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2007 Bonneville T100
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Discussion Starter · #1 ·
Finishing up my 12K service and I'm running into a couple problems. Unfortunately since I'm in medical school, this project took a lot longer than I thought. Essentially all I did was the spark plugs and valve clearances and switched out a couple shims. Here's a general timeline of what I did and the problems I'm encountering after.

Started off with removing the tank, valve cover, and measured the clearances. All the intakes were over the clearance, and all the exhausts were too tight. I ordered new shims and used a couple old ones I measured with a micrometer to put them all back into spec. Admittedly, after rechecking the clearances, the intakes were way too tight for some reason. I ended up using the old shims I had just taken out and put them all back and now they were barely out of spec, and on the loose end. I had read that overtime, the gaps generally get tighter, so figured it would be ok.

Meanwhile, I painted the tank since the previous owner stripped it down to bare metal. No real problems there.

Swapped out the spark plugs, measured the gap, smeared a little electrode grease on them, no problems here either.

Finally, (this is about 2 months later at this point), camshafts are in, oil line is in (took an extra 2 weeks since I had to order a banjo bolt that snapped), valve cover with a new gasket is on, tank is back on filled with relatively new gas (about a week old, sitting in a sealed gas container). I also fill it up with a little more oil to account for whatever got leaked from taking parts out. It also was leaking from the valve cover gasket so I figured it might need a little. I followed the method posted on this forum where you turn the engine with the rear wheel rather than taking off any covers. I go to start it, and here's where I'm encountering some problems.

Initially it starts but its really sluggish. I give it some time and it gets a little better. I assumed it was some bad gas remaining in the carbs from months ago that had to get cleared out. I let it run for a while and it's misfiring, sputtering occasionally, getting worse then getting better. Initially it wouldn't even rev up to 2k without shutting off. Now it seems like its doing a lot better, revving fine but a little erratic. I haven't balanced the carbs yet so that could be it, but one of my major concerns is the ticking sound.

Before I did any work to it, it had a mild ticking sound which I posted about and was reassured it was pretty normal if not just from valve clearances. Well now I've done the clearances and they should theoretically be better right? However, the ticking sound is much more apparent, and louder. Before I would only hear it after the bike had been running and gotten up to operating temp. Now I hear it the moment it starts up.

Any advice on what might be wrong and where to go from here? My plan for now is to just wait for it to cool off and then this weekend take off the valve cover and remeasure the clearances just in case.
 

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If you didn't drain the carb bowls then my first guess would be that in the two months it's been sitting the petrol has evaporated and left a horrible gunk gumming up the carbs. Remove, inspect, and clean.

Tim

~'05 Thruxton~Sport Evolution 1100cc~FCR 39mm~813 cams~shim-under-bucket~+1.5mm valves~Ignitech CDI~m-Unit~Acewell CA85~F3 Frankenfork~Hagon Nitros~6-piston Pretech~520 chain~wide 17" rims~tubeless conversion~Michelin Road 5~
 

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2007 Bonneville T100
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11 Posts
Discussion Starter · #4 ·
If you didn't drain the carb bowls then my first guess would be that in the two months it's been sitting the petrol has evaporated and left a horrible gunk gumming up the carbs. Remove, inspect, and clean.

Tim

~'05 Thruxton~Sport Evolution 1100cc~FCR 39mm~813 cams~shim-under-bucket~+1.5mm valves~Ignitech CDI~m-Unit~Acewell CA85~F3 Frankenfork~Hagon Nitros~6-piston Pretech~520 chain~wide 17" rims~tubeless conversion~Michelin Road 5~
Thanks for the suggestion, it's something I was considering but hoping to not have to do. I'll do some searching on the forum for a guide, any recommendations?
 

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Compared to shimming your valves this is a faaar easier job. Tank off, disconnect the throttle cables (fiddly), carb bowl drain tubes, overflow pipe and carb heater wires, loosen the hose clamps on the rubbers for the airbox and cylinder head and wrestle the carbs out the right side of the bike (there's a little more room that side). I'd recommend dismantling the carbs somewhere warm, dry and well ventilated - preferably with easy access to a cold beer or two and definitely with the permission of your significant other. A spray can of carb cleaner and plenty of lint-free shop rags is a must, but the carbs come apart easily with regular tools. Best practice recommends dismantling one side at a time to avoid mixing parts and installing them on the 'wrong' side...

