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L1 750 Track/Street build

32K views 230 replies 16 participants last post by  Todd_Sails 
#1 · (Edited)
A little background, I bought an L1 GSXr750 with a little over 2000 miles earlier this year and lowsided at the track. It was an easy lowside (at 65mph) and after a fairly simple rebuild to replace some plastics and maybe a lever I was back on the bike. Fast forward a few months and I decided I wanted to do a complete makeover, so I crashed at the track REALLY good. Managed to rash or crack EVERY last bit of plastic, bend a brake rotor, snap off a clip on, bent rearsets but the main part of the bike (fork, triples, frame, wheels, etc) survived amazingly well.

It's a work in progress and if anyone has any questions on what has gone before, I'm happy to share. Some of the highlights were an DIY FTECU flash, installation of their quickshifter, M4 Brembo brake installation with Braking's SK2 rotors. Stainless steel brake lines, Traxxion dynamics revalved and resprung forks, shimmed OEM shock and fork extenders up front, GSXR600 headers with a stainless steel stub welded to fit a DIY pie cut midpipe eliminating the cat. This ends in the stock location so I can use any of the slip on mufflers out there. Currently I replaced the rashed stock muffler with a Leo Vince slip on.

So, at the moment, I'm waiting on a superbike plastics kit from Armour Bodies. Seems they have very good reviews on their body kits. I ordered a superbike kit (one with the stock seat replaced with a one piece tail unit and a foam pad). Unfortunately, I was told it will be December before I MIGHT get it. Apparently they stock the supersport kit that utilizes the stock seat. Whatever, I'm healing from my clavicle fracture and I'm not riding seriously anyway.

I'm planning how to make the bike barely "street legal" while utilizing the race plastics. I was thinking a mini projector lights and a custom mount. I fabbed up a bracket to mount a tail/brake light sandwiched between the fender eliminator and the undersurface of the frame. I've been fortunate enough to have learned how to tig weld and brackets like this are an easy thing.
 
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#74 · (Edited)
UGGGGGHHH!

Installed the rear wheel. Bled my brakes front and back. Went out for a ride.

Came back and noticed the right axle block wasn't touching the adjuster. I swear I torqued the axle nut right...

Go to remove the axle nut and it's locked on. Tried too hard to remove it and sheared the axle block on the right side.

I'm F^cked, my trackday is Sunday...

Going to the local suzuki dealer to see what they have in the AM. Still have to figure how to get the damn nut off the axle. I could cut it off but...
 
#75 ·
Came back and noticed the right axle block wasn't touching the adjuster. I swear I torqued the axle nut right...

Go to remove the axle nut and it's locked on. Tried too hard to remove it and sheared the axle block on the right side.

I'm F^cked, my trackday is Sunday...

Going to the local suzuki dealer to see what they have in the AM. Still have to figure how to get the damn nut off the axle. I could cut it off but...
Been there, done that. Had to cut the nut off with a dremel. Now I'm sure to use a little anti seize on the threads.
 
#77 ·
So, I ended up tig welding a $.99 nut (3/4") on the right side of the axle.

Grabbed the axle with that nut and spun that mother Tucker nut on the left side off the rest of the way.

Why???? didn't Suzuki put a nut or an allen recess in this end of the axle instead of relying on some soft aluminum to do the job?

The axle threads were a little wonky. The locking mechanism on the nut had failed and was not going back on any bolt. Fortunately I had a couple nuts of the correct pitch and thread from old bike builds and I wasted one trying to clean up the threads of the axle.

Finally with the last nut and a small file, I was able to clean up the threads so the nut would spin on all the way to the bottom.

Assembled everything, drew a witness mark on the nut, axle and frame and went for a test ride.

Everything looked to hold OK. I'm back on.

May replace the whole thing with a Fast by Frank quick change rear axle eventually. When I save some money...
 
#79 ·
I'd really like to find a castle nut for mine like the prior bikes had. With the LighTech adjusters there's no axle protruding past the nut. I really ought to drill a corner of the nut for safety wire but think I'd prefer castle nut and cotter pin through the axle.
 
#78 ·
Why did Suzuki put that small plate in front of the oil pan so you can't drop the pan without removing the engine?
Stupidest thing I've seen.

So, I wonder if I should just change case cover and the oil and start her back up.

Ground a nice gash through the right side and wanted to clean the pan.
 
#81 ·
So I figure I'd better just drop the oil pan. I looked up a couple threads on loosening the engine bolts and wiggling the engine to get the clearance you need to remove the rear pan bolts. Looked easy enough.

Thought I might not need to loosen the thrust adapters but after loosening all the nuts and bolts, the engine is still stuck in place and won't budge.

Off to ebay for the special spanner nut tool...
 
