Loss of power around 5-6k RPM

[salty_monk]

I'm not sure how to tell. The coils and wires are yellow; I can take a picture later maybe if that would help. Would it be printed somewhere on there?



I have not done this yet. It's on my list. You're talking about the clearances right?



Is there a tutorial on the bikecliff site for this? I'm totally new to doing anything with the ignition system so I might need some more guidance here.

Thanks guys.

I suspect your COILS are ACCEL (given the yellow colour). This does not mean that your IGNITION trigger system is aftermarket though...
If you remove the small right side cover (throttle side) and take a picture we'll be able to tell you if it's stock or otherwise. It's reasonably common for the stock ignitor's to go bad after 30 years so it may be that you need to get a Dyna S in there or something...

There is a stock ignitor test in the Clymer manual that will tell you if it's faulty. You will need a multimeter.

You may find your bike does not have mechanical advance (saw that suggestion posted above). I think they went to electronic advance in 82 on the G bikes.

Valves - yes clearances.

 

[exzachtly1]

I suspect your COILS are ACCEL (given the yellow colour). This does not mean that your IGNITION trigger system is aftermarket though...
If you remove the small right side cover (throttle side) and take a picture we'll be able to tell you if it's stock or otherwise. It's reasonably common for the stock ignitor's to go bad after 30 years so it may be that you need to get a Dyna S in there or something...

There is a stock ignitor test in the Clymer manual that will tell you if it's faulty. You will need a multimeter.

You may find your bike does not have mechanical advance (saw that suggestion posted above). I think they went to electronic advance in 82 on the G bikes.

Valves - yes clearances.

Coils do appear to be ACCEL brand, it says that on the plug wires. Here is a pic of the ignition system.

This is electronic, right? The PO did say that it had an aftermarket electronic ignition. I do not have a clymer manual; can someone explain the test? I do have a nice recently purchased multimeter but I have not really done any tests with it yet since I'm not totally confident in what I'm doing in that area.

On my list:

• Remove carbs. Check float levels and slide diaphragm assembly.
• Attach vent hoses - these are missing but I have the OEM hoses now. Is it possible that this could affect performance at all? I've read some posts around the net stating that it could be a problem if these are missing or routed incorrectly...
• Check valve clearances
• Ensure good connection at airbox and check for leaks.
• Test ignition system (need help here)

I hope to get to some of this today, but the weather is nice so I might go for a ride instead and save all of this for a rainy day


Hopefully this week I can report back with some results. In the meantime any help with the ignition testing would be appreciated. I'll also check the plugs and see how they look after my ride today.

 

[tom203]

Nice day- go for ride. Not aftermarket,that's the stock ignition setup (signal generator coils). Grab hex nut and twist clockwise- should move about 30 degrees and spring back smoothly when released. Remove seat, right above battery ,there are two electrical connectors. The one with just two wires - blue and green - is the one that connects to signal generator coils. disconnect this plug and measure resistance on wires running to signal coils (step 11 in the link below)

http://members.dslextreme.com/users/storagecliff/images/electrical_odd-n-ends.html#A17

 

[salty_monk]

It's rare that the triggers go bad unless the bike has had a spill... Usually the ignitor. The test involves energizing some of the connections with an AA battery.
You should be able to get a copy of the page specific to your bike, I don't have that.

I can't see from that pic if it has the mechanical advance... it looks like it but I can't be sure.

 

[exzachtly1]

It's rare that the triggers go bad unless the bike has had a spill... Usually the ignitor. The test involves energizing some of the connections with an AA battery.
You should be able to get a copy of the page specific to your bike, I don't have that.

I can't see from that pic if it has the mechanical advance... it looks like it but I can't be sure.

Do I need to take the plate off to see that? Also, I tried turning it like tom suggested and it didn't seem to do any "springing back." It just kind of turned. I also watched it while the bike was running and revved the engine RPMs and it seems to move freely even at high RPM.

