl650/tfi_650.html

...and may be able to dither a little fuel in or out right there if the 'softness' truly exists.

More work to be done for sure- a day-long blast in the mountains will tell me a lot more than just cogging around town, but so far at least I'm thinking this is a net positive.

BTW also picked up one of the 180* Stant t'stats we discussed on the fan-switch thread, will dink around with that next week.

.

 

What did you do, just remove the plates and leave the motor and sensor hooked up ?

Yes. Absolutely the easiest way to play with them not strangling the intake. Would like to remove the shafts/motor/sensor et al but that'll be winter tinkering. The main throttle shafts ARE some serious looking pieces! But I think they need to be pretty stout to hold up to the sonic battering they'll get. Would suck Major to have a shaft fail.

Perhaps use the servo motor to drive the STV sensor directly ?

I think Mr. Schmidt did something like this in the past, but that looks like a bit of work to me...although it should work (I'd think). Better way would be to just fake the ECU out electronically and lose all the hardware.

One of the things I've read about STV removal was a reduction in gas mileage...which I wouldn't be happy about. So, last couple rides were mileage tests and I'm happy to report the missing STV's didn't hurt it at all...might have actually gotten a tad better. Very, very hard to ride steadily and near the speed limit set up like this. So I'm thinking the reports of mileage loss were more from the rider using more power.

Biggest change to me is the engines willingness to rev at part throttle. Just a crack open and it'll rev up to 7-8000 with smooth ease. Before it would need a lot more opening to get up that high. Other than needing to be really precise with the throttle (which we should be doing anyhow) I see no harm or downside to this. The fueling does need some richening, though. Blake, with your O2 sensor it might be interesting to document the changes.