So Close!...
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Hoop! Talking to myself! š
Bike chewed up a piston ring last night. Just lost power and started clattering, killed it like a heat seize with the clutch. Took the exhaust off tonight and peeked into the exhaust port. One ring down and a lot of shiny new scratches on my (previously pristine) 3MB cylinder head ā ļø
I had to nurse it 30 miles to get home to safety. So Iām guessing if any of it dropped down a transfer port Iāve lost the crank and cases as well. Oh well, shit happensā¦Canāt help thinking that there are loads more worthy candidates out there than me thoā šµāš«
@SpookDog wtf! I have never seen someone have as much bad luck with these engines as you.
All I can think is that you are caining it everywhere and you do lots of mileage. But in the 12 years of ownership of my bike I have only blown the head gasket after I used a cheap one after my bike got stolen...
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@SpookDog wtf! I have never seen someone have as much bad luck with these engines as you.
All I can think is that you are caining it everywhere and you do lots of mileage. But in the 12 years of ownership of my bike I have only blown the head gasket after I used a cheap one after my bike got stolen...
It feels like bad luck for sure, but the head gasket problems were just my ignorance and previous boners putting wrong jets in the wrong carb. My head problems are totally solved nowā¦
Iāve never had a two stroke or any other engine have a ring let go though. Iām guessing it happens at the exhaust port where the rings have to bridge the biggest āvoidā. My barrel/piston was a bit worn and egg shaped judging by the āslapā movement in the piston. So itās my own fault. I was really hoping it would see me through till the spring tho! Oh well š© happens!ā¦ -
It feels like bad luck for sure, but the head gasket problems were just my ignorance and previous boners putting wrong jets in the wrong carb. My head problems are totally solved nowā¦
Iāve never had a two stroke or any other engine have a ring let go though. Iām guessing it happens at the exhaust port where the rings have to bridge the biggest āvoidā. My barrel/piston was a bit worn and egg shaped judging by the āslapā movement in the piston. So itās my own fault. I was really hoping it would see me through till the spring tho! Oh well š© happens!ā¦ -
@SpookDog Did you make sure the Piston Ring End Gap was in tolerance upon assembly?
In most piston kits I've had, one is within spec and the other is almost always out.
No, I didnāt. They were new rings from pjme and they slipped in ok. I just did a quick visual with them in the barrel to make sure they werenāt doing anything extreme š
I was just hoping itād be ok cause I rarely go above 6k and never above 7k (I still donāt know what a late 88-90 engine shoul rev to!!) Just killing time & cruising up them miles till spring šThereās no mystery, Iām just feeling sorry for me~elf š±
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No, I didnāt. They were new rings from pjme and they slipped in ok. I just did a quick visual with them in the barrel to make sure they werenāt doing anything extreme š
I was just hoping itād be ok cause I rarely go above 6k and never above 7k (I still donāt know what a late 88-90 engine shoul rev to!!) Just killing time & cruising up them miles till spring šThereās no mystery, Iām just feeling sorry for me~elf š±
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@SpookDog Hhmm :thinking_face: I wonder whether the rings were out of spec then?
The problem is, if they're not measured properly, the engine can heat up and expand. The rings can then butt together and then catch on an exhaust port.
Nah, if I hadnāt of gotten nearly 6000 trouble free miles I could agree with you. I knew the barrel was oval shaped when I first fitted it. Like I said it was a bit āslappyā You could feel the excess movement in the front to back at TDC, side to side was OK. I just wasnāt expecting anything catastrophic!
I just find it really helpful to document my āhappeningāsā in this thread for future reference. I used to write it down on all sorts of cardboard, pads & things but always end up misplacing it, let alone keeping date of thingsā¦
I need the data to work out the problems. At the moment Iād love to know if my engine RPM peaked so low normally or whether I have a miss-balanced crank that wonāt let it rev to 10k+ šµāš« -
Nah, if I hadnāt of gotten nearly 6000 trouble free miles I could agree with you. I knew the barrel was oval shaped when I first fitted it. Like I said it was a bit āslappyā You could feel the excess movement in the front to back at TDC, side to side was OK. I just wasnāt expecting anything catastrophic!
