We have a 1985 kdx 200. I abandoned the stock carb for a new mikuni 33mm round slide from sudco. The jetting they sent me up with did not work at all for this bike. I believe I have it as good as it will be. The problem is that the bike is extremely difficult to start when the pilot and needle are set to run clean off the bottom. it is also extremely sensitive to temperrature. If i want it to start easily it has to be jetted richer and then ofcoarse is a smoky sputtery pig of idle. It is also not consistent. sometimes one kick, sometims many and a sore foot. I have experimented alot. I want it to start super easy and run fairly clean. Does any one have an experience with carbs for this model? Would a flat slide model work better for this range of the circuit? Would i have been better off to rebuild the original. This is a woods / enduro type bike ridden by a novice. the original carb had been bored. Eric Gorr did the motor and it works well. I will give him a call. Any experience? I did not find a phone number for J.F. Thanks
1985 KDX Carb ?
- Thread starter MR. V
- Start date
David Trustrum
~SPONSOR~
- Jan 25, 2001
- 1,396
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May I suggest that perhaps the problem is an airleak, esp on such an old bike. Checking the airbox & sealing all the joins.
A leakdown test would be a good idea. Suspect areas would be LHS crank seal & around the reedblock. I assume the reeds are in good order, as this would throw things to hell. Perhaps also the ignition components are a little suspect which may be throwing you off base.
Good luck. It will be exhilarating if you cure it.
A leakdown test would be a good idea. Suspect areas would be LHS crank seal & around the reedblock. I assume the reeds are in good order, as this would throw things to hell. Perhaps also the ignition components are a little suspect which may be throwing you off base.
Good luck. It will be exhilarating if you cure it.
- Thread starter
- #3
Thanks for the reply.The reeds are fmf and in good shape. I have considered the ignition system. I had ricky stator re-do it (stator)once before when it died about 2 years ago. I did not replace the cdi. I think it was a very expensive piece. I looked into the pvl but did not like the additional parts, custom mounting, timing drill and questionable flywheel effectiveness. I sent it back. This motor is in a '99 kx 125 chassis and space is limited. Any advise on how to ensure a strong ignition system from stock components? mid to top rpm performance is perfect. I will check dry seal. Is the old method of spraying brake cleaner on the points of possible leakage while engiine is running conclusive enough for the dry seal areas?
dirt bike dave
Sponsoring Member
- May 3, 2000
- 5,349
- 3
FWIW, when the ignition systems go bad on the '83-'85, it seems that it is usually the stator and the problem is hot starting, not cold.
I would try these things before cold starting: Fresh plug and gas. Drain float bowl to remove any condensation. Turn in the airscrew at least 1/2 turn to richen the bike. Lay the bike on its left side with the gas on - let it stay there for 5 seconds or so. Pull the choke on and kick the bike through softly a few times. Then raise the piston to TDC and kick it for real. Make sure you are not twisting the throttle open at all during cold start - put your right hand on the brake reservoir if you have to.
If all this fails, you might be better off with the stock carb. I had an '84 and it was a super easy starter until the stator went bad.
I would try these things before cold starting: Fresh plug and gas. Drain float bowl to remove any condensation. Turn in the airscrew at least 1/2 turn to richen the bike. Lay the bike on its left side with the gas on - let it stay there for 5 seconds or so. Pull the choke on and kick the bike through softly a few times. Then raise the piston to TDC and kick it for real. Make sure you are not twisting the throttle open at all during cold start - put your right hand on the brake reservoir if you have to.
If all this fails, you might be better off with the stock carb. I had an '84 and it was a super easy starter until the stator went bad.
Mr. V,
I am rebuilding an '85 KDX and was wondering how you hold the seat on. From the drawings, it looks like the two tabs on the seat are held by bolts that are threaded into the frame from the inside. Isn't that a hassle? The bike I am rebuilding has an aftermarket rear fender that prevents access from inside the frame. I have tried using JB weld to attach a nut to the seat tabs, but I don't think I let it dry long enough (24 hours). Maybe I will use a real weld. (Oops, I see you have a '99 kx125 chassis)
My 2 cents: Go back to your old carb. Replace main and pilot jets ($2 - $3 each) and maybe the needle jet and jet needle. Perhaps even go to a new needle and seat and then use carb cleaner with a red plastic tube extension to spray through all of the airways. That should be as good as new, unless there was gas left to sit in there for several years and there is corrosion going on in the float bowl... I don't think you should have an ignition problem, 2 years after a rebuild. The CDI and coil are pretty reliable. It seems like most problems are with the stator. Definitely check the reed block for cracks or leaks.
I am rebuilding an '85 KDX and was wondering how you hold the seat on. From the drawings, it looks like the two tabs on the seat are held by bolts that are threaded into the frame from the inside. Isn't that a hassle? The bike I am rebuilding has an aftermarket rear fender that prevents access from inside the frame. I have tried using JB weld to attach a nut to the seat tabs, but I don't think I let it dry long enough (24 hours). Maybe I will use a real weld. (Oops, I see you have a '99 kx125 chassis)
My 2 cents: Go back to your old carb. Replace main and pilot jets ($2 - $3 each) and maybe the needle jet and jet needle. Perhaps even go to a new needle and seat and then use carb cleaner with a red plastic tube extension to spray through all of the airways. That should be as good as new, unless there was gas left to sit in there for several years and there is corrosion going on in the float bowl... I don't think you should have an ignition problem, 2 years after a rebuild. The CDI and coil are pretty reliable. It seems like most problems are with the stator. Definitely check the reed block for cracks or leaks.
