After riding the bike for roughly 30-40 min on the highway, I got off the exit and stopped at a few stoplights. After the 3rd stoplight, I accelerated to roughly 50/60 mph. Once I hit 50/60, my bike started lose RPM and then they'd pick up again. Then after a few seconds it would do it again. After about a half mile of that, I had to turn so I slowed down/pulled the clutch, dropped into 1st, and then the bike stalled. I continued to hold the clutch in as the bike rolled slowly around the turn and then another 50 yards before I pulled off the road. Once the bike was stopped, I pressed the start button and it started up as if nothing was wrong. I rode it another quarter mile to my house with no issues.
Well, I can try those but both options require me to stop and pull over. At which point the bike turned back on easily. Are you trying to determine if the carbs need cleaned or the gas cap needs cleaned? I took apart the gas cap today and it didn't look dirty.
If the gas cap vent is blocked, the effect will happen less, if at all, as the tank empties, because it will take longer for the space above the fuel to begin to pull a vacuum strong enough to kill the bike, especially if you have a fuel pump. If the cap requires a key, use a spare key in it, so you can pop in open at the first sign of weakness.
Hello. I took apart the gas cap and it didn't appear to be dirty. Granted, I'm new to this all so I may not know what I'm looking for, but after taking it apart I didn't see any buildup anywhere.
Well I took the bike out last night and it seemed fine. I revved it pretty good in the lower gears, but I didn't ride it for the same 30-40 min (prob closer to 20)
I did notice a hint of RPM drop in top gear. Like if I was at 6K, it would drop to 5750 and go back up to 6K. It did that as I was accelerating but once I was cruising it seemed fine again.
Somebody else on another site suggested electrical, so I pulled the spark plugs out. Attached are the pics I took last night after my ride (Phones camera).
If you have a propane torch, you can use it to check for an air leak. Turn the gas on (don't light it!), and aim it around the intake boots and any other areas that may leak air, like the throttle arms, and, if the idle changes, you've found a leak. Make sure you don't have any leaking sparks - you don't want the propane to light. Some folks use a focused spray of WD-40 instead of propane; never tried it myself.
If you have a manual, it should provide the fuel levels; mine has instructions for measuring the levels with the carbs on, using a clear, U-shaped tube connected to the drain. When the drain is opened, the fuel rises in the tube, and you measure the height relative to the reference on the carb. The petcock is in the open position (prime if you have a vacuum-operated petcock) for this test.
I posted a youtube clip (see other reply) of me spraying carb cleaner in different locations around the carb. I think it is definitely a vacuum. Can I use something like "Permatex PermaShield - Fuel Resistant Gasket Dressing & Flange Sealant" or RTV Silicone to seal it as a temporary fix?
I watched the video, and it seemed the biggest effect was the first spray at the intake boot on the right side. The other times it changed was after a delay, which may have been because it took a second for the spray to reach that boot. Three possibilities come to mind: carb isn't fully seated in the boot, gasket or seal between the boot and cylinder head is failing, boot is cracking from age. Loosen the strap on the boot, and see if the carb will push into the boot; many have a groove, that a small cast ring on the carb drops into, and you'll feel that happen, if it isn't seated correctly. If that doesn't help, you'll have to remove the boot from the engine, so you can examine both it and the gasket. Re-sealing a cracking boot is temporary, at best, and sometimes doesn't help at all, so if you have cracking around the carb entry, replacement is the only long-term option.
Since both plugs show a very lean condition, you should check both sides for leaking boots.
Ok cool. I really appreciate your help with this (as well as the other person)! I don't have the resources available to do this myself but at least now I have an idea of what's wrong so the shop won't give me the run around.
:71baldboy:
Hello again. So the carb vacuum leak is fixed, still had issues. One of the coils was weak. Replaced it and still having issues. Already $400 in and it still has issues with high stress in higher gears. I think petcock issue?
It's the same issue as before, where at higher speeds it struggles to keep and gain power. Last night I got on the highway and when I hit 65-70 the bike was losing power, then it would gain some, then lose it, etc. Similar to me letting the throttle go and then twisting it again.
I think the petcock is going bad causing a fuel starvation issue. The mechanic I went to said the carbs looked ok and didn't need cleaning when he replaced the O-Rings causing the vacuum leak.
Oops! I meant 'plugs'. It does sound like fuel flow problems, though. You have a vacuum-operated petcock, so if the vacuum line is collapsing, the fuel would be restricted; or, if the vacuum diaphragm is failing, you may need a rebuild kit for it.
So, which petcock do I replace first? Do you know if one is typically the issue? The top one near the gas tank or the one where you can switch between ON, PRI, and RES?
The one on the bottom of the tank only switches between ON and REServe; unless there's enough junk in the tank to block the screen, that should not be the issue - at least it's on the bottom of my list. The vacuum operated petcock is more likely, unless the vacuum line to it has a leak or is collapsing. "http://www.partsoutlaw.com/oemparts/a/suz/50d3f30ef8700230d8b4c01b/fuel-****
Oh-oh, the net nanny struck. To use that link, replace the **** with c o c k.
The one on the bottom of the tank only switches between ON and REServe; unless there's enough junk in the tank to block the screen, that should not be the issue - at least it's on the bottom of my list. The vacuum operated petcock is more likely, unless the vacuum line to it has a leak or is collapsing. http://www.partsoutlaw.com/oemparts/a/suz/50d3f30ef8700230d8b4c01b/fuel-****
Oh-oh, the net nanny struck. To use that link, replace the **** with c o c k.
First, check the vacuum line for leaks and soft spots - tubing is a lot cheaper than a whole petcock.
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