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 Evolução dos motores KTM RFS de 2000 a 2007 
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Registado: 25 mar 2011 09:16
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Mensagem Evolução dos motores KTM RFS de 2000 a 2007
Andava à procura das diferenças de anos para anos da ktm 450 EXC e encontrei isto que considero util e decidi partilhar:

"Evolution of the RFS engine (ignoring chassis)
This go back to Husqvarna development engineer Urban Larsson & Lars Nilsson and, Folan AB a Husqvarna, spin off when Husqvarna sold the MC division to the Italians in 1987 some of the Husqvarna engineers that did not want to move to Italy created Huseberg. That engine revolutionized dirt bikes doing well at the ISDE (abt ’91?) then purchased by KTM about 1996 primarily to get access to patents.

2000 RFS (Racing Four Stroke) introduced,
The KTM is all different yet much design continued.
2000 MODELS:
400SX was 6 speed close ratio Kstart only
400MXC was 6 speed close ratio* E & K start
400EXC was 6 speed wide ratio E & K start
520 SX was 4 speed close ratio Kstart only
520MXC was 6 speed close ratio* E & K start
520EXC was 6 speed wide ratio E & K start
*In US MXC is close ratio, in Europe its wide ratio
All had a 39mm Kehein FCR carb I call “Gen I”
DISTICTIVE ITEMS; engines case had a somewhat rough sand cast look, that improved in 03 to a slightly smoother casting, oil fill plug had a dip stick, valve springs had aluminum retainers. Spark plug was 10mm thread, that increased to 12mm in 2003, The 4 speed models had a 6 speed shift drum stopped after 4 with a roll pin (this continued thru 2005). 400 had a shorter duration cam than 520, 520 cam is known as a 5521 and has survived the full 9 years of production in almost all models.
Clutch pack is 7 lined discs of 1.8mm, 4 intermediate discs of 1mm and 4 of 1.4mm = 22.2mm thick, all of the intermediate discs have an internal spline that matches a spline hub. The clutch basket was on a bronze bushing that had pressure oiling from the left end of the clutch shaft. In 2001 they replaced the bushing with two needle bearings, the oil supply continued for a couple years but was deleted at some point by 2003. The “locking lever” in the shift mechanism was aluminum and had a small ball bearing riveted to it. The clutch had pressure oil to it thru the clutch shaft and the bearing in the clutch pressure plate changed from ball to needle bearing. The Estart intermediate gear had several “lightening holes” drilled in it. The rod bearing had copper washers on each side (I believe this was 2000 only?)

ISSUES; Water pump impeller melted, the radiator was too small. The upper cam sprocket had a “stop bolt” that came loose and caused damage, problem in fixing it is they lasted a couple years so KTM did not know they had a problem to fix for quite a while. The accelerator pump was very prone to water intrusion/corrosion etc. and at high RPM oil pressure build up would push the slave cylinder in rendering the clutch useless.

2001 KTM
EVOLUTION: Radiator got bigger, Valve spring retainers changed to steel. I believe there is a change in shift forks that took place in the early years but I have never had one of each type open at the same time to compare. They replaced the bushing in the clutch hub with two needle bearings which probably eliminated the need for the oiling but oiling continued at least thru 2001, maybe 2002? The main shaft of the trans got a groove cut in it for a clip that controls side movement of the clutch hub. Dip stick disappeared (mid year?)

MODELS:
Only changes are a very rare limited production 540SXS with 97mm bore (in spite of what the parts book says).
ISSUES: KTM received a bad batch of cam bearings that failed frequently and the cam sprocket “stop bolt” issue continued, debris from both often got into the crankcase and caused bigger damage (see changes in 2003).

2002 KTM
EVOLUTION:
Cam sprocket stop bolt got a better lock nut. Cam bearings changed to a sealed bearing which fixed that problem. The water pump seal retainer was redesigned for easier service. Clutch pack is 7 lined discs of 1.8mm, 4 intermediate discs of 1mm and 4 of 1.4mm = 22.2mm thick however the design is changed in that there are steel drive sleeves between the intermediate discs and the inner hub.
MODELS:
250EXC was added mid year with lower internal gear ratios used a 35mm Gen I carb longer duration cam, smaller head to fit the smaller bore.
All other models continued.
ISSUES They improved lock nut on the cam sprocket but some still failed.

