[Boppyguy]

Hello everybody! Bought this bike project 15 years ago and need some advice from all you experts! Installed new starter and battery and it cranked right over. Green neutral light comes on but red oil temp light doesn't. Engine sounds good/normal as it rolls over and has 135lbs compression. Checked the ignition coil and it shows .3 ohms resistance on the primary coil and 8.58 k ohms on secondary coil. Neither of the wires leading to the ignition coil have power when the engine is cranking. I have the Honda manual and both of those numbers are out of spec high. If the ign coil had power going to it a new one should be the answer but I think its worse than that. Manual says test CDI with a CDI tester. Only have multimeter and not very skilled with that. Any help will be greatly appreciated!

 

[retro]

1986 has a battery/CDI ignition and requires a fully charged battery to produce spark, so keep that in mind as you work on it.

Did you check the kill switch on the handlebar? Also snoop around the fuel cutoff relay and make sure the CDI is sending a voltage to that while cranking. Does the fuel pump run?

Compression is low at 135 lbs... assuming you are testing with a known accurate gauge and the throttle is being held wide open while cranking with the starter. Should be nearer to 200 lbs....

 

[Boppyguy]

Hey Thanks Retro. I'll check those things tomorrow. The battery is good. A year old out of my Rincon and I have a battery tender hooked up to it. As to the compression, the tester I normally use (cars) did not have the adapter for the smaller atv plug so I used the old one with a rubber end you jam into the head. rubber hard so I think its probably higher than 135 but I doubt its 200. Manual said 135 so I thought it was okay. Bike hasn't run for 20 years at least. It appears to be fairly low mileage. original tires with 30%-40% tread, shifter rubber like new, frame and skid plates pristine. I plan on converting it to propane so I need good compression. Thank-you for your help.

 

[retro]

Ya ok, been sitting a long time so probably be a good idea to put some oil in the cylinder if you haven't already. I'd go through it and unplug and plug back in every wire harness plug on it in case any are corroding. Also check every ground cable/wire for clean grounds. Got any pics of the purdy girl you can share..?

 

[Boppyguy]

Thanks Retro for your help. I have 11v going to bl/br wire on pump relay when cranking. took stop/light switch apart. have continuity between g wire and bl/white wires of stop switch. made the lights start working. still no power to ign coil.
compression is only 135psi. Started pulling plugs and checking grounds. looks good so far. Bike sat outside for 8 or9 years before I bought it (15 yrs ago) missing starter. I've rebuilt/fixed 30-35 bikes since (mechanical stuff-not electrical!) I retired last year, working my way thru projects. I've got 600 in it, willing to put 1000 in it, but tires are 400 and Wiesco piston kit is 150. I've learned not to just start replacing electrical items to find problem. moneypit! But I'm a beginner on electrical stuff. I have a Fluke 117 but had to read manual to get info for you. So you're dealing with an idiot! lol I'd like to use this bike as a workhorse. seems built for it. I have converted 20-25 small engines (6-28 hp) to run on LP and they just run so much better, no carb issues, fuel is $1 a gallon and enters engine as a vapor so no diluting oil should help wetclutches. Fuel pump does not run while cranking, but I won't need it. Probably run it gravity feed to check operation of transmission, but everything (driveline) moves freely by hand now. I just need spark! Appreciate your time and expertise.

 

[retro]

Hi Boppyguy,

Alright, this all looks pretty simple in the manual. I thought the 1986 350s had a battery ignition (DC-CDI) but the manual shows otherwise. So, if the manual is correct then the battery is used only for cranking the motor and to operate the fuel pump while starting. Spark is independently produced.

So going by the above diagram the ignition switch should be checked for continuity between the Bl/W & G wires at the switch plug connector. You already have the neutral light working correct? I would unplug the CDI connector and make sure that looks clean and free of corrosion along with the alternator/pulse generator connector coming from the left side cover of the motor. Once all connectors are verified to be good and the engine ground cables (there are two of them, one negative battery cable and one system ground coming out of the wiring harness near/forward of the fuel tank?) verified good and clean it'll be time to test the pulse generator and stator exciter coil. While you are snooping around the above I'll need to study this system a bit more because it looks a bit incomplete to me. Let us know what you find...

