Going on 11,000 mile trip - suggestions for preparation?

[earlfor]

Steve, if I wanted to increase rearward visibility, I would add LED lights and keep the stock lighting. The slight increase in draw of LED's probably would not be enough to cause a problem. LED's usually consume aprox 10% of what a filament bulb would use. Bulb tail lights are 8 watts, so a pair of additional LED tail lights would only add 1.6 watts which is about the same as one of your dash light bulbs. :-) Go for it....she be jus fine.

Earl

Thanks for the primer, Earl! I knew the "cavalry" would be around to help out here soon!

I have contemplated putting LED bulbs on the bike to increase visibility in the rear, but after reading your in-depth explanation of how the charging system works and what it requires in terms of load, I think I may hold off until I can plan a conversion that maintains the "desired" load while still incorporating the LED's.

Regards,
Steve 8)

[Planecrazy]

My only issue is wanting to keep the bike looking more or less stock, so I was planning to replace the original filament bulbs with LED plug-in replacements ... obviously I can't have them both in at the same time, but I might break down and just add additional housings and LED's as you suggest...

Now if you really want a challenge, check out my latest plea for help in the Tech Forum ... I've got a doozy of a mystery waiting for you there... see "I GIVE UP ..."

Regards,
Steve 8)

[earlfor]

Dennis Kirk sells surface mount marker lights (with either a red or amber lens) that are large enough to put LED tail light size bulbs into. I am using a couple now as front running lights. You could piggyback the LED onto the tail light wiring. Not enough draw to be a problem on the wiring or switch.

Earl

My only issue is wanting to keep the bike looking more or less stock, so I was planning to replace the original filament bulbs with LED plug-in replacements ... obviously I can't have them both in at the same time, but I might break down and just add additional housings and LED's as you suggest...

Now if you really want a challenge, check out my latest plea for help in the Tech Forum ... I've got a doozy of a mystery waiting for you there... see "I GIVE UP ..."

Regards,
Steve 8)

[RacingJake]

Priceline

Sorry guys I just could'nt past this one up

[Anonymous]

Wow, again, thanks for all the replies.

Earl, you have given me all the numbers and explanation I was looking for, and I feel like I have a decent understanding of how the charging system works. The key for me was that I was comparing it to what I know of car systems, and didn't know that motorcycle systems (at least on my bike) are fixed output. That makes most everything else fall into place. I also assumed the output to be capable of at least 300 watts, figuring it to be half what my Geo is (the motor is half the size). Having those numbers and explanation makes it all fit in my head.

Yeah, delicate is the word I used, but really I meant that it requires a narrow set of conditions to run right. Car systems, being regulated, can stand a good bit of extra current draw, or very little, and be fine, but I guess my motorcycle can't - it needs a certain RPM, load, and battery condition for everything to be happy all at once. Since I've already been convinced about the differences in the light (and I know what color temperature is and what difference it makes - my LED flashlight puts out less light than my AA maglight, but it's far easier to see things and especially read text at a distance with the LED) I already got the H4 conversion, and will get a Silverstar and use the included halogen as backup.

I'm missing the right side cover on my bike and have no intention to replace it since it seems you can't get it for under $40 on eBay (indeed, at that price I considered selling my left side cover to make my bike symmetrical and get a bunch of money) so my electrical stuff, including the R/R heatsink, is already out in the wind, no need for a cooling fan. It's mounted with the heatsink facing backwards, though, and I might try to turn it around for better cooling. I'm glad someone suggested just installing some sort of extra cooling for the R/R as a cheap fix, since I had thought that sounded like a good idea also. Having built a lot of computers and read a lot about heatsink/fans for CPUs, I'm used to thinking "well, if it makes more heat, just get a bigger heatsink or more airflow" when coming to this stuff.

My bike runs at 5500 in 6th gear at 75mph, and with the new 16/50 sprockets I'm getting to replace the worn out stock 15/50 I have, I expect to run 5,000 or 5,100 at the same speed, and given that I expect to be around 5,000 most of the time, using basically the stock amount of power draw, I think it'll be fine. Since I have the bike half-apart right now, I'm going through all the non-soldered electrical connections and cleaning them and spraying with water-resistant connection helper. I'm also replacing the ground wire to the battery as it's a hacked wire right now.

