Draining the Carbs on a VT250F

[Sn0wcr45h]

Alrighty!

Ok, full disclosure first. I'm new... New to Perth, new to biking, and new to general maintenance of bikes.
Got a VT250F pretty cheap (its old, but still goes, and i couldn't afford anything else) from a pretty solid, reliable guy, and have been enjoying riding to work from Joondalup.

Except, yesterday, as i'm coming back from CBD, i pass hodges drive and suddenly get a loss of power....
The Bike still goes, but it feels like it's not gettign all the fuel, lots of stuttering..
My first thought was that i was out of fuel, so switch to teh reserve, no difference.
I then crawled to the caltex, filled her up, set off again, and notice immediatly that i don't have the same power.

With help from a friend, we syphoned the fuel out, and put in new 98 octane fuel, incase it was dirty fuel. Still no change.
SO, next was given derek bells number. Gave him a call, and he's advised two possible things. First is to check both exhausts, if one isn't hot, then its a cylinder gone. I'll be doing that when i get home.

Second thing is to drain the carbs. I've never had to do anyhing like this before, but still want to do it, best way to learn i reckon, but would be handy if any of you have any tips/pointers? I'm guessing theres a screw at the base of the carbs that will let out the fuel. but this being an old bike, i'm going to have to take of the fuel tank to get to the carbs.... bit worried i accidentally break something, so is there anything i should be lookign out for?

Appreciate all the heads up i can get...

Sn0w

[out_in_front]

1) Turn the bike upside down
2) shake it a bit....

Being serious - different carbs have different designs, some have an adjuster for the main jet there - so dont just assume it is a drain. (although It will drain the carby... just make sure you dont drop any bits that may be attached)

Others may have 4 screws that hold the bowl on - remove all 4 and the base of the carby drops off. Make sure no parts fall out. I am sure there are other types out there too, can you download a service manual for your bike from somewhere? It will probably have the best advice in it.

[Sn0wcr45h]

Thanks for the heads up.
So, yesterday i managed to get a load of tools (thank you gumtree!) and started to take the bike apart. managed to remove the seat and the fuel tank without too much hassle, but realised i hadn't drained the tank, and i had nowhere to store the fuel.

Also, After having a look under the tank, and thinking about taking the air breather off, i realised i didn't have to do any of this! i could have reached the carbs by just taking the fairing off! (thanks Derek!) Unfortunately by this time it was getting dark, and i had no option but to build her back again.

Also just noticed that teh bike doesn't seem to have any oil or coolant. The Oil Window wasn't showing me any oil, and the coolant reserve was empty... so i reckon i'm goign to get it fully serviced first, and then solve the carb drainage issue. Glad the engine hasn't siezed on me, and feel pretty stupid for not checking earlier...

[McGoo]

Thanks for the heads up.
So, yesterday i managed to get a load of tools (thank you gumtree!) and started to take the bike apart. managed to remove the seat and the fuel tank without too much hassle, but realised i hadn't drained the tank, and i had nowhere to store the fuel.

Also, After having a look under the tank, and thinking about taking the air breather off, i realised i didn't have to do any of this! i could have reached the carbs by just taking the fairing off! (thanks Derek!) Unfortunately by this time it was getting dark, and i had no option but to build her back again.

Also just noticed that teh bike doesn't seem to have any oil or coolant. The Oil Window wasn't showing me any oil, and the coolant reserve was empty... so i reckon i'm goign to get it fully serviced first, and then solve the carb drainage issue. Glad the engine hasn't siezed on me, and feel pretty stupid for not checking earlier...

You shouldn't need to drain the whole tank, you can turn the fuel tap off and just drain what is in the fuel line and carburettor.

[out_in_front]

If there is no oil or coolant, I doubt the lack of power will be from carby problems...

I would guess a blown head gasket could be one issue (I.e the coolant went out through the exhaust valve)

[FullThrottle]

I used to own a VT250J spada which is pretty much the same engine minus 5 hp and did alot of my own work on it, had a spare bike for parts at the time that really helped. I had to overhaul the carbies on my bike but luckily all the rubbers on the other spare bike were still good enough to swap.
It rode like it was only using one cyclinder it was that lacking in power, what I found was someone had used gasket goo on one of the float covers which blocked the little float valve on one of the carbies also found one of the diagrams was cracked. after installing the new rubbers and cleaning it really well it ran like new.

