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Kawasaki Lakota with Honda FT 500 engine

Revised 05/11/2008

The mating of a Kawasaki Lakota and a Honda Ascot. The Lakota engine let go. The step son was wanting more power anyway. So the FT500 engine is finding its way into the Lakota frame. The FT500 is basically the same as the XR,XL 500-600 dirt bike engines except it has electric start. Wow this thing hauls!

These FT500 engines get a lot of bad press for having wimpy electric starters. I took a look inside the solenoid, pivot fork, latch housing and saw corrosion keeping the parts from working. So I drilled a small hole near the top to vent the moisture back into the crank case, and another hole low to drain any oil back into the crankcase. Sure seems to be the answer.....

Something has gone away in the charging system, and the battery is always dead.


Using the stock carburetor required a spacer, which also angled the carb away from the air filter housing, to make clearance for the fuel inlet hose. You can also see the 2" exhaust pipe I used to get from the carb inlet to the stock air box.

We even used the stock snorkel. You'll notice the dent towards the front of the snorkel, its from the same wreck that damaged the front fenders. I will try to plastic weld them?????


I found plans to build the HRC road race pipe on the internet. That site continually moves and I can no longer find it, so I have used an inferior drawing, until I can get a better one. However I felt the pipe was large for a 4wheeler. So I am making it a bit smaller in diameter, I think it will have stepped tube design(since I don't have anymore smaller pipe). The primaries are 1.125"X7" and the front half of the pipe is 1.5". The rear part is 1.625". After he runs it a couple days I'll pull the exhaust to sandblast and paint it.

Left, the start of the home made Supertrapp.

Right, the business end of the muffler.


GEARING OPTIONS
XR
600
YZ 490, steel sprockets
42
44
46
47
48
49
50
51
52
13
3.38
3.38
3.54
3.61
3.69
3.76
3.86
3.92
4.00
14
3.00
3.14
3.28
3.36
3.42
3.50
3.57
3.64
3.71
15
2.80
2.93
3.06
3.13
3.20
3.26
3.33
3.40
3.46
16
2.65
2.75
2.87
2.93
3.00
3.06
3.12
3.18
3.25
This hat moves the sprocket inboard .75" to align with the narrower engine. The rear sprocket is from a YZ490. I am not satisfied with this gearing yet.

The gearing (15/42) is a bit to high for woods riding. The top end never seems to quit The Honda 400EX has 15/38, maybe it has different primary gearing? Finally have settled on 14/44, top speed seems to be around 75-80, 1st is ok for trail riding, and it wheelies easily.


THERE ARE SOME UPGRADES IN THE FUTURE FOR THIS QUAD

I just recieved an '86 XL 600 engine, purchased on eBay. It should have the 100mm bore, coupled to the FT500s 80mm stroke it will displace 628cc.

The XL 600 has hi perf valve gear, the cam is marked 148X9 but has a bad lobe. The exhaust will also receive a larger diameter head pipe, and retapered back section. The best thing will be the switch to dry sump oiling. Fins and air ducting on the tank will help cool the oil. Right, XL piston with a notch cut around the the top. This allows me to use it with the longer stroke crank from the FT 500, and not bump into the head. It also raise the compression ratio. To use this piston I will need to put the XL rod on the FT crank. The wrist pins are not the same size. There are pistons available to big bore the FT to 100mm though.

13 July 2011, a JE Piston #128995 has been ordered. A HotRods connecting rod is also coming, as is a 13 tooth countershaft sprocket. I will need to send the cam and rocker back to MegaCycle and have it repaired. Then I will have to start looking for jetting to get that HD carb working on the XL600.


Left, Thinking about 40mm CVKs from a Harley Davidson. The first HD carb arrives. Still thinking about a daul carb set up.

These early XL engines had dual carbs, one acted as a primary, the other a secondary. I plan to use two carbs. With one twist however. I will run the FT500 34mm carb as a primary, and a Harley 40mm CVK as the secondary. That should work similar to a quadrajet or thermoquad from 1970s GM and Chrysler cars.

Since both Keihin carbs are Constant Velocity they will only open to the amount the engine is actauly able to pull in (Vacuum Secondaries). I do like the idea of accelerator pumps on 4 stroke engines. The HD carb is equiped with a accelerator pump while the FT is not. The accelerator should be on the primary carb. 2 40mm Harley carbs? The GM quadrajet has reservoir that pretty much just drops a quantity raw fuel into the secondary air column...The Yamaha Raptor uses a dual carb setup.

The primary exhaust is 1.125" diamater, just under 29mm. The carbs should be somewhat larger, especially in an Individual Runner system (no plenum). 2 40mm carbs seem like too much.

ONE THING IS CERTAIN, THERE IS NOT A REED VALVE ANY WHERE ON THIS INTAKE SYSTEM. So how do we go about squashing a 30 year old misunderstanding. The port is oval shaped, wider than it is tall. At some point farther into the head a center divider splits in into 2 round ports that feed the 2 intake valves. Back at the mounting face there is a rubber adapter that has 2 spigots for 2 carbs.

If you use a dual carb set up and set it up as primary and secondary you must have a common plenum chamber,so both valves can move fresh mixture into the cylinder. If one valve doesn't get fresh cool air until the secondaries open it will eventually overheat and fail (burned valve). Remember you spend more time on one carb (primary) than on both.

Again there is no reed valve intake, there isn't any room where one could fit into the intake tract. I will post pictures to demonstrate what I have found.


