1985 KX125

Jon_Haynes
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Jon_Haynes
Edited Date/Time 9/20/2017 8:49am


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Aceofspades 9/18/2017 6:34pm
9/18/2017 6:34pm
Literal dream bike there Smile I got into mx at 12 years old in 1985, just as the 85 models were coming out, and the kx line and the ads for them burned into my memory. Great job!

The Shop

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MaxPower
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MaxPower 9/19/2017 12:46am
9/19/2017 12:46am
Nice work. Was the cylinder already ported by TUF? How does it run?
Are you sure the forks are from an 87? I was thinking they didn't get a dual piston caliper until 89
Jon_Haynes
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Jon_Haynes 9/19/2017 5:05am
9/19/2017 5:05am
I could not remember which bike I took the forks from 89 sounds right. I have parts from a few years on the build. I even put a part on from my old 82 KX125 that I still had. It's a 82,85,87,89 kx125
Jon_Haynes
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Jon_Haynes 9/19/2017 5:35am
9/19/2017 5:35am
I could not remember which bike I took the forks from 89 sounds right. I have parts from a few years on the build. I even put a part on from my old 82 KX125 that I still had. It's a 82,85,87,89 kx125
PN27416
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PN27416 9/19/2017 10:02am
9/19/2017 10:02am
Very nice. I have an 84 that I can't decide if I should sell or make race ready?
riv187
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riv187 9/19/2017 11:34am
9/19/2017 11:34am
Hi I have a 1985 as well... was thinking of swapping 1989 46mm kx250 front end on it... will the triple swap with no problems?
Did you save the old seat cover??? Would
Like to have it to copy a new TUF cover
Jon_Haynes
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Jon_Haynes 9/19/2017 5:16pm
9/19/2017 5:16pm
I may have thrown the seat cover away. I will look in a few minutes. The fork and clamps went right on but I may need to take them off at some point and add to the steering stop on the frame, the forks will hit the gas tank slightly. I have only rode in the yard so far so I don't know a lot about the porting yet, track time next week I hope.
riv187
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riv187 9/19/2017 5:35pm
9/19/2017 5:35pm
Thanks please save that cover if you find it,,,,I have had the logos copied and stencils made many times to make my own covers the way I want.
I actually had 2 1985s back in 86. I installed that same seat cover on one. When it came time to sell them,,the TUFF seat cover helped sell that bike 1st...even though I knew it was slower than other KX !!. ??
Eric Gore actually did TUFF porting back in the day. Is there any engravings in your cylinder?
Mine current one is still bone stock and runs well. Suspension is stock and soft. So I picked up a newer YZ 4.9K Titanium spring that should fit on back. For front I have 88 43mm forks, and the complete 46 front end I hoped would work.
Adding to your stops to limit triple shouldn't be hard...maybe done right on the bike with a TIG welder or MIG, build up a couple spots.


nicko-31
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nicko-31 9/19/2017 5:36pm
9/19/2017 5:36pm
I had that same bike and had Eric port it when he worked at Tuf Racing. Loved it but durability was not the highest. Enjoy your fruits of your labor.
Jon_Haynes
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Jon_Haynes 9/19/2017 7:11pm
9/19/2017 7:11pm
How was the porting done ? More top end or mid, bottom end ? I should find out soon but just curious.
nicko-31
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nicko-31 9/20/2017 6:42am
9/20/2017 6:42am
Jon ,I had Eric port for "top end" and had a pipe with Eric's jetting recommended. I don't remember the brand of pipe but it was mostly top end for sure.