Kawierider
Member
- Jun 7, 2001
- 281
- 0
Absolutly check for leaks. also make sure you float level is correct. i however also think the stock carb is good once clean and jetted correctly.
By the way, does anyone have a parts motor laying around ? All I need is a flywheel. if someone can help me out id really appreciate it !!!! My email is TCVezina@aol thanks.
Good luck
MX175.....I believe the bolts on the seat run in from the outside. its not that bad.....but I havent looked at my bike in awhile so i may be wrong.
By the way, does anyone have a parts motor laying around ? All I need is a flywheel. if someone can help me out id really appreciate it !!!! My email is TCVezina@aol thanks.
Good luck
MX175.....I believe the bolts on the seat run in from the outside. its not that bad.....but I havent looked at my bike in awhile so i may be wrong.
Hi MX175. I'm also rebuildiing an '86 KDX and the seat bolts are fitted from the outside through the alum seat brackets and into the bosses on the frame. If you want to see my progress it's in the KDX page on my website at www.550-spyder.co.uk
Cheers,
Andy
Cheers,
Andy
AndyD, nice job on that '86. I think I may have to weld some nuts on the seat brackets so that I don't have to stand on my head to take the seat off. I am looking for a headlight and rear fender with a taillight. I think I may just get replacements made by UFO. I paid $100 for the basketcase bike this last summer and had to do a lot to get it running again. I am probably up to about $800 now (stator rebuild, flywheel, front wheel, exhaust, top end, carb, swingarm bearings, etc.) and still it need lights. Andy will have a beautiful bike. I hope to have one that makes me smile on the trails in Colorado.
Mr. V, did you get that carb staightened out?
Mark
'80 KDX175
'85 KDX200
'81 XS850
Mr. V, did you get that carb staightened out?
Mark
'80 KDX175
'85 KDX200
'81 XS850
Kawierider
Member
- Jun 7, 2001
- 281
- 0
Mx 175-
where did you find a flywheel for you bike? do you still have your old one ?
where did you find a flywheel for you bike? do you still have your old one ?
Hi,, I have a Mint 85 kdx 200 that i rebuilt from ground up in my Kitchen. well was mint, Ive been riding it so things have a 2 year old ware now. I took this bike all apart,, down to the frame and re-painted. All the bearings everywhere were replaced. brand new dunlops, new sprockets, new gold renthal chain,new chain adj's,new chain guide,rear shock has been rebuilt and recharged(professionally done), forks have been inspected, new seals and new oil(professionally done), cylinder has been rechromed, wiseco piston and rings, mild port job(professionally done), boyseen reeds, stock carb taken apart, inspected and cleaned, uni-air filter, new kick starter, stat and coil checked, clutch taken apart and inspected(perfect) EBC front and rear drum(bummer but work great) brakes,P.S.I. pipe, DG silencer,new pet ****,new fuel filter,new front fender, KX plate(have headlight for night time riding) new KX rear fender(have stock fender with tail light) seat, sideplates and tank all our stock, renthal bars, scott grips,acerbis pro rally guards, quater twist throttle, i have the trip gauge but taken off, Page 10 in readers rides, funny thing is i have another one but not so nice.
Oh your Q. My 85's seats are bolted from the inside, Yes its kinda weird but i do like the clean look on the outside. You think thats bad i have a 96' kdx project thats taken alot of time, All of what the 85' has but black excel rims and polished everything, plus a hell of alot more, I couldnt stand haveing a 85' that kicks the 96's butt in speed and looks. But the 96 has way better suspension potential and better brakes and water cooled for the hot days. The 85 is just ballz out. I love my bikes tho, 96 is not done yet, and its right here with me in my living room, Iam single right now so it was my X-mas tree, i hung ornaments from it and sat around singing carols,, LOL oh there were presents,there were presents,,,, for my 2-wheeled tree!!! How do i put pic. on here?? I play with bikes, not computers!!!
jaguar
~SPONSOR~
that's great. another way to know a bike addict; he uses his motorcycle instead of a christmas tree! I love it.
Mr. V Sorry we got off your thread. How is your pursuit of main jets?
Speedy, I felt blessed when my wife came home early and my KDX was in the kitchen. She didn't kick us out. Must have been left over holiday spirit. Is there a chance you'd be interested in selling a rear fender-tailight or a headlight assembly? The KDX I am building has neither and I hope to make it barely street legal to get ride over to the trails.
I love your Christmas tree. Try to get a picture up. No, I don't know how to do it either. I'll suggest a KDX tree to my wife for next year, maybe early in the morning, before she is really awake.
Mark
80 KDX175
81 XS850 Special
85 KDX200
Speedy, I felt blessed when my wife came home early and my KDX was in the kitchen. She didn't kick us out. Must have been left over holiday spirit. Is there a chance you'd be interested in selling a rear fender-tailight or a headlight assembly? The KDX I am building has neither and I hope to make it barely street legal to get ride over to the trails.
I love your Christmas tree. Try to get a picture up. No, I don't know how to do it either. I'll suggest a KDX tree to my wife for next year, maybe early in the morning, before she is really awake.
Mark
80 KDX175
81 XS850 Special
85 KDX200
No, sorry im not selling anything. I was going to sell both 85 KDX 200s together a while back but the guy wanted to rape me,, Ill just keep the bikes untill i die.. lol.. There is a pic. of one of my 85s in justkdx. Its in readers rides on page 10. Ill have some posted of my 96' soon.
Oh Christmas Tree,, Oh Christmas Tree,,
How i love thy tires. lol!!!!!
Oh Christmas Tree,, Oh Christmas Tree,,
How i love thy tires. lol!!!!!
