Please Help engine bogging down

I took off on the bike (81 650 Maxim) this morning and as I was going down the road the bike wouldn't speed up. It was acting like a car with the plug wires switched around. This has been coming and going for a while now but has always gone away. Can somebody please direct me to the right area to check. If it is the coils or pick up coil please let me know how to check it.
Thanks.

 

read the ohms on the small wires (low tension leads) on the coil, the spec is 2.5Ohms +/-10%
next do the large wires (high tension leads) and the spec is 11KOhms +/- 20%
i tried the pickup coil resistance on my bike and couldn't find the blue wire the book mentions. the pick up coils go to the TCI box (under side left panel) to the 6 prong connector that only 4 wires will be connected to, check them with your meter, you should have low ohms there once you make sense of the wires. The 4 prong connector coming out of the TCI box goes to the coils, do continuity and Ohm checks there as well.

Maybe it's a fuel delivery problem? gas filter?

 

My filter is the first thing I'm going to change since it's three years old. I'm just looking for other things to look at if it doesn't fis it.
Thanks

 

thats a great start if it is a fuel problem check the filter and the petcock. another way to check the petcock is drive it when it starts to bog down switch it to prime see if that helps, does it do it after it gets warm or all the time? could you have gotten a little water in your gas last fill up? all things to take into consideration . check the coils and other electrical stuff first good luck

 

I tried to changing to the reserve side and it made no difference. I would say that it does it more when the engine is more on the cold side.
I got home from work tonight I did look at the filter and it looks pretty dirty (Will change ASAP). I checked all of my electrical connections and all looked good. Started it up and it sounded good, but after it was good and warm there was a little back firing, but not too bad. The really strange part is I took it out for a short ride and it ran fine. GO figure. Does anybody have an answer for this one now since it is so intermittent?

 

i had the same problem with one i just bought. sometimes it ran. sometimes it backfired. sometimes it just only idled. it was pretty obvious it was the fuel. the problem also went away if i disconnected the fuel line. i pulled the carbs down and one float was sitting at 19mm. 3 were sitting at 14. right now there all sitting at 16 and so far no fuel problems.

i also went through the fuel switch and replaced the automotive fuel filter with a motorcycle fuel filter. and replaced the spark plugs. the previous owner porsche plugs instead of yamaha maxim plugs. he had NGK plugs. BP7EVX instead of BP7ES.

 

fuel delivery is pretty sensitive with my bike. I have a small fuel filter But, if I don't get the fuel line perfectly horizontal or on a downslope the fuel won't flow quick enough and the bike will bog. It's strange because I actually have to shove the filter bewteen the 2 rubber intake airbox boots and the 'wedge' action keeps it there, but if it vibrates up again the bike sputters. guess I have to make different lengths tubing But I read the the filters should be installed to be Vertical, if I change the two tubing lengths on both sides of it it won't be vertical. Anyway, if yours is clear, i think they all are, check that it's full all the time during revving

 

Thanks for the advise. My filter is stright with the tube on the rear sitting at a 45. When I look thru it is is preety brown so I plan on changing it the weekend. I might have to change the length of the tubes because I get a air pocket in the filter sometimes if it's not sitting just right.

 

Have you done any work on your bike recently? If not it sounds like time to take the carbs out and clean them. Bogging down is a sign that the carb slides and sitcking.

 

I haven't done anything to the carbs lately but I changed a needle and seat a couple of years ago and they were spotless inside then and all I run is premium in it. Plus I run some lukus treatment at least once a season

 

If it has been a few years since you last cleaned them then its time to do it again. I take mine apart every two to three years to clean them. Seems no matter how good your fuel filter is the pilot jets seen to collect dirt and the slides become sticky with fuel residue.