Pulse generator

I do have the 87 F2 only Honda service manual . It says 450-550 ohms on the two sets of wires from the pigtail . I got lucky and found on Ebay a 87 pulse generator for $32 delivered . Keeping my fingers crossed they work out . On my parts bike the PO had cut the wires straight out of the casings for the pulse generators . Didn't want to risk using those . Now I'm just waiting for my casing gasket to arrive this Wednesday to give it a go . Wish me luck . And also a HUGE THANK YOU TO ALL OF YOU THAT OFFERED ME ADVISE !!!!

 

Just wanted to add the 86 ignition box has a separate green ground wire while the 87 has the green ground wire in the pigtail. Other then that I don't know enough about the inards to voice an opinion .

 

Is that a paper manual or one you found online? If online, I'd sure like to have a copy myself.

On the 86 ignition boxes there is a separate single wire for the tachometer. You can see it in the pictures I posted. Is that the wire your thinking is a ground? I think it's color is green and yellow.

 

Yes your right green & yellow . Sorry its the paper manual . If you could explain to me how to copy & send it , I would be happy to

 

Well, theres no easy way to copy the paper manuals. You could snap a picture of each page and post it online, but it's just too many pages.

 

Yea ,thats what I thought . I bought mine on Ebay a couple years ago . I think it cost me $35 or so . Was money well spent ! Thanks again for all the help .

 

Download from Hotblack_Desiato here
http://www.bikersoracle.com/vfr/forum/showthread.php?t=125057&highlight=rc24+service+manual

 

That's the "86 only" UK or European book. There is no 87 specific info in it. No US specific stuff either. Most of the info in there is good enough for most owners. If you need something specific to the UK or European 88-89 bikes there is the FJ FK addendum which is pretty cool.

I think most of the engine specs for the 87 bike are the same as for the 88-89, but it's a grey area. That's why I'm glad a1gatorz had an 87 specific book.

One thing neither of the online FSM's have is an American wiring diagram. I do have a copy of the US 86 wiring if anyone needs it. It shows the proper turn signal and switch wiring.

 

I have posted an 87 usa wiring diagram somewhere on here.
Do a search for my posts.

 

This any good.

 

Hey, that's great. Thanks a lot. I did a lot of searching for wiring diagrams for our model bike, but when I found them the links were dead because they were from really old posts.

The 87 is pretty close to the 88-89 as far as ignition circuits. The tach signal is from the coils instead of the ignition box.

Now I'm wondering if the 86 and 87 tachometers are interchangeable. I seem to recall the 88-89 tach signals being either twice as fast or twice as slow. Hmmm, maybe I could feed my 86 tach from a coil and see what it reads.

 

Now that I think about it, if the 86 bikes fire once per cycle and the 87-89 fire twice per cycle then it's possible the 87-89 tachs would read half the rpm's if mounted on an 86 bike. Then again, the 86 tach signal comes from the ignition box, not a coil, so who knows what the signal rate is.

Assuming the fuel safety relays are the same across all 4 years, maybe the 86 box puts out 2 signals per cycle (same as the 87-89 bikes coils) and all the tachs are compatible with each other?

I bet an ignition designer could look at a bikes firing order, pickup triggers and sensor inputs and figure out how it works. I might get all the data together and send it to Rae-San and see if he can give a quick explanation.

 

Just to update my progress with changing my crankshaft pulse generators . I received my new Ebay set & thought I should check the resistance on them before installing them . To my dismay they are reading 360 ohms on both sets of wires . Still way below what is listed 450-550 ohms . So I check the bare wires out of my parts bike & they also read 360 ohms . Now I own all three known to me service manuals available . I have the factory Honda manual , a Haynes & the Clymers . While rereading all three versions on checking the resistance , I noticed that in the Clymers & only in the Clymers it states . And I quote " In order to achieve accurate test readings the pulse generators should be WARM - at 20* C ( 68* F ) If necessary use a hair dryer and WARM the pulse generators . WOW ! Now for a FACT there is absolutely no mention whatsoever of needing to do this , or requiring to do this in either my factory Honda or the Haynes manual . So , I guess my next option is to heat the new set & check them again tomorrow . I am very interested in all of your thoughts on this . I want you all to know how much I appreciate all of your guys combined time & energy you have given me .I do have one more request if at all possible by any of you with a like model as mine ( 87 VFR700F2 FH ) If possible take a reading on your bike so as to compare with my readings . I'm almost starting to believe that maybe my meter is giving me inaccurate readings ? THANKS

