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2001 Bonnie: Installed TORS, changed jets, now bike runs terribly!

3K views 15 replies 8 participants last post by  Scot66 
#1 · (Edited)
I recently installed TORS on my 2001 Bonneville and replaced the stock 110 main jets with the recommended 115s and now my bike is running very poorly: Uneven idle, pops, chuffing, poor low throttle response, when running at a steady 30 or so miles an hour it almost feels like you are riding with the rear brake depressed (if that makes any sense). Last year when I bought the bike it ran very poorly. I pulled the carbs and thoroughly cleaned the pilot and main jets, blew out the various passages, removed the AI, removed the anti-tamper plugs and turned out the pilot screws two and a half turns. The bike then ran great. I ran it all of last season and have been riding it often so far this year....no problems or hiccups. I installed the TORS, dropped the bowls and swapped out the main jets with the recommended 115s and changed nothing else. Ever since then the bike has been exhibiting the problems I described above. It also seems to me that the problem(s) are progressively getting more pronounced. I'm pretty perplexed at this point as I'm not really sure where to begin to figure out what is now off. It was my belief (perhaps mistakenly) that the main jets have little to any influence on the bike's running at idle or low throttle opening positions, so I can't see where the increase in jet size would have created the problem. Any help or suggestions will be greatly appreciated.
 
#7 ·
I don't usually disagree with Pieman, but my experience was different. My 2003 ran very lean from day 1. Hard to start, slow to warm, lots of backfiring. 115s and 42s cured it.

OP -your problem really does sound more electrical than carb/fuel. Especially as you state that it's getting worse. Trying a new coil is a very good idea. Good luck.
 
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#4 ·
Mr. Scot66,

Do you have a friend with whom you could swap out the ignition coil and see what happens? To me, it sounds like that could be an issue.

Charles
We know that drill don't we Endoscopy? Thanks again by the way.:wink2:
 
#8 ·
With a 15 year old motorcycle there are certain things that need to be checked and changed just because of age. Have you replaced all of the vacuum caps on the carbs? Have you replaced spark plugs and wires? Have you checked the rubber carb boots for cracks or vacuum leaks? With a 2001 you should also check the pick up coil gap and make sure that it is adjusted to 0.8mm . Check the fuel filter at the t fitting on the carbs. Also pull the petcock and check and clean it. Make sure that all of these things are done first. After that then try ignition coils and cdi.
 
#12 ·
All excellent suggestion! So far I have checked and replaced the vacuum caps (they did have cracks in them, though I couldn't blow through them). I currently have the carbs off so that I can fully inspect the carb boots, though they appear to be in good shape with no obvious signs of deterioration. I removed the carb tops (I didn't do that last year and wanted to verify that the diaphragm rubber was still in good shape and not deteriorated) Both sides were in excellent shape. I currently have the float bowls off and am just verifying that everything is as it should be. I also pulled the small inline fuel filter and though it didn't have any major particles or sediment in it, it was very misshapen and almost wadded looking when I removed it. I'm not going to reinstall it and will, instead, replace it with a small inline filter at the junction where the two fuel lines come together under the tank. I also want to check and verify the float heights once I completely get my head wrapped around how to check it. Once I get the carbs back in place, I am going to check the valve clearances since the Bike recently turned 11,000 miles and I don't know when they were last checked. The air filter looked good, though I will probably go ahead and replace it as I'm sure it is the original. I may go with a UNI. I pulled and checked the plugs and they look as if the bike has still been running more on the lean side though last year I set the pilot screws to 2 1/2 turns out. I will replace the plugs anyway as they are cheap and I don't know when they were last replaced (if ever, as the bike only had 8,000 miles on it when I purchased it late last Summer). That's where I'm at, so far. Again, she was running great before I swapped out the exhausts and main jets. That's what has me perplexed, as it's the only thing that I changed. 3 weeks before I did this, a couple of friends and I rode around 250 miles and it never missed a beat. The only other thing that is different is that I changed the seat with a Triumph Scrambler seat (the solo seat with the integrated rear rack). I know that some owners have had problems with the main connector at the CDI being crushed or having too much pressure exerted on it with their seats, but it doesn't appear to me that I have been having that problem. All connections looked tight and there didn't appear to be any signs anywhere of having been distressed.
 
#10 ·
If it is running better when first started/engine cold and gets worse as the bike gets hot, then the jetting is too rich. If it runs better hot than cold, then the jetting is lean.

My guess is that the old girl has grown fond of your attention and has created another problem so you get to spend quality spanner time with her...

Regards,

--Rich
 
#14 ·
Thanks everyone for the replies and great suggestions! I'm checking all of these things out and doing preventative maintenance as I go. I'm trying to get the heart of this problem and get a few other things checked and rectified (if needed) for 1000+ mile trip I'm planning on going on next month. Please keep the suggestions coming.
 
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