 

[retro]

Also, after verifying Ign switch, kill switch, neutral light operation, all connectors and ground... with everything hooked up try tapping on the CDI box while the motor is cranking over and see if it produces spark at the spark plug while it is out and laying against the head, even momentarily.

Edit:
Also look at the CDI connector pins (inside the CDI connector plug) for a pushed in pin that may not be making good contact with the harness plug.

 

[retro]

I have 11v going to bl/br wire on pump relay when cranking. took stop/light switch apart. have continuity between g wire and bl/white wires of stop switch. made the lights start working. still no power to ign coil.

According to the manual there should be NO continuity between the Bl/W and G/W (G?) wires from the ignition switch AND from the kill switch, with the ignition on. Continuity in either one of those shuts down the ignition.

Attached are the switches continuity, ignition components resistance, fuel cut relay continuity and voltage tests along with the system wiring diagram.

 

[Boppyguy]

WOW! okay thanks Retro. Alot of info to digest. I have the Honda Service Manual for the 86. I'll check it all out and let you know what I find. I saw your post on the 87! congrats on that. Has anybody out there ever used a Power Probe? Thanks again for your help Retro.

 

[Okie]

I would check the pulse generator.
It has to first produce pulses to the CDI when the engine is cranking. Resistance is listed in the ign troubleshooting section, probably 300 -360 ohms for a 86.

Let us know what the resistance of the pulse generator is? Don't try to read the pulses just yet with a DMM they are spikes and might damage the meter internally.
The pulses then after they leave the pulse generator come out of the CDI when the engine is cranking and go to the ign coil and the fuel relay if all is ok in and around the CDI. The pulses on the + post of the ign coil trigger the coil for spark. Check for spark with the spark plug removed from engine head and
grounded real good to the engine. Don't let it just flop around not grounded good when looking for spark.

The pulses are the heartbeat of the system at first.

 

[Boppyguy]

Thanks Okie. Just discovered the Kill switch is bad which I'm hoping is the only problem. Same switch as my 95 300fw(i think) but neither are available at BikeBandit. can I jumper past the kill switch. the light switches still work. or are the kill switch/light assembly switches available somewhere else?

 

[Okie]

Thanks Okie. Just discovered the Kill switch is bad which I'm hoping is the only problem. Same switch as my 95 300fw(i think) but neither are available at BikeBandit. can I jumper past the kill switch. the light switches still work. or are the kill switch/light assembly switches available somewhere else?

I don't feel safe telling you how to do the bypass because they are different on some from 86 to 87. Some switches ground to kill, break ground for run, some switch 12v thru for run and open 12v for kill so make sure you get the correct switch. You did not say if it's the kill switch or key switch.
Some switches switch 12v thru the switch and some ground the CDI and even a late 86 could be 87 wiring and vice versa. Have to go by the serial/vin number to determine correct year, etc, for correct parts and wiring diagram.

My wiring diagram trouble section pg 20-6 shows the 86 fourtrax HANDLE BAR STOP SWITCH OPENS or breaks the circuit for RUN
But the same year foreman does just the opposite, make the circuit for run. You need to make sure you get the correct switch.

If it's a 86 or maybe 87 fourtrax you might try removing or disconnecting the wire from the handlebar stop (kill) switch and it it fires or starts you can kill it with the ignition key. If it's a Foreman the switch has to make connection or switch 12v thru so the stop (KILL) switch contacts would have to be jumpered for a run. (and be careful and not get a wire grounded or you will blow a fuse)

 

[retro]

The kill switch should be open (no continuity) for there to be spark. If the kill switch is closed the Ignition is switched (CDI primary is shorted to ground) off. See the switches page:

Aye... Okie beat me to it. I'll leave this up anyway.

 

[Boppyguy]

Okie and Retro; you guys are professors talking to a grade school kid! lol The ignition switch (key) works fine. The kill switch is bad (continuity between G and BL/white wires in the run position, it won't move to off on either side. The tag on the front of frame says 1986. The vin#JH3(S)TE707042708

 

[retro]

Find the kill switch wires in the harness plug coming from the handlebar switches assembly and unplug the kill switch wires... It should have spark with those unplugged if that is the only issue.

