1985 Big Red 250es and 250sx

[NVL]

I just recently picked up a 1985 250sx, that stalls after shortly riding. The stalling is AS SOON as you put it into 1st or reverse from neutral. It just shuts off like you turn the key off. I did some looking around online and people are saying possible CDI box. So i took ths good CDI off my Big red and it seems to take care of the problem. The new problem is finding a dang CDI box for an '85 model Big Red or SX. The ones on ebay are all for 86 models which have 2 plugs, that arw square/rectangular. 85's have the 6 wire, round connector. Ive found some for many 200 models, like the 200m, 200x and 250r, not sure if those would work being that they are for the smaller engines?

Any info you guys have would be greatly appreciated!

Thanks

Nick~https://uploads.tapatalk-cdn.com/20181025/da8ca1404b9fdb5f10cc4102caf3495f.jpghttps://uploads.tapatalk-cdn.com/20181025/93c10a90fd0bc0f707491c32db139c53.jpg

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[ps2fixer]

Well you could cheat and make the neutral safety wire always shorted to ground so the safety circuit in the CDI can't fail. Under normal use, that neutral wire has to be shorted to ground to get spark for starting, once it's running it's not needed, but likely that part of the CDI has failed. The switch that the wire connects to is located on the bottom right side of the engine under the little metal cover. There's a reverse switch as well, I don't recall which is which, but the switches just short to ground, so not too hard to test with the key on to see which light lights up. Down side to the bypass is the neutral light will always be on, you could remove the bulb if it's annoying. If you don't want to hack up the harness, I can make a short wire you bolt to a spot on the frame so your harness is unmodified.

The wire you need for the neutral safety bypass is the light green with red stripe wire. Could tap into it where it plugs on the neutral safety switch or where the sub harness connects to the main harness (around 12in long just above the engine near the back of it). The last spot that makes sense to tap into would be right at the starter relay switch, green/red wire this time, and just short it to ground to bypass, however you have to make that connection for both the harness and starter relay side. Just for data completeness, the reverse switch is solid green wire and it's only use is for the reverse light in the dash.

I'm pretty sure the 250sx and 250es CDI boxes would be interchangeable, if you find one and want me to validate, I can try to dig up a harness to validate the pin out matches. A lot of the 84-85 machines used that round CDI connector, but be aware that pin-outs did change on some machines, I don't have a built list on hand for the pin-outs but it's in the list of things to do.

Seems to be a common theme lately, but if you want, you can run an 86-87 250sx on the 85 sx if you replace the CDI connector with the standard 4+2 style. If you want to use your existing terminals you can extract them out with a fairly cheap tool, and buy the new connector housings. If you want to go with new terminals, you'd have to splice in a pig tail that I'm planning to make for another member as well. Price is $19 for the first one, or $35 for two (saving the shipping difference).

FYI, the 200 series CDI boxes will not work well at all, they use a mechanical spark advancer on the cam, while the 250es/sx does the advancement electronically inside the CDI box. Besides that factor they would probably work if the pin-out matches, but it would feel really sluggish with no spark advancement. The 250r one could be a maybe, but it's also 2 stroke so I'd guess the advancement curve is quite different compared to a 4 stroke.

Post if you have any questions, I'm not always the best at explaining things with words.

Also nice 3 wheeler collection =), I see a 350x near the back. The nearest machine looks interesting, appears to be a 200x with a motorcycle engine twin cylinder. I have something similar unfinished, a late 80's blaster frame with a Yamaha TX500 bike engine in it and swing arm moved back about 6in. My dad built it, but didn't finish the electronic side of things. I need to dig up some 250es parts and make the electrical work on it and ride the beast. Engine spec is 49hp lol.

[wonderboy]

I am thinking that maybe it is something in the clutch system being locked up. If the centrifugal clutch system isn't disengaging properly, there could be a load pulling the engine RPM too low to keep running.

Try and make it happen again, but then quickly pull the plug and check for spark. Or does the machine always start right back up once you pop it into neutral? I'd go ahead and try kicking it over with the kick starter with the plug out (looking for spark) with the machine in 1st gear to see what happens.