And for what its worth I checked the spark plugs and they looked good. Mostly tan colored.

 

[exzachtly1]

Took off the carbs and checked float heights, all were pretty spot on so I don't think that was the issue.

Here is the fiche for my Signal generator http://www.boulevardsuzuki.com/fich...ory=Motorcycles&dc=2763&name=SIGNAL+GENERATOR

You're saying to turn it using bolt marked #6 in the fiche? When I tried that it did not spring back... Just kind of kept turning. Is that wrong?

I have a tappet tool, feeler gauge, and compression gauge in the mail so I will be checking valve clearances and compression soon. I haven't ruled out an air leak, ignition issues, or electrical issues... Just gotta find some time to get the manual out and learn how to take these readings. Im a total newbie with electric stuff.

Also think I will be ordering those airbox boots and clamps this week...

 

[exzachtly1]

Nice day- go for ride. Not aftermarket,that's the stock ignition setup (signal generator coils). Grab hex nut and twist clockwise- should move about 30 degrees and spring back smoothly when released. Remove seat, right above battery ,there are two electrical connectors. The one with just two wires - blue and green - is the one that connects to signal generator coils. disconnect this plug and measure resistance on wires running to signal coils (step 11 in the link below)

http://members.dslextreme.com/users/storagecliff/images/electrical_odd-n-ends.html#A17

I'll start with this one when I do get to testing the electrics.

 

[koolaid_kid]

Part #7 on that fiche locks into the spring loaded advance. See the two tabs on part #5?
It would be the one you want to test the springs with.

 

[exzachtly1]

Part #7 on that fiche locks into the spring loaded advance. See the two tabs on part #5?
It would be the one you want to test the springs with.

Ah yes, thank you. Gotta grab a 19mm socket tomorrow and try that.

 

[Mr. Sinister]

This sounds EXACTLY like my problem. I have yet to tear into the airbox, but I think I'll be starting there along with checking the valves before I tear apart my freshly rebuilt carbs.

 

[exzachtly1]

This sounds EXACTLY like my problem. I have yet to tear into the airbox, but I think I'll be starting there along with checking the valves before I tear apart my freshly rebuilt carbs.

Please do report back here if you figure out the issue! I have been ignoring the problem for a couple weeks now because we've had a run of nice weather here in Ohio. And the issue doesn't really affect normal riding, I still get pretty good power. Only really a problem when I'm really jamming on the throttle for fun

New airbox boots and clamps just arrived in the mail today. I am now also armed with a compression tester, feeler gauge, tappet tool, etc. etc. so there is some work in my future. I know that I need to get the valve adjustment done to rule that out, but I'm just taking it slow. Waiting for another paycheck so I can get new gaskets before I take things apart too.

I did try turning the ignition advancer by hand, and it didn't really "snap back" as described. I'd describe it more as "snapping forward." I turned it clockwise and after around a half turn it would snap forward (clockwise) a bit. Is that what I should expect?

 

[Toasty]

Do you have an inline fuel filter?

 

[Mr. Sinister]

Please do report back here if you figure out the issue! I have been ignoring the problem for a couple weeks now because we've had a run of nice weather here in Ohio. And the issue doesn't really affect normal riding, I still get pretty good power. Only really a problem when I'm really jamming on the throttle for fun

Will do!! I plan on tacking it one piece at a time, then testing, so I will know for sure what it was.

 

[exzachtly1]

Do you have an inline fuel filter?

Me? Nah, no inline filter. All stock. It is possible that the vacuum and fuel lines are NOT stock though, so the thought has crossed my mind to order some OEM hoses for those to rule that out as a potential issue.

 

[tom203]

......

I did try turning the ignition advancer by hand, and it didn't really "snap back" as described. I'd describe it more as "snapping forward." I turned it clockwise and after around a half turn it would snap forward (clockwise) a bit. Is that what I should expect?

I erred in my prior explanation ....
Using a screwdriver to push it clockwise, the tab on advancer ( the projection that spins by the signal coils) should move easily about 30 degrees and spring back smoothly when released. The hex nut is anchored to crank.

