Looks like I've got a carb problem

[slobinski]

A completely unscientific observation here:

Last week I put my 2007 T100 on the lift table to change fork oil (yecch! I waited too long again!) and install a new front tire. Finished with those chores, I started the engine and warmed it up, thinking I'd change engine oil while I was at it. The bike's mufflers were about a foot and a half from the (white painted) wall. Once finished with the oil change I saw that the pattern of soot splattered on the wall from the pipes was uneven.

The right side left a noticeably darker blob than the left. Also the left pipe is a bit more blue than the right, near the engine.

This is a second bike and doesn't get ridden as often as it should, but starts easily most of the time and gets around 44 MPG on a regular basis. About 12000 on the odometer.

Whatcha think? Float level? Synch? Idle mixture out of whack on one or both carbs? Jets and other items are all stock; I've never fiddled with the carbs. Would appreciate any suggestions.

 

[rndtaylor1]

Sync.
Good set of vacuum gages and a 6 pack for patience will balance them at idle.

I'm intrigued with your new method of checking balance, and wondering what the device looks like to check at full throttle under load.......

I am envisioning a white painted board attached to riders boots to get a good splatter pattern at the ton....

A brave partner with a steady hand to adjust for you at speed will make balancing a little quicker.

 

[slobinski]

Synch, huh? Guess I'll be learning how to do that.

As for the full load balance testing, after spending several minutes doing exhaustive scientifical ree-surch, I've designed a system using an outboard motor trolling plate, clamped to each muffler, operated by a cable. The rider could then get the bike up to speed, lower the trolling plates into place, and whack on the throttle. The resulting splat patterns could then be compared and analyzed. I've got to hurry and get this system built and patented; could maybe sell it to Motion Pro?:d

 

[beemerrich]

Does the bike run strong? If so, just ride it and don't worry about it.

The differences you describe are minor and could just as easily be a result of differences in how the rings broke in or slight variation in how gummed up the left carb gets vs. the right. Put some seafoam in the tank if it makes you feel better.

Regards,

--Rich

 

[craigc1947]

A completely unscientific observation here:



The right side left a noticeably darker blob than the left. Also the left pipe is a bit more blue than the right, near the engine.

Sounds like my bike! 2006
Tuned by a pro. 125 mains 42 mids @ center groove and 2 1/2 turns on the idle jets

 

[slobinski]

Update...

Well, I got industrious the other day and ordered a carb synch gadget and a fresh set of spark plugs. Dug out the feeler gauges etc and went to work.

Valve clearances were still all within spec, so once everything was back together, the bike got fresh plugs and a stern talking-to. It fired up easily, and once warmed up I installed vacuum hoses and zeroed the balancer. The carbs were indeed out of balance a fair amount. A bit of fiddling with the adjuster fixed that. The idle is noticeably smoother now. Haven't taken it out for a romp just yet (colder than a witch's tit this morning).

The tool I used is called the Harmonizer; it's all electronic with a small display calibrated in millibars. I was able to get things within 1-2 millibars vacuum in just a few minutes and the thing is kinda fun to use.

 

[Motley]

So it seems you have your problem solved, good.

I used a homemade manometer of sorts for a while, it worked to synch the carbs but wasn't the best. I invested in a Motion Pro Syncpro and it works really well.

These bikes are a pleasure to work on, aren't they?

 

[slobinski]

I nearly bought the Motion Pro tool you mentioned, but liked the idea of having no mysterious fluids to spill or evaporate while not in use.

Compared to its Tiger 800 stablemate, the Bonneville is truly a piece of cake to work on; pretty much instant gratification.