 

My 700 f2 reads as the factory manual states.
I dont recall the figures, but theyre within spec.
20ºc is room temp.
You may have been sold a set from an rc36. There are some untrustworthy people out there. That or just plain ignorant, and sent you a set of "because they'll fit" rc36 pick ups.
Roger

 

I personally was thinking your old ones are still good and your problem is else where. Yeah, 360 ohm is below spec, but they are both the same. Now if one were 360 and the other 500 then you'd know something wasn't right. Same as if your readings were way higher or they were shorted out.

I've read it's pretty difficult getting an accurate reading from them. Are you using a digital meter? Are there any magnetic fields nearby?

Can you explain your original problem? Was your bike running good at first and as it got warmed up it started to cut out?

Here's a neat video to check out about how heat can effect the coils.
http://www.youtube.com/watch?v=54mNJaAleCo&feature=youtube_gdata_player

Also, have you checked the coils resistance back at the ignition box? Maybe there is a wiring issue from the coils to the box. Perhaps a coil wire rubbed and sometimes gets shorted out on the frame, etc...

 

Ok , My bike ran great for the past three years & then started to drop one cylinder ( # 2 ),then two ( # 4 ) after 20 to 30 minutes of run time . Plugs were clearly not firing . In the past I have swap tested the ignition box & all four coils back when bike was running good for the purpose of verifying electronic bits from my parts bike were good & worth saving . Long before this current problem arose . The seller of the pulse generators that I just bought guaranteed me that they came from a well running but wreck 87 VFR700F2 that was just one of many recycled bikes that he parted out & sold on Ebay . That is why I feel the need to get recent readings off of a good running bike such as one of yours if possible ? It makes no since to me that any other reading but which is specified in all three of my manuals is an acceptable replacement ! I don't think that they just a grabbed this figure out of thin air ? ( 450-550 ohms ) Please correct me if I'm wrong , but isn't that the whole reason to have a proper manual ? I will check my coil readings again from the ignition box wire harness as you advise . I only checked them from the coil posts & I agree with you that there might be a problem in the wiring ? Thanks again

 

Not much help but I'm having similar issues on my CBSupersport, runs fine when cold but starts a miss fire after about 20 mins riding. I have fitted new igniters with varying results but I now suspect the pulse coils warming up to be the problem, bloody hard to find some answers when they do this sort of thing

 

A1gatorz, since your problems occur after the bike warms up have you tested your original pick up coils after heating them? I would then heat test your new coils as well just to make sure they don't suddenly short or "open" up on you.

It's also possible some circuit in the original ignition box is opening when heated. Before you pulled the pickup coils off did you try swapping to the spare ignition box and running it till it got good and hot?

 

I had to ride my 86 over to my brothers house to use his multimeter (couldnt find mine) so the hot reading was 627/630 ohms. I'll try and get a cold reading soon.

 

The next day, a room temp reading of my 86 coils is 500/504 ohms.

Lets apply some deductive reasoning here. You say your bike runs fine until 20-30 mins when it starts to loose spark on 1 or 2 cylinders. Do you really think only 1 cylinder stopped firing? If it were 2 cylinders (#2 and #4) then a pickup coil (the forward most one) would be the obvious source as that particular coil controls cylinder #2 and #4. That's actually a common problem on older motorcycles. Each pickup coil is filled with tiny copper windings insulated with a thin liquid film that hardens (like a small electric motor) and they can either short or open up when heated.

Now if only 1 cylinder was not firing then we would look for the problem elsewhere. Maybe spark plug coil or ignition box.

If your bike ran fine when cold then it stands to reason the 360 ohm pickup coils were working as they should. If they were both bad, then the bike wouldn't run, or wouldn't run well.

I would recommend testing the original coils with a heat gun and see if the front one goes bonkers. If so, then that's your problem. Then test your replacements with heat, if they are good, then swap them in and problem solved.