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Post by mattb on Nov 16, 2008 6:51:26 GMT -5
Went out for a ride today. I should have guessed when it started that things were against me: joined up with a very large bunch of vintage British bikes, and when they all left the carpark, the Japanese bike wouldn't start! That (familiar) problem was dealt with and I got on the road and met that crowd later at their end point, where it was nice to see the SR getting lots of attention from serious vintage enthusiasts. Then I travelled further with a mate and we swapped bikes for a bit. As he was riding along at 100km/hr he said it suddenly died on him. We let it cool and I kicked it into life - it was fine - and rode off and it changed through the gears accelerating up to speed with satisfactory gusto...until I hit fourth or fifth (I can't remember) when it felt like a it was starting to die, losing power in waves. I dropped it down a gear and it was fine, then returned to that gear and the same thing happened! I decided not to ride it any further in case I compounded the damage (not that I could ride it in a lower gear down the highway). It's now in a garage 100km north of here, waiting to be towed to my house on Tuesday by the roadside service of which I am a member. I'll push it to a local trusted shop to have it inspected and see whether I can afford to fix it or have to have it sit out the summer  I have to get out for a whole day ride at least once a week - it would be very painful for me not to be able to - so luckily I also have a GR650 at hand. But nothing compares to the feeling I get from the SR! Looks like the annual SR rally is out as well. Any speculations about what this might be? - I'm assuming it must most probably be a gear issue, a worn or broken part in there, given that the problem didn't occur at a particular rpm but rather only in a certain gear. |
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Post by davedunsboro on Nov 16, 2008 7:12:47 GMT -5
Matt , just an idea but didn't you play with ratios & sprockets just recently? Just I've got one of mine does something similiar . It gets to 100ks through the gears but in top it will just die & it wont go any faster .I've got a 17t on the front & a 42t on the rear .If I change my exhaust to a straight through type it will go to 140ks(but so do all my other SRs with the 16-42 ratios) If I change the said bike back to 16 front it will perform just like the others with the standard exhaust ! So I think the gearing gets too tall for top gear & the bike seems to flood & cant burn the fuel properly ? I wouldn't expect that you've broken a gear as these things are fairly bulletproof in that area (I only know of one guy blowing up a TT gearbox & he totalled it doing about 140kph when it let go) I hope its something simple you sound bummed ,cheers Dave.
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Post by wotavidone on Nov 16, 2008 16:43:12 GMT -5
Sounds like missing/breaking down under high load.
How old is the plug and what heat range is it?
Are you running high octane fuel, preferrably with octane booster in it?
I guess I flog this one a lot on this forum, but my bike (10:1 Wiseco, 17/42 gearing and really big fat rear tyre) used to do similar things. I'd be cruising along fine, roll the throttle on, then suddenly she'd start missing and surging, accompanied by very metallic clanking and tinkling noises. I'd stop, let her cool down, and ride home gently and she'd feel OK. I'd look for blocked fuel, buggered plug, buggered carby, CDI, etc, all to no avail.
Then one day I was riding alongside my mechanic mate who had an extremely quiet 900 Hornet. Next stop, he said, "Man that thing pings bad, I can hear it through my full face helmet ". I said it "breaks down and misses, etc." He said, "Mate, how many Cleveland V8's have I taken you for a drive in (he did his trade in a dealer ship, working on XY and XA GT's and stuff) over the years? Reckon I might know a pinging engine when I hear one? Your bike is pinging."
Gotya.
I increased the main jet and started running 98 octane BP ultimate. No more problem, apart from uphill or head winds on hot days. Pro strength magnesium based octane booster fixes that.
Course, this little niggling voice in my head keeps asking how much damage I did before I found out was going on, but while it sounds a bit rattly, they tell me Wisecos do that anyway.
Same mate had a Buell he bought with a lot of work done. Big pistons, hot cams, big valves. It pinged like buggery, and being a mechanic he couldn't be stuffed working on it, he said, "she'll go or she'll blow". She blew.
He said the other day after a ride alongside my bike, that maybe he should have tried a bit harder like I did, he'd probably still have the bike.
Mick
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Post by mattb on Nov 16, 2008 17:37:38 GMT -5
Thanks for the replies. I rode without earplugs as I like to keep a close ear on my engine (my first bike blew after three weeks, my first big bike after a year when I was flat broke, so I'm a bit pedantic about monitoring and babying my engine!  and it didn't sound like metal going bad so much as a fuel thing, but I assumed because it was happening in that gear that it must be a gear which was the cause. So hopefully some messing around and tuning when I get it back will fix things. After a week of the 17/41 set up, I had been thinking I might go back closer to stock - probably to 16/41 - the bike does feel strained in top gear, even if it is reving less. I was running a BPR6ES, which I usually do (because of the fouling and starting issues), and it was a cool day (under 20). The bike fouls plugs badly, but the plug (which was new, as per the story above) was a nice tan colour - at least I got a plug chop out of this! Fuel was Shell 95. Oil was full and one week old (for the 18 months I've owned her, she's had premium oil every 2000kms, and previous owner claimed the same). |
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Post by mattb on Nov 19, 2008 5:36:51 GMT -5
Well I put a 16 sprocket on front today, replaced the new plug just in case, and took the bike out on the freeway. I did it earlier during peak hour, which was silly except that I had to go to dinner and was impatient to test the bike first. Got on the freeway and...the bike did the same thing! It did it badly in 5th but also a little in 4th. I pulled over in eth emergency lane and held it at 4000rpm and it was fine, so it was an issue of being under load obviously. The indicators were going crazy at 4000rpm, so I fiddled with the connections to the capacitor and they lights settled down, got back on the bike to ride it to the earliest exit...and the bike rode fine, though the exit came up very quickly and I decided to exit and come back when the freeway was quiet. Went back there tonight, did about 10kms up and down the freeway, and the bike didn't miss a beat. I mostly sat on 90km/hr as I usually do, but pushed it to 100 a couple of times just to see what would happen - all good. 90 is back to 4000rpm now that I'm 16/41, but I guess I'll just have to live with that - part of the nature of the beast.
I'm assuming the change back to more standard sprockets did the trick, though it did repeat the problem at first. I'm assumiong again that fixing the capacitor connection would not have effected engine performance but just lights, on the SR (unlike most other bikes where loose battery connections could be an explanation of the problem)? - and that the repeat of the problem with 16/41 was just some left over cobweb from Sunday. Waddaya reckon?
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jeffz
Full Member
Posts: 215
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Post by jeffz on Nov 19, 2008 13:19:46 GMT -5
I had a problem with mine missing at different RPM, generally when the bike was cold. I took the battery cover off and the pos. connection to the battery was corroded. I replaced the end of the wire and It never did it again. I know they don't need a battery to spark, but from some of the things I've read on here, it must do something.
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and it didn't sound like metal going bad so much as a fuel thing, but I assumed because it was happening in that gear that it must be a gear which was the cause. So hopefully some messing around and tuning when I get it back will fix things. After a week of the 17/41 set up, I had been thinking I might go back closer to stock - probably to 16/41 - the bike does feel strained in top gear, even if it is reving less. I was running a BPR6ES, which I usually do (because of the fouling and starting issues), and it was a cool day (under 20). The bike fouls plugs badly, but the plug (which was new, as per the story above) was a nice tan colour - at least I got a plug chop out of this! Fuel was Shell 95. Oil was full and one week old (for the 18 months I've owned her, she's had premium oil every 2000kms, and previous owner claimed the same).