Difference in air fooler cdi's

[Tecate250]

I just rebuilt a 83 250r. A long time ago this bike might have had a atc 200 cdi. I purchased a brown plug type cdi thought to be a early air fooler. Stock exhaust on the 83 and there is little to no power band. I had a 83 with full dg pipe and worked amazing. Any ideas?

[Tecate250]

Wow! Has this site gone to crap. I remember the good ol days when qusetions would not go unanswered. ANy of you honda guys cant help me???

[82 250r]

It's a good question and i'd like to know the answer myself.
I have a brown plug on my 82 250r. The motor from 81-84 is the same or at least similar so you would think 81-84 CDI would be interchangeable, but I can't verify it, sorry.

[Tecate250]

The guy i bought the brown plug cdi has 2. But both have different white numbers on the back. But the 83-84 have a 2 plug type cdi box.

[RIDE-RED 250r]

Quite to the contrary, I would say the fact that people don't comment if they don't know the answer for sure is proof the site has not gone to crap....

[stroberts22]

81-82 cdi are the same. 83 has 2 plug ins and is different. 84 has a single round plug and is different.

[Tecate250]

Yes. I know this but if you could wire up a 84 to an 81 Would you notice a difference. Ive rebuilt a 83 and its fouled 4 plugs in less then a tank of gas. 20-1 carb is set right new 71 mm piston stock exhaust.

[82 250r]

FWIW,
My 82 has fouled plugs and smoked at low rpm's for 28 years. I have surrendered to the fact that the round slide PE carb is not a good fit for these motors. This is a known issue by Honda. They changed the carb settings, or the carb itself every year 81-86 until they finally got it right with the flat slide PJ in 86.

I don't think 20-1 oil/gas is helping you. Try 32-1 and maybe adapt a 34mm PJ.

Doesn't sound like a CDI problem to me.

[stroberts22]

I think they all can be interchanged just have to modify your harness to accept the cdi. I don't think there would be any performance gains in any of them. 20-1 is alot of oil in my opinion.

[Tecate250]

Ive ran 20-1 all my life. Had 4 running 250rs with same oil and never had a problem. Also been running 20-1 in my tecate year long in Canada for 13 years. So other then cdi plugs there all the same. Thanks.

[RIDE-RED 250r]

Fuel/oil ratio shouldn't make a huge difference as long as your jetting is dialed in. You can dial in to run 20:1 or 50:1. Different ratios require different jetting for safe operation and good performance.

Might be beneficial to dial in your jetting a little better. The symptoms you are describing sounds more like a jetting problem to me.

CDI's are a funny thing... In my limited experience, CDI's either work or they don't, and the wrong CDI for your machine won't work either.

[Tecate250]

Lol. The bike came with a atc 200 cdi box way back in the day. White plug type.It worked fine but had no power band. I later put that on a 86 atc 250 cause the cdi didnt work at all on that one, Which is long gone now. It only had a power band when the planets aligned and honda owners finnaly agreed the kawies were faster. lol. So nothing was touched in this bike for 7 years. No carb mod,s changed stators, spark plug caps, Spark plug coils switched cdis even advanced my timming. I dont remember any of the other air foolers I had to be so fussy.

[fabiodriven]

Dude you're running way too much oil. 20:1 was for the crap oil from the 80's, castor oil and what not. You want to ask questions and complain when nobody replies, but then you poo-poo the facts. Fact of the matter is, you're running way too much oil. Start with that and work from there.

[Tecate250]

So that means banshees should not run 20-1 that is listed on there tank? Cause of crap oil from the 80s? I guess Hondas are fussy over there oil. All of the 250rs Ive had liked there plugs. Guess thats why hondas sells them by the box.

[conbon]

It's a shame you didn't get an answer for this question, only a bunch of people questioning your oil usage. Right now I'm wondering if I put an '83 harness and cdi on my '84 if it will run worse, your thread is only one of two references I can find stating the cdi's are even different between the two years.

-Connor

[christph]

In my experience 20:1 is way too much oil. Manufacturers may recommend more than necessary to avoid new bike seizure and warranty issues. Also, oil displaces gas and reduces performance. That's why some people run 50:1. Personally I run 32:1.

[ATCT]

If I remember, I might be able to check the differences this weekend. I have an '83 and '84 in semi-disassembled states at the moment.

[ps2fixer]

I don't have a for sure answer, but my understanding on CDI's is that each one is designed for the properties of the paired engine which is why even extremely similar engines have different CDI part numbers. However, generally speaking they can be interchanged. One of the major differences between each one is the timing curve, I suspect the 84 CDI would advance quicker than the 83, with a tuned/upgraded 83 engine that should be a benefit, but this is purely based on the note a few posts up that the 84's put out more power, better tuned pipe etc.

Personal experience, I put one of them chinese cheap CDI's on my 350x for testing, It would start, but it was hard to start, and it would run upto around 2k rpm before it would start back firing. Any more throttle and it would just die out. OEM CDI back on it and runs flawless. It was just a test, and the CDI was for a china quad, so the advancement must be way too slow for the 350x engine. I'd guess the CDI was designed for a 2 valve engine which is much different than the 4 valve 350x. 2 Stroke wise, I'm pretty lacking in experience, so I can't offer much advice.

Oil could be an issue too, but since you have ran 20:1 for so long, I'd assume you are well aware of how to tune for it etc. I have a 83/84 mixed machine and it never ran very well, I could go check which harness it has to validate, but I'm guessing it is an 84 engine with the 83 harness. I also have an 81, and it doesn't foul the plug and runs much better than the other, too bad it has a broken frame.

To get back to the answer, I think the only ones that could properly answer your question would be someone from Honda that has the spec sheet on the two CDI's, unless someone knows how to record CDI performance to compare them.

Good luck with your project, and if you figure anything interesting out, I'm sure there are plenty of people that would like to know your results.

[mendoAu]

Wow! Has this site gone to crap. I remember the good ol days when qusetions would not go unanswered. ANy of you honda guys cant help me???

Well I'm pretty new to this site and will just give ya a quick "I disagree" 'cause I find responses are usually quick and helpful. Thank you 3wheelerworld. Now if I had to make a comment I guess after over a year and a half since you started this thread you've had plenty of time to figure your question out and could have posted your answer so this thread you started actually helped....but I'll just keep quiet.

[ps2fixer]

Wow didn't notice this thread was started so long ago, still sparked quite a few replies though.