 

[Toasty]

Sorry if this sounds dumb but how do you have the carb vent lines routed? They should come up out of the carb and rest on the airbox, above the fuel bowls.

 

[Mr. Sinister]

So my problem was caused by the lack of an air filter and airbox lid. I made a makeshift filter out of seat cushion foam, and used duct tape to make a V shaped opening in the top of the box. Bogging is gone, and the bike is running great now.

 

[exzachtly1]

I erred in my prior explanation ....
Using a screwdriver to push it clockwise, the tab on advancer ( the projection that spins by the signal coils) should move easily about 30 degrees and spring back smoothly when released. The hex nut is anchored to crank.

I see, I'll have to give this a shot next time I get some garage time.

Sorry if this sounds dumb but how do you have the carb vent lines routed? They should come up out of the carb and rest on the airbox, above the fuel bowls.

They are routed the way you describe. Originally there were none on there so I replaced them and made sure to route them that way.

So my problem was caused by the lack of an air filter and airbox lid. I made a makeshift filter out of seat cushion foam, and used duct tape to make a V shaped opening in the top of the box. Bogging is gone, and the bike is running great now.

Cool! Lucky that's all it was for you!

As I mentioned before I've got new boots and clamps for the airbox now so I'm gonna try that next. And valve clearances will be checked soon (want to order new gaskets before I take the valve cover off). It's also been tough to find time to get out and work on it lately. Hopefully this week.

 

[Mr. Sinister]

Could very well be your problem. If my bike is any indication, these bikes are very sensitive to airflow changes.

 

[exzachtly1]

OK, so unfortunately I am reviving this thread because the problem still exists. Since my last post I have done a few things to try to eliminate the problem, including:

• Valve adjustment. Exhaust 1 was too tight, intakes 3 and 4 were borderline (0.03mm). Those have been corrected.
• Carb sync. I did this before the valve adjustment, actually, so I need to do it again.
• Confirmed operation of the mechanical advancer on the ignition. It's working fine, the spring is fine.
• Investigated the air box - the filter was maybe a little heavily oiled so I patted it down with some paper towels. Inside the airbox I noticed there was a film of what smelled like gasoline. Not enough to be really alarmed, but definitely a little gas getting into the air box.
• There are exhaust leaks. I have noticed some light smoke coming from the exhaust connection to the headers during warm up. I think it's just normal condensation burning off, but I believe that should be coming out of the end of the exhaust, right??? And the crossover underneath has a small hole in it.
• Clamps on the intake boots are bottomed out. I believe this is probably contributing to a small air leak, leading to a creeping idle issue (that's another issue but wanted to mention here).
• Checked the compression. Getting ~135psi across all cylinders, this was done with the engine cold. I have not done a warm check yet.

The more I go through everything, I keep going back to thinking it is the carbs. I have not checked the fuel level in the bowls using the clear tube method. I'm working on getting something to do this with, and will check that soon. Could a low fuel level in the bowls cause this kind of issue?

The other thing I have not done is any electrical tests. I need to go through and check the battery voltage and voltage at the coils.

Other than this symptom and a creeping idle (creeps up to close to 2k when fully warm... I'll probably do another thread for that haha) the bike has been running great and very smooth in all other aspects.

EDIT: After reading this thread I am really beginning to suspect my air filter as well. He describes almost exactly the symptoms I am experiencing. The bike originally had an OEM filter in it that was all torn up, worn out, and barely there. I replaced it immediately. Unfortunately, as this is my first motorcycle, I did not actually drive it when it had this old filter in it so I have no basis for comparison. A friend drove it home for me when I bought it. I asked him if he experienced these symptoms at all when he drove it, and he said he didn't think so... he drove it on the highway, too. I am thinking of cleaning the filter completely, and riding it with a SUPER thin coating of oil on it... it's one of the UNI brand foam filters.