Help for a young guy?

General discussion about Street two-stroke Suzuki motorcycles.

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blaknift
On the street
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Joined: Sat Jan 20, 2018 8:29 pm
Country: United States
Suzuki 2-Strokes: 77 GT250
Location: Ohio

Re: Help for a young guy?

Post by blaknift »

10-4. Thank you! I'll give her a quick flush before I put everything back together. Gonna tape over the crankcase openings and scrape off the base gasket remnants. They are on there good!
dollydog
Yeah Man, the Interstate
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Suzuki 2-Strokes: several gt250 ramairs

Re: Help for a young guy?

Post by dollydog »

when you put your new base gaskets on, put a smear of high melting point grease either side. there shouldn't be ANY gasket goo on them. a lot of racers i know use a smear of grease, it stops the bottom of the barrels sticking to the gasket and ripping it when you take the barrels off :D
cheers, dd.
GTS250 road registered. TS250 engine, Ramair frame.
GT250 big bang road registered. Both pistons fire the same time. USD forks.
GT285 road registered. Overbored - 58mm and TS125 +2 pistons fitted.
GT10 road registered. '65 T10 engine, GT250 frame.
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blaknift
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Joined: Sat Jan 20, 2018 8:29 pm
Country: United States
Suzuki 2-Strokes: 77 GT250
Location: Ohio

Re: Help for a young guy?

Post by blaknift »

I'll keep that in mind! Thanks. I had a hell of a time getting the cylinders off the studs, They had corroded on there a bit. Gonna put a little bit of anti seize on there make sure it doesn't happen next time.
dollydog
Yeah Man, the Interstate
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Joined: Fri Aug 11, 2017 7:09 am
Country: england
Suzuki 2-Strokes: several gt250 ramairs

Re: Help for a young guy?

Post by dollydog »

something i always do - you can't beat a smear of copper grease, especially on any stainless fasteners or where steel and ali go together :)
cheers, dd.
GTS250 road registered. TS250 engine, Ramair frame.
GT250 big bang road registered. Both pistons fire the same time. USD forks.
GT285 road registered. Overbored - 58mm and TS125 +2 pistons fitted.
GT10 road registered. '65 T10 engine, GT250 frame.
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blaknift
On the street
Posts: 27
Joined: Sat Jan 20, 2018 8:29 pm
Country: United States
Suzuki 2-Strokes: 77 GT250
Location: Ohio

Re: Help for a young guy?

Post by blaknift »

Ill fabricobble some pipe cleaner drill attachment to get the corrosion out of the stud passages on the jugs as well haha. I think I've got some fairly high temp grease at the house that should work fine. Thank you!

I got the piston rings out and measured them and they were well under replacement size. Bores are fine with no discernible ridge. Guess that will happen on a engine with less than 5k Miles. Now to order parts. Once again, Thanks everyone for your help. It's truly appreciated!
dollydog
Yeah Man, the Interstate
Posts: 630
Joined: Fri Aug 11, 2017 7:09 am
Country: england
Suzuki 2-Strokes: several gt250 ramairs

Re: Help for a young guy?

Post by dollydog »

hope you remember which ring goes where? otherwise you'll be running her in again :D
i'll always help a person with manners :P
cheers, dd.
GTS250 road registered. TS250 engine, Ramair frame.
GT250 big bang road registered. Both pistons fire the same time. USD forks.
GT285 road registered. Overbored - 58mm and TS125 +2 pistons fitted.
GT10 road registered. '65 T10 engine, GT250 frame.
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blaknift
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Joined: Sat Jan 20, 2018 8:29 pm
Country: United States
Suzuki 2-Strokes: 77 GT250
Location: Ohio

Re: Help for a young guy?

Post by blaknift »

I had planned on replacing them. Never heard of any real good coming out of using them again, and they are about half way to throw out spec. Might as well, they aren't too expensive.

edit: They measured .50mm. New spec is .15 to .35, Replace is .80
Craig380
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Location: Manchester, UK

Re: Help for a young guy?

Post by Craig380 »

0.5mm gap is OK for used rings but it is better to get the gap to within the 0.35mm that Suzi specifies. New rings don't cost a fortune anyway.

Do remember that they are keystone rings, so look for the tiny lettering on each ring and make sure that the lettering is facing UP to the top of the piston.

One thing I would recommend is to gently chamfer the edges of the cylinder ports. Even from the factory, the port edges could be pretty sharp, and this can snag the piston rings. You can feel the edges with your fingers, sometimes they can be sharp enough to cut your fingertip.

If you can, get one of those jeweller's polishing stones, and just holding it in your fingers (don't fix it into a Dremel), gently smooth off any sharp edges on the ports by hand. You're not looking to remove much metal at all, just to blunt and smooth off any 'knife edges' on the ports so that it doesn't feel like it will give your fingertip a 'paper cut'. The rings will last a LOT longer as a result, because at every stroke up and down the cylinder, the rings bulge out slightly as they pass over the ports. That smooth edge you're making helps to ease the rings back into the grooves.

