I need to tame down a 1997 KX60...

slider
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slider
Edited Date/Time 1/27/2012 1:47pm
I fixed a 1997 KX60 for a neighbor. Rebuilt crank, top end... and it has a FMF pipe and silencer, stocker was tossed by original owner.
The little 6 year old neighbor kid does not know how to keep this nice running engine on the pipe and his daddy is an old XR rider and thinks the '60 is not right.
I played with the minor adjustements I know of in the carb (needle and air screw) but it is not "good enough" for them yet.
Is there any tricks I can do to tame the power and be more like a trailbike instead of a racer? At this time I don't care if I rob 5hp off the top end, he just needs it to not die when he throttles up in gear at an idle and just off idle rpm...

I have a metal lathe and was thinking of making a collar to insert into the exhaust port or maybe a sleeve for the carb...?
I put almost $750 into this bike (much more than just motor work) in exchange for a broken honda 50 and two broken y-zingers and hope to make this deal stick.

Rick
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newmann
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newmann 11/28/2009 10:12pm
11/28/2009 10:12pm
Could you add some flywheel weight to it?
DAYKIN17
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DAYKIN17 11/29/2009 4:42am
11/29/2009 4:42am
slider wrote:
I fixed a 1997 KX60 for a neighbor. Rebuilt crank, top end... and it has a FMF pipe and silencer, stocker was tossed by original owner...
I fixed a 1997 KX60 for a neighbor. Rebuilt crank, top end... and it has a FMF pipe and silencer, stocker was tossed by original owner.
The little 6 year old neighbor kid does not know how to keep this nice running engine on the pipe and his daddy is an old XR rider and thinks the '60 is not right.
I played with the minor adjustements I know of in the carb (needle and air screw) but it is not "good enough" for them yet.
Is there any tricks I can do to tame the power and be more like a trailbike instead of a racer? At this time I don't care if I rob 5hp off the top end, he just needs it to not die when he throttles up in gear at an idle and just off idle rpm...

I have a metal lathe and was thinking of making a collar to insert into the exhaust port or maybe a sleeve for the carb...?
I put almost $750 into this bike (much more than just motor work) in exchange for a broken honda 50 and two broken y-zingers and hope to make this deal stick.

Rick
I'd probably go with 2 or 3 teeth bigger sprocket on the back, that fly wheel weight that bobbym suggested is'nt a bad idea also. In regards to that exaust insert, why not give it a try, you've got the lathe.good luck.
Cygnus
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Cygnus 11/29/2009 5:05am
11/29/2009 5:05am Edited Date/Time 11/29/2009 5:05am
A washer in the exhaust works wonders. No need to machine one.
MX Dad #27 11/29/2009 8:43am
11/29/2009 8:43am
Cygnus wrote:
A washer in the exhaust works wonders. No need to machine one.
Makes plugs foul. Go with the larger sprocket on the back.

The Shop

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Big Lenny
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Big Lenny 11/29/2009 5:53pm
11/29/2009 5:53pm
Sock in the airbox?...
JOHN CHOATE
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JOHN CHOATE 11/29/2009 6:00pm
11/29/2009 6:00pm
If it has a copper head gasket, try adding another one to take away a little compression. Seems to me that adding teeth to the rear sprocket would just give it too much torque which seems like what the kid wants to get away from. I'd say change the front sprocket(cheaper than changing the rear sprocket whether you go up or down) by going up one tooth to take away some torque(taming the power like you wrote).
project racer 11/29/2009 6:33pm
11/29/2009 6:33pm Edited Date/Time 4/17/2016 7:11pm
Race bikes do not make good beginner bikes. Once a beginner upshifts a few times, they expect to get the same response from opening the throttle as they do in the lower gears. The concept of downshifting is not one of most beginning riders better attributes. Stress the point of staying in the lower two gears.You will never get "trailbike" manners out of a KX 60. They are close to being over ported from the factory.

Honestly, I feel a bit sorry for the kid trying to learn how to ride a full blown race bike that barely starts to come alive at 6K RPM's and runs it's best at 10K RPM's.

Tried it with my nephew with an '88 RM80. Ended up with a mellow DT Yamaha enduro. He was so much happier ,being on something that would actually pull in taller gears, instead of the bog and stall of a high RPM racer not being kept on the pipe.

That ain't no fun for a kid just learning how to ride.
slider
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slider 11/29/2009 7:02pm
11/29/2009 7:02pm
Thanks for the advise.
The kid has a few years on the Y-Zingers I now own and can ride his bro's new RM65 much easier but not this KX yet.
I will probably try the washer first as it is free *wink* and being there is a slight coolant leak around either the head or base of the cyclinder I can try two head gaskets at that time.
He really just needs more seat time, a few months from now he should have it mastered. Well, the first 6k RPM's. LOL
Any other ideas?