These bikes are pretty tough but having no oil will kill anything make sure your oil is compatitable with a wet clutch as the oil in that bike does the gearbox motor and clutch. The spare parts bike I aquired had a really hard life with lack of oil I suspect being the contributing factor to the bottom end bearings failed causing some nasty piston knock i was going to fix it but then aquired the spada instead. These bikes are getting old and the parts on them are getting to the point of needing replacement to continue running I was lucky with my spada that it was in good nick.

[Sn0wcr45h]

Thanks for all the info..

I might take back the oil statement. being a newbie, i had the bike on the side stand, which obviously rolls the oil over to the side where there is no window... hence it looking like there is no oil. I'll rememebr to check with the bike level next time.

Also, i think the fuel tap may be faulty, as i let the bike idle with the tap off, and it kept running for 5 minutes.... gave up in the end waiting for it to go off...

Have called Derek Bell to service the old girl and have a look on Monday. Hopefully its not anything serious, i'm not getting anywhere, and i'd rather learn from seeing a professional...

On the plus side, just noticed that 2 wheel wreckers have a vt250f on their website that looks in better condition than mine... might go in and get parts from them if needed....

I'll post back what the issue was, if we figure it out... Gotta say though, riding on trains and buses when you have a bike licence just feels wrong!

[Sn0wcr45h]

So, quick update. derek came along and had a look, ive lost a cylinder.
As a TOTAL noob, i didn't check the oil when i bought her a couple of weeks ago, and have basically been riding without almost no fuel.
She's sparking ok, and idles on two cylinders, but give her any throttle and its just one cylinder running.
Not gonna be worth fixing, as it might cost more than the bikes worth... so think i'll cut my losses, sell her, and save up for a newer bike.

At least now i'll NEVER forget to check the oil.......

Thanks again for the advice...

[McGoo]

So would this be burnt valves? Rings?

[Sn0wcr45h]

The Mech was talking about the rings possibly being the issue. But didnt bother opening her up to check.
On a plus side, ive 2 wheel wreckers have an almost exact same bike they're wrecking. Will check the engine out, and if its suitable, will buy it and swap out the engines. I'll try to take pics and upload exactly what i do. Thankfully, previous owner had a workshop manual that he gave me, which details nearly everything i need to do to take the engine out. Should be an interesting saturday...

[K1GxR]

what year is the vt250f??
if it's late 80s and is the 43 - 45hp version, it's worth a bit as it's a direct bolt in for any VTR250 from 1999 (any vt250 anyway) onward, which has less power.

[Sn0wcr45h]

Its the integra, special.edition, 1985 is the year. I believe they onle came out for one year..... i wouldnt know anything about power though.

Anyway, beforeni go down the whole engine change, have decided to get her opebed up to figure out whats wrong. Am taking her today to grumma racing and hoping they can figure out whats wrong....

[Sn0wcr45h]

Last Update.
Bike is Alive!

Never managed to get the time to take it to a mech, and as i had the shop manual, thought id try cleaning the carbs myself.
To bring this topic back on track, to drain the carbs, you will find a screw on each carb that will drain it.
On the right hand side, this screw is actually hidden behind the thermostat, so you will have to remove the thermostat before you can see and get to the screw.

To take the carbs off, you first have to get the seat and tank off. Seat is easy, two metal clips on each side (one is beside the helmet holder) just pull them back to unlock the seta, and remove. Fuel tank was bolted on with two bolts, front and back. Make sure the fuel switch is off! Once th bolts are off, you will find two pipes coming from it down to the carbs/engine. You should be able to pull these off easily enough, and simply lift the tank away.

Now you will see the airbox (black plasticy box under the fuel tank). The carbs area ctually attached to the underside of this box, so remove the two bolts at the top and remove the airbox. you will now be looking into the base of the airbox, and will be able to see the slides that allow air into the carbs. there will be four screws that attach to the carbs, but for me theses screw were worn and therefore couldn't go down that route. to be honost the route i chose was easier, which was unscrewing the butterfly clips that were attaching the carbs to the cylinders, and yanking the whole thing off. Meant i could take the carbs inside and look properly at them.

Anyway, once you have the carbs off, you can open up the float chambers, and start looking at any blockages/start doing a bit of cleanup. There will be needles and jets which you'd want to blow compressed air through, theres also small rubber hoses attached which i assume were the vents, as they didn't go anywhere. Cleaning out the vents and the float chambers resolved the issue for me. If you need a hand with your VT250, i have the shop manual, and more than happy to help.