650 Mod's 78 Fighter Build

Just to give a starting point with what I've done to try and diagnose this issue.

- check float heights and make sure they're within spec- all good
- clean pilot circuit
- clean carbs, fully dismantled, blow air through passages
- disconnect vacuum line from cylinder and run engine- no response
- take spark lead head from problem cylinder and swap with head from ok cylinder- no response
- pull choke circuit apart, check plungers, springs, replace one that was sticky- no response

The only thing I can think of left to do is swap the spark leads out. I can't do this unless I get new coils, because the shop that put new coils in for me epoxy'd the leads in place....

Any ideas anyone? I also have to still put my Dyna in, so who knows, maybe that will sort some of this out...

tight valve????????

leon

Tight as in the bucket is too close to the cam letting too much of a fuel charge in? Could be, but the bike only has 1000 miles on a full rebuild including the head, and everything was shimmed then. I can check it, but not for a little while. My friend and I are taking off for the states this Monday for a week. Trailering to just outside of Duluth, then riding wherever. I ordered a rebuild kit for the petcock just to rule that put. It never hurts when the thing is almost 40 years old...

Duluth, GA? Not that it's close to there but you may want to check this out. tailofthedragon.com/

No sorry Duluth Minnesota, an hour and a half north of Minneapolis. I'd love to ride the tail of the Dragon. ..

prolly not a tight valve being as how you all just set it up.
btw,
i meant tight as in not enough clearance and the valve not closing completely.

riding around minnesota will be freakin awesome.
my wifes inlaws all live in wis/min i haven't gotten to take a bike up yet tho

i have been wanting to go to moorhead mn to check out the replica viking ship at
www.hcscconline.org/current-exhibits/hjemkomst-viking-ship/
we are headed back up in september,
leon

Leon- it's more than worth a shot. Who knows, maybe a new guy did the shims and forgot to double check, and I didn't notice the issue before because I didn't have it as dialed in then as I do now.

Ah ok, so a floating valve that doesn't actually seal shut.

Minnesota around Duluth and superior, Wisconsin is gorgeous. The shore of superior is a gorgeous ride. I live in Thunder bay on the north Shore in Ontario, it's so nice.

Oh cool! That would be sweet to see! If you're ever up that way with a bike, let me know. I can head down and go for a cruise.

Devin

Did you push the little .009", .012" and .016: diameter wires through the relevant passage ways? If not, you have not cleaned the carbs...
To be honest, I don't care what any naysayers have to comment on... if you have not rodded the passage ways in these old carbs, especially if they have been sitting for months to years with gas.... you will regret it. LOL!!
My tools below:
www.kzrider.com/media/kunena/attachments/4138/Carbwire.jpg

Mission- I didn't have any wire like that, or a wire tool like that, so I took as small a screwdriver as I could, and scooped out any gunk in any passageways/carb bits. Then soaked in cleaner, repeated, and blew out with air. I agree with you- only the proper tools do the job right and fully.

Alright, so after about 3 weeks of head scratching and wondering what I missed in trying to diagnose my cylinder running rich, I have cured the issue. Drum roll please...... The winner of "who can properly diagnose Devin's strange one cylinder running rich" is...... 650Ed!

I was at my local Kawi dealer today bouncing ideas off the shop guys with my issue, seeing if they could help diagnose. And the vacuum line issue kept coming up, or a valve that wasn't shimmed properly. So I ordered in a rebuild kit for the petcock to be safe, and took the petcock apart when I got home. I thought why the heck not, might as well. Fingers crossed the almost 40 year old diaphragm held together when I took it apart....




And look at what I found... Dried up gas gum in between the diaphragm wall and the backing plate. And there WAS gas going down the vacuum line... So I cleaned the aluminum up as best as I could, and sprayed the diaphragms off. Put it all back together, crossed my fingers and toes and fired her up. And presto, no more running rich and dry fouling the plugs. So out came the Colortune, and the pilot circuit got fine tuned again. Leveled the idle right out, she purrs now. I'll most likely do a vacuum synch tomorrow too just to double check that part.

Thank you so much to everyone who has given their input on the issue. It's great having a support base like this to help you figure out what an issue could be!

Devin

glad you got it straightened out devin!

leon

She's back to running rich, I guess there's a micro tear I can't see in the diaphragm, so it's still letting fuel into #2. My rebuild kit will be in when i'm home, so it will be rebuilt then. I'll have to suck it up and ride a little rich til then. I don't think it's bad enough to fuel wash the jug at all, fingers crossed.

Got home last night from our trip through Minnesota. We stayed just outside Duluth, and rode around there for the first night. Second day packed up and hit Minneapolis. Stayed on the south west side, rode up to the Mall of America, and around there for a bit. There were nasty thunder storms on the way for 2 days later, so the following day we packed up, and went west to Albertville for a little while to check out the outlet stores there. Then took the back highways through smaller towns back towards the I-35, and went north again. Stayed just outside Duluth, and then rode around Duluth again for a bit. Overall, we covered 1,000 miles in the 3 days we rode, and the 650 held up fine. Who knew I'd get the best fuel mileage at 80 mph... I got an average of about 40mpg at 80 mph. Maybe I'll have to ride her like I stole her more.... No issues with the bike other than that diaphragm, but I'm picking that part up today and swapping it out, so she'll be fresh again

Devin