Check your gaps (A long story of stupidity)

[davesax36]

So.... Danny built me a set of Venture carbs with the internals from my stock carbs that had been totally gunked up by the PO and apparently also by me (by mistake). I got them back and was super excited to have things running smoothly. I put them on and got terrible mileage. I changed my plugs and still got terrible mileage. I bought tools-compressions tester, leak down tester, new air comressor (hey, I told my wife it was for safety). I used all of those things to determine that although I had a little bit low overall compression, there wasn't really anything wrong with my motor. My leak down was 4-5%. I took the carbs off, suspecting that I'd done something stupid again. I tore them all the way down and found two partially blocked emulsion tubes and a bunch of rusty grit in the bowls. Those got cleaned, reassembled, and installed. The bike started right up (SWEET). Then it started to suck again. I couldn't figure out what was going on with my fuel pump. I posted and searched. I bought a Mr. Gasket fuel pump. It seemed to work, but it was still a bit strange that it was running every time I flicked the kill switch. I HAD LEFT THE RESERVE ON. I took the stock fuel pump off again, took that apart, and cleaned it out. It was what pumped the grit into my carbs this time anyway. I'm an idiot. During all of this mess, I got my COP kit from Gannon. I already had wires with no resistors that I'd been running on my rear coils, but I put the resistor equipped ones on all four cylinders with the coils Gannon sent and headed out for a test ride.
I'd previously gotten only about 20 mpg. I was sure this would have fixed everything. Super clean carbs, a disassembled/cleaned/reassembled fuel pump that was now pumping very clear gas into my trusty glass jar should have cured my problems so I went to a little test ride. I decided 20 miles would do the trick, so I rode the bike 20 miles and stopped for gas..... Hoping for the best, I filled the tank right up to the neck, looked up at the pump, hoping to see .5 gallons on the display and.....:bang head::bang head::bang head: .8 GALLONS?!?!?!?:confused2: You gotta be kidding me!!!

I came home, parked the bike, stayed angry for a while, and then went to read some stuff. I pulled out the instructions Gannon sends with his COP kits and started reading about what I'd messed up. On the very first page, at the beginning of the instructions, he gives the gap spec for the plugs so they can produce the proper park based on the resistance of the wire and COP. I had not even thought about it and was just running everything with the plugs I'd already thrown in there. "Hey, they're new plugs. They should work great." Boy was I wrong. When I pulled those plugs out, I checked them against the factory spec. Not only was there only ONE PLUG in spec for stock coils, a couple of them were as much as .015" out of spec for Gannon's COP kit.

I got the plugs Gannon had sent with the kit, gapped them all as instructed, put them in and went for a ride. I passed 20 miles, 35, 40, 60... no fuel light. 67... no fuel light. 74.. no light... 82, 87, 90. 96, 100....STILL NO LIGHT :clapping::eusa_dance:unk:
I stopped for gast at 107 miles and put 2.6 gallons of gas in my tank!!!! unk::biglaugh:

At least some of this could probably have been avoided by properly gapping my plugs in the first place. I know that the fuel pump would have messed up my carbs, and it wasn't unreasonable to test compression and leak down on my motor since the bike was in such bad shape when I got it. BUT- if you're having mileage issues, CHECK YOUR GAPS!!! You might just be able to get yourself back to the sunny side of the street.

 

[Karmakatt]

Thanks for the reminder..
Great Post, thx!!

 

[dannymax]

Kind of the long way around Dave but sounds like you got it!! You should be seeing mileage in the low 40's consistently....way to go, congrats!! :thumbs up::thumbs up::thumbs up:

It's not a story of stupidity tho! We've all been in similar situations! unk:

 

[95spfldmax]

Kind of the long way around Dave but sounds like you got it!! You should be seeing mileage in the low 40's consistently....way to go, congrats!! :thumbs up::thumbs up::thumbs up:

It's not a story of stupidity tho! We've all been in similar situations! unk:

I have the same lazy attitude for plug gap too.....and my milage is never great.....I just moved my plugs from one motor to another last week and guess what....yup didn't stop to check the gap.......first thing on my to-do list next session in the garage......thanks for the advice.........

 

[Ost85vmax]

So would the gap be the same for a resistorless setup? I plan to pull my plugs tonight and check them but would like to know if the gap would be the same since I do not have any resistors in with the wires going to the cops.

 

[davesax36]

I originally had the wires with no resistors. The gap worked for both IIRC.

 

[Ost85vmax]

I originally had the wires with no resistors. The gap worked for both IIRC.

Perfect timing. Soon to head to the garage. Thanks.

 

[rollin thunder]

Ok I work in manufactoring every day and I dont see how a gap that is a little big can cause such a drop in mileage.

 

[davesax36]

Ok I work in manufactoring every day and I dont see how a gap that is a little big can cause such a drop in mileage.

I didn't think it would either, but it at least helped.

 

[Diablotin]

How much is the gap for the COPs? I forgot

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[Traumahawk]

how much is the gap for the cops? I forgot

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.026

 

[naughtyG]

Well that's interesting. I will be sure to check the gaps on both my '86 (OEM coils) and my '00 (COPs).

The '86 always gets **** mileage, although to be fair I haven't really gone through its carbs and I do have a misfire issue I need to check.

But the '00 should be sweet - I have a good running motor, I've done the carbs myself, and it's got the bigger (21L) tank, yet it only ever gets 200km b4 fuel light, and the guy that just came to buy my Corbin seat was getting 200kms on his '00 with an OEM tank!

So if the gap for COPs with Gannon's kit is .026, what's the gap for OEM coils?

 

[davesax36]

Stock coil gap is .031-035

 

[srk468]

I run my gaps at .24-.25 too, works great on nitrous too

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[Mr. Max]

A little OT: How you guys have wired your COPs? I know that is kinda simple job, but can be done wrong too..?

 

[davesax36]

You can only screw it up by running the front ones the wrong way. They need to be crossed to fire properly. Other than that, I can't really see how you could mess it up. The rears run straight from the harness plug to the cylinder that matches.