Topic: CB550 Inconsistent Performance

[MicahDT]

Today I took my first long distance trip, around 4 hours, on my new CB550.
The problem is this: for thirty minutes the bike ran wonderful. Full range of power and plenty of top speed, we were twoup at 85 mph and could have gone more. Then the performance deteriorated. At constant throttle in any gear as the rpms rise, it tops out at 5000 rpms and loses power. In 5th gear with some play in the throttle can get to 80mph slowly. I was able to complete the trip and had a wonderful time in the Carolina twisties, but I would like to get this right.
Any advice?

First of all, I have been restoring it for 6 months. It has new tires, rebuilt carbs, synced carbs, new cables, new bearings, brakes cleaned and adjusted, petcock rebuilt, airbox rebuilt, plugs and caps replaced (ngk 7), oil and filter changed, points entirely replaced and set, throttle cables adjusted, fuses replaced, has a 4in1 delkevic exhaust with 2 size increased mains, float levels adjusted, battery and regulator/rectifier replaced, and probably some more.

[scottly]

For starters, take a look at your spark plugs and describe them, or better yet, post a clear picture.

[jgger]

Plus what brand points and condensers?

[TwoTired]

There have been a spate of posts recently where new condensers have failed quite early in their expected life.

After you verify those, review the standard 3 K tune up checklist.

Cheers,

[Bankerdanny]

I'm not sure that the Delkevic required a 2 number jump. You may be running too rich (some time in the mountains could also have contributed to this). Plug color will tell the tale.

[MicahDT]

Suprisingly it actually ran better in the mountains, I assume because it was cold and raining. I pulled the 4 and 1 plugs when we stopped for lunch. They we're light tan, perhaps a bit closer to the lean side.

Last night I found an old forum where hondaman hinted these cold hot differences could be due to worn spark advancer springs. I had checked that it was moving freely and responding, but I didn't think to inspect the spring elasticity. I'm going to clip the springs as mentioned by hondaman today and report back.

[Deltarider]

Any "extra" inline fuel filters that could hinder the flow? The CB500/550 doesn't like inline filters.
Are the dimensions of the fuellines correct? Stock length for the fuellines are 18 and 30 cm. Models with the newer petcock have 17 and 28 cm. Only the correct length guarantees no kinking and good flow. Inside ⌀ ideally is 5,5 mm.

[MicahDT]

Nope, no inline filters. I'm using a stock petcock (rebuilt) that has the two lines. I used Honda replacement  hoses running the stock lengths and routes. I disassembled to clean the petcock strainer at a car wash when it stormed during the trip and it had some debree, but didn't change the performance. I checked the flow rate as well and it was proper.

[MicahDT]

Just modified the spark advancer as per Hondaman's instructions. When cold, the bike did have much better mid-range as promised (Hondaman is great), but when it got warm, it exhibited the same problem. HOWEVER, the condition shifted down to 4000 rpms and if i pushed it past 6000rpms and kept the rpms high, the performance was great. To me it says that the problem is in the ignition system. It may be time to bite the bullet and invest in an electronic ignition system.

[BomberMann650]

I remember having to rev high when the consdensers went bad on my 550.
But it wasn't a better or worse performance feeling.  It was a Go or Don't Go scenario.  It was dramatic, made me think the engine had broken.

[MicahDT]

I remember having to rev high when the consdensers went bad on my 550.
But it wasn't a better or worse performance feeling.  It was a Go or Don't Go scenario.  It was dramatic, made me think the engine had broken.

You got me thinking, I replaced the points and condensers, but that doesn't necessarily mean the condensers where "good" when I installed them.  I have heard that some condensers can go bad when not hot. That would match these symptoms. I may have some spares in the garage. It would be worth trying it before I consider and research more expensive repairs. Points have treated me well in the past, so I'd like to keep them.

[Deltarider]

Just modified the spark advancer as per Hondaman's instructions. When cold, the bike did have much better mid-range as promised (Hondaman is great), but when it got warm, it exhibited the same problem. HOWEVER, the condition shifted down to 4000 rpms and if i pushed it past 6000rpms and kept the rpms high, the performance was great. To me it says that the problem is in the ignition system. It may be time to bite the bullet and invest in an electronic ignition system.

Did you have a look at the sparkplugs yet?
What airfilter do you have and is air intake as it should.
Just buying stuff is no guarantee to solve... what we actually don't know.
If the problem is ignition related, there are simple tests to find out where the problem is.
Gap sparkplugs can be too wide.
A condenser can become less 'cooperatve' when warm and the same goes for a coil although the latter is rarely the case.
Also see vid in: http://forums.sohc4.net/index.php/topic,171571.msg1996948.html#msg1996948

[jgger]

I remember having to rev high when the consdensers went bad on my 550.
But it wasn't a better or worse performance feeling.  It was a Go or Don't Go scenario.  It was dramatic, made me think the engine had broken.

You got me thinking, I replaced the points and condensers, but that doesn't necessarily mean the condensers where "good" when I installed them.  I have heard that some condensers can go bad when not hot. That would match these symptoms. I may have some spares in the garage. It would be worth trying it before I consider and research more expensive repairs. Points have treated me well in the past, so I'd like to keep them.

Probably should have read post #2&3 in this thread???

[MicahDT]

I remember having to rev high when the consdensers went bad on my 550.
But it wasn't a better or worse performance feeling.  It was a Go or Don't Go scenario.  It was dramatic, made me think the engine had broken.

You got me thinking, I replaced the points and condensers, but that doesn't necessarily mean the condensers where "good" when I installed them.  I have heard that some condensers can go bad when not hot. That would match these symptoms. I may have some spares in the garage. It would be worth trying it before I consider and research more expensive repairs. Points have treated me well in the past, so I'd like to keep them.

Probably should have read post #2&3 in this thread???

Literally just saw them :/ I use my phone and the first repsonse it showed was asking about the delkevic. Would have saved a bunch of time... Still have yet to verify though. Hopefully will have an update tomorrow.

[MicahDT]

Plus what brand points and condensers?

There have been a spate of posts recently where new condensers have failed quite early in their expected life.

After you verify those, review the standard 3 K tune up checklist.

Cheers,

[/quote]

Probably should have read post #2&3 in this thread???
[/quote]

SOLVED: Thank you everyone for your advice. Sorry to TwoTired and Jgger for not seeing your posts sooner. Thank you for bringing my attention to them as well. I replaced the condensers with a second set from 4in1. The bike worked great for a 20 minute ride, even up to 85mph no stutter or bogging. Hopefully it'll hold up on longer rides as well. Thank you again SOHC Forums.

[jgger]

No problem, I'm glad you got it sorted out. Now if your new condensers are not Tek you may have the same issue soon.

[DaveBarbier]

No problem, I'm glad you got it sorted out. Now if your new condensers are not Tek you may have the same issue soon.

+1 Daiichi ignition components are know for being low quality. Look for a three pointed flower. If you see that, buy some genuine TEK condensers, swap them over and keep the others in your tool bag as spares. Glad you got it figured out!

[MicahDT]

The ones I had on hand are from 4in1, but does appear to have a marking. I'm glad y'all have mentioned buying TEC as I was shopping for spares now. I'll be sure to buy some and swap as suggested. Thanks again!

[Jooky]

The ones I had on hand are from 4in1, but does appear to have a marking. I'm glad y'all have mentioned buying TEC as I was shopping for spares now. I'll be sure to buy some and swap as suggested. Thanks again!

I bought the same condensers from 4into1 and the 1-4 condenser lasted all of 15 miles before it went on my 550. I don't recall there being any markings on them, but be wary of them for sure.