DAN'S MOTORCYCLE REPAIR INDEX
http://www.dansmc.com/indexindex.htm

Dan says:
"The first thing you should buy for your motorcycle, even before gas and oil, is a Shop manual. Every thing you need to know about your motorcycle is in that Shop Manual. It will save you time... Lots of time, and it will save you money... Lots of money. EVERYTHING I tell you on this web site is meant to be used with a Shop Manual. You absolutely, positively MUST have a Shop Manual for the bike you are working on."

"If You Don't, It's OK, I Don't Care, It's Not My Bike...It's Not My Money."




Honda Common Service Manual = 7.5 MBytes
http://www.vf750fd.com/vf750f/Honda_Common...vice_Manual.pdf




All internal combustion engines are “air pumps” that move air and a little fuel to create torque/horse power or “work”.
Some required reading:
http://science.howstuffworks.com/fpte.htm
http://auto.howstuffworks.com/horsepower.htm
http://auto.howstuffworks.com/camshaft.htm



The LTZ400 Quad engine is a DRZS400 Dirtbike engine.... both the LTZ & the DRZS are de-tuned DRZ400 engines... (Different valve-springs, cams, carb, base gasket, and exhaust)

There are two models of DRZ400's; the DRZ400 = kick-start and DRZE400 = electric start. So; if you buy DRZE engine parts, they will fit your LTZ (except the exhaust cam).



My engine mods were based on Mr. Sommers' posted results @ http://www.gtthunder.com/400z.html





Engine building should start with a plan... where in the RPM range do you want to build for Torque and Horse Power? Higher RPM’s ? Lower RPM’s? Or a noticeable increase from bottom to top?

In stock form, the “Z” is pretty peppy... but after a year of getting to KNOW the Z, I wanted more power, and keep my Z reliable...

First, I “UN-CORKED” the intake by modifying the air box and installing an import car air filter (Spectre P.N.: 8138 from AutoZone), vented the lid and installed a Honda 400EX air-boot. We all know that if you open up the intake, you need to open the exhaust, so I bought a full exhaust system to insure “what could come in could get out”.

I installed performance cam shafts with a higher lift and longer duration than the “stockers”.

The DRZ-400 dirt bike uses a thinner base gasket to achieve 12:1 compression, so I installed one.

While I had the head off, I did a mild “clean-up port job”... and installed DRZ valve springs in anticipation of a higher revving CDI box.

These engine modifications were all I needed to get from “off the show-room floor” power (in green) to what I ride now (in blue):



Click to view attachment










Intake Mods I like:

Free flowing filter of your choise.
Vented airbox lid and snorkle baffle removed. (holes covered with nylon mesh)

A 400EX air-boot is bigger / straighter / tougher than the Z air-boot ... AutoZone has a 90 degree PVC fitting that works for the crankcase vent on the 400EX airboot... HELP! part number 47032.(I trimmed off the carb mold, as the Z's carb has a smaller intake bell)


For those who ride without lids, but would like to protect their air filter from the big-stuff… I found a cost effective alternative to SPENDY “Outerwears” lids.

@ Hancock Fabrics
Manufacturer: Hyman Hendler
Part Number: SKU 837690 100% Nylon weave
Price: $5/yard (3 feet X 3 feet…. Big enough for several lids)



[
Stock Carb mounted pull choke
= Dealer item = Suzuki 1993 DR 650 = around ten bucks?


Mikuni Carburetor Tuning Guide
http://www.mikuni.com/fs-tuning_guide.html



Set-up and tuning theory articles similar to the LTZ stock carb


The "V Max" uses Mikuni BSR-36 downdraft carbs:
http://www.vmaxoutlaw.com/tech/

Ken "The Mucker" Sexton's "carb theory/tuning article for the "BSR-40 RoadStar"
IMO...the very best Mikuni CV carb post on the www!

http://www.roadstarmagazine.com/art_muckercarb.shtml

Good articles on carb tuning and maintenance:
http://www.hondanighthawks.net/carbhelp.htm




