Thumper Club Forum
Technical => Bike Problems/Questions => Topic started by: Moto63 on April 26, 2015, 04:42:56 PM
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Good evening all, hopefully someone out there can shed a little light on my problem. I parked my XBR cafe racer up last September after doing approx 4000 miles on it last summer, it ran as sweet as a nut all last year, I have just gone to it today and there does,nt appear to be a spark. Hence it won,t start. I have,nt done anything with it since it was parked up. Anyone suffered a similar problem before??. I would be grateful for any input . Thanks Michael
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Could be something silly like the engine cut out in the off position, we have all done it. Is the battery charged up? The spark can look weak, or if you have been turning it over and the plug is wet, game over if its an NGK, just get a new one, no use trying to dry it out. Is the fuel fresh?
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Hard to say.
Do you have compression on the kickstarter? A Favourite lay up trick is to lose compression - I think it is a valve that gets hung up - but it clears after many kicks.
Fresh fuel? - is it getting through to the carb - rust in the tank filter during lay up or rust in the carb when you turned the fuel on? Did you drain the carb- modern petrol can gum up the jets and airway during a long stand up.
Def no spark? - Mine was laid up for 2 years with what appeared to be no spark but the problem was actually a valve clearance/decompressor adjustment. The spark isn't always that bright.
Plug? Fuses? Good earth/connections? It's most probably something simple, you would be unlucky to get a major component just go during lay up.
Sure you haven't adjusted anything? - I'd forgotten I had done the valves during the lay up and that turned out to be the problem ( well the decompressor adjustment actually).
Time to get your hands dirty!
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Just a long shot, but can oil drain from the tank into the sump after a while? If it does, will it affect the output of the pulse generator? Or is the pulse generator not troubled by oil?
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Good morning all, thanks for the input chaps. Yes fresh fuel was put in and float chamber drained, originally started trying to start it with plug I had in last year but have since popped a new one in. Propellor raises a good question, does anyone know if what he asks can happen, the bike was left on it,s side stand for the best part of six months. Again all your input is gratefully accepted. Cheers Michael
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Of course oil drains from the tank into the sump, it does that pretty quickly after shutdown, but it doesn't affect the spark, which comes off the magneto rather than the battery. But when it's been sitting for a long while there's a tendency for the rings to stick or something ao there's not enough compression to start at cranking speed. The easiest solution is to run it down a hill and dump it into second or third gear. It will start if none of the cutouts (side stand. clutch) is jammed.
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Choke operating OK? choke valve not stuck?
I was going to say the same as GB500nz but he got in first!
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Thanks again chaps for the input, the bike or engine are,nt standard. It was completely stripped and rebuilt along with the rest of the bike when I built it as a cafe racer. The engine is now approx 560cc and has a high comp piston fitted along with a brand new mikuni carb. (Timbo has some photo,s so if your reading this thread Tim please will you post the photo,s up) It was completely re wired at the same time. It has plenty of compression (believe me) and turns over ok just no spark. The thing that is clearly puzzling me is that it ran perfectly when it was parked up. I,ve tried bumping it down the steepest hill you ever seen but no joy. Anyway, I,ll work my way back thro the leccy system and see if anything is amiss. I,ll keep you posted. Thanks again. (And thanks Tim if you do find time to pop the photos up). Michael
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Oh I forgot to mention that the bike no longer has an electric start only the kick start, which as I understand needs a real swift kick to produce the spark.
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Oh I forgot to mention that the bike no longer has an electric start only the kick start, which as I understand needs a real swift kick to produce the spark.
With the standard bike it's just full choke, prod the kicker over until it stops then let it come back up to the top again and a steady swing through - usually starts first or second kick - doesn't have to be particularly swift. Thanks to the decompressor it's very easy to start for a 500. ( unless you forget to adjust it of course! :-[).
I use to have a Suzuki SP370 which didn't have a decompressor. The starting routine was to prod it over until a cross head bolt appeared in a little window in the rocker cover then let the kicker up and leap on it with much force from a great height. Most of the time it worked but occasionally something would 'stick' and when you hit the kicker sod all happened and whole thing majestically keeled over and you ended up in a heap on the floor with the bike on top of you!
- this only ever happened when you were with your mates or trying to impress the girls with your manly motorcycle starting skills!......it was a l..o..n..g..time ago! :(
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Ha ha, yes been there Steve. Last summer we stopped off at devils bridge near Kirkby Lonsdale after a real good run thro the dales, had a brew and bacon sarni, lovely day so the place was heaving. Came back to my bike ready to leave with a dozen or more blokes having a good look at it. Went to kick it into life, would it start, would it hell. I had only gone and flooded it. Did I look a plonker. OH YES.
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If we want to test the output of the pulse generator, can we just attach a multimeter and watch for a "pulse" of voltage as we kick it over? What level of voltage does it produce?
How do we test that the cdi unit is sending an output to the LT side of the coil?
Will attaching a basic strobe lamp help to prove whether there is HT voltage produced?
Cheers
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Good evening all, just to let those who posted to try and help me out. The problem has been traced to a faulty ignition switch, (most probably of eastern origin) the switch itself was bought new and installed when I built the bike into the cafe racer. Anyway problem sorte, bike running again with it,s new zorst system and sounds the absolute bizz. Thanks again chaps for the input. Regards Michael
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Good to hear you've got it sorted! It's usually something simple. Mine goes in for MOT tomorrow so fingers crossed it will back on the road for the weekend!! ;D
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Good to hear you've got it sorted! It's usually something simple. Mine goes in for MOT tomorrow so fingers crossed it will back on the road for the weekend!! ;D
Good luck.
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Yes best of luck with the MOT Steve and fingers crossed you get some decent weather this weekend where ever you,re based so you can get out for a spin on the old girl