GZ250 Sluggish, hesitates, slower than normal????

[Todubs]

Hello all! Long time lurker and sponge for all the info presented here! Thank you!
My wife has a 2006 GZ250 and recently found an issues we are trying to deal with.

The bike starts without any issues and runs fine at idle. But, when riding, the bike has no "power." Yes, I know it is a 250cc, but it seems to be MUCH slower than it was last season.

When accelerating, the bike "bogs" and is sluggish, but as the RPM slowly increases, suddenly the engine speeds up quickly and you take off with power. It's like a turbo lag kinda' thing.

Holding the engine at higher RPM doesn't seem to change it, still the sudden increase in power after a slow wait. The bike will go freeway speeds, but it takes a lot of time and is SLOW to get there. Also, the bike seems to backfire more when decelerating/engine braking (little pops from the exhaust).

The bike was parked in our carport over the winter with a full tank and Stabil fuel treatment. Ran fine before winter. This issue happens with full tank and low fuel level. Gas cap looks good. Spark plug was light brown and gapped correctly, even replaced with no change. Air filter and air box are clean and free. Vacuum lines are clear and I can't find any leaks in the carb boots. Petcock flows fine and the petcock filter was clear. No change with or without the air filter in place. No change when tank was flushed and fresh gas added. I drained the carb from the bowl and found no junk.

Any carbs issues with these bikes? I'm thinking I need to yank the carb and hose it out? This issue sound familiar with anyone? Bike needs the post-winter oil change, could that have an effect?

Any help would be great! I have no problem getting dirty and breaking out the tools, but I need an idea where to start!

Thank you for any help!

[patrick_777]

You probably need to clean the carb. Sounds like your jets are gummed up.

[blaine]

You probably need to clean the carb. Sounds like your jets are gummed up.
STABIL is not a carb cleaner,only a fuel stabilizer.You might get away with putting some carb cleaner in the tank and going for a ride.

[alanmcorcoran]

There's lots of posts on here about carbs (many by me!) Bottom line, the GZ carb doesn't take well to non use. For many (most?) levels of gumminess, you can solve the problem by putting 150 miles (a tank of gas) with some carb cleaner. Occasionally, it can only be solved by cleaning the carb directly.

You can check your filter (easy to do and can't hurt) but is usually not the problem.

Make sure you shut the choke off after four or five minutes max, so you aren't running with it on. Try to get a good half hour at least of high speed riding in and ride it every day for a week.

[Easy Rider]

Any carbs issues with these bikes? I'm thinking I need to yank the carb and hose it out? This issue sound familiar with anyone? Bike needs the post-winter oil change, could that have an effect?

Yes, no, yes and no !! :biggrin:

Sounds like a lean condition; congrats for covering the air input stuff first. Did you actually check for vacume leaks with some spray or just visual inspection ??

Dirty carbs usually exhibit different symptoms than you describe BUT I would still try some carb cleaner in the gas first before tearing things apart.

Do I need to tell you what my favorite carb cleaner is ??? :roll:

[dannylightning]

Any carbs issues with these bikes? I'm thinking I need to yank the carb and hose it out? This issue sound familiar with anyone? Bike needs the post-winter oil change, could that have an effect?

Yes, no, yes and no !! :biggrin:

Sounds like a lean condition; congrats for covering the air input stuff first. Did you actually check for vacume leaks with some spray or just visual inspection ??

Dirty carbs usually exhibit different symptoms than you describe BUT I would still try some carb cleaner in the gas first before tearing things apart.

Do I need to tell you what my favorite carb cleaner is ??? :roll:

berryman B-12 chem tool, now you don't halve to say it lol.

if you put some kind of gas stabilizer in there over the winter i would make sure you get all of that out of the gas tank before you add the chem tool.

[Easy Rider]

if you put some kind of gas stabilizer in there over the winter i would make sure you get all of that out of the gas tank before you add any kind the chem tool.

I was going to mention that an excess of Stabil can cause running problems but since he mentioned being on his SECOND tank of gas, I figured that wouldn't be a factor; maybe I figured wrong !! :)

[dannylightning]

if you put some kind of gas stabilizer in there over the winter i would make sure you get all of that out of the gas tank before you add any kind the chem tool.

I was going to mention that an excess of Stabil can cause running problems but since he mentioned being on his SECOND tank of gas, I figured that wouldn't be a factor; maybe I figured wrong !! :)

here is the thing about the second tank of gas, when he filled up those two times how much gas was left in the tank when he did fill up. if the tank was not close to being empty there is still going to be some left over stabil in there. if so would it be ok to add the b12 on top of that little bit of left over stabil. i don't know for sure but me personally would make sure it is all out of there before i add any thing else into the tank.

[Easy Rider]

if so would it be ok to add the b12 on top of that little bit of left over stabil. i don't know for sure but me personally would make sure it is all out of there before i add any thing else into the tank.

Don't know for sure but I tend to agree with you and try not to mix things together.

[mrlmd1]

You said "Bike needs the post-winter oil change, could that have an effect?"
Next time you put it away, change the oil first before you store it. No reason to have dirty acidy oil sitting in the engine for months at a time, Store it with fresh oil.

[Todubs]

Pulled the carb and tore it apart, per the shop manual. BTW, inside of carb was clean and shiny. Put carb back on and no change. Still bogging down under load. It starts and revs fine, but when riding, it has the hesitation and is sluggish (same as reported in the start of this thread).