Try to figure out if it is the ignition dropping out, or something else.


@ PS2fixer: Is the neutral safety wire you mention just an interlock on the starter relay (so you can't use the starter button if not in neutral) or does that actually stop the system from providing spark to the plug somehow? My assumption (in the advice that I provided above) is that the circuit is simply a starter relay interlock, but he still be able to get spark by kicking the machine manually... let me know your thoughts.

[NVL]

Ps2fixer, and wonderboy I appreciate your help and wonderful info.

Ps2fixer, I feel like repinning the connector from a 6 round to a 4+2 is going to be the best and least invasive option, since the rest of the harness is unmolested, plus the CDI's are cheap. Then if I EVER have an issue again, its just plug and play.

My next question is, how do the pins need to be layed out from the 6 round to the 4+2. A wiring diagram for an 85 and an 86 would probably do the trick I would think.

I work in an automotive shop, more or a steering/suspension and brakes guy, not into the whole electrical aspect of things, but i can read/look at a wir9ng diagram! ;)

As to your comment wonderboy, when the engin dies, it is a "slow" die, like shutting the key off, not a clutch seizing, which I would think would stop it almost immediately. Also, when you shift it into gear, and hold the shifter UP to remain disengaged from the engine, it still stalls. And as soon as put in neutral will start back up and idle great.

Once again, thanks you guys for you QUICK responses and extremely helpful info!

Nick~

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[ps2fixer]

@NVL

Yea I have the CDI pig tail listing made last night, for some reason couldn't find this post to post the link though. My dad was an auto tech too, I grew up with that + computers, so I'm a bit more on the electrical/programming side of things, but can still rebuild and engine lol. The terminals can be extracted and installed in the new 4+2 style connectors, however, it won't be a sealed connector. I didn't think about that till I made the pig tails last night. The round 6pin plug has that round gasket all the wires run though, the 4+2 style has a rubber plug per wire. Terminals do fit in the other housing though, I've used the 4+2 style terminals in the old 6 pin housings when building older harnesses and reusing the round plug to keep it OEM like.

I didn't make an 85 pin-out, but the wire colors match up anyway. See the last photo on my 3ww shop listing for the 86-87 pin out. Sadly the wire diagram doesn't give an actual pin-out, only what wires run to which connector, unless they are ordered pins 1-4 and 1-2, never really checked into that.

http://shop.3wheelerworld.com/index.php?route=product/product&path=304_307_312&product_id=417



@wonderboy

I was going to say about the same thing as you at first, however the OP swapped the CDI out and it fixed the problem, so clearly it's related to the CDI. I have first hand experience with a 250sx with no spark when not in neutral, but spark when in neutral. I bought the machine non-running and it was just in first gear.

Anyway, following the wire diagram the starter relay grounds though the neutral switch, so it only engages when in neutral, also the positive wire comes from the ignition switch, so it only has power when switched on. The CDI is wired to the neutral switch with the same wire that is the ground side of the starter relay, so it has a wire to detect if it's in neutral or not. Same wire is the ground side of the neutral light. Anyway, I like sharing wire diagrams when talking electrical anyway, so below is the 86-87 wire diagram. Only major difference from the 85 is the diode the neutral ground wire runs to before the other components, not sure why it's even there when it was the same wiring without it in 85. Actually I'll throw the 85 diagram up too since that's what the OP is working with.

Edit: Learn something new every day, the 85 also has a diode, it's hiding right by the neutral light. Pretty sure it's non-replaceable, so I guess it's just soldered in the wiring and heat shrinked or something. If OP didn't swap CDI's and have it fix it, I'd be thinking the diode might cause a similar issue now that I see both versions of the harness use it.


1985 ATC250SX Wire Diagram
https://i.gyazo.com/3847bb3b6285b14d346fee24c9dcdacd.png

1986-1987 ATC250SX Wire Diagram
https://i.gyazo.com/baae3e27ca8ff182f944f6976c82d53f.png

[NVL]

So i can buy that pig tail you have made up already, which looks great! Cut and splice that pig tail to my harness, and use the 86 model CDI box.