Keith, I've read a lot of your posts about the carbs, and you seem to know everything there is to know about carbs, pipes, pods, spark plug color, etc, so I hate to say this, but my roomate says in all the 30 motorcycles he's owned and hundreds he's worked on as a professional mechanic, he's installed pods and pipes etc and never re-jetted and never experienced it running too lean. I was trying to find a place that stocks jets around here and he said why bother? I said if I use stock jets with pods and new pipes it'll run lean and hot and burn exhaust valves and pistons (echoing what's been said here). He said he'd love to see it run lean, he's never seen a bike run lean enough to actually make that kind of excess heat. And why would I not be able to play with the jetting on the road? As you said, I'll be able to remove the float bowls by themselves easily, and I'll also be able to change main jets easily. Are you saying that I wouldn't notice the extra heat until it's too late? I don't want to contradict what you say about the jetting and consequences of it, but my roomate recommends me to just carry a few sizes bigger jets and see how it goes, and I've never known his advice about anything mechanical to be bad.

My carbs are in a plastic bag in the garage and I'm about to take them apart and clean everything real well and put them back together, and then do a bunch of other stuff that's waiting to be done on the bike. Keep talking!

Alex

[earlfor]

One of my least favorite things to do on vacation is have to stop and work on the bike everyday because it isnt running right. I would take Keith's advice and make the trip with it stock and do any mods when I returned. Keith knows what he's talking about. I too worked for a motorcycle dealer and was/am a factory trained and certified mech. Your friend's experience is the opposite of mine. Go with Keith. :-) Also, experience on new bikes with CPU controlled injection etc doesnt count. In fact, only experience on old GS'S counts for this situation. :-)

Earl


[quote="alexlockhart"]

Keith, I've read a lot of your posts about the carbs, and you seem to know everything there is to know about carbs, pipes, pods, spark plug color, etc, so I hate to say this, but my roomate says in all the 30 motorcycles he's owned and hundreds he's worked on as a professional mechanic, he's installed pods and pipes etc and never re-jetted and never experienced it running too lean.

[KEITH KRAUSE]

A "Professional" mechanic, and he says re-jetting for pod filters and pipes is not necessary? I'm not trying to be a smart-a## but that's at least a tie for the dumbest thing I've ever heard regarding motors. Unbelievable.
Go visit any website and read about jetting and how it effects combustion.
If you increase the air intake and do nothing to the jets supplying fuel, then you'll have a lean mixture. Lean mixtures run hotter. The fuel itself acts as a coolant. Less fuel in the mixture, less coolant. Lean mixtures combust too easily and will cause pre-ignition in severe cases. The valves burn, etc. It's just the way it is.
I don't care how many bikes he says he's worked on, he's wrong. You CAN get away with a lean running motor if you don't ride it in extreme conditions. The life of the engine will suffer, but you can get away with it usually. But drastically increasing the air intake with pod filters and no jet changes, and then going on an 11,000 mile trip is a perfect way to overheat the motor. I could go on and on, but you'll probably just believe your mechanic. But try looking up a good website on jetting and see if you still believe him.
And like I said before, you can't just take off and decide to install a larger main when you want and make everything fine. At the throttle position you'll be running at, the needle jet circuit is what the bike is running on, and some "overlap" from the pilot circuit jetting. For this, you have to remove the tank, carbs, and adjust the needles. Nobody starts re-jetting on the side of the road on a long trip.
Would someone else do this member a favor and tell him about jetting? Maybe if a few of us agree, he'll stop listening to this mechanic.

[Anonymous]

OK, I've got the carbs apart for cleaning/adjustment, and the needle settings were in the middle (of 5 settings) with a fat nylon washer above and a thin nylon washer below the little clip on the needle. I moved the clip to the bottom setting (2 below where I found it) and kept the nylon washers in the same place. There's a little junk in there, mostly gas varnish, which comes off and out of the little passageways easily. I'll blow it out with compressed air before reassembly.

Why does it take so long to get the jetting right after changing the flow properties (pods and pipe) ? Can't you tell relatively immediately from the spark plugs if it's running rich or lean, and then swap jets and ride 30 minutes and pull the plugs again? Why can't it take a day or 2 to get the jetting right? Even adjusting the needle settings doesn't take too long to do twice or 3 times between riding it in one day.

I don't want to disrespect anyone or their advice, but I'm hearing opposite things from 2 sources I would typically trust for this kind of information, so I want to make sure I understand how it works and what I need to do before taking off. I really appreciate your experience on these bikes and your input, and I want to do "the right thing" for my bike, which will probably be what you say - I just need to get this all understood now before I leave. Thanks again.

Alex

[crc1214]

DUCT TAPE, ENOUGH WATER TO LAST YOU A DAY, SALT, A CELL PHONE, AND FIX-A-FLAT.

