86 vs 87 CDI

[airtrafficguy]

Fellas I have a 87' rebel 450 that has a bad cdi. Will a 86 model CDI work on an 87? Or for that matter will a CDI off another bike work? Maybe a nighthawk? Does anybody know where any CDI's are?? Thanks for your time.

Corey

[GearJammer]

That's an excellent question, ATG...

I'd assume that the '86 & '87 Reb CDI's would be the same. The Nighthawk ? I dunno, but it might be possible.

eBay usually has used CDI's for the 450 Rebs fairly regularly. There's also Jack's Rebel Warehouse in FLA.

What I like about the question is that since the CDI's can be the source of various problems, it wouldn't be a bad idea to stock up on a few used ones for cheap just in case. If the Part #'s of CDI's from various models could be cross-referenced, it might give us a broader range of bikes to acquire CDI's from.

[GearJammer]

Just checked www.crotchrocket.com & they show the same Part #'s for the CDI's, both used on the '86 & '87 Rebs. They've apparently got 'em in stock for around $82.....but I'd keep shopping around to see if there's better deals out there.

[airtrafficguy]

Hey thanks a lot for the info GJ. I am going to call tommorow and verify that they do have one in stock. I had checked them before on a gas tank and they didn't have any in stock. Again thanks for the info.

[GearJammer]

Ubetcha, ATG.......I tried searching Google for cross-referencing of CDI's, but didn't have much luck. Even read a couple posts here & there that said some shops/dealerships are either reluctant to offer cross-referencing or simply don't have the info themselves.

Sure seems as tho' there should be other Honda models using the same CDI, but I dunno......

If anyone has the Honda Part # for the 450 Rebel CDI, I might be able to get it cross-referenced by a local parts guy. This guy is excellent. He gets on his computer in the shop & reminds me of the Wizard of Oz, checkin' here, typing in this, typing in that, checkin' back over here, ROTFLMAO!!!!!!

[airtrafficguy]

I called crotchrocket.com and they in fact did not have what I was looking for. Personally I wouldn't rely on them for anything other than part numbers myself because of the fact that they do not update their inventory online. Anyway, I have a contact here locally that has found me one so I got it for $85.00 shipping and everything. But I appreciate your help. I will continue to use the crotchrocket.com but I will no longer rely on their inventory on line. Again thanks for your help again. Hope to hear from you guys soon.

[GearJammer]

Glad to hear that you were able to find the CDI thru your local vendor. Some parts sites have been hit or miss lately, but the important thing is that you've found it & that's cool :wink:

ATG, If you have either the Honda Part # or an aftermarket part # for the CDI, could you please post the Manufacturer's Part # here so's I can see if my bud can possibly cross-reference it in the hopes of giving us several brands/prices to choose from in future ?

Thanx in advance & Ride Safe........

[uneasyrider]

I have a contact here locally that has found me one so I got it for $85.00 shipping and everything.

ATG, Would you mind shareing your contact info w/us, I may need one also.

BTW Please keep us informed as to how everything works out.

Howard

[airtrafficguy]

The part number for the 86' rebel cdi is: 30410-MM2-000
The part number for the 87' rebel cdi is: 30410-MM2-010

As for the contact information: 662-369-4542 The guys name is Gene Crump. He is a super nice guy and will help you out in any way he can. Hope this helps you guys out.

[airtrafficguy]

By the way the CDI worked great and the bike is now firing on both cylinders. I guess that type CDI is like a 2 phase CDI and one phase had malfunctioned on mine. I'm just taking a shot in the dark here though. Anyway if you guys are having the same problem you might want to check that after the coil and plug wires. I know I was at a stand still for a while because I thought if the CDI was bad then neither plug would fire. I was wrong. If you have some insight on this let me know GJ.

[GearJammer]

Thanx very much for the contact info & the part #'s, ATG, it's much appreciated. I've also got to call Jack once I get a chance here in the near future.

Please keep in mind that my working knowledge of electrics is basic at best & going out on a limb here without any manuals in front of me. If I stand to be corrected or others see additions to be added, by all means, please chime in.

For ready reference, I equate the CDI to an Electronic Ignition Module on my old Ford truck. The EIM on the old Fords are notorious for going south. An auto mechanic friend of mine explained the EIM in this way: There's 2 white wires, one for "Start", one for "Run". Turn the key ("Start" mode), one wire allows the motor to crank & fire. Upon fire-up, the EIM switches over to the other wire for continued "Run" mode. The EIM can go south in 2 ways.....

1) Crank, but no fire to plugs (similar to what you thought about the CDI stopping both plugs from firing)
2) Crank with fire to plugs & an initial fire-up, but then cuts out & dies when the switchover from "Start" to "Run" mode occurs.

Onto the Rebel CDI.....

Pulse generator supplies signal to CDI ? (Guessing, as no manuals here) The CDI can no doubt malfunction in various ways. I believe the manuals also provide a way to bench-test the CDI.