The cylinders have very generous tapers at the bottom so it's easy just to squeeze the rings with your fingers while you slide the cylinder down. If you smear a generous amount of oil round the cylinders and rings, the pistons should slide in smoothly. No force should be necessary, just gentle pressure. If you feel any snags or resistance, STOP, lift the cylinder off and double-check that the piston ring gaps are over the ring pegs in the piston grooves.
1976 GT380 - wounded by me, and sold on
2006 SV650S - killed by a patch of diesel and a kerb in Feb 2019
2017 SV650 AL7 - naked and unashamed
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blaknift
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Suzuki 2-Strokes: 77 GT250
Location: Ohio

Re: Help for a young guy?

Post by blaknift »

I'm gonna give them a light hone before I put her back together. I have some dremel bits so I'll remember to take down those ports a bit. Thanks for the advice as always!

I filled up the oil lines last night and left them hanging in some Starbucks cups the wife had lying around. There is a pretty small amount of oil hanging below the lines. Just a few drops. It seemed to flow in ok, I guess that means they are alright? Info seems kinda foggy regarding them.
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blaknift
On the street
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Joined: Sat Jan 20, 2018 8:29 pm
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Suzuki 2-Strokes: 77 GT250
Location: Ohio

Re: Help for a young guy?

Post by blaknift »

As always, Sorry for the double post!

Is there supposed to be some sort of detent in the oil pump control lever? If I move it all the way open and let it spring back sometime it hangs up and doesn't return all the way. Is this normal? I have looked around and haven't seen anything regarding it. This is with the engine still out of the machine, so the cable is out of the question.
dollydog
Yeah Man, the Interstate
Posts: 630
Joined: Fri Aug 11, 2017 7:09 am
Country: england
Suzuki 2-Strokes: several gt250 ramairs

Re: Help for a young guy?

Post by dollydog »

these oil pumps are terrible for it - sticking halfway across. sometimes it's the arm being bent and catching on something, or the shaft the arm moves is bent, other times the spring has weakened or broken. sometimes the arms get piled up with crud where they pivot. answers to those symptoms are obvious. if it's inside the pump it's a different matter. there's only one part that can catch and that's the shaft inside the pump [with the arm on the end of it]. again, the answer is obvious, but more difficult to cure. i've had that many of these and not cured them [fast enough for me, that is] i ended up fabbing another return spring for the arm. cured it permanently :D
cheers, dd.
GTS250 road registered. TS250 engine, Ramair frame.
GT250 big bang road registered. Both pistons fire the same time. USD forks.
GT285 road registered. Overbored - 58mm and TS125 +2 pistons fitted.
GT10 road registered. '65 T10 engine, GT250 frame.
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blaknift
On the street
Posts: 27
Joined: Sat Jan 20, 2018 8:29 pm
Country: United States
Suzuki 2-Strokes: 77 GT250
Location: Ohio

Re: Help for a young guy?

Post by blaknift »

Thanks for the reply! There is still a fair bit of crud I am yet to clean up around the pump still. If I let it go completely it seems to spring right back, But If I help it back slowly that's when it catches. Might just be some left over goo. If not I know where to look now. Thanks for the help! "New Springs" Sound like a good idea if it comes to it 8)
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joethebike
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Re: Help for a young guy?

Post by joethebike »

Just rereading your first post about the bike knocking under deceleration and steady throttle after warming up. It sounds like detonation caused by either carbon build up on the pistons, (you would have seen if that was the case during the strip down), an air leak at the carb flange, air screws set too lean or leaking crank seals.
On my T350 the main cause of your symptoms was leaking crank seals but even with good crank seals the air screw setting was important.
1972 Suzuki T350 160,000km +2 Castrol 6 Hour races
1982 Honda CX500 EC 272,700km
2005 Suzuki DL650 145,000km
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blaknift
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Joined: Sat Jan 20, 2018 8:29 pm
Country: United States
Suzuki 2-Strokes: 77 GT250
Location: Ohio

Re: Help for a young guy?

Post by blaknift »

I was getting everything ready to get put back together tonight and ran into a bit of a snag. The air filter was absolutely ragged. One of the elements looked original and basically fell apart in my hands, And there was a piece of generic filter material zip tied to the other side. I got them taken off and cleaned the metal up. Can I just get some filter material and make new filters, and zip tie them to the frame? Do I need to seal the top and bottom with silicone or anything? Looks like there is some snot around the metal, not sure if that is factory or not. Thanks again for all the help. I really appreciate it.


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dorT500
To the on ramp
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Suzuki 2-Strokes: '75 T500M since '93 Ridden it over 100,000 mi
Location: Galveston County, Tx.

Re: Help for a young guy?

Post by dorT500 »

That goop is factory. In the past, I have just made my own filters by cutting about 1/2" foam like the original to the width ( width such that it compresses just a bit against the air box door and that factory seal) and length needed to go around the cage and just sewing the ends together. No zip ties, such as you found, needed. Soak them in 30-40 weight engine oil and squeeze out excess oil...do not 'wring' them out. They will last for many years with an occasional cleaning in gasoline. re-oil and squeeze out excess. I would not just use some uni-filter paper type filter. I believe I got the foam I used from an Academy Sports store.

Another option is here.... https://www.ebay.com/itm/Suzuki-T250-GT ... 7539!US!-1" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;"
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