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Tech Tips Index > Suzuki King Quad 450/700/750 Sign up or Logon

Fuel Injector upgrade mod (M109R Injector)- 700/750

by Glenlivet, 2008-04-09

Noticeable power increases, reported to be "across the band" have been had by replacing the stock fuel injector with the one described below, in conjunction with suitable adjustments to the VDI Copperhead EFI ECU.

The Power Commander III may also be used to tune the 700 and 750 KING QUAD using the M109R injector. However, this article focuses on making the proper adjustments to the VDI ECU to use the M109R fuel injector.

The M109R injector does not "max out" at Wide Open Throttle at low altitudes the way the stock 700 and 750 KING QUAD injector can. Also the M109R injector's 12 spray ports atomize fuel better than the stock 700 and 750 KING QUAD's four hole offering.

For a new M109R injector: Suzuki part #15710-48G00 from a 2006 or 2007 GSXR or 2007 M109R Boulevard. Other Suzuki models may also use this injector, but these are the known compatible models.

A forum member, theroosterb, has cleaned and tested used M109R injectors in his classified add. For every M109R injector theroosterb sells he makes a $5 donation to NYROCATV.

Basic required VDI Copperhead ECU adjustments to permit the use of the M109R injector are:

Injector Open Time: 1.15ms (edit by SmoothKing700 the Copperhead application will hold 1.18, but will not hold 1.15 when clicking in and out of the cell)
Battery Correction: 0.070 ms/V
Flow rate: 44.6 lbs/hour

Edit on 12-28-08: The injector open time was changed to 1.55ms. Edit by SmoothKing700 on 01/07/2013: This was done to keep the same Air Fuel Ratios as the stock injector at idle and in the low and low/mid RPM. The reason was to simplify fuel mapping, however, it causes the same fueling problems found with the stock injector. It makes the hot idle and the low and low/mid RPM too rich. Having the overall hot idle too rich helps prevent lean stumbling after heat soaked starts with short after start cycles at 70C, but it wastes fuel during normal operation idle. There is a better remedy for heat soaked after starts than making the overall idle too rich. Using the 1.18 injector open time will lean the operating temperature idle to the same Air/Fuel Ratios as a showroom stock KING QUAD. With the idle in the same target AFR as a stock KING QUAD, the after start cycles at 70C can be adjusted longer to apply the after start enrichment longer. This prevents lean stumbling after heat soaked starts and can result in mirrored Air/Fuel Ratios as stock (with proper adjustments).

Either injector open time you choose will require adjustments to fix fueling problems. Leaning the operating temperature idle by making adjustments in the VE tables, to correct the rich hot idle caused when using the 1.55 injector open time, will result in requiring the same fuel adjustments to correct the heat soaked after start lean conditions and will require adjustments to richen the warm up scale. So why use the incorrect open time???

For more information on tuning the VDI ECU read the VDI ECU tuning guide.

An image of the basic adjustments to the Copperhead application's options page for using the M109R injector is below.

vibe, and other forum members, have done a great deal of diligent work toward efficiently mapping the M109R injector for use in the King Quad. Look for any vibe post and click on the red link at the bottom for his library of M109R injector maps. As well, Velocity Devices posts their map for the M109R injector on their website.

VDI map for M109R injector. The changed fields are circled.

Here is a writeup by cleverklutz on what is involved with changing out the injector. Edited and posted by Dr Z. Pictures are courtesy of Thumper700.
-Remove the airbox cover and side panels.

Edit by SmoothKing700: Also remove the screws and plastic push pins that fasten the plastic floorboards to the front fender on both sides. Also remove the left inner fender.

Unfastening the floorboards from the front plastic will allow the front plastic to flex more to give more room for the airbox to slide out.

-Remove the air filter.
-There are 3 bolts holding the airbox in place. One is on the front under a rubber flap, just in front of the handle bar mount. Two are on the back of the airbox on the frame. They are 10mm bolts. Remove the 3 bolts.

* Watch out for the three brass spacer collars inside the rubber airbox mount grommets, they're loose when the bolts come out. Don't lose them or drop any down the throttle bore.