#82 · (Edited)
Since the peripherals are all off the bike at the moment, I decided to remove the left switchgear. I always thought a proper trackbike looked better without it. Looking to install race buttons on the right side, too.

I removed the two clutch wires from the harness and depinned these from the connectors on both sides and wired them together. Taped the clutch wires together and reconnected them to the clutch switch. The left switchgear and short harness is now in a box. I did have to cut a wire that was spliced into one of the clutch wires coming from the switch. I assume it's another ground wire. But otherwise, everything can be returned to stock fairly easily.







I believe i read that the map switch defaults to A mode. If not, I can always flash the ecu to make sure both A and B are the same...


Here's what I'd like to put on the right from Bike Sport Developments. plug and play.
 
#83 ·
Pushing the bike around sans fluids, radiator, race plastics, exhaust. And already without lights. I salivate to think what this bike would feel like on the track at this weight.

No weight reduction thread really makes it anyplace. Replies usually devolve into- you'd be better off losing some fat off your ass. Well, OK, why do you think the two are mutually exclusive? Sure, lose your own weight, but I'd also like to have the lightest bike possible. (I also think that you can manipulate your weight on a bike with body positioning. Not so much with the bike itself.)

Anyway, if anyone has weighed their bike and would like to brag, post up. Man, I would like to get down 350# or less track ready. Removed all the usual suspects. Unfortunately, the next significant areas are wheels which I can't afford at the moment. Looking at Mag or CF. Dymag, BST or Rotobox.
520 chain and sprocket will be the next minor mod.

I remember removing the counterbalancers off a big bore bike before (BMW K1200R). Made the bike rev like a two stroke...
 
#86 ·
They are pretty sweet. You can brake farther into the turn, steer quicker and accelerate faster.
But if you get BST's be very careful who mounts your tires, I elected to change my own with my tire machine. A pneumatic machine with it's torque can crack a rim lip if it gets in a bind.
I've also got Marchesinis but they arent as light as BSTs.
 
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#85 ·
Dropped the pan. Figures it was clean as a whistle.
At least I can say I did it and I removed that stupid plate. The back left corner bolt is still obstructed by a frame tab that mounts the side stand bracket. Even though I removed the side stand (weight savings- see above :wink), I would prefer to keep the tab for the times I ride on the street and need to reinstall it.
Manipulating the engine was difficult. A second set of hands would have helped tremendously. Skinned one knuckle but I was able to do it. I think that if I get an offset 8mm box wrench, I could replace that back bolt without ever having to mess with the engine mounting bolts again.

I'll remove the side stand switch and jump the connector. Start the reassembly.

Ordered a Superlite alloy rear sprocket and 520 conversion. down one in front, stock in rear for now.
 
#87 ·
Last night I was checking the side stand switch.
It appears on the wiring diagram, it is at least a diode allowing current in one direction.
But additionally, when I put the multitester on it, the resistance is rather high. 6-7 megaohms.
I wonder if my side stand switch is going bad?
 
#88 · (Edited)
Fun fact:
So the 2011 side stand switch is a one year part for the 600 and 750. They changed the part immediately the following years 2012-present. Why? who knows.
The 2011 part also lives on the thousands of suzuki burgman scooters as well.

Anyway, I looked up diode testing and it is not unusual for the resistence to measure anywhere between 1 kohm to 10 Mohm even in the forward bias position. I found the section in the service manual on testing the switch. Per the manual, switching to diode testing mode on the multimeter, the switch tested 0.52V drop which appears to be within specs in the forward direction and open switch the other direction.

There are some electrical bypass plugs that nicely replace the switch with a weather proof connector on ebay.
https://www.ebay.co.uk/itm/Side-Sta...17-/263681702429?hash=item3d64a77a1d#shpCntId

But then I looked further into the wiring diagram and I may be able to bypass The entire thing through the connector for the flasher/side stand relay and remove the side stand switch and relay completely.
Basically, I would provide 12v power directly to the engine cutoff switch bypassing the need for a side stand relay to activate this since the side stand is removed. If I do it through the connector where the relay plugs, I could easily remove the jumper wire and replace the side stand, switch and relay and be back to stock in no time.
We'll see...
 
#89 · (Edited)
Well, for better or for worse, she's back together again...
That means another opportunity to bin it, I mean ride it at the track this weekend!


The mod for the side stand bypass worked. I was able to remove the entire switch and relay and jump two wires (12V to engine cutoff switch) at the relay connector under the seat.
I should/could have jumped the dash neutral wire as well, but on the wiring diagram, it is diode protected and I didn't have time to get one. Seems to start and run fine in the garage without it. Just don't have the neutral light on the dash.

Removing the left switchgear except for the clutch wires appears to be working fine as well.



BTW, WD40 is great for getting out trackday grime on fairings. Not sure what it does to paint or gelcoat, but it works...