IMO.... Folks with "High-Flow" intake mods and aftermarket exhausts (full or slip-on) should get an ALBA Stage 2 or 3 Jet Kit (for a starting point). Kit includes a "Dynojet clone adjustable needle", Mikuni 25 pilot jet, and Mikuni 150 or 155 main jets... $23

http://alba.buyol.com/Item/LTZ-JKIT.htm

ALBA's jetting recomendations are very good too!
http://www.albaaction.com/service/jetting.htm#z400

The LTZ400 was jetted lean from Suzuki to pass "Emissions Testing"... when we "uncork" the engine with free flowing air filters and high flow exhaust systems, the 22.5 cc/min pilot jet is no longer adequate in many cases. Some folks try to “get by” with the 22.5 pilot by opening the fuel screw more… this is not a good practice for hard working, small engines like the 398cc LTZ400… some might be on the ragged edge of lean when “getting on it” from idle. I recommend a 25 cc/min pilot and judicial fuel screw placement to remove all doubt about going lean from “punching it” from idle, or from closed throttle deceleration.

Chart with Dynojet and Mikuni jet size comparisons
http://www.vmaxoutlaw.com/tech/dyno-mikuni.htm

Flow rates based on size markings of Mikuni and DynoJet jets are not comparable.


Mikuni Jets
http://www.sudco.com

Main Jets
Small Round N102/221
004.300 N102.221 #137.5 $3.00
004.301 N102.221 #140 $3.00
004.302 N102.221 #142.5 $3.00
004.303 N102.221 #145 $3.00
004.304 N102.221 #147.5 $3.00
004.305 N102.221 #150 $3.00
004.306 N102.221 #152.5 $3.00
004.307 N102.221 #155 $3.00
004.309 N102.221 #160 $3.00
004.311 N102.221 #165 $3.00


Pilot Jet VM28/486
004.032 VM28/486 #25 PJ $3.00







FCR Tuning Links
I do not own an FCR... so I am no help! Here are some links :


James Dean's Keihin Tuning Spreadsheet:
http://home.att.net/~wbarrow/jd/download_jet.html

Alternate petcock vacume sorce, DRZ carb boot:
http://silvervette.com:81/Bikes/CPW_FCR.htm

ThumperTalk Tech
http://www.thumpertalk.com/forum/forumdisplay.php?f=104

Thumper FAQ, FCR Jetting Guide:
http://www.thumperfaq.com/jetting.htm

Factory Pro FCR Tuning Guide:
http://66.47.68.116/tech/carbkei.html

FCR IPB:
http://www.motorcyclecarbs.com/keihin/frames/FCRHframe.htm





Reading "Plug Chops":

A quote from Ken "The Mucker" Sexton @ RoadStarMagazine

“Reading” spark plugs on a street bike, running modern, lead-free gas, to determine the jetting is of little use, if at all. Racers do it, while running consistently superior gasoline of known qualities, on race tracks and they can get very good results. Any time you examine your spark plug deposits, you’re mostly seeing the results of combustion that existed at the moment the engine was last shut down. If you rode it, pulled into your garage in a normal manner, let it drop to idle and then turned off the ignition, the plugs will show the result of combustion at idle just before you turned the key off- NOT how lean or rich the main jet or needle setup are running. Add to that the dubious quality of modern, “pump gas”, which can give all sorts of doubtful deposits on the spark plugs and you’ve got no reason to waste your time with such folly.




NGK number/code chart:
http://extremegarage.com/techtips/sparkplugs.htm


http://www.4strokes.com/tech/sparkplg.asp


Plug recomendation for higher compression: CR8E









Exhaust:
A Full Exhaust System is an improvement over the stock system. :lol



Great exhaust article from the TRX450R site:
http://www.trx450r.org/forum/index.php?showtopic=1658

My thoughts on LTZ400 Aftermarket Slip-on mufflers:
The stock header was designed with an emphasis for torque in lower rpms; the lower rpm torque emphasis becomes restrictive above its “design limitation” of about 7500 rpms. Slip-on mufflers DO NOT help this engine make HP above the limits of the stock header. In addition, the stock header negates the potential performance gains of aftermarket exhaust cams.



Performance CAMS:
Get the cams of your choice, I chose Hot Cams.

Per Tony Tice, the stock valve springs will eventually sag when using higher lift cams.

