1983 GSX250S Build

[Woodsy]

Hey Everyone, Thought it was about time i put my bike in here. It is a 1983 GSX250S, have had it for almost a year now and its a great bike for around town and twisty roads.

Here it is how i bought it, it didnt idle and needed a good tune up and the paint was really faded and worn.

This is it recently, i have started to paint the front mudguard, i stripped and sanded the side covers and rear section and have painted them matt black for now.

Here it is as it sits now, Its a video so you have to click on it to see it. I have started painting the mudguard black here, i plan on having the whole bike gloss black with the white line down the middle.


The new paint job starts.

More updates to come.

 

[Woodsy]

Rode the bike down to Sydney today, about an hour south along the pacific highway which is nice and twisty, on the way down i must of blown a gasket as on the way home i noticed an oil leak and apparently it left afew oil drops where it was parked in Sydney.

Looks like its the base cylinder gasket, it was leaking a little bit before hand but now its leaking oil, so i have to fix it. I assume its an engine out job, should i do anything else while i have it apart? Any advice?

 

[Guest]

About time you did a build thread

As to your gasket issue, bugger! Not sure if you have the O rings under the barrels or not, but if you do replace them while you're at it.

Depending on the km's you might wanna go the whole hog and do your camchain as well.

If you just need to do the base gasket though, you can probably leave the crankcases in the frame and do it all in place, although it would definitely be easier with it out unless you have access to a bike lift...

 

[Woodsy]

Yeah i thought it was about time i made a build thread. Nah no bike lift, i dont know how many km are on the bike as it didnt have the original speedo when i got it. I'm doing it on a budget so i dont want to go nuts but i would like to get rid of the cam chain whine. Should i do rings etc while i'm at it?

 

[mike-s]

If its the base of the barrel gasket then it's not an engine out job, but it IS a job that will require you to remove the head and head gasket, you'll need to put a new head gasket in there as chances are the old one won't seal up quite as nicely if re-used. Especially as you don't know the engines history/when it was last torn down, etc. Also there is a chance that the rocker cover gasket won't come off in one peice, but then again, it might if your lucky.

I would suggest you get a dry & wet compression test done before you go much/any further as well, just to make sure there's no need for any work on things like piston ring replacement or valves reground. When i had the head off mine recently i took it to a local engine rebuild place and they tested the valves for leakage and told me which ones were acceptable and which needed to be re-ground.

If nothing further needed to be worked on and you lived a lot closer, i'd offer to swing by your place and give you a hand once you've gotten the parts together, but the central coast is a bit of a hike from here unfortunately. However I've got a manual for the preceeding model, GSX250-E as the engine is the same and 95% of the chassis is too. Which your welcome to borrow if you need it, or i can scan the engine (dis)assembly section for you if that works for you too.

But as far as tear-downs go this is a pretty easy one, especially as it is an in-frame one. Then again i've done it a half dozen times on my bike in the past and aside from faffing about with taking the exhaust. I can give you my number if you want in case you've got any questions regarding this, but as it is a very straight forward job there won't be any real quirks you couldn't pick up elsewhere.

[edit]Oh and there is no o-ring at the base of the barrels, From memory (and this parts pic (page link)) there's a steel tube that fits in there to centre everything but there's no o-rings[/edit]

 

[Woodsy]

Thanks Mike, i do have a factory manual but havent looked into how far it goes into the engine tear down. If i'm going to pull the engine out i'll give it a repaint while i'm at it, All i can see is 2 gaskets that need replacing with the parts manual, i looked on the cmnsl website earlier. i havent pulled a bike engine down before, plenty of car engines though. But i'm happy to get my hands dirty!!!!

 

[mike-s]

Here's a quick mental rundown of the process from what i remember. It's rather straight forward. If you've taken a car engine apart before then it won't be that new to you, just a lot smaller.

* Tank off

* exhaust off

* Carbs out (this can be a bit of a prick to do, but not as much as putting them back in, that's where most of the "practice" has come in handy for me).

* Nip up the cam chain tensioner (undo the retaining bolt on the l/h side, screw the slotted nut in as far as it will go to hold the tensioner in place, then nip tight the nut again) and remove it (you may find it handy to take the plate over the starter motor out for a few mm extra room)

* Rocker cover off, then As your not planning to muck with the valves or anything, you don't need to worry about what's under there aside from removing the end-caps on the cams so you can take the cams out. Don't forget to tie something to the camchain, i usually use a couple of long zip-ties, one done up around the chain to hold it, but i leave enough room that i can fit a couple fingers between the tie and the chain, (i.e. mega loose), then another zip tie put onto the end zippy bits of the zip tie to act as a massive extension, so even if you do drop it, it's retrievable.

* Remove the cams, you may need to gently lever them up to unseat them from their bearings, usually a gentle pull suffices, but it may need a gentle lever against a non-machined surface with a screwdriver to get it up & out.

* Remove the 8 crown nuts 14mm i think, on the the head, you'll need a long socket that is thin-walled to get into the space between the head and the socket. Remove the nuts carefully so you don't drop them down the cam chain well.

* there is a bolt located between the exhaust ports that screws UP through a lip in the barrel into the head, this has to be removed before you attempt to take the head off.