Funny. Originally, I bought the bike used with an ASV clutch lever. Recently, I bought a spare OEM clutch perch and lever off ebay and decided to replace the rashed ASV. The ASV has a noticeably longer pivot arm and subsequently the pull is much easier.
I thought they were all like that stock. Looks like I need to pick up another ASV lever.
 

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#90 · (Edited)




I wanted a quick turn throttle, so I thought I would try a Motion Pro Rev2 quick throttle system.
This meant modifying the stock switchgear or installing an aftermarket push button “race” pod. I chose one from Bike Sport Developments.

The MP throttle is bulky and cramming this and the new pod on the clip on was not easy, but fortunately everything just barely fit.

The quality is OK. OEM throttle I thought was excellent in terms of smoothness and fit obviously. MP is just a 1/2 step down.

I depinned the two brake light wires from the connector, separated them from the OEM switchgear harness and slid them in the OEM style connector of the afermarket pod wiring harness. That way I retain brake light function when needed.


The side stand switch and relay removal and mod worked like a charm and passed a track day test.(see previous post) Didn't miss not having a neutral light so I'll just leave it disconnected.

The OEM style clutch lever replacement with a stock lever ratio was fine. I even maybe liked it better than the super soft pull of the ASV.
 
#91 ·
My seat must have fatigued enough with the last wet trackday crash that I cracked it all the way on the following dry trackday this month. Damn this is too fuckin expensive.
I purchased an armour bodies superbike tail. Much nicer quality than the eastern european ebay stuff.
The Armour Bodies seat/tail unit is reinforced with a beefy seat pan that braces on the stock mounting points on the rear subframe. The other ebay tailpiece relies on the four mounting point bolts and the structure of the seat itself. I think it's one of the reasons it cracked.
The Armour Bodies tail only attaches with two bolts, though. Strange...


Brocks is having a 10% sale on BST currently. Man I am tempted to pick one up even if I can just get a rear now and maybe a front later. Trying to figure if there will be a bigger black friday sale anywhere else.
 
#92 · (Edited)
Adjustable triples update...

After a couple of dry trackdays (and a couple partial wet ones) with the new triples, I decided to make a change to the offset.
Stock offset is 30mm but because of the geometry changes from shimming the rear shock, I wanted less offset to regain the lost trail. I ran the -2mm collar on the IMA triples which gives me a 26mm offset. Huge difference from stock really, but I wanted to start conservative.
The bike was very stable but was difficult to tip in especially on the fast corners at the trackdays. I believe it was sllightly harder to make midcorner adjustments if needed but pretty close to stock. My precision with turn in was hurting a little too I think because of the extra effort required. So last night I finally made the switch to -1mm collar to give me 27mm offset.
The difference was immediately noticeable. I'm still 3mm from stock, but I think I won't need more offset at least for a while. The bike is like 30% easier to turn in from just this little change. And now is quicker than stock as far as I recall prior to the rear shim. The faster you go, the less the difference, but it's still significant.

The real test will be the next trackday on labor day weekend!
 
#94 ·
Just for reference sake.
assuming a stock 23.45deg rake and 97mm trail with 30mm fork offset...
assuming a 5mm rear shim raises the rear of the bike at the axle about 1" and decreases the rake 1 deg...
then using the -1 collar for 27mm offset in the IMA triples...

I calculate a trail of 94.3mm which would be just about spot on with what I was looking for, about 3mm less trail.
the -2 collar will give you 95.4mm, closer to stock to maybe not make a huge difference.
 
#95 · (Edited)
After 1+ seasons on the stock suspension (forks with some Traxxion reshimming and refreshing, rear shock with 4mm shim), I decided to look for some aftermarket stuff.

At the track, I felt the stock suspension needed to be set stiff to feel planted when braking and cornering hard, but then was too stiff for the bumps. Also, they just didn't feel as precise or as "plush" as other bikes I've owned with aftermarket suspension. Nothing seriously wrong with them. The oem rear shock probably needed a rebuild.

I found some used gear on ebay and wera forums. A penske rear off a racebike(old motoamerica bike I think) and AK gas cartridges (these might have been passed around to more racers than I care to know) that had just been serviced.

A good point about servicing these components. I thought I was saving money, but I didn't consider the almost $200 for servicing the penske I was charged by a local suspension guy. After shelling out that money plus the price I paid, the difference was a couple hundred more for a brand new shock. So, just FYI.


Installation was uneventful other than I think my old forks were bent slightly as I had to use the shims that came with the IMA triples with the new (used) gas charged forks. I went through the whole sag measurement and preload set up. 30mm front, 25 back. I added a little extra rear shock length to the Penske to add to the shim I had under the upper shock mount. Everything was straightforward and easy.

I will over the next few days try to dial these in but in a short ride, the bike felt really well damped.
 