NOTE AMA changed the rules for 4 strokes competing with 250 two strokes from 400 to 450CC.

2003 KTM
EVOLUTION:
A shield added that keeps errant pieces from the cam drive area from getting into the engine. Cam bearings changed to sealed type. Case gasket changed to metal shim. A small gasket was added to the clutch slave cylinder. A very small diameter clutch gasket alignment pin added. Clutch pack of 2002 continued as 7 lined discs of 1.8mm, 4 intermediate discs of 1mm and 4 of 1.4mm = 22.2mm thick. Clutch was attached to the transmission shaft with a nut rather than a cir clip. Shortly after the start of production the dreaded cam sprocket was changed to a design that eliminated the stop bolt. The short cylinder of the 450SX (below) necessitated a hole being drilled & tapped in the case for moving the chain tensioner down. This alternate hole is in all cases after 2003 regardless of model. All cylinder heads except 250 the intake port got taller, spark plug changed to 12mm. All carbs updated to FCR MX or Gen II. Some valve & valve spring changes for the SX models noted in their section below.
MODELS:
250EXC carb increased from 35 to 37mm
450 EXC/MXC replaced the 400 via a stroke increase from 64mm to 72mm, (same as the 520/525). A new valve spring was added for the EXC/MXC with white & purple markings, has inner & outer and a steel retainer. This is a good no problems piece used by abt 80% of the KTM 4strokes.

450SX was added with big bore, short stroke, short rod, short cylinder, 4 speed trans, smaller magneto, 41mm Gen II carb, lightened crank, a forged piston with a high dome rev limiter raised from 9,800 to 10,800.
In the cylinder head, Ti valves that initially had conical valve springs, second batch had a high tech spring with aluminum upper & lower retainers and I believe there was a change in the valve supplier? Replacement and later production valve is from Del West (top quality stuff) but they failed, (see 2006 changes). Also note the SX head had the valve spring pocket cut 1/2mm deeper for the springs. Siamesed head pipe first appeared here on SX only.
450SXS limited production bike also offered, strange in that is has a 5 speed trans, like the 4 speed it is a 6 speed with a gear left out, a spacer in place of one gear and the drum blocked at 5th.

525 (really 510) replaced the 520 (also 510)
525SX got the smaller magneto, lightened crank, 41mm Gen II carb, conical valve springs, lightened crank, rev limiter raised from 9,800 to 10,800 (black box ending in part #200). Rumor was that a “hotter” cam called the “806” was in this bike. Its in the parts book and often used as a hop up item but I have never seen one in a factory installation.
540 SXS changed to 100mm x 68mm bore & stroke (very rare)
ISSUES
450SX the conical valve spring was way too strong for Ti valves, the Ti did not get along with the bronze valve guides and the domed pistons dome was too wide & often hit the head. Clutch discs failed.
525SX, Many blew up and there was a recall to go back to the generic rev limiter (9,800, part # ending in 100) aimed at keeping the engine alive. Clutch discs failed.
All of the EXC/MXC line was quite problem free which is a good thing as production increased dramatically.

2004 KTM
Evolution:
All models got the Siamesed head pipe. Swing arm pivot got bigger, Water pump seals changed to double lip. Some of the machine work that was done to lighten the 03 SX cranks was deleted so they are not quite as light. Clutch cover gasket changed materials. The kick starter lever shortened. Clutch pack changed to 7 lined discs of 2mm, 8 intermediate discs of 1mm = 22mm thick and the pressure cover had holes drilled (attempt to eliminate the screeching when the discs become glazed).
Rear brake master cylinder and caliper each got smaller,
Battery on Estart models got smaller (common mod is to get a 05 battery box and go back to the bigger battery.
SX’s in 03 got super light weight cranks and that proved to be a hand full in some off road situations, too prone to stalling. In 04 KTM did three things that addressed this problem:
1) on the 525SX a heaver crank
2) added a crank mass (ie more weight to the right side where the starter freewheel normally goes on the e-starts and
3) went back to the -55 cam.


