Thansksgiving day woes

[HobbyMan]

Well, Somehow it managed to be quite hot in my garage today. It took longer than I wanted in the blistering sun, but I must say a did a dang good job on the wires. I only had some black meter leads that were very flexible. I looks good all black. I know know that this bike has more than one problem. Today, on a short test run, I had trouble getting aboce 80mph. It wasn't just because of cops either. It feels as though it is starving for gas.. I decided to play around with the "choke" to richen the mixture. Then maby it would might make it above 80. When I pulled it, 2 cylinders cut out completely. So, I believe that I have solved the electrical problem, but now that has exposed a carb problem previously unnoticed. The good thing is that it will run(no ignition cut out I believe), but there is a fuel starvation problem. Ahh more frustration

[Ken Talbot]

Just wait till you've got it running properly i.e. firing on all cylinders all the time, all four carbs working in sync, air filter element cleaned so it is not restricting high-speed breathing, etc (hint, hint). You're going to think you've got a whole new bike!

[HobbyMan]

Actually, some day I am going to invest in all new K&N stock replacement filters. Untill then, I am going to tear down the carbs and see if all of the jets are clear. With all of these bikes, I feel I am going to be a professional carb mechanic. I am going to spend tonight going over all the sytems (fuel, air, electrical, etc..

[Goin Commando]

Not that this is your problem, but one time after doing the pickup wire repair, when I was finished I put the cover back on, went for a ride and had the same problem. Come to find out I had caught one of the lower wires in the bottom of the cover.
This is the way we learn.

[HobbyMan]

Well, here is the update. The emulsion tubes were plugged solid. I mean that around them was a thick layer of black "stuff." The tubes didn't fall out like normal, two had to be tapped and the other two had to be tapped/lightly-pounded. Also, one of the tips of the choke actuator rods was broken off, so when you pull the choke, only 3 cylinders actually are affected. The octupus vacuum diaphram is stuck on and when I reset it by taking it apart, it worked for a second and then got stuck on again. The intake manifold boots were cracked horribly. Because they were cracked, I have 10 used spare boots that I chose the best 4 of and coated them in rtv silicone. They went on with much difficulty because they seemed to have shrunk from age.(the carbs would not slide in very easily) Then after getting all of that taken care of, I took a look at the mess of wires that is supposed to be the fuse panel. It will need to be replaced. THe PO had ran a wire from the main fuse to the rear running light. I couldn't figure out why he did this because when I removed it, the light ran fine. He also told me that the oil light came on at random intervals. I traced the two problems down to the connection on the light checker device. When you jiggle the connection, the rear light cuts out and the oil/brake like comes on. I cleaned it, but it still cuts out. Any ideas? Well, now that is all back together I am going to take it on a high speed run(Ime talking 100+) on the 2 mile road over the dam at the lake. At 4 AM there are never any cops there. Sorry for the long post and any errors contained in it. I have been working on this bike from sun down to 4AM non stop. I am XStreemly tired and My mouse is broken. I hate using the tab button.

[HobbyMan]

Update part B: After a 1.5hr run, I am very pleased with the results. I topped out at around 115mph at 7.5k rpm.(Does that sound right for a special? My spedo could be off) I didn't want to go any faster than that because I started feeling some major vibration. Then under various loads on the freeway, it didn't cut out one bit. Now just a little tweaking and some cosmetics, it will be one sweet ride. I was very suprised that after 28k miles, the intake was very clean. I didn't see any carbon or grime. My 80G was completely covered with black sludge when I cleaned it out at 22K miles. I guess it all depends on the quality of the gas. Once I get a nice side cover and replace the fuse panel, I might end up taking it on few road trips. Thanks for all the help and suggestions. I wouldn't have known where to start by myself.

[DiverRay]

Did you sync the carbs once again? If not, try the sync and you will see what the bike can REALLY do!
The vibration may be the middle drive, drive shaft, out of balance wheel/tire, or final drive unit. I would change the oil in the middle and final drive units, after riding for about 20 miles, and pull the rear tire, then the 4 bolts holding the final drive on, and grease the slider on the drive shaft.
If you still have a vibration, have the tire balance checked, and be sure all the bolts on the front end and swing are are adjusted and torqued.
Ray

[HobbyMan]

The vibration was definitaly engine/ drive train related. I felt a shudder and a loud noise cooming from somewhere in the depths. I will change the fluids and grease the shaft. I synched the carbs right after I cleaned them, but I think that they are out of synch again. Our of curiosity, what is the max rpm that the engine is safe at? My over revving it, what damage might occur? Thanks for the tips.

[John]

Andrew

Check the U joint where the mid drive output flange meets the front end of the drive shaft. Under the rubber boot. You may need to remove the swingarm to slip the U joint and flange out of the end of the swingarm, or if you have a new gasket, pull off the mid drive, and access the U joint from there. It may need greasing.

[prometheus578]

My over revving it, what damage might occur?

Float a valve: valve spring can't return valve fast enough... valve stays down a little and piston hits it.

[TopCatGr58]

Originally posted by prometheus578
Float a valve: valve spring can't return valve fast enough... valve stays down a little and piston hits it.

To continue this, you may want to recheck your compression. IF it's good, then you probably haven't hit a valve.

The redline is at 8500, best to stay at or below that to avoid what Prom said!
T.C.

[HobbyMan]

Yeah, I am sure that I havent done this unless I have some really weak valve springs. I was just wondering what would happen if the engine ran too fast.

[HobbyMan]

What is the best way to adjust the idle mixure screws. The only way that I know how to adjust idle mixture screws is based on how I tune my RC engines. When tuning a simple 2 needle carb on an RC engine, you set the high speed mixture and then the low speed is set by rpm. Then you Jam accel the throttle and if it hesitates, then your idle mix is off. This isn't really possible with a 4cyl engine. Maby I could let it run at idle with a cooling fan on the engine. then after a few minutes I could adjust the screws by looking at the plugs? Right now, they are set 1.5 turns out. Do these screws affect performance all that much?

[Ken Talbot]

The pilot screws do have a major effect on the low speed operation. The best way I have come across for setting them is using a colortune tool and listening very carefully as you adjust the screws and watch the flame color. Even more important is using a vacuum sync tool, either mercury type of vacuum gauge type, to get all four carbs sync'd to each other.

[prometheus578]

The other technique (mentioned frequently, I can't remember by whom and I don't want to insult anyone if I guess incorrectly...) is to run the idle down low, maybe to 800 or 900rpm.
One carb at a time, slowly turn in the idle screw(giving the engine time to adjust itself) until the rpm drops or the engine falters.(easy to due with the low rpm) Count the turns... and then turn the screw out(richening) . The rpm will go back up, level off and then start to falter as it gets too rich. turn the screw back in to a point between the two extremes. Do all four carbs, and then set the idle back where it should be.

Always set a fan on an idling engine... unless you like that blue color on your pipes!