Good luck on your trip. I too have a 78 GS550E that I just purchased in February!!!!! If you by chance get into Ohio give me a shout. 614-595-3651. I'll show you some roads in southern Ohio that will give you a work-out. Just got back today from about 60 miles of some of the windiest roads through some of the most beautiful country in the mid-west.

Oh-by the way... definetely change your wheel and swingarm bearings. Cheap and well worth the trouble.

Also... sprocket sizes and chain sizes are of constant debate on the 78 GS550E. Stock is 15 front , 50 back. Don't let anyone tell you otherwise. Also, the standard size chain is 530-110 links. Some suppliers list 112 links, others 108 links, others 116 links. 110 LINKS!!!!!!

You will find out that for the most part, yes, 77-79 GS550 / and GS550E parts are interchangeable. But the 78 has some quircky parts that just aren't the same as the other GS550's from the time period.

Also, don't be freaked out by the emblem that says GS550 (without the E) on your sidecovers. The "E" didn't appear on the sidecovers until the 79 model year

Also, the 78 GS550E was only made for a short while, then the 79's came out. What we have are what I consider to be some rather rare bikes.

Enjoy your road trip. Again, call me if your in the area. I'm sure we'll be chatting back and forth on this forum for years to come about our 78's.

Good luck,

Chad
1978 GS550E, Columbus,OH

[earlfor]

Ok, here is a brief breakdown of the overlaps of the various carb stages.

http://204.71.0.3/motoprof/moto/mcycle/carb101/carb101.html

It could take a half dozen or more sets of main jets to find the appropriate size. Sizing the mains is the beginning and the simplest part. Also, you will need to vacuum synch the carbs.

Earl

[quote="alexlockhart"]

Why does it take so long to get the jetting right after changing the flow properties (pods and pipe) ? Can't you tell relatively immediately from the spark plugs if it's running rich or lean

[KEITH KRAUSE]

Alex, it's not necessarily how long it can take to jet correctly, it's because you can end up taking the carbs apart several times. I would'nt want to do that during a long trip. On the VM carbs you should synch the carbs with a vacuum tool every time you disturb the needles. A poor manual synch will cause different levels of vacuum between the four cylinders and you'll get different mixtures being burned regardless if you set the jetting right.
Because there are so many variables to consider (equipment/mod's, engine compression, state of engine tune, elevation, etc,) regarding jetting, it can be a lot of trial and error. Lean mixtures can be harder to detect, especially at higher speeds. You could be buzzing along on your trip and not realize your motor's overheating. I would'nt want to see that happen, so I reacted like I did to your roomates comments. He may be a good mechanic, but he does not understand carburetion on these older bikes.
What you did, raising the stock needles 2 positions, is what I would have done also. You should always jet "rich" and work your way back. Your needle is now raised as high as it will go but you may be lucky and find the plugs read good. You may even find that you'll have to lower them a 1/2 position or even a full position. A 1/2 position would be achieved (in your case) by leaving the clip where it is (#5) and placing a jetting spacer on top the clip. A jetting spacer for your carbs is about .022" thick. Of course, always replace the plastic spacers (thick and thin) in the same order. The next step leaner would be removing the jetting spacer and moving the clip to #4. It all depends on how well your pipe/pods flow. You may find the stock needle won't get you the reads you want and in that case you'll have to go to a jet kit.
As for the mains, I would GUESS 4 full sizes up from whatever is stock and go from there. You'll also have to adjust your pilot screws (underneath) out some. I would try a 1/4 to 1/2 turn out (c-c-w) beyond where they are now. Then adjust the side air screws for the highest possible idle and re-set the idle with the idle screwknob. Adjust the side air screws with the bike warmed up and on the centerstand. Get low speed plug reads. If you reach the point that you have to adjust the pilot screws past 3 turns out, you are leaving their range and you'll have to go up a step (2.5) on the pilot jet and re-adjust the pilot screws back and start over. Be sure to do a good vacuum synch. To avoid mixture problems, get the vacuum levels all within 1 cm of each other. I ALSO RECOMMEND replacing the 4 manifold o-rings if they are hardening or have any cracks. Put some hi-temp' bearing grease on them and torque to 6 ft/lb.
Another factor in jetting is the owner. Some of us are just lucky and get the jetting right quickly. Some of us have to trial and error ourselves to death. Also, some of us are just more easily satisfied and don't care if the jetting is "perfect" and run out of patience. If the bike runs "OK" they're happy. So this also is part of "how long" jetting takes some people.

[Anonymous]

Thanks for your number, Chad. If Ohio is the midwest, what's Nebraska? I thought the midwest started at the Mississippi River. Coming from Oregon, anything east of the Mississippi is a 4-day drive away and seems like it might as well be on the Atlantic. I will be re-packing my wheel bearings with synthetic grease, and replacing them if they're worn out. I know the stock chain and sprockets sizes, but the bike shop recommended I get a 112 chain since I'll be going to a bigger front sprocket - I can take out 1 or 2 links if that's what's needed to make it fit. I don't think 1 tooth bigger on the front will make that kind of difference, but it cost the same for the 112 as for the 110 so that's what I did.

Thanks for that link, Earl - it helped me a lot with understanding what does what inside my carburetors. I'm a pretty good amateur mechanic, but most of my knowledge is limited to how to do a certain thing, not how to diagnose problems with an understanding of how the thing works as a whole, so your help and the page you linked help me a lot.

Yesterday my roomate got his air compressor working so I blew out the carbs with carb cleaner and compressed air, put them back together and back on the bike, and found the #2 cylinder was dumping gas out the vent tube, so I pulled them off again and set the float bowl levels (which I had forgotten to do at first). #2 was way off, the rest were a little off. It starts a little easier now than before I did any carb work, but riding around the block last night without air filters, it was fairly temperamental. Just from the feel of the throttle position, it seemed that it bogged just a tiny bit right off idle, then was excellent from around 1/8 to maybe 1/2, beyond which it bogged down progressively worse. I'm about to vaccuum synch the carbs and run around the block again to see if it's any different. Just for reference, before I did anything to it, it was a little slow off idle, OK but not great for most of the midrange, and there was basically no difference in engine performance between 3/4 and full throttle. Also, running it faster than 5,000 RPM made very little noticeable difference in power, regardless of speed or throttle position. So, these are the problems I am hoping to solve, and it's already better in the lower throttle positions than it was before. This being Memorial Day, the bike shop is closed and tomorrow when they're open I'll get all the jets I think I might need and go from there.

Keith, I know I might have to take the carbs apart several times, but with pod filters on there, it takes about 30 minutes to get the carbs off, change the main or pilot jets or both, and have them back on ready to ride. That would take about an hour if I had to also adjust the needle position. Checking to see how it's running at a given throttle position takes less than 10 minutes, so if all I'm doing is changing jets, it would take about 45 minutes to test a set of mains or pilots and be ready to do it again. I haven't done the vaccuum synch yet, but I expect it to take around 30 minutes. I'm planning to get a bunch of jet sizes that I might need (mains and pilots) and do carb tuning all day Wednesday or Thursday, expecting to get it right by the end of the day. Is that an unrealistic plan? You said you'd guess 4 full sizes up from stock on the mains. Stock (what I have now) mains are 80, so would 1 size up be 82.5 or 85? I'm guessing 82.5 would be a half-size up, so 4 full sizes up would be 100. I have a '78 GS750 for parts, and it has size 97.5, 100, or 105 mains as stock, so I could pull those and try it today. My pilot screws (the ones underneath, accessible without taking float bowls off, with factory yellow paint on) were all at 1.5 turns out, and that's where I put them when I put it back together. The air screws on the sides are at 2 turns out, which is also factory spec. I'm sure I need to play with those some to get it right, and I'll be doing that some today, following the advice you gave. I suspect I'm the type of owner that will be happy if the bike is not too rich or lean at all throttle positions and has power all through the throttle range and RPM range, whether it's "perfect" or not. The needles and seats and air screws all had barely-noticeable rings around them, so I'm not expecting perfection, just hoping to make it happy all around.

Again, thanks for your advice, it's much appreciated. As I said before, I'm just trying to understand all this stuff and get it right, and I had conflicting information from different places. I'll keep you guys updated as I play with the carbs more.

Alex

[KEITH KRAUSE]

Yes. A step up in jet size is 2.5 and a full step is 5. I would try 100 to start. I would also post a topic here asking what other 550 owners have done if they have pipe/pods. It does matter what brand/design of pipe/pods you have, but someone may have the same setup you have or similar and help you out? Do a good carb synch before testing and if you move the needles, re-synch. Also, pod filters require that you remove the two float bowl vent tubes. This helps the bowls vent better and "keep up" with the increased intake. Fuel starvation will occur if the tubes are left on, especially at sustained/steady speeds. This is also recommended by jet kit makers. Don't worry about the vent nipples being exposed, I've never known this to cause a problem with dirt getting in.