#96 ·
Put on the 520 conversion with 16/45 sprocket set. I destroyed another axle nut trying to remove it and this time the axle went with it. Fortunately, I had a spare axle and used an old nut.

What is it with these lock nuts??? I'm never using one again. If the ones in the frame seize, I'll be up sh!t creek.
 
#99 · (Edited)
Maybe, but not sure... The locking mechanism seems to get crossed up on the axle threads either putting them on or taking them off. Once they decide to cross, forcing them off just makes it worse. I have and use a torque wrench since I f'ed up the first nut. Didn't do much good.

I was able to get the first nut off, but the second one required the angle grinder and cutoff wheel. Lost the axle, too.
 
#98 · (Edited)
I measured my swingarm angle thinking it would be on the high side with the longer shock and 4mm shim in back. I was worried both about rear traction with too much anti squat and about front end stability problems.

With the gearing at 16/45 (-1/+0), I measured the swingarm length at about 32 1/16". (should it be longer?)
Swingarm angle with the bike on the floor was measured 9.7deg. Offloaded measured 10.8 deg. I've read a good starting point is around 12.5deg offloaded.

So I THINK I'm still well in the safe zone particularly with the triple offset reduced by 3mm to regain the lost trail from the rear ride height increase.

Hopefully tomorrow I will be able to ride a little and see how she holds a line coming out of a corner. And if the front is stable enough at these geometry numbers. Usually, gassing it on a cloverleaf ramp is a good indicator of whether a bike want to hold it's line or not.


Man, Suzuki really neutered this bike's geometry. It's like it could have come from the factory with a 1/2" longer shock and smaller offset triple and still be easy to ride.
 
#101 · (Edited)
Yeah, I looked at the Fast by Frank quick change axles. They are PRICEY but come with the lightech adjusters and a custom machined axle.
I really have no NEED for a QC axle, but would seriously consider it if the quality is much better and/or some weight savings can be realized. As it is, though, It almost looks like it would add weight. Sure would be nice to have the lightech adjusters and the nice machined axle, though...



Went out for a 40 minute ride today. Not long, but the loop I ride and the corners I pick are pretty work intensive. I pushed pretty hard and did some heavy braking tests from 100-130.

Turn in is same to a little more sharp. Not a huge change.
Mid turn stability is fine. No real issues I noted. The suspension was managing smaller bumps a little better in turns, but it still felt harsh on larger bumps
Corner exit was improved. Not by leaps and bounds but it was noticeably less running wide.
Braking stability was definitely compromised. I would rarely brake this hard on track on purpose at my level, but today with heavy brake applications, the bike would do the slow weave dance. You know that feeling? Looking at my zip tie on the fork, it appears I'm blowing through the fork travel.

I bought my tools to adjust the suspension but had no clue. Everything felt fine so I left it alone. (maybe the only thing was weaving on hard brakes could have used some more compression dampening) It will probably have to wait for the track where you are really using the suspension range to fine tune things. Otherwise, for the street, they were a huge waste of money. LOL but I knew that...
 
#102 ·
Back in the garage after the polar vortex passed.

I was doing some clutch maintenance and an upgrade and noticed my clutch basket is worn. The fingers on the clutch basket look like a ribbed condom.
The basket and gear assembly is expensive at almost $300. I'll replace the needle bearing at the same time since I'm there and it's not expensive.

If anyone has any suggestions on this job, please post them.
Is it worth drilling extra holes in the new basket??? I'm thinking no...
 
#103 ·
Doing a Suter slipper clutch install and wanted to jot down some notes.

To get close to the specs of the drive/driven plate thickness recommended by Suter, I had to order an additional thin steel plate to replace one of the standard steel plate. That makes a total of 6 standard steels and 2 thin steels to go with the 9 fiber plates.
This gives me around 1.583" thickness which is just 3 thou over the high end of the recommended plate thickness spec'd by Suter. I figure with some wear, it should fall right into range.

I replaced the clutch basket due to wear and needle bearing out of priciple; the base washer and spring washer that fits at the bottom of the clutch hub were replaced as well.

hopefully I'll get everything buttoned up by next week.
 
#104 ·
Clutch is in.

Not sure why but with the correct number of plates installed, 9 fiber, 8 steel, the last fiber plate did not reach far enough on the basket that I could insert it in the alternate slots that don’t go all the way down. So I just slid it in the same slots as the rest.

Since the slipper action depends partly on the height of the plates, I can’t just add plates to the hub. That would make it way too thick.

I could add a shim under the hub (there is the OEM washer there already) but I that would mess up the clutch push rod length. The clutch looks like it disengages just fine now, sitting in the garage.

Does anyone know why those alternative slots on the clutch basket are there and why they say to put the final fiber plate in them?
 
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