Xciting 500 2007 won't turn over

[willembop]

So I've installed a new starter and with battery voltage applied directly to the starter, the engine only makes about one turn and stops when it gets to the compression stroke (at least that's what it sounds like). Nothing wrong with the starting circuit. Does this even with a car battery. With the engine side cover off, I can turn the engine over with a wrench, but it has quite a bit of resistance at the compression stroke. I'm thinking the decompression mechanism should make it easy to turn. With the spark plug out, it turns over easily, with the starter or wrench. So I'm going to next look at the decompression mechanism on the exhaust cam.  (The part identified in the service manual as the "decompression system" on page 8-9). I can't think of anything else. Anyone ever done this?

Bill in Fredericksburg, VA

[xsel777]

Good luck Bill. It sounds like you have some mechanical skills.
Good for you, since sending it in for repairs will hit your pocket hard.
It definitely sounds like you are on the right track here.

I am going to check my manual now, and see if that issue requires a new exhaust camshaft.

At my local workshop I saw XC 500 requiring a new exhaust camshaft since it was hard to start as well. This one is EFI, and it turned out eventually it actually needed a new computer.

This is a 5 month story ; I know because the owner saw me working on my scoot outside and stopped to talk, and told me his sob story. It brings tears to my eyes, the frustration of waiting, and no doubt the expense.

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[CROSSBOLT]

I do not have your kind of scoot(s) but I am curious like a cat as to why these 500's seem to have these start problems. I will wait to hang on your every word(s)!

Karl
DT300i

[xsel777]

Crossbolt, the answer I see most often is the battery was under- specced for this model.
Then there is the decompression cam story.
Another one  is the charging thingy inside the engine(stator) , that seems to wear out over time.
Then there is the regulator.
Another one would be bad earthing.
Mine was battery & regulator. "WAS"  is where I want it to stay!
Being stranded is no joke.


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[CROSSBOLT]

I have been really spoiled!

Karl

[wkreps]

I want to be spoiled. Having a few starting issues myself. Only started since the cooler weather. Maybe cooincidence, don't know. Replaced the battery. New iridium plug going in today along with synthetic oil. The stator seems to be working cause the battery was 13.5v when idling the other day. This may turn into a help post later if these things don't help.

[xsel777]

I trickle charge every night. I also carry jumper cables and a spare battery. Probably the cables will go, as space in my top box is becoming cramped with all this rescue equipment!
I also have the battery compartment loose, so I can read my voltage at any time. The reason for that is my charging voltage is all over the place, not consistent. Stator is the only thing not replaced.
I also ordered led headlamp and parking lights to lighten the load.
It will take a month from Hong Kong to South Africa by China mail,  so there will be a delay with photos.... 😊
Wkreps, I wish for you to be spoiled too.
Hopefully you have sorted the issue now.

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[willembop]

So I finally got the top end apart and the exhaust cam out. The cam lobe appears to be worn beyond limits. Calipers measure it at 1.46" and the service manual gives a limit of 1.4744. I'll have to find my micrometers and confirm the measurement before I order parts. Also need to check the intake cam. The decompression cam looks okay, but I removed it from the exhaust cam to see what it looks like inside, and released three tiny sets of springs and balls from inside the mechanism, and I'm not sure how to get it back together, although I'll attempt it -- with the shape of the springs, there's only a couple of ways they could go. Doesn't matter because I probably need a new cam and can order the whole assembly with a decompression cam.

When I finish measuring I'll try to post some photos.

Bill in Fredericksburg

[koutsouk]

So I finally got the top end apart and the exhaust cam out. The cam lobe appears to be worn beyond limits. Calipers measure it at 1.46" and the service manual gives a limit of 1.4744. I'll have to find my micrometers and confirm the measurement before I order parts. Also need to check the intake cam. The decompression cam looks okay, but I removed it from the exhaust cam to see what it looks like inside, and released three tiny sets of springs and balls from inside the mechanism, and I'm not sure how to get it back together, although I'll attempt it -- with the shape of the springs, there's only a couple of ways they could go. Doesn't matter because I probably need a new cam and can order the whole assembly with a decompression cam.

When I finish measuring I'll try to post some photos.

Bill in Fredericksburg

My dear friend sorry that i will disappoint you but a new cam will not solve your problem . ( i have had changed 2 , with the decompesor )
As i can understand you bike has a carburator and not injection fuel system.
Try to close the idle bolt fully so the bike can not hold idle ar all.
If you try to start it the starter will not hesitate at all.
Try to find the epitome of good idle , maybe a bt less than 1300-1400 rpm . perhaps 1200 rpm so the butterfly is a bit closed.
The bike will start more freely. I did not solve the problem until i sold my bike    but this trick made my life a bit easier particularly in the winter season .
I hope you find the solution and please post it here.
I will be glad to reading it.

[willembop]

My dear friend sorry that i will disappoint you but a new cam will not solve your problem . ( i have had changed 2 , with the decompesor )
As i can understand you bike has a carburator and not injection fuel system.
Try to close the idle bolt fully so the bike can not hold idle ar all.
If you try to start it the starter will not hesitate at all.
Try to find the epitome of good idle , maybe a bt less than 1300-1400 rpm . perhaps 1200 rpm so the butterfly is a bit closed.
The bike will start more freely. I did not solve the problem until i sold my bike    but this trick made my life a bit easier particularly in the winter season .
I hope you find the solution and please post it here.
I will be glad to reading it.

You could well be right. I'll try out your suggestion when I get it back together. (I'm still waiting for some parts.) I'll keep you posted.

[xsel777]

I feel for you buddy. My 500 has had 3 camshafts already in the 2 years I have owned it.2010 efi model year.
Fantastic on your technical proess. You are saving a mint this way.
I had to go via the dealers so the bills were large.
This will absolutely solve your starting and driving problem, but not necessarily the cold start problem.
I eagerly await a progress update.

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