650 Mod's 78 Fighter Build

650mod wrote: So I know this is probably a question that has been beaten like a dead horse....

But... Ever since I changed the ignition over to the Dyna unit, my tach has been reading all over, within a span of 300 +/- the actual RPM the bike is running at. Right now, I have the tach line for my Acewell unit (electronic) just wrapped around one spark wire like it said in the installation instructions. I know that I can also hook it up directly into a coil wire, but I just want to make sure I'm thinking of the proper one before I go and splice the line in.

Hooking the tach line up to the hot line (power to coils) wouldn't be right, so I'm assuming I tie it into one of the output lines on either coil. Am I right in thinking this?
Any input is appreciated as I just want to get a more steady tach so I know when I'm pushing the limits too hard instead of trying to gauge it off sound.

I don't think the Dyna has anything to do with it unless you're getting a hotter spark. As for hooking it up to the coils, I'd be interested how to do that too. I'm thinking on going electric too.
Steve

My factory tach is hooked directly to one of the coil's at the trigger wire

Steve- I'll be giving it a try hooking it right up to one of the trigger wires on the coil like GPZ says. I'll let you know what I end up doing. I might end up getting a mini 3" tach with needle on it so I'm not looking for a number on my digital screen.

Ok, so as for today...

I decided to try and get that new fuel filter in so that I wouldn't have any lean issues when I really lay into the throttle at highway speeds. Ripped the carbs off, drained them, and cracked them open. Only to find what I thought- some nice little particles in the bottom of the bowls... So to be safe, out came all the jets, and everything got sprayed with carb cleaner and high pressure air. Here's what I found.

This sure was a nice surprise to find when I took the main jet towers out... So if this is sitting right in the needle valley, I can only imagine what's already been sucked into the engine.


After rinsing and shaking the jets and internal pieces in carb cleaner, here's what's left...


took a little peek at the main jet tower o-rings to be safe, and they're all dried up or cracked...


So off to the local Kawi dealer I went to get some new gas line, a few hose clamps, and some new orings.


This is the filter I'll be using for now. I don't like how long the ends are on it as it places the filter at a really weird angle, almost enough to kink the line


So for the time being, I have an inline filter in place to catch all that lovely small particulate. I know, you can all say it, I'm an idiot for not having an inline filter in before... Lesson learned. You can never be over safe with these old girls. Everything is all done for now. The next step is to get a new petcock for the bike to clear up my rich issue on cyl #2. Actually get a set of B7ES plugs out of the US as they're impossible to get up here in Canada... And keep on riding it to gain the most from summer

Devin

Well, I for one can't be pointing any fingers and saying "tsk tsk tsk" since I pretty much found the same thing on my own 650's carbs after thinking I "rebuilt" them a decade ago and then discovering pretty much the same thing (and worse) when the dang bike wouldn't start/run.

I know my tank is probably going to pass some crud for a while since my frankenstein electrolysis rust removal so I bought 2 small inline fuel filters so I could watch both and see if the 1st one gets dirty compared to the second one. Haven't installed them yet since I had to order another #3 carb body and new rebuild kits for that one mangled idle jet. :dry:

I was just thinking about the tach. There is a wasted spark which means it fires every rev instead of every other rev. Unless you can calibrate it to that you'll be reading double revs if you hook to the trigger wire.

a lil heat on the barb ends of your filter will let you put a lil bend to help ease the line bend.

leon

Lots of crud in there and the split O ring can cause a rich condition. I use these filters. I have two lines, one on each. All the bowls have a galley that connects them together. I guess Mik wanted as much fuel as possible to be available to the big boys. (33's) I put in larger needle valves on my 28's years ago. Stopped running out of fuel on extended WOT.
Steve

650mod wrote: So I know this is probably a question that has been beaten like a dead horse....

But... Ever since I changed the ignition over to the Dyna unit, my tach has been reading all over, within a span of 300 +/- the actual RPM the bike is running at. Right now, I have the tach line for my Acewell unit (electronic) just wrapped around one spark wire like it said in the installation instructions. I know that I can also hook it up directly into a coil wire, but I just want to make sure I'm thinking of the proper one before I go and splice the line in.

Hooking the tach line up to the hot line (power to coils) wouldn't be right, so I'm assuming I tie it into one of the output lines on either coil. Am I right in thinking this?

Any input is appreciated as I just want to get a more steady tach so I know when I'm pushing the limits too hard instead of trying to gauge it off sound.

Thanks!

Devin

If I remember right I connected my Trail Tech tach wire to the black trigger wire.

swest wrote: Lots of crud in there and the split O ring can cause a rich condition. I use these filters. I have two lines, one on each. All the bowls have a galley that connects them together. I guess Mik wanted as much fuel as possible to be available to the big boys. (33's) I put in larger needle valves on my 28's years ago. Stopped running out of fuel on extended WOT.
Steve

I use these also except I buy the ones with a 90° bend

Wrench- let me know how the twin filters work out. I think i'll run a single for the time being, maybe change it after.

Leon- good call on the bend- that would save my butt for sure. I'm going to get some good 1/4" rubber braid fuel line as the shop only gave me the clear plastic cap. Change the line when I get the new petcock in.

Steve- yup, definitely some good chunks of junk in there. Nothing a good clean and some new o rings can't sort out. As for me and extended WOT, I know i'm not exactly fuel efficient as I'm running the super tapered Dynajet stage 3 needles. Oh well, I don't really hit WOT too much. But when I do, I make sure I make it count

GPZ/Kaw- i'll have to give it a go on either wire and see what she reads at. I'll be sure to post up once I get it figured out.

Thanks for the help boys!

Devin

So after a long and tiring battle with that damn petcock, I decided to bike the bullet and jump on the Suzi petcock that Wrench is putting on his bike. I think I'll have a little more clearance room around the frame for the fuel line because mine is a C2, but we'll see. Regardless, I'm tired of the leaky (just rebuilt) petcock, so on to a new one it is. I have a strong hunch that this is going to eliminate my rich issue on the cylinder that draws vacuum to run the petcock as well. If it does, the performance of the bike will go up a little bit

While I was at it, I ordered a set of B7ES NGK's from Z1 as well. No shop up here in Canada can get them, and none of their US suppliers carry them anymore... Which I thought was quite strange. So when my lovely Christmas present arrives from Z1, I'll change the tap first, and take the bike for a spin to see what it does to the performance. After that, if the plugs aren't too light, I'll pop the 7's in and see what kind of a burn I get.

One thing though- right now, I get a coffee and cream colour burn on the electrode of the 3 cylinders that are running right, while the threading is dry-foul looking. If I run the B7ES, how much hotter am I going to run? I don't want to pop the new plugs in, go for a ride, then have some detonation occurring....

Devin

Where you live hotter plugs shouldn't be a problem.
Steve