Tim

Sent from my MI PAD 4 using Tapatalk
 

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I have found that the valve clearances tend to be quite variable and I need to rotate the engine a few times in between readings, take about 3 readings and use the average. I don't know why it is like this, but it is a pain in the arse. If the clearances are within a couple of thou (.002") of the limit - Hi or Lo - I would leave it alone.

As you took your cams out, did you get the timing correct when they went back in? Did you do one camshaft at a time?
I don't think it would even run if you mixed them up, but, it might.

The ticking may be caused by the backlash spring in the cam shaft driven gear not providing enough preload to stop the gears slapping from one side to the other as the valves push on the cams. Only check this after you are sure the timing is correct. If fact you don't even have to run the engine to hear the noise - see this video
 

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2007 Bonneville T100
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Discussion Starter · #7 ·
Compared to shimming your valves this is a faaar easier job. Tank off, disconnect the throttle cables (fiddly), carb bowl drain tubes, overflow pipe and carb heater wires, loosen the hose clamps on the rubbers for the airbox and cylinder head and wrestle the carbs out the right side of the bike (there's a little more room that side). I'd recommend dismantling the carbs somewhere warm, dry and well ventilated - preferably with easy access to a cold beer or two and definitely with the permission of your significant other. A spray can of carb cleaner and plenty of lint-free shop rags is a must, but the carbs come apart easily with regular tools. Best practice recommends dismantling one side at a time to avoid mixing parts and installing them on the 'wrong' side...

Tim

Sent from my MI PAD 4 using Tapatalk
Thanks for all the info and reassurance! I'll hopefully get that done this evening or tomorrow, the holidays have really cut into my time. I'll post some updates when I get it done.
 

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2007 Bonneville T100
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Discussion Starter · #8 ·
I have found that the valve clearances tend to be quite variable and I need to rotate the engine a few times in between readings, take about 3 readings and use the average. I don't know why it is like this, but it is a pain in the arse. If the clearances are within a couple of thou (.002") of the limit - Hi or Lo - I would leave it alone.

As you took your cams out, did you get the timing correct when they went back in? Did you do one camshaft at a time?
I don't think it would even run if you mixed them up, but, it might.

The ticking may be caused by the backlash spring in the cam shaft driven gear not providing enough preload to stop the gears slapping from one side to the other as the valves push on the cams. Only check this after you are sure the timing is correct. If fact you don't even have to run the engine to hear the noise - see this video
Before I started the valve's I also was considering that it was one of the backlash springs. I actually bought 2 of them just in case I need to replace them. My plan was to see how it sounded after doing the clearances but since my values were off by so much when I measured them I assumed that's what caused the ticking. Also before, the ticking was only audible after getting up to operating temp.

I did both cams at the same time but double checked everything and had a piece of cardboard with holes in it to hold all my screws, labeled where they all go. So I'm sure nothing got mixed up, cams were back in the same place aligned with the dots and dashes, and the engine wasn't turned while they were out.

I did notice that when putting the cams back there was a little play in the alignment though. Id say it could be moved about a fraction of a centimeter along the length of the camshaft and still make contact with the other gears and be held down by the holders. Could that cause anything? Should it be pushed as far as it can go towards the left or right side of the bike or something?
 

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If it was my project I would go back in to double check my work pertaining to valve clearances. As RichBin mentioned I would rotate engine several times and check clearances and all related parts again. Once your are positive that all is well in that department I would look for other causes. It might be possible that something else has gone wonky at the same time you worked on your valves, this can make troubleshooting difficult as we tend to look at what we just did instead of a new problem.
I once put together my Suzi 1000 with the cam timing one tooth off :rolleyes: and it still ran but poorly. Luckily it did not do any damage.
 

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I think axial thrust on the camshafts is controlled by the right side cam caps. Should be some slight play, but not a lot.
You won't be able to control the position of the camshafts once the engine is running, they will go where they want to.
 
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