Chris46 Posted January 6, 2018 Share Posted January 6, 2018 Hello all. I have a old '81 gs250 e, yep the little scallywag doesn't want to play, it turns over. The saga so far, I have been through the loom, replaced and cleaned various connectors. Tested the signal generator got 125 ohms, book figure is 60-80ohms, it states if figure lower it's rubbish and if open circuit it's gone also but nothing for higher. I got a NOS geny and that was 130ohms. I've also replaced the coils as they had failed, with plugs caps and leads. I've checked timing and timed it against the right hand cylinder, the book says left, but the timing marks have a T mark next to a R, on the L side no T mark. I've put the plugs against the head and I have a massive spark. I've stripped cleaned the carbs, they are set to the book figures. The valves are gapped as per the book figures and are timed also correctly, I've tried to start it on carb cleaner and not even a burp. I've tried fuel through the carbs and after a while it did fire up ran for 30 seconds with the choke open, I opened the throttle and it stalled, hasn't ran since. I've carried out a compression test and I've got 60bar on the L and 80 bar on the right, did a wet test and got 100 L and 90 on the right. I know I have to do a check when warm but can't get it warm. So is it rings? I know I have fuel in the carbs, is it that compression is low. So can't draw the fuel through, without enough squeeze it won't go bang? How do I test a tr ignitor? I'm confused by Haynes. So any ideas please would be great. Chris Quote Link to comment
Chris46 Posted January 6, 2018 Author Share Posted January 6, 2018 My bad, I mean psi not bar. Quote Link to comment
wraith Posted January 6, 2018 Share Posted January 6, 2018 Hi and welcome to OSS As to your starting problem, anything below 100 psi you will have a pain to get it to start. Before striping the motor redo the compression test BUT put a small drop of oil in each cylinder, if the compression goes up it your rings, if it stays the same its your valves that are leaking. If so may need a regrind, if they are set right. Quote Link to comment
Chris46 Posted January 6, 2018 Author Share Posted January 6, 2018 Thankyou and Hello, Yep I've done a wet test, the left cylinder went up while the right only increased ten psi. Ill check valves again tomorrow. I'm leaning towards a top end rebuild. The more I think about it. Quote Link to comment
Sheep Posted January 7, 2018 Share Posted January 7, 2018 Did you WOT when testing the compression? Quote Link to comment
Chris46 Posted January 7, 2018 Author Share Posted January 7, 2018 Yep, throttle wide open. Quote Link to comment
nlovien Posted January 7, 2018 Share Posted January 7, 2018 has it been sitting a while dormant - or has it just decided to stop playing Quote Link to comment
Chris46 Posted January 7, 2018 Author Share Posted January 7, 2018 It had sat for some time but the last owner had used it and it started, smoked and misfired. Which would be a symptom of low compression, thought it was just something simpler. Has sat with me for about a year in my garage. Quote Link to comment
Chris46 Posted January 9, 2018 Author Share Posted January 9, 2018 Stripped it down, surprised only took and hour and a half. On inspection of the L/H cylinder it's glazed which is to be expected at 28000 miles, rings are free on the piston, this one gave me about 80psi, the R/H was the same, glazed and the rings stuck solid in the piston, this one was at 60psi. Both Pistons give a bore clearance of 0.20mm. Off to machine shop to see if the bores are round and square. Probably not.Surprisingly Suzuki still hold stock of 0.50 piston ring sets, standard rings. Will come back with prices and how it got on. Not many people ever come back with replies or fixes on forums. 3 Quote Link to comment
Blubber Posted January 9, 2018 Share Posted January 9, 2018 6 hours ago, Chris46 said: Not many people ever come back with replies or fixes on forums. Depends on the forum... And the members. Hope you stick around long enough to see what OSS, makes OSS 2 Quote Link to comment
gsx Posted January 11, 2018 Share Posted January 11, 2018 I had one of them 28 years ago . Hammered it mercilessly and only changed the oil when the gear change started playing up ,used the oil me dad had drained off his car and strained it through a tee shirt ! Was only 18 Did Lincoln to Kent custom on it and loaded it up with me tools and clothes to work in London , shame it was the middle of the late eighties recession . No wonder prices are creeping up on flea bay, bit of a unsung hero ! Anyway sounds like your bores are glazed , hone and thrash lots Quote Link to comment
Chris46 Posted January 12, 2018 Author Share Posted January 12, 2018 Been to machine shop, the engineer has checked the bores, they are fine within tolerance and the Pistons haven't collapsed in, so it's a glaze bust and new rings. I was expecting worse, as small bikes tend to have a tough life. Charged £20 for deglaze, just sourcing rings now. 1 Quote Link to comment
wraith Posted January 12, 2018 Share Posted January 12, 2018 The little gsx250 is a great bike, they just keep going the only thing that let's them down is the Suzuki electrics As said above, stick around and see why OSS is the best Suzuki forum about, the more you take part in the forum the more you will get out of it 1 Quote Link to comment
DarrenC Posted May 19, 2020 Share Posted May 19, 2020 Hi Chris46 just wondering if you ever got the bike sorted, I’ve got one with exactly the same symptoms ? Quote Link to comment
Gixer1460 Posted May 19, 2020 Share Posted May 19, 2020 On 1/9/2018 at 11:43 AM, Chris46 said: . Will come back with prices and how it got on. Not many people ever come back with replies or fixes on forums. That was fairly predictable - stayed for 6 days - last seen in 2018 ! ! ! 1 Quote Link to comment
DarrenC Posted May 19, 2020 Share Posted May 19, 2020 Yes Gixer1460 It would have been interesting just to hear how he got on with his not starter Quote Link to comment
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