Edit:
Actually its just lights and kill switch in that harness plug so just unplug that connector and use the kickstarter to crank it over. Won't matter if lights don't work for this test...

 

[Okie]

Find the kill switch wires in the harness plug coming from the handlebar switches assembly and unplug the kill switch wires... It should have spark with those unplugged if that is the only issue.

Edit:
Actually its just lights and kill switch in that harness plug so just unplug that connector and use the kickstarter to crank it over. Won't matter if lights don't work for this test...

Agree that should give you a bypass of the kill switch. If it happens to start just turn off the key switch.
Do you have a spark plug rigged so as you can see spark?
Also on the 86 you must have a good 12v battery installed to get a spark, just foot cranking without a battery will not produce a spark.

Just a hint. If you ever have the intake box open or off and squirting gas into the snorkel going to the carb for a prime keep a fire extinguisher handy and do not do such inside a garage. Them Hondas will ignite into the carb throat.:wink

 

[Boppyguy]

I do have a good battery (over 12v) found the plug( a four prong plug I think is lights and a single bl/white wire plug. un plugged both, key on, kicked over. no spark. new plug and held tight to cam box.

 

[retro]

Hmmm.... Since you already found continuity in the kill switch (while it was unplugged correct?) where it shouldn't exist, I'd unhook just the kill switch Bl/W wire from that plug and continue. From there I would go back and unplug the ignition switch, then follow the manual page that I linked above to recheck continuity of wire colors listed in the table for that switch in both on and off positions. Just to double check your work... cause next up is the pulse generator and that may lead to spending some cash, so don't wanna make any mistakes with the free or cheap stuff.

 

[Boppyguy]

no I checked continuity of kill switch with it still plugged in. I followed your instructions tho and re checked unplugged and there is no continuity unplugged, with the key on (green light) I will check the pulse generator tomorrow. two questions. 1. is the kill switch okay (even tho its stuck on the run position) and 2. is the cdi okay since it is sending voltage to the pump relay, but the fuel pump does not run.

 

[retro]

no I checked continuity of kill switch with it still plugged in. I followed your instructions tho and re checked unplugged and there is no continuity unplugged, with the key on (green light) I will check the pulse generator tomorrow. two questions. 1. is the kill switch okay (even tho its stuck on the run position) and 2. is the cdi okay since it is sending voltage to the pump relay, but the fuel pump does not run.

Ya, when checking continuity of any and all switches, the switch must be disconnected from the circuit. Continuity tests are in reality resistance tests and use the resistance (ohms) reading function in your meter to indicate whether a switch (or circuit, depending on your measurement target) is OPEN (no continuity) or CLOSED (Continuity). Measuring a switch while it is still in-circuit includes other components within that local circuit loop, so its misleading and useless information you'll receive from that test.

I'm sorry about not being more clear with instructions. Luckily though, my oversight hasn't cost you any of your hard-earned cash, just some of your valuable time.

To answer question #1 -- Yes, the kill switch is fine if it has no continuity while unplugged, even though the sliding switch doesn't move from the "Run" position. You can plug the handlebar switches assembly back into the wiring harness where it belongs for the remainder of testing. You'll need to use the electric starter button to crank the motor over fast enough for the pulse gen to work good anyway.... So plug those switches back into the harness where they belong.

You can come back later after the motor is running to disassemble that kill switch and fix it. It has a rusted/corroded or missing detent ball in it and is easy to fix. Ask about that detent later on if you need any help with that...?

Answer to question #2 -- We don't know anything about the CDI yet... cause I screwed up during these continuity tests when I forgot to tell you to disconnect switches before testing. We gotta start over, sorry about that. :-(

So, now that we are back at square one with intent to do things right...

Next test in the logical order is to unplug the Ignition switch from the wiring harness and check for continuity through that switch for each color-pair of wires according to the table in the manual. Note you'll be checking that switch in both the "Off" and "On" positions: