Tuning Question 83 550e

[zig06]

I'm just wondering, but how does the shop know that your down on power by 50%? Todays 600's are A LOT more powerful than your 550, so a seat of the pants dyno isn't a really fair way to judge power ~ or a lack of.

Personally, I think that after it warms up, if it idles good and clean off choke, doesn't studder at any point while it accelerates, and can hold a steady throttle. It's mose likely that your bike is running as it should.

Of course, I am counting on you having good gas, good & clean carbs, good spark plugs, a clean air filter, lot's of compression, correctly adjusted valves and the exhaust is good (no leaks and the mufflers aren't plugged or imploding).

If you were down in power by 50%, and it was totally the valves not closing all the way, you would know it because it would spudder big time.

[550ERAT]

Just got back from the shop with the bike. Mechanic showed me the dyno data. bike pulled hard for first couple of thou rpm, then flattened out and hit a wall at 5-5500 rpm @ 80mph. Seemed as if bike was looking for more but it was not there. Peaked at 22 hp (should be 50 ish). He also vac synched the carbs (or tried), left side needed screws turned out almost twice what the right side needed ( i think 4 on left and 2 1/4 on right). Bike should pull hard all the way to red line, but does not. He said to check timing and timing advance first. Then, pull valve cover and check to see if it jumped time and then to adjust valves. I hope it didn't jump time, I don't want to pull the cams 8-[ There were no air leaks to be found and everything is bone stock on the bike. I am looking for any ideas about what else to check.....Carbs again? been rebuilt and are super clean. Any electrical parts effect bike under load? Electrical timing advance box maybe? Nothing binds on the bike, brakes are good, tires new, tranny/clutch good, chain good. I am being told and have read that this bike should be a "Skreemer" (lol, thought i'd throw that in there) but it is nowhere near that. If any other info is needed please ask. I am gonna tackle this since I didn't want to pay several hundred dollars for them to look for the problem and another several to fix it. Thanks to anyone who helps.....Hopefully if I can get this thing all squared away I can go on a nice ride and meet some of you.

RAT

[Nessism]

No disrespect again but what did that dyno guy do for you? Put a poor running bike on a dyno and confirm that something is messed up? Shame on them for taking your money.

Something is obviously malfunctioning. Most likely related to the ingition system if the carbs are truly as clean as you say. Too bad those dyno guys couldn't help you out more. It should be fairly easy to figure out which cylinder(s) are misfiring. Could be the ignitor if the bike runs on all cylinders at low rpm - again, assuming the carbs are properly clean.

Regarding the valves, it's not likely to cause the problem you note unless you have burned valves already. Hopefully that's not the case.

[LeeGS550E]

I agree that your ignition could be causing problems. The ignitor was out on my 550 and it would break up in the higher RPM's. Putting a timing light on the signal generator showed the spark jumping all over.

I also agree that the mechanic you took it to should not have put it on the dyno. What a waste of time, and YOUR MONEY. I hope he did not charge you much for that dyno run. I would recommend learning to wrench on it yourself. Don't trust someone you don't know with your bike.

Do the valve adjustment still, but also check your ignitor per the factory specs. Someone has also posted a good ignitor check method on the forum here. Search around and you will find it. I believe it was Nabrams (or something like that) that posted it. I checked my ignitor per the resistance figures provided in the 550 FSM.

[550ERAT]

Thanks guys. I think you are right with the ignition theory. The mech was a fairly decent guy, did not charge me for dyno time, only 2 hrs labor. He checked a few things, test rode it etc.... and before he started to rack up hours, he called. I will search for the igniter post and I have the Haynes manual too. I am not afraid to tinker or work on this thing, just have had more time on cars than bikes. Again, thanks for all the info....will keep you posted.

[zig06]

A smooth idle and a decent pull down low, but breaking up at a higher rpm is a sign of a weak ignition. This is because as the rpm's increase, you need a progressively stronger spark.

What bothers me is that the left carb wanted the air screw turned out farther than the right.... So either the left carb's main circuit is still plugged up, or cylinder #1 and #2 is doing all the work, thus needing more fuel.

Now each carb circuit does have some overlap. So the pilot jet does "help" the needle jet and the main jet circuit "some". But if your dialing in almost 2 turns more on one side vs. the other, then your close to your problem.

I forget what my current main jets are, but I do know that all of my pilots are the same, all the air screws are 2½ turns out and cylinder #1 & #4 and #2 &#3 have the same main jet. What's yours?

Try installing a good set of plugs and swapping your coils from left to right. If the problem moves over then you've got a bad coil.

[550ERAT]

Thanks...assuming the ignitern or coils are bad, do i need to get the exact same one for make/model year? ebay has several, but from different years and larger displacement....

[zig06]

Buying used ignition coils is a crap shoot ~ they could be bad too. So unless the seller is willing to waranty them, you might have to pop for new ones.

A few dealerships out there can actually test them correctly. That is, instead of using an ohm meter, they will actually put a load on them. That's how I discovered I had a bad coil. 2 dealerships insisted that I had a good coil after an ohm check, but I just couldn't get it running. A third one finally load tested it and pronounced it bad. $125 and 2 months later I had a good running motorcycle again.

So before you buy, let your fingers do the walking and find a dealer that can actually load test it. It's possible that even an auto shop might be able to check it out. And then you'll know.

[Schweisshund]

There is a way to test ignition coils with an electrical ohm meter. Billy Ricks is an excellent person to ask about electrical issues.