melloyellow to live again!

[Fred Camper]

One victory at a time, way to go Ernie. Glad you found that coil issue. Yes, you can check a coil but will not have to now. A search on "coil test" should pull up a "how to for wings" post that will describe the process. Now a throttle shaft leak is one possible issue, but you should get some good troubleshooting guidence on the tech forum.

[polkadot]

I am glad you are along for the ride Fred! Really wish I had gone to Gillmore to see the bikes and cars and meet some of you guys. I will not miss it next year. I might even take the Caddy up to see the museum this summer. Is it something like the Henry Ford museum?

[Fred Camper]

Yes, but Gilmore is layed out in different buildings and the separation between buildings makes the walk between very pretty. So different that Henry Ford in that it is really a heavy auto bias.

[polkadot]

My most recent tech post:

I have the spark issue fixed. Started the bike and took it for a 7 mile ride. It got up to temp and everything ran great. I was cruising at 65 at about 3800 rpm. The bike was running great. When I began to brake for a stop, the rpms came down like they should. It started sputtering/backfiring as they decreased. As soon as I pulled in the clutch, the rpms reved up to about 3500 to 4000. It was kind of like riding a wild horse. (actually kind of fun). The idle speed never drops below 3000 with no load on the engine. If I put it in gear and ease out the clutch, the rpms fall. Any other ideas of what might be wrong before I pull the carbs?

Any thoughts? I'll listen to any suggestion!

[polkadot]

I decided to try again. The "idle" was at 3000.

The gauges were synched.

Then I tried backing out the idle adjustment screw. It started losing rpms as I adjusted. It got to about 1200 and the it died. It then would not restart until I adjusted the idle screw back in. Tried again and same thing. What?

[Fred Camper]

Get it to idle at 1600, then ride it some. Sounds like it might me those internal slow jets being clogged, maybe they were clean when you assembled but some particles were between the filter and the carbs. Yet seems very strange for all 4 to clog. So I suggest a ride or two before your next carb removal.

[polkadot]

I checked the timing on the dyna this morning. It was off so I reset it. The bike started much better, but same idle problem. Since I have set valve clearance, have spark to all 4 cylinders and timing is good, its time for the carbs to come off . So . . . . .




My game plan is to do a re-rebuild with an eye to anything that would involve the idle and air leaks. I will keep you re-posted. Happy Fathers Day!

[vapor_trail]

polkadot, do these guages for synch have restrictors in trhe hoses? it's pretty much impossible to see anything at idle without a restrictor.

earlier you mentioned replacing a butterfly. if the butterfly plate isn't perfectly centered, the idle will be goofy. I've had some heroic struggles with butterfly plates, two or three evenings spent checking. I gave up more than once, and got another carburator to end the self torture. I shine a halogen desk lamp behind it to see that it really closes EXACTLY the same as an untouched plate. i never found this easy to do. food for thought.

also, if this were mine, I would remove the dyna system and put back the stock stuff temporarily.

[Fred Camper]

In my opinion this can no longer be considered ignition related, so I agree with Ernie to leave the ignition alone for now. Since it would idle on less than 4 cylinders, in hindsight maybe it would have been good taking a plug off at a time and seeing how the idle speed would set. But since the carbs are off, that can wait for a proven need.

[polkadot]

Vapor, I wondered about the butterfly issue. I am going to complicate things even more by replacing 2 more carb bodies with spares I bought. I went "cave man" on the carb bowls and they have a small leak when the bike is not on the center stand. Not sure if I can get this carb back in good order or not. My second option is to rebuild a set of 77 carbs that I have (I have the appropriate rebuild kits too). I wanted to keep this as much 76 as possible. I feel pretty confident that my problems are in the carbs. I think the rest of the bike is pretty much good to go. What do you guys think?

[Fred Camper]

, You should not go after a float that does not seal on the side stand, as that is pretty common on these and the reason why they need a good petcock. I would stick with the 76 carbs for now as putting in 764's would drive work later on as this bike wants to be stock in that regard.

[vapor_trail]

polky, the butterflys have all GOT to snap absolutely shut. any one of them sticking even a tiny bit open will ruin everything. I beseech you to shine a halogen lamp behind each carb throat, excersise the throttle, and make pretty brutal comparisons. if they are not, it wont run, it'll just aggravate you.

the floats have to seal tight when closed. any leak which causes excess filling will change mixture at any throttle position. tie a hose to all four fuel bowl drains, and fill with an electric pump. they've all got to fill to the bowl joint, no higher or lower. and no fuel flow through the bowl when full. NONE. if they are dont, it wont run, it'll just aggravate you

i agree with fred about the choice of carburator, but i dont think the differences between one and the next are really significant in the face of mechanical problems. get 'em working right, and it'll run pretty good. forgive me being a little harsh. you busted your ass on this bike, i want you to have good results without fooling around anymore.

[polkadot]

Vapor and Fred, Thanks for all your help and thoughts. I really want to finish this bike, but I expected issues on the carbs. They seem to be the part of the bike requiring the most precision. I checked the butterflys on carbs 1 and 3. The fit seems pretty good, but no 3 does not close all the way due to the slack in the connecting joint. I'll see what I can do. I may rebuild both sets of carbs that I have and see what works. Main thing is to just keep plugging along.

[polkadot]

I am going to rebuild both sets. I really have nothing to lose except some shop time. I know that on the 76 I will need new throttle shaft seals. Can those felt seals be purchased somewhere or just cut out of some felt? I have also seen that some guys use o-rings. Does anyone know what size? I have a bunch left over, so maybe I could just see what fits. Thanks, ernie

[vapor_trail]

I am going to rebuild both sets. I really have nothing to lose except some shop time. I know that on the 76 I will need new throttle shaft seals. Can those felt seals be purchased somewhere or just cut out of some felt? I have also seen that some guys use o-rings. Does anyone know what size? I have a bunch left over, so maybe I could just see what fits. Thanks, ernie

I dunno where to buy them, so far, I recycled from an old set. Polkadot, some photos of your efforts with the seals would be great, it might invite some comment from the community.