The picture of the Carillo connecting rod didn't turn out. It was in this junk yard engine too!
In the early 1990s ATK made an experimental Quad with a 604cc Rotax, and one of the magazines installed a Honda 600 in a 4TRAX.
Some comparisons
 
whlbse
width
gearing
primary
tire size
induction
area of carb
weight
horse power
bore/stroke
KEF 300
44.9"
42.5"
12X43
 
22X11-10
CV Keihin
 
448 lbs
 
 
400 EX
48.4"
45.3"
14X39
 
20X10-9
35.5 w/accel pump
989 sq mm
375 lbs
 
85X70
ATKuad
 
 
 
 
20X10-9
42 BSR Mikuni
1384 sq mm
 
 
100X83
Raptor
50.4"
46.1"
13X40
34X71
20X10-9
2X 33 BSR Mikuni
1710 sq mm
398 lbs
 
100X84
DS 650
49.0"
48.5"
 
 
20,22X10-9
42 BSR Mikuni
1384 sq mm
494 lbs
 
100X83
FT500
 
 
15X42
 
22X11-10
35 CV Keihin
961 sq mm
 
34@6200rpm
89X80
XL600R
 
 
14X44
 
22X11-10
 
 
 
44@6500rpm
100X75
Big Bore 628
Mega Cycle, 148-9 cam
13X46
JE Piston
22X11-10
40 CVK
1256 sq mm
 
 
100X80
XR650
 
 
 
 
 
42.5
1417 sq mm
 
61.2@6750
100X82
 

Ok, I need some internal gearing to slow this machine down. A 4-wheeler needs a smaller axle sprocket, for ground clearance. With the stock FT500 engine the gearing was way to tall. By the time I get the speed low enough for low gear trail riding the sprocket is constantly crashing into anything sticking up on the trail or road. So I like the XR650R gearing, but no one seems to know it the 650R parts will fit in the 600 cases. Now There is a big difference in the primary gearing. The transmission will be spinning a lot faster in the XR650R, this is good for torque capacity.

Lets suppose the engine makes 20 foot pounds of torque, at the crankshaft. If you multiply that 20 lbs by the gear ratio - 20 X 1.651, the XR650R transmission will feel 33.02 ft-lbs. The XR600 will see 20 X 2.188 or 43.76. Quite a bit of change in torque handling capacity by changing the primary ratio. If the XR600 transmission was designed to operate with 50 ft-lbs, and we swapped in the XR650R primary gears the same gear set should withstand 66 ft-lbs.

Now we need to consider the effect primary gearing has on % change (closing or widening the spread). lets assume a counter shaft speed of 1000RPM, and a main shaft speed of the same, and a 4:1 primary, this would give a crank RPM of 4000. Now lets shift down to 3rd. same 1000 RPM on the counter, but the main shaft jumps to 1250, so now the crankshaft is turning 5000RPM. So lets change to a 3:1 primary ratio. Same 1000 RPM on the counter shaft, and main shaft as the above examples. In direct the crank shaft will be spinning 3000 RPM, and shifting down to 3rd, the crank would see 3750 RPM. You can see the gear change produced a 1000 RPM split with 4:1, and a 750RPM split with the 3:1. This is a radical example, to demonstrate the point.

. .
Gearing Chart
 
Primary
1st
2nd
3rd
4th
5th
Comments
FT500
70/29 2.413
32/13 2.462
28/17 1.647
25/20 1.25
23/23 1.00
21/25 0.84
FT, XL must have different CL on crank to input shaft
GB500
72/29 2.482
31/13 2.385
28/18 1.55
24/20 1.20
23/23 1.00
21/24 0.875
To allow use of smaller rear sprocket, ground clearance
XL500
70/29 2.413
31/13 2.385
28/18 1.55
24/20 1.20
23/23 1.00
21/24 0.875
See FT
XL600R 83-84
70/32 2.188
32/13 2.46
28/17 1.647
25/20 1.25
23/23 1.00
21/25 0.84
 
XL600R 85-87
70/32 2.188
31/13 2.385
28/17 1.647
25/20 1.25
23/23 1.00
21/25 0.84
 
XR600
70/32 2.188
31/13 2.385
28/17 1.647
25/20 1.25
23/23 1.00
21/25 0.84
 
NX650
69/34 2.029
32/12 2.66
28/16 1.75
25/20 1.25
23/23 1.00
20/25 0.80
???
XR650L
69/34 2.029
32/12 2.66
28/17 1.647
25/20 1.25
23/23 1.00
21/25 0.84
 
XR650R
71/34 1.651
37/12 3.083
34/16 2.125
30/18 1.666
28/21 1.333
29/26 1.115
Wide ratio for low1st gear
HRC kit
69/34
 
 
 
 
 
 
KEF 300
 
34/11 3.09
31/15 2.06
27/18 1.50
25/22 1.136
22/25 0.88
 
400 EX
65/23 2.826
35/15 2.533
31/16 1.937
28/19 1.473
26/22 1.181
26/26 1.00
 
TRX700
 
38/12 3.166
35/16 2.188
31/19 1.631
28/22 1.272
26/25 1.04
 
Ratio to countershaft FT500
 
5.94
3.97
3.01
2.413
2.024
 
Hypothetical Mix
70/32 2.188
37/12 3.083
34/16 2.125
30/18 1.666
28/21 1.333
29/26 1.115
XR650R gear set w/XR600 primary
Ratio to countershaft Hypo.
 
6.74
4.64
3.64
2.91
2.43
 

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