MODELS: All of the prior years plus;
400EXC returned same specs as the prior one but with the evolutionary changes of the 2004 product.
450XC was added being a hybrid of 450SX engine, with 6 speed, wide ratio 1st & 2nd gears, close ratio for the upper gears and EXC valves/springs, magneto & carb, SX cylinder, rod & piston but not the light crank.
450SMS, First venture into a factory Motard setup with full on brakes, shortened SXS suspension, Akra pipe,
Also, to the best of my knowledge there was a bunch of SX’s left over at the end of the year and KTM made a dealer installed Motard kit available to help sell them. But remained a 4 speed.
ISSUES:
Apparently someone stopped rounding an edge on the holes in the rocker shafts and it resulted in two bolts on the cam cover braking. This was allegedly corrected at Motor # 04-594*69364 and VIN number till: VBKRCA 4024M371530 are concerned (I put hardened bolts in all of them!)
All of the 450SX issues continued, also applies to the SMS.

2005 KTM
Evolution: Very minor, harder bolts where installed to reduce the breakage of the cam box cover bolts, only a partial fix.
The EXC/XC/MXC flywheel was lightened. 450SX oil ring reduced from 3mm thick to 2.5mm
Clutch pack changed to 7 lined discs of 2mm, 8 intermediate discs of 1mm = 22mm thick and the pressure cover had holes drilled (attempt to eliminate the screeching when the discs become glazed)

MODELS: All of the prior years plus;
450 & 525SMR models added basically SX engines with Ti valves and 6 speed close ratio transmission.
A limited production 450SXS was made available, has a slipper clutch and I believe a hotter cam, also had a steel shim base gasket (do not believe its available).

ISSUES:
On the 525 EXC an “idler gear” in the Estart system commonly broke (I suspect not properly heat treated?) As far as I am concerned this was 525EXC only. Valve guide issues with Ti valves now applies to both 450SMR & 525SMR as well.

2006 KTM
EVOLUTION:
Change in valve guides to sintered iron which works well with Ti, fixed issues that we had with Ti in 03-05 models!! Some 4 speed models the shift drum is 4 only so 6 speed conversions now require a new drum.
Carb updated to Gen 3 on all except 560SMR (has a non removable air bell on the back).
Starter gear improved and clutch cover machined 5.7mm deeper to make room for the improved gear. Clutch pack was made thicker making the inner hub, drive sleeves and release rod all longer. 560smr was upgraded to a ball bearing on ignition side. 560smr has all four poles on stator wound for ignition coil power versus two on a normal SX and one big one on EXC/MXC.
Clutch pack changed to 7 lined discs of 2mm, 4 intermediate discs of 1mm and 4 of 1.4mm = 23.6mm thick. To accomdate the thincker clutch pack the clutch basket changed to deeper style, the release rod & drive sleeves made longer to accommodate.

MODELS: All of the prior years except;
250EXC 4 stroke RFS engine bike was no longer imported to US
450MXC discontinued
525MXC got renamed 525XC but remained pretty much the same
560SMR replaced the 525 SMR via a big bore short rod, short cylinder
ISSUES: The right side main bearing in the 560 was problematic
540SXS was added, I have never seen one but I assume basically a 525SX with a 540 kit, slipper clutch??????? Or is this a 100 x 68 engine?

2007 KTM
EVOLUTION:
Clutch cover changed to one that the clutch can be serviced without removing the entire cover. Carb updated to Gen 3 on 41mm models, mid year the “locking lever” in the trans was changed from a ball bearing to a roller tip. Dual map ignition on some models. Nicer machined crank half's in 07.

New cases made for Quads supplied to Polaris hold more oil and are 5 speed with reverse. Note these do not use a case gasket, lots of sealer, cases are wider so you can not interchange trans with other models.
MODELS:
450SX, SXS, discontinued/replaced with RF4 engine thru the KTM line.
Other models remained pretty much as they where in 2006

2008 2009 KTM In the KTM line up the RFS engine is only in Quads. KTM continues to sell the RFS engine to some other manufacturers. One noted change on the quads there is a head drilled above the intake port for a motor mount and the manual compression release disappeared.