(IMO,you should install DRZ valve springs if you are building for reliability.)

http://www.hotcamsinc.com/instructions/Hot...nstructions.doc
http://www.hotcamsinc.com/instructions/Hot...nstructions.pdf


Valve shimming is required when changing cams, refer to Service Manual Chapter 2

NormalZ's quote from Ticeman (factory Rep):".004"-.006" on the intakes and .008"-010" on the exhausts."


Z400 Service manual page 2-6.
IN: 0.10 ~ 0.20mm (0.0039 ~ 0.0079in.)
EX: 0.20 ~ 0.30mm (0.0079 ~ 0.0118in.)

When installing both cams, some folks report a small loss of low-end torque, the "fix" is to increase compression by installing the DRZ400 base gasket.




DRZ Gaskets bump compression up about 0.9:
(From 11.3:1 to 12.2:1)


The base gasket located between the engine case and cylinder.
The LTZ base gasket is THREE layers, while the DRZ base gasket is ONE layer.
The LTZ base gasket is priced higher also.
HEAD gaskets are the same for the DRZ & the LTZ.


NormalZ reports Base Gasket Specs:
DRZe/k.........0.010"
DRZs/LTZ......0.027"





I bought DRZE valve springs, Head & Base gaskets, and valve seals for $84 delivered in Jan 04.
www.bikebandit.com... look @ top of page...OEM Parts, 2001, Suzuki, DRZ400EK1

(4 each) SEAL, OIL... 472448-001...$3.69
(I always replace valve seals when I have a head apart)
(4 each) SPRING SET, VALVE....480416-001....$9.71
(1 each) GASKET, CYLINDER (base)...476353-001...$8.27
(1 each) GASKET, CYLINDER (head)...475820-001....$24.97






Pistons
Aftermarket piston manufacturers make pistons based on the DRZ400 dirt bike engine. If you install a “high compression piston” in your LTZ400, you must install the DRZ base gasket to achieve the “advertised” compression.





Engine Compression Pressure Testing:

Standard: 142 psi with Automatic decompression actuated.

Perform test with a "warmed up" engine; ensure battery has a full charge.
Remove spark plug and install compression tester.
Make certain the spark plug wire connector's end is away from you and metal quad parts.
Hold throttle wide open while cranking engine, stop cranking when gauge stops climbing.
Record data in the back of your service manual: Date / XXX psi.

Page 2-29 of Service Manual:
Low compression can indicate any of the following conditions:
*Excessively worn cylinder walls
*Worn piston or rings
*Piston rings stuck in grooves
*Poor valve seating
*Ruptured or otherwise defective cylinder head gasket


If your compression measures lower than factory specs, you need to diagnose further.
Squirt a little motor oil (about 1/2 oil bottle cap) in the plug hole and test compression again.
If compression goes up, you probably have a worn or stuck piston ring.
If compression remains low, check for poor valve seating.

My latest (4 March 2005) compression test was around 180 psi with DRZ base gasket and both HotCams, stock bore and piston.




Lock-Tite your Starter Clutch bolts!
Too many "starter clutch bolts" posts for my comfort level... so I checked mine.
I found them to be torque’d to about 5 ft/lbs.

Starter Clutch Bolt Torque: (5mm "hex key drive")
Bolt size = M6 - 1.0 X 16mm
Grade = 10.9 = 16 N*m
16N*m = 11.8 ft/lbs

*Purchase a new generator rotor cover gasket. ( Suzuki PN: 11483-07G00)
*WASH / CLEAN your Z... pay careful attention to left side cover area and the starter, un-do "twist-tie" on case saver and clean area behind wire bundle.
*Disconect the battery!

Refer to the LTZ-400 Service Manual:
Drain Engine Oil: 2-12
Remove Gear Shift Lever: 3-3
Remove and service the starter motor: 3-9 and 7-12
Remove starter cover bolts and carfully twist/turn cover while pulling (gears may come out with the cover): 3-12
Remove generator rotor cover bolts, twist/turn reverse cable bracket out of the way
Drape an old towel over left nerf netting to catch left cover
From right side of quad, gently tap left cover's front flange using a long screwdriver and mallet
Remove starter driven gear (mind the 2 washers)

Remove starter clutch bolts (I left one finger tight while cleaning the others to keep the starter gear aligned for ease-of-assembly, then did the last one): 3-35
(My manual has an error... it calls out a 27 mm wrench, but a 26mm fits the large nut on my Z)

Clean/flush each bolt and bolt-hole with "rubbing alcohol" to remove oil from threads... dry completely with compressed air.

