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Post by chrisa83 on May 7, 2024 9:59:40 GMT -5
Hi all,
New to the forum, nice to meet you all.
Picked up a very cheap (and very modified/chopped about) SR500 last Autumn and planned to start working on her this spring. Never had a kick start bike before so it's a challenge to start to say the least (I imagine it's all down to technique which no doubt will come either time!).
My question is, there doesn't appear to be a decompression lever which I understand these came with. Is it normal for this to have been removed? Is it not being present likely to be causing me more problems when it comes to starting the bike?
Thanks in advance.
Chris
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Post by stevep on May 7, 2024 12:22:49 GMT -5
Hi Chris, you're not coming at it from the easiest angle. While not a deal breaker, the decomp serves a couple of useful functions. It takes some of the strain off the kickstart mechanism when kicking over to find TDC
It helps find, by feel, when to kick. Like when you put your finger on a fishing line to feel a bite, when the decomp cable goes slack as you slowly kick it over, it helps you know when it's in position to kick.
Try and track down a LHS lever perch with decomp lever.
Welcome to the forum!
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Petes2Wheels
Full Member
Out riding the country roads
Posts: 102
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Post by Petes2Wheels on May 7, 2024 16:50:35 GMT -5
Hi and welcome to the forum. Have a look at the top of the engine above the exhaust header pipe. Is there a engine mounted Decompression lever? Some down here in Australia use an engine one as it cleans up the handlebar looks.
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Post by chrisa83 on May 7, 2024 17:52:54 GMT -5
Thanks. What would be the benefit of the previous owner removing it? Just for looks? I have checked on top of the engine but there is nothing on there either. I can feel when it is coming round to TDC by touch and then obviously it appears in the small window so im sure I am kicking at the correct point. Is replacing this a big job?
Can I also check what is the correct Spark Plug please. Currently got a BPR7ES in but read online a BP7ES is recommended. Is there much difference here?
Thanks again.
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Petes2Wheels
Full Member
Out riding the country roads
Posts: 102
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Post by Petes2Wheels on May 8, 2024 0:51:43 GMT -5
Some people change the looks of the bike often. It is a simple job of replacing it. Run the cable from the engine up to the handlebars. Take off the grip and the clutch/mirror mount. Mount the new one with the decomp lever and connect the cable up to it. The engine lever is even easier, undo one bolt, connect a short included cable from the engine to the lever. Depends on the look of the bike you want.
As to spark plug go by the service manual as some years varied. Plus can't rely on between 400, SR500 and XT500.
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Post by chrisa83 on May 8, 2024 8:10:25 GMT -5
Thanks for your reply again. OK, I'll see if I can source one. Am I best not to try in the meantime to start it without one?
I've checked the manual like suggested and have ordered the plug it says in there (which is different from the one it currently has in it). I did get Yamaha to do a search on their database of the engine number and they very helpfully came back to me quite quickly confirming it was a 1981 SR500. Presumably the wrong plug will affect the spark? It does appear quite weak currently when testing it. I have also drained the fuel tank and carb so I can start a fresh. Is there anything else obvious I'm missing?
Thanks
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Post by stevep on May 8, 2024 8:52:28 GMT -5
I think it's just hard work, starting without a decomp. Also you have far better control over accurately getting it to the point you want to kick with one. If you asked 10 SR riders if they'd be happy to ditch their decomp, 9 would say no. (But there'll always be one!)
I wouldn't say don't start it without one, but perhaps don't make it your long-term plan. You'll get sick of it anyway.
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Post by chrisa83 on May 8, 2024 11:12:52 GMT -5
Thanks, it is proving very hard to start it so anything that would help would be great! Is the attached the area where it should be if its fitted to the engine ie. as an engine lever? its just nice to get some advice of people in the know. I've had bikes on and off for over 20 years but it just seems harder and harder to find people who can and/or actually want to help! Attachments:
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neal
Junior Member
We may need a bigger hammer.
Posts: 37
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Post by neal on May 8, 2024 11:35:09 GMT -5
Hello mate, The decompressor is the part I have marked for you, it seems all that is missing is the cable, which attaches to a lever on your left hand perch. Have a look, it may be a very small job to get sorted. Good luck. .  |
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Post by chrisa83 on May 8, 2024 16:50:22 GMT -5
Thanks mate. Yes that is where i thought it was. Lever has been completely removed from the left hand but I'm going to try to source something one way or another to get this decompression working again.
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Post by redgalvin on May 9, 2024 8:25:02 GMT -5
Until then, put in 1st gear, roll backwards till you stop at the compression stroke, neutral, kick,
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Post by skyshadow on May 9, 2024 8:59:46 GMT -5
I have a completely stripped down SR and I kept the Decomp lever ha. One of my favorite things to use it for is roll starts. If I don't want to kick and kick because it's flooded or something. I run with the bike, Jump on, throw in gear with decomp then release. It will fire right up.
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pops
New Member
Posts: 22
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Post by pops on May 9, 2024 10:12:10 GMT -5
As to the difference in plugs, the "R" stands for resistor. You should have a 5K resistor plug cap on the end of your high tension lead. This eliminates the need to run a resistor plug. Having both would lead to a weak spark.
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Post by chrisa83 on May 11, 2024 13:03:17 GMT -5
Hi all,
Put fresh fuel in today and changed the plug. Would I be able to get this going before the lever etc arrives by just holding my finger on the spring loaded bit on the engine? Same as I would the lever? I can feel the pressure in it build up and release with my fingers as I move the kick start slowly with my foot.
At what point in the window where the white bit appears is it at the perfect point aswell? As it enters the window or when the window is fully white? I am determined to get it going but its certainly proving a challenge!
Cheers
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Post by stevep on May 12, 2024 2:08:40 GMT -5
It's so long since I relied on the window, using just the feel on the cable, but I'd say given the difficulty in achieving precise control of the crank with the Kickstarter alone, either of those two positions will do as your reference point right now. Best of luck!
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