Notes;
Cylinder height combos;

RFS model/ bore/ stroke/ base to head/ cc/ sleeve hanging out the bottom
250EXC /75/ 56.6 /78 /250cc
400EXC /89/ 64 /84 /398cc
450SX,SXS,SMR,XC 95/ 63.4/ 69/ 449cc
450EXC,MXC 89/ 72/ 84/ 448cc 25mm hanging out the bottom.
520,525 95/ 72/ 84/ 510cc with 31mm hanging out the bottom
540SXS 2001-2002 & 540 kit: 97/ 72/ 84/ 532cc with 31mm hanging out the bottom and coolant flows around the head bolts.
540SXS 2003-2006: 100/ 68/ 76/ 534cc with 39mm hanging out the bottom in front & rear 7mm less on sides requires special cases or welding/machining!
560SMR 100/ 72/ 76/ 566cc 534cc with 39mm hanging out the bottom in front & rear 7mm less on sides requires special cases or welding/machining!
570 kit 99/72/84/ 554cc
576 kit 97/78/84/ 576cc
610 Crate Motor 100/ 78/ 84.5*/ 613cc534cc with 39mm hanging out the bottom in front & rear 7mm less on sides requires special cases or welding/machining!
*(note this is because they do not use a base gasket) and 38.70mm hanging out the bottom front & rear, timing chain side - 25.15mm and clutch side - 31.15mm (if used on common 525 cases this requires some welding & machining.)


Common hop up kit combos
Big bore
250EXC to 350 is 89 X 56.5
400, to 453 is 95 X 64
400, to 472 is 97 X 64
400, to 483 is 99 X 64
450SX, 450XC, 450SMR, 450SXS to 472 is 97 x 63.4mm = 472CC
450 EXC/MXC AND 520-525 to 540 is 97 x 72
450 EXC/MXC AND 520-525 to 570 is 99 x 72

Strokers
KTM at one time offered a 78mm stroker crank
89 X 78 = 485cc
95 x 78 = 553cc
97 x 78 = 578cc
99 x 78 = 600cc

Note, the below engines have a short rod & short cylinder and are not commonly stroked
450SX 2003-2006
450 XC 2005-2007
540 SXS in 2003 - 2006 is 100 X 68 = 534CC
560SMR is 100mm X 72 = 565CC

Rod Length (center to center)
250 = 129mm
400 = 129mm
450SX/SMR/SXS/XC = 11_mm (114?)
450EXC/MXC = 129mm
520/525 = 129mm
78mm stroker = 126mm
540SXS (01-02) = 129mm
540SXS (03-05) = 1__mm
560 = 121mm

400-525 rod spec per Travis
Big end bearing (mm): 35x43x21.7
Big-end bore (mm): 43.00
Big end width (mm): 21.90
Center to center (mm): 129.00
Pin diameter (mm): 35.00
Pin length (mm): 64.60
Small end bearing (mm): Bushing
Small-end bore (mm): 20.00
Small-end width (mm): 21.90

Other notes:
450SX crank pin is smaller (abt 31.5mm)
2000 400 had thinner crank cheeks and used a copper washer each side of the rod.
Cam chain link is 8mm so custom stroker combos should try to maintain those increments.

Crank Weight
525 SX 2003 only Pork chop style 590.30.18.300 8lbs 7.1oz
525 SX/SMR & 560 Full Circle design shorter counter weight 590.30.18.400 9lbs 9.5oz
450/520/525 EXC/MXC Full circle design 590.30.18.200 10lbs 3.5oz

The 03 525 SX configuration has proved to be a hand full in some off road situations too prone to stalling. In 04 KTM did three things that addressed this problem: 1) a heaver crank 2) added a crank mass (ie more weight to the right side where the starter freewheel normally goes on the e-start models and 3) went back to the -55 cam.
Note: the 450 SX retains the lighter crank in 04 but also gets the crank mass and -55 cam.

By Dave Hopkins (DJH) Credits to Travis @ Thumper Racing, Glenn @ GWR Racing engines, Kevin in Yorks, Skullhat, Art Astle and Caflash Bob for their input. "

_________________
1999 - KTM LC4 Adv R

Um quilo de lama por dia nem sabe o bem que lhe fazia!!


Editado pela última vez por mendti em 13 abr 2012 09:53, num total de 1 vez.



04 abr 2012 11:33 { SHARE_ON_FACEBOOK } { SHARE_ON_TWITTER }
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Registado: 17 abr 2009 20:57
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Mensagem Re: Evolução dos motores KTM RSF de 2000 a 2007
Boa recolha de informação! :study: Obrigado!! :hello:


12 abr 2012 22:23 { SHARE_ON_FACEBOOK } { SHARE_ON_TWITTER }
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