GS250 idles but won't rev

[first timer]

dumb question but you have the air filter installed right? If not try that and report back.

 

[Zwaylo]

lol yes the air filter is installed.

 

[Wallowgreen]

What tires are fitted on the machine?

Been looking for something to replace the sorry pair on ours but having trouble finding the right size, especially the rear. Just thought you might be able to shed some light and point me in the right direction.

 

[Zwaylo]

The tires are original actually and are practically brand new

 

[Wallowgreen]

Probably not going to help me much then but I was actually after the make and type but I doubt they're still in production if they're original.

Brand new 30 year old tires.... hmmm, your choice but personally I'd consider some new rubber as part of making the bike safe for the road.

 

[Zwaylo]

Ya I plan on replacing the tires before I take it on the road. The bike sat on a stand for the last 20 years with the tires off the ground so they are in good shape, but like you said 30 year old rubber is still hard to trust. I can check on the make of the tire later tho

 

[Zwaylo]

Have an update for everyone. I replaced the intake boots and intake boot seals, and the seals between the air box and the carburetor. After replacing these i still had the same problem. I looked at the airbox next and noticed that there is no seal between the airbox lid and the airbox, it looks like their should be one there? Also the handle part of the airbox lid is hollow and runs to the airbox is this normal? when I put my hand over the channel and blocked the air flow to the airbox I was able to rev the bike off choke. Let me know what you guys think. Thanks

 

[DanTheMan]

You need a gasket between the lid and the box. I guess I don't know what the "handle" is, is it possibly the spot the snorkel is suppose to fit into? Your diagnosis is correct though, too much air flow.

 

[DanTheMan]

Oh, I got my question answered by re-reading the earlier posts. The "handle" is the air intake for the filter box. But ti does need some weather strip material put around it. That is a beautiful bike, by the way.

 

[Zwaylo]

Thanks for the reply. I'll have to get some weatherstripping and add it to the airbox lid then, would that be enough to cause the bogging when i go to rev it?

 

[teddux]

Thanks for the reply. I'll have to get some weatherstripping and add it to the airbox lid then, would that be enough to cause the bogging when i go to rev it?

As you were told, you are wasting time on the airbox.
And yes, nice bike. Pitty it fell into YOUR hands (and not mine, lol).
What year is it?

Regarding tyres, if they weren't in direct sunlight, as it seems, then they should be okay.
I would be more concerned on inner TUBE condition.

 

[BassCliff]

Thanks for the reply. I'll have to get some weatherstripping and add it to the airbox lid then, would that be enough to cause the bogging when i go to rev it?

Hi,

Yes, the stock air intake system can have NO leaks. This insures the proper amount of air being taken into the carbs with the stock jetting. If you have air leaks, more air gets taken in and throws off the fuel/air mixture. When you have more air, you need more fuel. This means installing larger jets in the carbs to get the proper fuel/air mixture.

Your airbox is different but check these out anyway.

Here you see weatherstripping on top of the air filter cage being inserted into the airbox...

And here you see weatherstripping applied to the side covers of the airbox...

And here are more pictures illustrating an airbox fixup...

Airbox Sealing
(by Mr. Roostabunny)

Here is a guide to an entire air intake refurbishment...

Air Intake Repair:
(Airbox removal, intake boots and O-ring replacement)​

Your airbox is different, but you get the idea.



Thank you for your indulgence,

BassCliff

 

[teddux]

The 250 and 425 are similar.
The airbox was never an issue on my 425, ran without it:
this was.
Especially if it runs on choke only.
Since it has been sitting and the fuel "varnished" that orifice.
Year, pls.?

 

[BassCliff]

Hi,

Yes, clean carburetors are mandatory. This cannot be stressed enough. That picture is from the venerable carb rebuild series in the garage section of the GSR homepage. Here's the link to the whole thing...

Carb Cleanup Series


Thank you for your indulgence,

BassCliff

 

[Zwaylo]

The bike is a 1980. Thanks for the responses guys this will give me some things to check into. The bike starts right up on choke and will immediately idle after turning the choke off, but will accept no throttle at all with the choke off. I'm planning on tearing the carbs off again next week to thoroughly clean them, I just saw the link to the carb rebuild series and will follow that exactly, assuming that the gs250 carbs are similar to the 850.

 

[teddux]

The bike is a 1980. Thanks for the responses guys this will give me some things to check into. The bike starts right up on choke and will immediately idle after turning the choke off, but will accept no throttle at all with the choke off. I'm planning on tearing the carbs off again next week to thoroughly clean them, I just saw the link to the carb rebuild series and will follow that exactly, assuming that the gs250 carbs are similar to the 850.

NO!!!
That series is for REBUILD!
AKA, OVERHAUL!

Just stay to the CLEANING parts.

I would just drop the sumps in situ and give a quick spray test as in pic.
It should have a VERY NICE STREAM out the other end. It (spray) won't work the other way around.
Keep clear of face or use protection.

Just drop the bowls using a stubby #2 Philips screwdriver.

 

[Zwaylo]

Thanks for the heads up! I'll make sure to pull the bowls off the carbs and clean that particular passageway. I'm almost positive that i overlooked it when I had them apart.

 

[a747freak]

Zwaylo,
Welcome. I also have a '80 250T and I must say..I am very jealous. I wish mine looked half as good as yours! I didn't even know the side covers shined up that nicely. I think I'm actually going to use your pictures as a guide for how mine SHOULD look! I'm afraid I can't offer any advice that hasn't already been offered to you, but I wish you the best of luck in getting that beauty running properly!

-Steve

 

[teddux]

Zwaylo,
... I also have a '80 250T... I'm afraid I can't offer any advice that hasn't already been offered to you...

Can you go take off your air-filter and leave the cover off?
Start bike and observe how ?IF? runs.
I/we am/are interested in knowing if the air-filter affects this bike as BassCliff mentioned and I don't want to misguide...

Maybe someone should start a sticky on which bikes are affected by air-filter.

I just pulled my T-shirt off me back & STUFFED it in my AIRbox and my CDI functions FLAWLESSLY, Matchless.
-----------------------------------------------------------------------------------------------
Whoever made slanderous comments on my repairs and "OIL/chain" remark WILL be SUED 4 LIBEL.
Sheesh.
Most of you have 30-yr. old parts when I MAKE MINE NEW!!!
Oh, ALL by MYSELF, steve, not some crap paid for from CHINA that you think will be successful.

 

[a747freak]

Can you go take off your air-filter and leave the cover off?
Start bike and observe how ?IF? runs.
I/we am/are interested in knowing if the air-filter affects this bike as BassCliff mentioned and I don't want to misguide...

Maybe someone should start a sticky on which bikes are affected by air-filter.

I just pulled my T-shirt off me back & STUFFED it in my AIRbox and my CDI functions FLAWLESSLY, Matchless.

My bike runs perfectly fine without the air filter and cover. I ran it almost exclusively without the air filter for a while when I first got it.