I just find it really helpful to document my āhappeningāsā in this thread for future reference. I used to write it down on all sorts of cardboard, pads & things but always end up misplacing it, let alone keeping date of thingsā¦
I need the data to work out the problems. At the moment Iād love to know if my engine RPM peaked so low normally or whether I have a miss-balanced crank that wonāt let it rev to 10k+ šµāš« -
@SpookDog The chap who rebored my cylinder after it got stolen mentioned how oval it was :rolling_on_the_floor_laughing:
Ditto my first rebore. Itās normal wear, front to back. There is no side to side pressure on a piston/barrelā¦
I have to make a list of bearings for a rebuild now. I donāt know whether to get the crank rebuilt and balanced though. I wish I could find somewhere that could check the balanceā¦
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Ditto my first rebore. Itās normal wear, front to back. There is no side to side pressure on a piston/barrelā¦
I have to make a list of bearings for a rebuild now. I donāt know whether to get the crank rebuilt and balanced though. I wish I could find somewhere that could check the balanceā¦
The top ring retainer pin came loose and worked itās way out and up (in a bounceabout kinda way š) into the head and through the exhaust port. So luckily both rings are still intact and never made any shrapnel down into the crank š. Just scratch (lol!) 1 head, barrel & pistonā¦
Fitting a donor tomorrow I hope šā¦MerryXmess!ā¦
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The top ring retainer pin came loose and worked itās way out and up (in a bounceabout kinda way š) into the head and through the exhaust port. So luckily both rings are still intact and never made any shrapnel down into the crank š. Just scratch (lol!) 1 head, barrel & pistonā¦
Fitting a donor tomorrow I hope šā¦MerryXmess!ā¦
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Like I said before, I didnāt measure, just a quick visual check in the barrel. Itās a jap Mitaka piston. I donāt blame the brand, itās just a mechanical join between the aluminium piston and the brass pin that can fail in any brand piston, just bad luck š The piston had been overheated (judging by the black inside the crown) before I even brought the top end second hand. Couple that with possible vibration problems?ā¦
I think the rings were RIK from PJMEā¦
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Like I said before, I didnāt measure, just a quick visual check in the barrel. Itās a jap Mitaka piston. I donāt blame the brand, itās just a mechanical join between the aluminium piston and the brass pin that can fail in any brand piston, just bad luck š The piston had been overheated (judging by the black inside the crown) before I even brought the top end second hand. Couple that with possible vibration problems?ā¦
I think the rings were RIK from PJMEā¦
Day 1: 40 mile shakedown has shown no problems. Barrel & piston is a lot better condition/fit than the previous one, but by no means new. Choosy Beggars and wotnot š
Rehoned the barrel before fitting so am being gentle with the revs to let the rings settle. Nothing above 6000rpmā¦ -
Day 1: 40 mile shakedown has shown no problems. Barrel & piston is a lot better condition/fit than the previous one, but by no means new. Choosy Beggars and wotnot š
Rehoned the barrel before fitting so am being gentle with the revs to let the rings settle. Nothing above 6000rpmā¦ -
Howdy, I'd love to answer your question but my tachometer does not function. If I fix it or get a digital guage I will let you know!
These are the first pics of the Romeu Henrique stainless steel expansion chamber and tailpipe/serviceable muffler that I brought in Dec. I will take pics when itās fitted to the bikeā¦
Also below, there are the progressive fork springs. Shown next to a standard springā¦
The 27mm hex tool (1/2 inch drive) that I got for Ā£25 to dismantle the fork bottoms without drama! š fitted to a 1/2inch extension bar (2 needed to reach inside fork)ā¦
With the fork bottom inners. The inners undid with very little effortā¦
One of the fork bottom Allen bolts came out eventually. Iād already nearly rounded off the head before I removed the inner with the 27mm tool bit, so it needs replacingā¦
The second one is still stuck in the fork bottom as you can see. The head is rounded off badly and needs heat and banging out from inside, which is now possible since removing the inner with the 27mm tool bit. Itās corroded into the fork bottom because of the dissimilar metals and the tiny gap between themā¦
Iām waiting on a new blowtorch since my old one ha given up the ghost!ā¦
Iāve gotten new bottom bolts, seals and bushes (top & bottom) to go with the springs. So the forks should be as good as new when done and powder coatedā¦
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These are the first pics of the Romeu Henrique stainless steel expansion chamber and tailpipe/serviceable muffler that I brought in Dec. I will take pics when itās fitted to the bikeā¦
Also below, there are the progressive fork springs. Shown next to a standard springā¦
The 27mm hex tool (1/2 inch drive) that I got for Ā£25 to dismantle the fork bottoms without drama! š fitted to a 1/2inch extension bar (2 needed to reach inside fork)ā¦
With the fork bottom inners. The inners undid with very little effortā¦
One of the fork bottom Allen bolts came out eventually. Iād already nearly rounded off the head before I removed the inner with the 27mm tool bit, so it needs replacingā¦
The second one is still stuck in the fork bottom as you can see. The head is rounded off badly and needs heat and banging out from inside, which is now possible since removing the inner with the 27mm tool bit. Itās corroded into the fork bottom because of the dissimilar metals and the tiny gap between themā¦
Iām waiting on a new blowtorch since my old one ha given up the ghost!ā¦Iāve gotten new bottom bolts, seals and bushes (top & bottom) to go with the springs. So the forks should be as good as new when done and powder coatedā¦
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@SpookDog Pipe looks well smart!
You're not linking the picture, just the Imgur post.
You have to link in each picture individually.
Cheers bud, my mistook š
Also in pics are the 400 x 18 & 90/90 x 21 Kenda tyres I brought for the spring. Iām running on Kendaās at the moment and they are way better than the Ā£100 Pirelli mtās that I was using beforeā¦Also I wanted to say that the carbon ceramic Brembo brake pads have stood the test of time and are still performing absolutely top notch! Wet or dry they are a lot better than the EBC pads I used to run before. Well worth the Ā£24ā¦
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Cheers bud, my mistook š
Also in pics are the 400 x 18 & 90/90 x 21 Kenda tyres I brought for the spring. Iām running on Kendaās at the moment and they are way better than the Ā£100 Pirelli mtās that I was using beforeā¦Also I wanted to say that the carbon ceramic Brembo brake pads have stood the test of time and are still performing absolutely top notch! Wet or dry they are a lot better than the EBC pads I used to run before. Well worth the Ā£24ā¦
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@SpookDog Yeah 100%, I found the Brembo pads well worth their money! I've got a few sets under the bed waiting for a project in th future.
Dunno if this will work but the Japanese exotica arrived last month
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Dunno if this will work but the Japanese exotica arrived last month