Oil was changed before storing for winter, I usually change it agian before the warmer weather and riding again.

Wife wants to take it to dealer to let them figure it all out, but I would rather save money........

[bonehead]

Just a thought, how long has it been since the valves have been adjusted?

[dannylightning]

Just a thought, how long has it been since the valves have been adjusted?

if you cant hear the valves tick they might need adjustment, i asked my local mechanic about checking the valve clearance on my bike, he says can you hear them, i said yes, he said do they make a strong ticking sound, i said yes he said more than likley they are fine, when they start to quiet down is when you want to get it checked out.

[Easy Rider]

Wife wants to take it to dealer to let them figure it all out, but I would rather save money........

Have you actually tried carb cleaner in the gas ?? You didn't mention that.
Some of the tiny little passages are hard to get to and easy to overlook.
It would be worth a shot before you take it in.

Put the recommended amount for a full tank in only HALF a tank of gas; run it for a while and sit overnight; if there is any sign of improvement, then fill the tank and pray.

Have we asked about mods.....like pipes or air filter ??
Have you checked the air filter ??

[mrlmd1]

"Oil was changed before storing for winter, I usually change it agian before the warmer weather and riding again."

Tell me why you do that? What are you trying to gain by changing out the clean oil again?


You also could squirt some carb cleaner right into the carb and let it sit for a while before running it, to see if it can clean some junk out.

[patrick_777]

Tell me why you do that? What are you trying to gain by changing out the clean oil again?

Condensation in the crankcase can separate from the oil and gum up the cylinder after it sits for a while.

I personally think it's being a little anal-retentive though.

[blaine]

Condensation in the crankcase can separate from the oil and gum up the cylinder after it sits for a while.

I personally think it's being a little anal-retentive though.


I change my oil before putting bike away for winter.I don't change oil in the spring until 5000 kms.

[Easy Rider]

Tell me why you do that? What are you trying to gain by changing out the clean oil again?


OCD. :poke2:

There really is NO good reason for doing that for an annual storage of a few months. NONE.

I think it probably got started by someone seeing that as a recommendation for LONG periods of storage......like YEARS....and ASSumed that it would somehow be beneficial for short periods too.

It is not true. Total waste.

[mrlmd1]

That's what I was getting at, but the written word doesn't convey a sarcastic tone (which is probably a good thing).
To me, that's a waste of time and money and resources and environmentally very unfriendly and accomplishes nothing.

[dentheman]

"Oil was changed before storing for winter, I usually change it agian before the warmer weather and riding again."

Tell me why you do that? What are you trying to gain by changing out the clean oil again?


You also could squirt some carb cleaner right into the carb and let it sit for a while before running it, to see if it can clean some junk out.
The owners manual does say to fill the crankcase COMPLETELY with fresh oil for storage, then drain it and add fresh oil to the proper level before riding. I didn't see a length of time considered storage, but I would say 'over the winter' seems like a long time for it to not be run. To me 4-5 months is pretty long-term for an engine not to be run..

[Easy Rider]

The owners manual does say to fill the crankcase COMPLETELY with fresh oil for storage, then drain it and add fresh oil to the proper level before riding. I didn't see a length of time considered storage, but I would say 'over the winter' seems like a long time for it to not be run. To me 4-5 months is pretty long-term for an engine not to be run..

Ah, so THERE is the culprit. :roll:

Anything up to 6 months really is not "long".

If you are that concerned about it, about the 3 month point, fire it up and run it long enough to get it hot. We usually have a couple of days in January when it warms up enough for a short ride and that is even better.......unless there is still ice or salt on the roads. :cry:

A few months of non-use does NOT constitute "storage". :tup:

[mrlmd1]

I have had many boats over the past 40 years and either did all the maintenance myself, or had the yard do it on occasion- everything from innumerable outboards, to 350cid gas engines, to a 50 hp VW based diesel, to twin 450hp turbocharged Detroit Diesels. I always changed the oil in the Fall before winter layup, NEVER changed the oil again in the Spring, never saw that recommended in any owners manual or diesel course I took, and I never had any problem with any mechanical breakdown of any engine, especially not due to oil problems. The oil was analyzed spectroscopically in both engines of my big boat every year and there never was any engine wear problem or any premature wear detected over a 14 year period I owned the boat. IMO, changing the oil again before Spring startup after doing it in the Fall is a complete waste. Boats, stored in a marine environment, are also subject to much more moisture in the air than would be a motorcycle. The manufacturer (Suzuki) is telling you to do that to cover their ass for whatever reason, maybe making it easier to deny a warranty claim or some such thing. I have also had cars stored for prolonged periods, like for a year or two, and also never had any engine problems by not changing the oil again prior to putting them back in service. Moisture really shouldn't collect in the engine anywhere and condense in the crankcase or cylinder if the engine is stored properly. It's also a lot easier to pull the plugs and spray some oil into the cylinders if you want, or spray fogging oil into the carb - there's no need or reason to change the engine oil again .But if that's what you want to do and it makes you happy - have at it.

[Water Warrior 2]

Filing the crankcase to the very top when taking a machine out of service is probably a military or industrial standard. A bike parked for the winter is not really out of service, it is just waiting for spring. If our bikes are going to be parked for a few weeks I just make sure the tires are rolled a bit to avoid flat spoting and there is reasonably clean oil in the crankcase. A battery tender is a must of course. This from a lazy bastard who killed 2 batteries in 2 years by not using the tools for storage.