Timing Retard Eliminator (TRE)

What Is It?

TRE means "Timing Retard Eliminator". And that is what it does. It makes the ECU think it's in 6th gear, and it maps accordingly. The lower gears are mapped to retard the ignition timing and thus not as much performance can be had. Bypassing it, for some bikes improve trouble spots, such as hesitation at certain rpm's and cures lean backfires (that we just found out)....It was initially conceived as an anti Smack the Newbie in the face with the triple clamps device. (TLRMan)

Why Do This Mod?

Well you might expect increased performance but to be honest you'd be hard pressed to notice the difference although throttle response does seem a little better.  This mod will work alone if you plan on just running the bike in stock trim. It does not change total HP output on top, it just cleans up some F/I and timing issues at lower throttle positions. It will also work in conjunction with using a PCIII.

The main benefit is that the TRE smooths out the uneven running (surging) that the unmodified SV exhibits in the 3000-4500 rpm rev range

Switched or Un-switched?

(AndyW) Up to personal preference really.......the un-switched version is quicker and easier to do but personally I like the switched option for three reasons:

  • Suzuki technicians can bypass the TRE if needs be when the bike is in for service
  • If the resistor should fail (unlikely I know) when you get the FI warnings at least you can bypass the TRE. If you don't want to go to the trouble of mounting the switch under the tank I just ran the cable through to under the pillion seat. The switch is mounted in a small plastic box which is fixed in place with Velcro pads.
  • Bypass for easier cold weather starts

GPS Switch to ECU Connector

Now where is that connector?...Under the tank right at the back on the left side of the bike by the hinge...
Blue, Pink and Black wires....


Are There Any Downsides?

No one has reported any truly adverse effects and there are now hundreds (at least) of SVs fitted with TREs of one sort or another.  Some members have reported a problem with tickover/idle in real cold weather i.e. the bike stalls, after the initial fast idle quits although this is easily resolved by adjusting the tickover/idle speed or for the switchable versions of the TRE....leave it off until the bike warms a little.

Suzuki were casting aspersions at one time (see comments reported by Kilo below) but I think it's safe to say that whoever Kilo was talking to from Suzuki had his facts confused.

Want to get flashy - add an LED!

Lockers 02/2004  Just like rog fog.. I mounted the switch on a aluminium bracket next to the water reservoir, but i also drilled a hole next to the switch, which is where the LED is... (more)

And Flipper's method for testing the set-up which works so why re-invent the wheel !! (thanks Flipper)

TRE Testing

To test your little project start the bike and let it warm up for a minute. Then slowly increase the revs to about 3500 rpm and hold steady. When you have the revs held steady pull in the clutch..............if nothing happens flick the switch the other way and do the same again............the revs should drop about 500rpm or so. When you release the clutch the revs should rise back to the 3500rpm. If it doesn't you fucked up somewhere so you will have to go over the whole thing again to find the mistake and there's a few hours detention waiting for you my lad.

Jimbo77 19/06/2003
No problems with the mod, only one issue. She starts fine, but when the engine is cold the rpms will vary during warm up depending on whether you have the clutch lever pulled in or not. For example, when starting cold, She fires then idles at about 1500 rpms while warming up with the lever pulled in. If you let the clutch out (in neutral, of course) the rpm's drop to about 1100. This only happens when the engine is first started from cold. As soon as engine temp hits about 130 degrees F, idle speed is fine. If I blip the throttle while cold with the clutch lever not pulled in, she has stalled once on me...Don't know if it was related to the TRE mod. Doesn't bother me though, and was worth the effort....

Flipper 19/06/2003
Sorry forgot to mention at idle it has the opposite effect, ie the bike should idle normally when warm and clutch out, when you pull in the clutch the revs rise a bit. It is not as pronounced on the euro bikes for some reason, possibly to do with the neutral maps we run over here, this is one of the reasons a switched version comes in handy as you can switch it off until the bike has warmed up. It should run fine after that. As I said if your TRE is switched you should turn it off until warm, you don't need to stall when pulling out of your driveway into traffic.

Kilo 24/11/2003
During my "discussion" with Suzuki at the NEC ..........

.....Apparently as well as changing the ignition map to 5 th gear it also changes the fuelling map. This has the effect of over fuelling in the lower gears,3rd sees a benefit, but 6th runs very weak and they reckon these engines run VERY lean for emission purposes.

This is one mod they don't recommend cos they say it don't work! Plus you can kill the cats' & get bore wash as well as using way more fuel.

They also said the oxy sensor thing has only a minute range of adjustment and is just not up to coping with any change in engine spec!

Sorry to piss on any ones ride but it does seem very reasonable given the financial restraints on the SV.

One good thing tho, they were singing the praises of doing the thing properly with a Power Commander or Yoshi box + cans etc. Even went as far as recommending
a nice sounding legal can that required minimal if any tweaking ,so the're not against modding per se.

TLRMan 25/11/2003
They (Suzuki) are still hooked on the "pink wire" cut of many years ago...
Plus the TRE will map to 6th gear, not 5th... and nothing will change in the lower RPM's.

Unlike the TLR, the SV DOES NOT have ram air, and the extra 5% increase in fuel duration is only seen at approximately 6000 rpm's or higher...If you had Ram air...

The resistor mod will only affect "partial throttle" positions, and has NO affect "WFO" (wide F--king open)...So you 6th gear 3/4 throttle pull is telling you to add 2 or 3 more teeth on the rear sprocket, cause it doesn't have anymore torque to pull it.

Funny thing is my brother's SV pulls like a mother all the way up? And it's a Copper colored one!..........

drmudd 25/11/2003
"Apparently as well as changing the ignition map to 5 th gear it also changes the fuelling map.This has the effect of over fuelling in the lower gears,3rd sees a benefit, but 6th runs very weak and they reckon these engines run VERY lean for emission purposes."

Funny mine ran rich before the TRE mod and after it. On the dyno turning on and off the TRE had negligible affect on power, torque or fuel. Holes in the air box helped the fuel air ratio and mapping made the fuel air good.
The bike runs better with the TRE on. After it warms up I switch it on. The bike runs right up to the rev limiter in 6th (even quicker with the 42). The TRE seems to have diminishing effect as I go up through the gears and 0 effect on 6th.

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