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86 carb and clutch experiences?

Posted: 01:02 pm Feb 12 2018
by pkenney
Looking to improve the motor a bit on my 86.
It is stock, pretty fresh, and runs well but I don't feel it has the "tractor" factor I see on the newer bikes.
It has a good top-end hit but I have not been able to move any power to the bottom and don't really want to add a flywheel weight.

I'm using the 30 year old VM34 and looked into the RB mods but he does not offer anything for the Air Cooled KDX.
I have seen references to upgrading to the newer KDX Keihin but have not found much detail.
Anyone have first hand experience?

I've also been looking for a pipe but only find the DG available.
FMF tells me they don't have anything for the 86.
I also have seen some Hop-Up notes that say the stock pipe is fine.
Any feedback?

I'd also love to get a recommendation on a clutch kit.
Shopping the online stores, I have not been able to find a good clutch kit for the 86 but found that the KLX300 uses the same part number so I ordered an EBC kit.
Maybe it is my riding ability but it completely gives up on long hill climbs where a lot of clutch slipping is needed.
It comes all the way to the bars and takes a while to come back.
I use ATF but plan to switch to Maxima MTL-80 this year.

Thanks for any feedback,

Re: 86 carb and clutch experiences?

Posted: 03:37 pm Feb 12 2018
by KDXGarage
FMF pipe is definitely stronger than stock. DG may be your only choice for new and readily available.

1988 switched to Keihin PWK35 with the right side tab that reached over to the left to do the choke lever. It also has the air screw on the right and the idle knob on the right. Some have wedged it into the old boots and some have purchased the 1988 carb to engine and airbox to carb boots.

Not sure on the clutch kit.

I have been using Maxima 80 for a few years, works great for me.

Re: 86 carb and clutch experiences?

Posted: 03:39 pm Feb 12 2018
by doctord23
88 model year had the Keihin carb so you can get the reed and air cleaner boots from that year.
Then you can use a Keihin carb off of a newer kdx, but it's tight to get to the choke lever from the left side.

I like what you did with the rear disc setup. What year brake parts did you use?
I had done a conversion with an 80's kx on an 87 that I used to have.
It makes a huge difference to have discs front and rear.

I just finished putting an 88 back together.

Re: 86 carb and clutch experiences?

Posted: 04:03 pm Feb 12 2018
by pkenney
I used 2002 KX125 Forks, wheels, and brakes and they were a huge improvement.

Converting the rear wasn't that bad but I had to machine a caliper stay that I bolted around the stock swingarm boss.
Also had to fab and weld the master cylinder holder to the frame which took some trial and error to get the angle right.
The sprocket side worked with the stock KDX axle spacer but the brake side needed an additional spacer with the KX caliper.

Thanks for the carb recommendations, I'm disappointed that RB doesn't have anything he'd recommend.
A carb is a carb right? I'd have liked to try his mods based on what I know about them.

Re: 86 carb and clutch experiences?

Posted: 08:00 pm Feb 12 2018
by doctord23
The air cooled C years are quite peppy on the top end.
I few things could be hurting the low end including ignition timing and kips timing.

Re: 86 carb and clutch experiences?

Posted: 09:52 pm Feb 12 2018
by pkenney
I've tried the ignition timing and didn't see much difference but have not really messed with the KIPS system.
I have verified that it opens at higher revs and the timing dots lined up at 11:00 with the rod all the way in.
I also read about a KIPS chamber spacer and it seems like a 10mm spacer is beneficial.

My carb isn't in the greatest shape and there is an odd needle in it so I want to be sure I get that system right.
I'm going to look for some 88 components and a fresh carb.

Thanks for all the suggestions,

Re: 86 carb and clutch experiences?

Posted: 03:38 am May 19 2018
by targetman
Have you found an '88 carburetor yet?

Re: 86 carb and clutch experiences?

Posted: 07:37 pm Aug 08 2018
by pkenney
Followup to an old post:

Last weekend I finally got to put some time on the KDX after doing my first enduro in March.
In the enduro, I rode with a buddy on an XR400 and he got a flat tire after 18 miles which we tried to fix on the trail.
Once the sweep riders came through we knew we were done but the experience showed me a lot of opportunities to improve the KDX.

I decided to stick with the stock carb but replaced the manifold and fitted a DG pipe.
I also took the clutch apart to see if I could find a source for the overheating problems I have always had.
I did find that the plates were backwards from the manual - maybe this causes oil to pushed out of the clutch?
I also switched to Maxima MTL-80 instead of ATF and put the whole quart in the cases.
The clutch still heats up and I always need to adjust the cable but at least t does not completely lock like it used to.

The pipe and manifold were more of a precaution since both the old components were in bad shape.
I've seen chambers blow out on roadrace bikes and my stock pipe was very rusty.
The bike ran great last weekend and I was able to keep up with a pretty fast group.

I also added some ROX 2" bar risers which are one of the best improvements I have made.
I am 6' and the bike is so much easier to stand on and I wasn't nearly as tired after my last ride - highly recommend these.

Re: 86 carb and clutch experiences?

Posted: 08:12 pm Aug 08 2018
by KDXGarage
1. Fork
2. Springs

:grin:

Congrats on the improvements. Do look into getting some proper fork springs for it, assuming you have not already.

Re: 86 carb and clutch experiences?

Posted: 10:17 am Aug 18 2018
by pkenney
Thanks as always for the input, the suspension is on my to-do list.
The forks still have the KX125 springs but I'm very happy with the performance.

The rear is my focus now, I rebuilt the shock not long ago and still have the stock spring.
Actually, I think it is the stock spring... I had 3 old shocks to choose from and I chose the one that was least banged up. :roll:
Guys riding behind me say the rear deflects a lot over rocks but honestly I've never ridden something with a good suspension so maybe I don't notice.

I've been reading a lot of info on how to do a woods setup and know springs are the first thing to do.
Its hard to find the time to work on suspension though, every time I load the bike we're riding not testing.