Rick
Cygnus
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Cygnus 11/30/2009 4:58am
11/30/2009 4:58am
Cygnus wrote:
A washer in the exhaust works wonders. No need to machine one.
MX Dad #27 wrote:
Makes plugs foul. Go with the larger sprocket on the back.
I should have said you will need to lean it out just a bit. The bigger sprocket on the rear will do just What John said. It will be a wheelie machine.
lumpy790
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lumpy790 11/30/2009 8:14am
11/30/2009 8:14am Edited Date/Time 4/17/2016 7:12pm
I used to sell a ton of these to tame all the 2 stroke beasts....make one 5mm thick. I may still have a set. Making the jetting rich helps too.




roost251
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roost251 11/30/2009 8:09pm
11/30/2009 8:09pm
Cygnus wrote:
A washer in the exhaust works wonders. No need to machine one.
MX Dad #27 wrote:
Makes plugs foul. Go with the larger sprocket on the back.
Cygnus wrote:
I should have said you will need to lean it out just a bit. The bigger sprocket on the rear will do just What John said...
I should have said you will need to lean it out just a bit. The bigger sprocket on the rear will do just What John said. It will be a wheelie machine.
X2, you can open up the hole little by little also
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Tiki 12/1/2009 7:14am
12/1/2009 7:14am
newmann wrote:
Could you add some flywheel weight to it?
Newmann is on it. My opinion your lil guy will love it after. Larger sprocket as well but put it on the front. Rear will only make it grab that much quicker. Front will draw the speed out of it.

Flywheel weight is really the way to go.
Nutty C
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Nutty C 12/1/2009 12:38pm
12/1/2009 12:38pm
Race bikes are for racing. You have stood on your head for the guy . He knew what he was getting now you have to decide whether to pull the plug on him. Myself I would pull the plug.
project racer 12/1/2009 8:33pm
12/1/2009 8:33pm
By going to a taller gear ratio, such as a bigger countershaft sprocket, that will only make the bike more prone to bogging . Kid will be having to rev it higher, to pull the taller gearing. If he can manage the bike in low gear, by adding 2-3 teeth on the rear sprocket this will make second and third gears more usable at low speeds. It won't make the bike a wheelie machine, just a little more manageable as far as keeping the RPM up to keep it out of the bog zone. He's having trouble keeping it in the proper RPM range as it is. Tighten up the gearing and help him out.

A larger counter shaft sprocket will only hinder the kid in low speed situations, making the bike more prone to bogging/stalling due to the fact the engine will be operating at an even lower RPM. It would be almost like making him start off in second gear by going to a bigger countershaft sprocket. That's the wrong direction to go.

slider
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slider 12/1/2009 9:43pm
12/1/2009 9:43pm
lumpy790 wrote:
I used to sell a ton of these to tame all the 2 stroke beasts....make one 5mm thick. I may still have a set. Making the...
I used to sell a ton of these to tame all the 2 stroke beasts....make one 5mm thick. I may still have a set. Making the jetting rich helps too.




lumpy, I am liking this over all other ideas.
By 5mm thick you mean to narrow off the opening 2-3mm, right? Or do you mean to make a shim? The distance of 5mm longer head pipe to the stinger area won't matter much to the sound waves, am I correct?

Rick
project racer 12/2/2009 12:37am
12/2/2009 12:37am
Basically ,you are trying to lengthen the head pipe length with Lumpy's shim. Lengthening the head pipe on a two stroke improves low to mid range power , taking away from the top end power.

lumpy790
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lumpy790 12/2/2009 6:37am
12/2/2009 6:37am Edited Date/Time 4/17/2016 7:14pm
The two rings shown are 2mm & 3mm thick for fine tuning but everyone I spoke with said they just put both in (5mm) and were happy and they did make a difference.
JOHN CHOATE
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JOHN CHOATE 12/2/2009 7:03pm
12/2/2009 7:03pm
project racer wrote:
By going to a taller gear ratio, such as a bigger countershaft sprocket, that will only make the bike more prone to bogging . Kid will...
By going to a taller gear ratio, such as a bigger countershaft sprocket, that will only make the bike more prone to bogging . Kid will be having to rev it higher, to pull the taller gearing. If he can manage the bike in low gear, by adding 2-3 teeth on the rear sprocket this will make second and third gears more usable at low speeds. It won't make the bike a wheelie machine, just a little more manageable as far as keeping the RPM up to keep it out of the bog zone. He's having trouble keeping it in the proper RPM range as it is. Tighten up the gearing and help him out.