Does your pig tail wire colors match with the wires ill have on my 85?

Nick~

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[ps2fixer]

Yea, that pig tail allows you to use the 86-87 250es/sx CDI on your 85 250sx. Wire colors match function across both sets of machines. Honda was nice and made things quite standard. Like 95% of all ignition switches for Honda's have a black/white wire which is the kill wire. The only wire that isn't marked the greatest on my part is the black/red wire, the red ended up really dark from my supplier. Once I run out of that wire I'm going to ask them to make it a brighter red stripe.

Probably should mention, it's not some cheap china pig tail, the connector housing and terminals are Japanese made and the wire is USA made. I buy high temp GXL wire and use it in all of my harnesses, no melting the insulation and such when soldering =). Down side is the wiring is a bit more stiff because of it vs new wire from Honda on their parts I've bought. I think they use the old size system for the wire too (18 guage). I have to strip with 16 gauge (one size larger) because the 18 gauge spot cuts 1-2 strands of the copper. On the Honda wire I get, it's not a problem with 18/14 gauge setting, but can't say 100% sure what gauge spec the wire is meant to be.

I'll be honest, this is a new product, so it hasn't been used yet, but I'm nearly 100% positive everything will work out fine. Once I get some feed back on it, I'll probably list them on ebay and focus on other machines like the 200es which somewhat commonly has CDI issues too. If it ends up that there's no way to make it work, I'll do my best to make things right.

Anyway, let me know if you have any more questions.

[BarnBoy]

I just recently picked up a 1985 250sx, that stalls after shortly riding. The stalling is AS SOON as you put it into 1st or reverse from neutral. It just shuts off like you turn the key off. I did some looking around online and people are saying possible CDI box. So i took ths good CDI off my Big red and it seems to take care of the problem. The new problem is finding a dang CDI box for an '85 model Big Red or SX. The ones on ebay are all for 86 models which have 2 plugs, that arw square/rectangular. 85's have the 6 wire, round connector. Ive found some for many 200 models, like the 200m, 200x and 250r, not sure if those would work being that they are for the smaller engines?

Any info you guys have would be greatly appreciated!

Thanks

Nick~https://uploads.tapatalk-cdn.com/20181025/da8ca1404b9fdb5f10cc4102caf3495f.jpghttps://uploads.tapatalk-cdn.com/20181025/93c10a90fd0bc0f707491c32db139c53.jpg

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Hope you get your CDI issue figured out. I know this is slightly off topic, but I was curious. Could you post a pic of that '84 200M in the back, with the little yamaha sitting on it? It looks like it has some crazy high lift on it......

[ps2fixer]

Hmm I thought it was a parts machine or something in the back, but I don't see a machine under it. If it's lifted and on wheels, holy crap is that thing high up there lol.

[NVL]

It isnt mine personally, a good friends dad made it. Theyre into making crazy contraptions. That 4 wheeler (polaris i believe) has 35" tires off a pickup on it.

A large group of us is into 3 wheelers, and have quite a large posse of them!

I am also interested in purchasing one of your pig tails for the CDI box, what is the process of buying that from you?https://uploads.tapatalk-cdn.com/20181026/f1fca380e1ee949349eebfc5488b57ff.jpghttps://uploads.tapatalk-cdn.com/20181026/7b82a76e8ddcab3885fa9b8b370fe31d.jpg

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[ps2fixer]

Man I think the 200m should get the 35's lol. Wonder where they sourced that sprocket from, looks massive like 60 tooth or so? Seems like they used an extra rim to use as a wheel spacer on both machines? Seems to be functional :D.

Ironically the 200m would perform similarly with 1/2 the lift and a good snorkel setup, rider would get wet though lol.

Anyway, probably the easiest way to buy the pig tail is though the 3ww shop at the link below. It also helps support the site since 5% of the price goes to 3ww. A lot cheaper than ~15% fees on ebay (including paypal fees).

http://shop.3wheelerworld.com/index.php?route=product/product&path=304_307_313&product_id=417

If you really want it for the $19 offer, I can pm you a paypal.me link to pay for it.