In the case of my 450 Rebel, I believe it's been a matter of outside temperatures affecting the CDI's ability to function properly or not. During the colder winter months, she ran O.K. There was one cooler day in early spring when she ran the best she ever has, with absolutely NO problems.....I mean, she was COOKIN'!!! LOL!

When the outside temps began to climb, the intermittent firing problems returned. It would either cut-out & continue to run, sometimes catching again, sometimes stalling (dying, tho' those times were rare) or upon hitting the starter button, she'd fire & then immediately die. The bottom line observation seems to be that the CDI would overheat & then react in various forms of frustration. Once cooled down, she'd run like a top again.

I'll guess the overheated condition either inhibited or altered the CDI's resistance and/or firing values. Beyond this theory, my understanding goes from "guess" to "I dunno", LMAO!

[uneasyrider]

:P :P :P THANKS for the contact info.

Howard

[airtrafficguy]

thats some pretty interesting stuff there GJ thanks for the time and I defineately have a better understanding now.

[GearJammer]

Ubetcha, ATG, I just wish I could provide a better explaination based on the actual technical aspects but again, electrical tech goes w-a-y beyond my own understanding.

Could you please tell us if the symptoms mentioned were the same as the ones you were encountering before installing the new CDI ? I'm leaning towards a new CDI as the next step & hoping that it's the right move. TIA..........

[airtrafficguy]

Well first of all I identified the problem: Firing on one cylinder. Then I of course checked the gas flow which was found to be ok. Next was the firing. We switched the plug wires and found that it was the same wire that was not firing. So we replaced the coil. Still that did not work we just kept going deeper and deeper until we got to the CDI. Contrary to popular belief, if a CDI malfuntions on a 2 or more cylinder motor, the motor will still run. However if you have a one cylinder motor, more times than not it will not even fire. I hope your still following me. I had talked to a very experienced mechanic who told me that IT WAS NOT the CDI. I'm pretty hard headed so I replaced it anyway. Sure enough that was it.
The problem I was runnning into before I started trying to fix it was that when the bike was idleing it was running on one cylinder. Even when you were riding down the road at low RPMs. When I would rev it up to a very high rpm I could hear the second cylinder trying to fire. I don't know whether the weather had anything to do with it as you mentioned because we were having normal tempretures here, 68-75 degrees. I hope this better helps you understand.

[GearJammer]

Well first of all I identified the problem: Firing on one cylinder. Then I of course checked the gas flow which was found to be ok. Next was the firing. We switched the plug wires and found that it was the same wire that was not firing. So we replaced the coil. Still that did not work we just kept going deeper and deeper until we got to the CDI. Contrary to popular belief, if a CDI malfuntions on a 2 or more cylinder motor, the motor will still run.
***Sounds "similar but different" than what I've been experiencing. I usually have both cylinders firing, but when it acts up, the intermittent power loss seems to be one cylinder only, with the other cylinder continuing to fire normally. Many times, the intermittency would stop & the signal to the non-firing cylinder would kick back in & run on both sides again. Apparently, the CDI provides fire-power to both cylinders seperately (thru the coil), with the malfunctioning CDI on your's not providing juice to one cylinder at all & intermittently to one on mine.***

However if you have a one cylinder motor, more times than not it will not even fire. I hope your still following me. I had talked to a very experienced mechanic who told me that IT WAS NOT the CDI. I'm pretty hard headed so I replaced it anyway. Sure enough that was it.
***Very glad that you got it sorted out, ATG! I'm going to start with a new CDI, but I may also have to be prepared to replace the coil if the CDI doesn't completely do the trick. In either event, whether CDI alone or CDI & coil, at least the Reb should be in good shape & the problem eliminated.***

The problem I was runnning into before I started trying to fix it was that when the bike was idleing it was running on one cylinder. Even when you were riding down the road at low RPMs. When I would rev it up to a very high rpm I could hear the second cylinder trying to fire.
***I can see where the coil might have been suspect, but it looks like the coil wasn't firing due to the CDI not providing the signal to it (the coil) for that one side.***

I don't know whether the weather had anything to do with it as you mentioned because we were having normal tempretures here, 68-75 degrees.
***As mentioned earlier, the CDI sounds capable of malfunctioning in various ways. It could very well be that the outside temps weren't affecting the problems on your's at all. It seems like temps over 75 degrees is when the problems start to show on mine & I'm keeping in mind that it "might" be primarily a coil issue on mine. Problem is, it might be hard to determine whether it's the CDI or coil here since the problem is intermittent & not sure if I could isolate it to one or the other, or both, unless it's actually acting up. Oh well, it's only $$$ & if it requires buying both, then at least there's the piece of mind in knowing 2 of the main components have been replaced & should be good to go for quite some time (if it even comes to having to replace both. Might not be required, we'll see......)***

I hope this better helps you understand.
***Yes, it does & thanx VERY much for the response, Brother! Ride Safe.....***