Apply BLUE thread locker to bolts and tighten to 16 N*m -OR- 11.8 ft/lbs.

Assemble in reverse order.




Fly Wheels
http://www.bikebandit.com/

2002 DRZE 400
1: STATOR ASSY 491327-001 $292.97
2: ROTOR, MAGNETO 491405-001 $282.63

2003 LTZ-400
1: STATOR ASSY,MAG 1768394-001 $242.22
2: ROTOR ASSY 1768395-001 $282.63

2002 DRZ-400
1: STATOR, MAGNETO 491328-001 $292.97
2: ROTOR, MAGNETO 491406-001 $282.63

I do not know why they have different part numbers???
Perhaps they are different weights?




DID Cam Chains:


DID SCR-0409 SDH Silent Chain - stock 3/4 replacement
DID SCA-0412A SDH Silent Chain - wider 4/5 replacement. Rides ON, not IN the chain guide. Slides side to side on sprockets, too.


Performance CDI:
Some aftermarket CDI's are now close to $100... choose carefully!

"High-Rev" valve springs are a must when installing a High -rev CDI.

http://alba.buyol.com/Item/LTZKFX%2DCDI.htm
http://www.yoshimura-rd.com/contact.asp
http://www.dynaonline.com/english/index.htm
http://www.vortex-performance.com.au/
http://www.duncanracing.com/atvproducts/index.phtml?id=270
http://www.procomengineering.com/


Dynatek CDI Install & Kill Switch Instructions
http://www.dynaonline.com/english/instruct/DFS3-9P_2-11P.pdf






CDI operation/theory/trouble shooting thoughts:

STOCK CDI NORMAL OPERATION:
(some after-market units do not illuminate the "water temp" idiot light)

The "Engine Coolant Temperature Indicator" will glow when you first turn the key to "ON" before the engine is turning.(part of the CDI's "built-in self-test" firmware)
When you push/bump the start button to turn the engine over one or two times, the "Engine Coolant Temperature Indicator" should go out. (pulses from the "signal coil" and "pickup coil" tell the CDI to change from the "built-in self-test mode" to the "operate mode").

If the "Engine Coolant Temperature Indicator" doesn't go out, check the "Engine Coolant Temperature Switch" ((Service Manual page 5-11)) and the plug/connector (top switch on right side of radiator).

Also, double check the pins on the CDI unit and the wiring harness plug for corroded or bent pins.




Easier Starting with High AMP Battery:
http://www.motorcyclebatteriesusa.com/batt...asp?battery=424


"...Yuasa YTX14-BS battery fits in the Z. It provides half again the cranking power,very nice with oversized/raised compression motors. It fit best after removing the padding on the bottom of battery tray. I was able to re-use the holddown bar by turning it over. It was really easy to put the rubber pad on the other side as it just presses into holes. It doesn't seem to rub the seat at all."






LTZ 400 Suspension Preventive Maintenance:

Suzuki used just enough grease to assemble both of our LTZ-400's.
I suggest greasing the rear linkages and A-arms right away!




Tech Articles on the www:

http://www.stealthcharger.com/articles.asp

http://www.atving.com/Departments/Techtips/

http://www.nightrider.com/biketech/

http://www.4strokes.com/tech/

http://4wheeldrive.about.com/od/techtipsforatvs/


http://www.thumperfaq.com/

http://www.thumpertalk.com/forum/forumdisplay.php?f=94





Installing Graphics and Seat Covers
http://atvrideronline.com/features/100_0304_graphic/





Good luck!

holey smokes!

what a public service to Z400 owners this post is!!

You have just been given a "sneak-peek" inside the mind of the Madman!

yeah rstaw is beenvery helpful walsys have some nice tips to give!!

thanks rstaw

WOW thanks man, this is great!

[attachmentid=7373]

very nice....can we pin this by any chance...even though it a z?...I want to make it easy to find.

whats your needle and air screw set at???????