A larger counter shaft sprocket will only hinder the kid in low speed situations, making the bike more prone to bogging/stalling due to the fact the engine will be operating at an even lower RPM. It would be almost like making him start off in second gear by going to a bigger countershaft sprocket. That's the wrong direction to go.

I know what you're saying,but he was asking how to "tame" the motor and a bigger rear sprocket would be the wrong direction.

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project racer 12/2/2009 10:52pm
12/2/2009 10:52pm
JOHN CHOATE wrote:
I know what you're saying,but he was asking how to "tame" the motor and a bigger rear sprocket would be the wrong direction.
It's not really a matter of taming the engine down in this case. Put a 30 tooth sprocket on the rear of it, and see how much bogging/stalling takes place. Then put a 50 tooth sprocket on the rear, and watch the kid idle away with much less difficulty.

Tiki
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Tiki 12/3/2009 10:08am
12/3/2009 10:08am
project racer wrote:
By going to a taller gear ratio, such as a bigger countershaft sprocket, that will only make the bike more prone to bogging . Kid will...
By going to a taller gear ratio, such as a bigger countershaft sprocket, that will only make the bike more prone to bogging . Kid will be having to rev it higher, to pull the taller gearing. If he can manage the bike in low gear, by adding 2-3 teeth on the rear sprocket this will make second and third gears more usable at low speeds. It won't make the bike a wheelie machine, just a little more manageable as far as keeping the RPM up to keep it out of the bog zone. He's having trouble keeping it in the proper RPM range as it is. Tighten up the gearing and help him out.

A larger counter shaft sprocket will only hinder the kid in low speed situations, making the bike more prone to bogging/stalling due to the fact the engine will be operating at an even lower RPM. It would be almost like making him start off in second gear by going to a bigger countershaft sprocket. That's the wrong direction to go.

I agree, but its cheap. Flywheel is the way to go. Actually the way to go is send this guy down the road and tell him his kid needs to learn like the rest of us.

Expensive way to go would be add a rekluse clutch.
nov8r
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nov8r 12/31/2009 8:15am
12/31/2009 8:15am Edited Date/Time 4/17/2016 7:42pm
An exhaust restrictor works well in these bikes, but a simple washer doesn't cut it. By the time you have a washer small enough to take away the two stroke hit, the restriction is so great it will clog. The solution is a longer restrictor. I spent many hours and itterations creating the right combination of length and diameter, and sell them for a nominal fee via ebay. The link is below if you would like one of the "power tamers". They will fit KX60s and the similar design RM60s, and are easily installed then removed when the rider is more confident with the bike.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=170281314…
floridaflash
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floridaflash 1/1/2010 11:29am
1/1/2010 11:29am
you can also retard the timing, it will help take away some of the hit
MaxPower
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MaxPower 1/5/2010 11:38pm
1/5/2010 11:38pm
I rode a KX80 once that had a heavy flywhee
I found it very hard to ride. It bogged until it got on the pipe and I had to keep it screaming because if it dropped off it was hard to get it going again
Maybe lower the compression and reeds or a couple other things but that motor is made to live at 10000 rpml
Cygnus
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Cygnus 1/6/2010 7:32am
1/6/2010 7:32am
nov8r wrote:
An exhaust restrictor works well in these bikes, but a simple washer doesn't cut it. By the time you have a washer small enough to take...
An exhaust restrictor works well in these bikes, but a simple washer doesn't cut it. By the time you have a washer small enough to take away the two stroke hit, the restriction is so great it will clog. The solution is a longer restrictor. I spent many hours and itterations creating the right combination of length and diameter, and sell them for a nominal fee via ebay. The link is below if you would like one of the "power tamers". They will fit KX60s and the similar design RM60s, and are easily installed then removed when the rider is more confident with the bike.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=170281314…
Post a larger picture. That pic on there is tiny.
Blake
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Blake 1/6/2010 9:05am
1/6/2010 9:05am
I had a 1983 KX 60 as a kid, that fucker barked and breathed FIRE.

I never wanted anything less, hold it WFO and slip the clutch.

At WFO, there is no hit. Then I got a 83 KX 80 and was in LOVE. That bike was the shizzle.,



Blake
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Blake 1/6/2010 9:16am
1/6/2010 9:16am
89'cr dude
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89'cr dude 1/16/2010 4:49pm
1/16/2010 4:49pm
one of the best ways is a reed spacer. reed spacers make the powerband shift from an up high screamer to down low woods bike.

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