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riv187
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riv187 9/20/2017 7:56am
9/20/2017 7:56am
WOW I bet that is a fast KX!

riv187
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riv187 9/20/2017 8:03am
9/20/2017 8:03am
Back in the day..1986 when I freshened the '85 KX125 with TUF seat cover bike,,I remember raising the exhaust port a small amount...020" and that made it hit harder up top. Gave the feeling it was faster with harder hit...but the other '85 was done by Barr Comp in (NC I believe) and it was faster and easier to ride with wider powerband. Both used stock pipes and carbs.
Jon_Haynes
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Jon_Haynes 9/20/2017 8:49am
9/20/2017 8:49am
I'm getting old and slow, so if it has something on the bottom to mid range I will be happy. I just got back into racing after a 30 year break.
MaxPower
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MaxPower 9/22/2017 5:02pm
9/22/2017 5:02pm
riv187 wrote:
Thanks please save that cover if you find it,,,,I have had the logos copied and stencils made many times to make my own covers the way...
Thanks please save that cover if you find it,,,,I have had the logos copied and stencils made many times to make my own covers the way I want.
I actually had 2 1985s back in 86. I installed that same seat cover on one. When it came time to sell them,,the TUFF seat cover helped sell that bike 1st...even though I knew it was slower than other KX !!. ??
Eric Gore actually did TUFF porting back in the day. Is there any engravings in your cylinder?
Mine current one is still bone stock and runs well. Suspension is stock and soft. So I picked up a newer YZ 4.9K Titanium spring that should fit on back. For front I have 88 43mm forks, and the complete 46 front end I hoped would work.
Adding to your stops to limit triple shouldn't be hard...maybe done right on the bike with a TIG welder or MIG, build up a couple spots.


You may have to swap and mess with shock collars to fit the KX shock
I remember the YZ TI shock being a larger ID
And clearance against the air boot may be close
riv187
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riv187 9/26/2017 11:22am
9/26/2017 11:22am
riv187 wrote:
Thanks please save that cover if you find it,,,,I have had the logos copied and stencils made many times to make my own covers the way...
Thanks please save that cover if you find it,,,,I have had the logos copied and stencils made many times to make my own covers the way I want.
I actually had 2 1985s back in 86. I installed that same seat cover on one. When it came time to sell them,,the TUFF seat cover helped sell that bike 1st...even though I knew it was slower than other KX !!. ??
Eric Gore actually did TUFF porting back in the day. Is there any engravings in your cylinder?
Mine current one is still bone stock and runs well. Suspension is stock and soft. So I picked up a newer YZ 4.9K Titanium spring that should fit on back. For front I have 88 43mm forks, and the complete 46 front end I hoped would work.
Adding to your stops to limit triple shouldn't be hard...maybe done right on the bike with a TIG welder or MIG, build up a couple spots.


MaxPower wrote:
You may have to swap and mess with shock collars to fit the KX shock I remember the YZ TI shock being a larger ID And...
You may have to swap and mess with shock collars to fit the KX shock
I remember the YZ TI shock being a larger ID
And clearance against the air boot may be close
Yes I may have to use a collar on shock spring. When I compared specs it was about 1-2mm different at base coil. Small amount and may not create any problem,,will see! thanks!
Jon_Haynes
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Jon_Haynes 10/2/2017 5:35pm
10/2/2017 5:35pm
I talked to Dave Antolac of TUFF racing Saturday night and he said CEET will make the Tuff seat cover for the bikes if that helps anyone.
1
riv187
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riv187 10/2/2017 6:15pm
10/2/2017 6:15pm
I'll ask. I may have met Dave a few years back when he visited Florida and stayed at a mutual friends track.
I've made about 20 seat covers in past,,, the cover is not too difficult,,,the screened stencil is. Takes time with a graphics designer to get right. Helps if there is a actual size one to measure and plot. If Ceet has the stencil already then that is great.
Have you got to ride your KX and test her out?
Jon_Haynes
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Jon_Haynes 10/2/2017 6:39pm
10/2/2017 6:39pm
I raced it on Saturday. I need more time to get the suspension set and I need some jetting help, but it will be a fun bike. Any good jetting info available ?
riv187
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riv187 10/2/2017 7:28pm
10/2/2017 7:28pm
My bike is bone stock currently.....and runs stock jetting with 32-1 race gas and b8es plug. I'm a porky 140lbs and still the stock suspension felt like a soft couch. I added air to front and preload twisted caps all the way in and added compression to rear to make it through race day.
Jon_Haynes
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Jon_Haynes 10/3/2017 2:20pm
10/3/2017 2:20pm
I may try a B8 I just bought the stock B10 to start with. I have 35 pounds on you but I sprung it for that.

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