* You may need to use some GENTLE persuasion with a rubber mallet to get the head off the barrels, especially if a prev owner used hylomar type gasket stuff, that stuff grips like nobody's business

* Same goes for the barrel, but mreo than likely it'll just slip up and off easily.

Now go about removing all the old gasket and make sure you're familiar with the use of a torque wrench before you start buttoning her up.

 

[Woodsy]

Yeah thats one tool i do have!

Heres the leak.

 

[Guest]

Mike, that's a great summary of info there, and I went through that with my tear down and rebuild also.

I did the leak test myself with some kero after getting the valves faced and lapping them in. I also did new rings and camchain.

Josh, follow Mike's advice and it will do you well

 

[Woodsy]

i'll have to find someone with a compression tester i can borrow before i go any further.

 

[mike-s]

*puts hand up*
But for the sake of having the tools handy for yourself (there's nothing wrong with building up the number of tools you have) go to supacheap in Newcastle and pick up a compression tester for $25. The only thing you may have problems with is getting a downsizing adaptor to suit, i had to go to Rocket Industries near Eastern Creek to buy this adaptor as one the right size wasn't included with the tester kit.

 

[Guest]

$25? Awesome! Wonder if they're the same price up here?

I haven't gone down the compression testing path because I did the valve leak down test and put new rings in and the price of the compression testers I've seen has been stupid. If they've got one for $25 though that'll be cheap peace of mind...

 

[Woodsy]

One thing you will find is supercheap online prices are different to there instore prices, if they are only $25 i'll buy one, bonus is i have a trade card for supercheap so i get 10% off that. I've used screw in ones before at my old work. Bike is acting a little weird today, making afew noises. See how the compression test goes, if its no good, it might be worth putting another engine in it? Might see whats legally involved with putting a bigger engine in.

 

[mike-s]

last time i checked was a while ago as unfortunately the one closest to me was closed 4 months ago after someone decided it would be prudent to set the store on fire . They had two different ones, the one that you want is in the triangilar shaped blister packs and has blue white and yellow packaging. they had it with all the other nifty bits like spark plug retrievers, valve suction cup thingo's for regrinding valves, the brake & piston bore cylinder hones as well as the 2 & 3 claw pulley removal doodads (hey i have one of each of these and have used 'em all and they work well).

They had another brand one that was around $50 or so and looked similar, but from comparing the two there was very very little difference between them, and i think i preferred the cheaper one anyway.

 

[Guest]

They've got three online between $40 and $60, the cheapest having a universal "push in" adaptor to suit most plug sizes.

Next one up's $45 and has 14 and 18mm adaptors.

$60 one seems to have a "push in" adaptor like the cheap one, but not much description of it...

Not sure on the bigger motor, but I know in Qld if the same model car was released with different motors you could providing you used the brakes etc. from the larger capacity.

Not sure how that would translate to bikes though...

 

[mike-s]

Oh, well it's the $45 one that sounds like the one needed, combine that with a threaded adapter i linked to earlier for 12mm, and that's deal done.
I've heard that the push-in one is a plain joke as it comes out unless you've got superman hands.

 

[landshark]

See how the compression test goes, if its no good, it might be worth putting another engine in it? Might see whats legally involved with putting a bigger engine in.

It would be simpler and easier to fix you engine or buy a bigger bike i reckon.

 

[mike-s]

Simple indeed. If compression is down, then take it apart, check the ring wear, check the barrels for oval wear, (0.1 is the tolerance from what i remember), check the valves are seated and sealing properly (a properly equipped engine rebuild autoshop can check this for you, if they are nice they will do it for free) and if they aren't sealing they can tell you just how bad they are leaking.

If you start getting big end wear, like your getting crank play or you suspect one of the big ends has worn and the engine needs to be totally split, that is when it goes from being a couple hundred dollar inconvenience (if doing the labour yourself) to costing a lot more money.

Also if you DO end up having to redo the barrel and get new pistons (newaint cheap) i can help as i accidentally bought 4 sets of 0.5mm oversized rings i have yet to offload onto ebay and will trade 2 sets for some beer.

 

[Woodsy]

Hmm looks like its the headgasket leaking not the base gasket, for ****s and giggles i have contacted the local suzuki dealer for a price on the gaskets, he never has anything on file for my bike and always has to fax someone in order to get the parts and prices, and not surprisingly i very rarely hear back from him!

 

[Woodsy]

Hmmm very interesting today, Went to start the bike and the starter motor was really sluggish, to the point where it stopped. I sat the bike up and tried again and it was fine.

Tonight i went to start it, this time it was upright, same problem, the starter motor couldnt turn the motor, i give it a rest for afew seconds and try again, there is a THUD between my legs and the bike coughs and splutters and eventually comes up to revs. I'm assumeing that was a backfire out the carbs, so i will have to check the filter to make sure it isnt a molten mess.

Overnight the bike leaked abought a 10cm puddle out the air box hose that runs to the ground. I'm assumeing my petcock is leaking, the bike is getting hard to pull off from the lights too, it feels sluggish.

I checked the oil and it does not smell fuelly at all and it isnt watery.

Could any of that have caused the gasket blow out from the day before?