Man I keep seeing that pic and it reminds me so much of my family lol, just with cars and such. My dad had around a 1970 Monte Carlo that was turned into kind of a dune buggy, no body, some seats welded in, no dash or anything. They shortened the frame and used those junks of frame to make a "dash" for the steering column and such. Driver's side had a make shift floor, passenger side didn't lol. Was only a two seater. I don't remember much about it, but stories were when they did a burn out it posied and always lost control and spun out.

He also built a 3 wheeler from one of them USA built 3 wheelers with the 5hp brigs engines, it was so gutless he cut the front end off and slapped on a 370 Suzuki enduro front end on it. I rode it like once, but I guess it was quite a wheelie machine. Engine always had a carb issue where sometimes it ran great, other times it would stumble when you goosed it. He cleaned the carb like 5 times and couldn't find any issues with it.

[NVL]

I want to get that pig tail from you, whatever way is easiest for you, wether it be the link you posted, or the other way you talked about.

They are an awesome group up friends, i would love to build some crazy things like that, but lack the ambition and resources to so.

I just stick to fixing things that are already manufactured lol.

I am also new to this forum, so im not real sure how the PM thing works, im using the tapatalk app, which i just downloaded the other night and in still figuring it out. (Couldnt figure out the forum on my phone through the website, so decided to finally try the tapatalk app)

Nick~

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[NVL]

The quad with the 35's has ATV wheels welded to 15 inch chevy truck wheels. (WAY too heavy, its a belt smoker if your not careful)

I dont know much about the 200m, he has a source he gets a lot of weird parts from, older guy has all the hookups!

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[ps2fixer]

A great supply for random metal bits to manufacture random stuff with is your local scrap yard. There's always square tubing and round pipe at my local scrap yard. Might not be the prettiest stuff but as long as it's not rusted out it should be plenty strong for most projects. If you want a pretty looking machine when you're done, new metal is about the only way, but that can get expensive pretty quick.

The atv rim welded to the pickup rim makes sense. I doubt it's the weight that causes it to burn belts, probably a lot more to do with the gearing lol. Not sure what can am's do, they run crazy sized tires on them fairly often too, atleast 30in+ and I don't read about belts being a problem on those machines. I rode a stock 800cc Renegade once and it has been the quad that felt the closest to a 3 wheeler so far. Just felt a little weird up front because of the 2 front tires vs 1, besides that, it felt light and nimble like a 350x.

No clue how the site would work on a cellphone, I always use a pc for web stuff, cell phone is too small of a screen to deal with and I'm only 30 and have great close up vision (near sighted). I'll shoot ya a pm and hopefully something pops up in the app to signal the PM. Normally on PC you just click the username on the post and click private message.

Anyway, either way of paying works for me, the 3ww shop might require you to sign up since it's a separate login database vs the rest of the site. Never been a buyer yet so not sure what the process is like.

[350for350]

Here's what I noticed in that awesome line up. The 200X has a four cylinder motorcycle engine on it, not a twin and the little trike on top of the skyscraper looking lifted trike is a Suzuki ALT50. I also noticed what appears to be a 1986 200x.

[ps2fixer]

Ahh yea, you're spot on, that is a 4cyl, I didn't see the 2nd set of pipes O.o that thing must be interesting to ride. That reminds me of a tractor pull built 200e or similar machine with a 4cyl motorcycle engine. It was like $1500 on my local craigslist a few years ago.

[BarnBoy]

It isnt mine personally, a good friends dad made it. Theyre into making crazy contraptions. That 4 wheeler (polaris i believe) has 35" tires off a pickup on it.

A large group of us is into 3 wheelers, and have quite a large posse of them!

I am also interested in purchasing one of your pig tails for the CDI box, what is the process of buying that from you?https://uploads.tapatalk-cdn.com/20181026/f1fca380e1ee949349eebfc5488b57ff.jpghttps://uploads.tapatalk-cdn.com/20181026/7b82a76e8ddcab3885fa9b8b370fe31d.jpg

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Wow! That must be weird to ride, so high up. Thanks for the pics, neat stuff!