-Remove the crankcase breather line from the airbox

-Unplug the IAT sensor. It's on the drivers side of the quad, on the bottom of the airbox.

Edit by SmoothKing700: You also need to pull the IAP/MAP sensor from the tab on the left front of the airbox (driver's side front). I believe you can access it by removing the left front inner fender. If you can not access it well enough at this point see my other edit below. Sorry no pic' of the MAP sensor.

-On the bottom of the airbox there is a clamp that connects the throttle body to the airbox. Loosen the clamp, it's a Phillips. Dirt will probably fall into the throttle body so do not press the throttle until you get it all back together and clean the throttle body.

-Lift the airbox up. Wiggle it around, stretch the plastic apart to get it out. It's doable but requires you to cut your fingers a few times, get mad, throw a wrench and speak a language you didn't know you spoke! FatTireRacer said he "loosened the connection with the front plastic and footrest to allow a little more clearance to get the airbox out."

edit by SmoothKing700: If you do as FatTireRacer describes and remove the floorboard/front fender and inner fender screws and plastic push pins the plastic surrounding the airbox will spread easily and allow the airbox to be pulled free without the cuts, scrapes and language spoken of above.

If you did not remove the IAP/MAP sensor from the tab on the left front of the airbox (driver's side front of the airbox) in the earlier step, now is the time to do so as you are GENTLY pulling the airbox off the throttle body and back a few inches. Reach down the front of the airbox and pull the MAP sensor from the tab on the left front of the airbox. Then the airbox should pull out with ease if you unfastened the floorboards from the front plastic.

-Now you have access to the injector, it is at the back of the throttle body.

-There are two #3 Phillips screws holding the injector in place. A few guys have stripped these, so make sure you're careful.
You are best off using a #3 Phillips impact driver to loosen these screws. They are really in there tight and Phillips screws are notorious for stripping out their drive heads during inept attempts at removal.

Edit by SmoothKing700: Once the fuel rail screws are removed take them to a local hardware store and match them to allen or hex head bolts. I am almost 100% certain they are 6mm, but I would take them along to be sure. If you can not match the exact length use a bolt that is slightly shorter than the stock screws.

Reinstalling using hex or allen screws will ensure you will be able to easily remove the fuel rail to service the injector in the future. Several members, including myself, have been able to remove the hex screws without removing the airbox to service the injector.

-Pull the injector out of the throttle body. Make sure the black rubber ring comes out of the throttle body.
-The injector pulls out of the rail, you might have to wiggle it a bit.

-Undo the plastic electrical connector on the injector. This connector I found to be a pain. If you use a small screw driver to help undo the clip you should be able to get it.

-Check the o-ring and the round black gasket on the new injector. If your old ones are better you might want to use those.
-Put a dab of dialectric grease on the electrical connector and a bit on the o-ring for lubrication.
-Plug the new injector into the electrical connector and seat it in the fuel rail.
-Screw in and gently snug the injector mounting plate in place using the new hex or allen bolts.
-Push the fuel hose back on the fuel rail and ensure it engages the plastic clip properly.
-Wrestle the airbox back in place.
-Bolt the airbox down. Do the front bolt first because it is a bit hard to get started.
-Tighten the throttle body clamp on the bottom of the airbox, being sure that the boot is not pinched between the airbox and the throttle body.
-Push the MAP sensor back on the left front tab of the airbox.
-Push the IAT sensor back in place.
-Reconnect the crankcase breather tube.
-Install the air filter.
-Put the airbox cover on.
-Change the VDI ECU parameters for the larger injector as Glenlivet noted above.

-Take it for a rip and smile!

The question has been asked many times: "Can I run my M109R injector fitted King Quad with the stock ECU, and will this hurt anything?"

The answer is yes, you can run it like that as long as you need to. The quad will not run as well as with the VDI of course and will not be optimally mapped. It will burn a bit more fuel than you are accustomed to and will not idle for more than a few seconds when you stop but it will run acceptably well.
The author had to run his M109R equipped King Quad with the stock ECU for 600 kilometers in the summer of 2008, without issue.

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