i've ordered a multimeter and i think next weekend i will start for tuning carbs. Today something weard happened. i was riding, and when i was waiting on red light my bike stopped, i started it again and increased the idle a little. it was ok but 2 mins later my bike wasnt reacting the throttle and just after that it stoped, i had pulled over my bike and tried start but it didnt start, then i tried again and again. sometimes it was almost starting but then stopping again. then after trying 2 mins i heard some backfiring on exhaust and it started. i think my carb was choked. Same thing happened last weekend.

What's the reason of this? I've tried to clean my carb 3 weeks ago. and then i couldnt do tuning of the carbs. While decelerating i can hear some popping from my exhaust. and on idle and low rpm, its not working so good.

If I do carb tuning, is it enough or should I clean the carbs again?

 

You might check your r/r on the right side of the bike, behind the rear side cover.
Look at the r/r and connector for signs of heat. Warped/melted plastic, burnt pins,
cracked/melted epoxy fill on the r/r. If it's going bad you lose current to the ignition.
As it starts to fail, the heat from the running bike will trigger it. When it cools down,
at first, it will "fix" itself.

Ern

 

JScottB My multimeter arrives on thursday but I did a quick read of the manual that you can find online. Try using the wire that goes to the tach on the bike itself, and just ground the other wire out. I can't elaborate right now because I am just starting work. Hope this helps a little though

 

I think what stumped me was that I was expecting the same response that I did when adjusting the pilot screws on my kids previous '85 vf500f, its pilot screw adj procedure was literally word for word the same as the one in the CBR's manual and when backing the screws out on the vf500 from their initial setting would make the rpm rise around 200 rpm just as its manual said I should expect so I was expecting a similar response from the CBR as well. The carbs were synced prior to any pilot screw adjustments and when I didn't get the response I was expecting when I did adj them I started looking for a vacuum gauge instead but couldn't find one. It turns out that I had given the vacuum gauge that I had to my oldest son when he left for college so I'll have to get another one.

As far as hooking up the tach, I've searched and searched the internet trying to find just exactly where to hook up the tach/multimeter but haven't been able to find an answer. I did spot the the page in the manual about testing the tach of the bike itself but had assumed that was for checking the voltage that the ECU was sending the tach and wasn't sure whether that could be used for the tach function of the multimeter as well. I basically didn't want to aimlessly hook the multimeter to any old wire and running the risk of something going up in smoke unless I knew for sure. I'll give it a try and let you know what I find.

 

Hello JScottB,

How do we gonna connect the vinyl tubes to the carb, is there any adapters? Or can we just plug them directly?

 

And the winner is IDoDirt!!!!
I just tried it a few minutes ago and the tach on the multimeter read accurately this time. With the tach switch on the multimeter set at 4cyl, black lead from meter to ground and red lead from meter touching the terminal in the above pic. The idea of attaching a wire to it for future use is a good one as well. I just still need to get a vacuum gauge for setting the pilot screws.

If possible I think it would be a good idea to post a "sticky" on hooking up a multimeter tach because while searching the internet for an answer, I came up with a few posts on this site where someone was asking the same question but got no response.

Grkan13, if you're referring to the vinyl tubing I used on my DIY manometer, I'm using 3/16" OD 1/8" ID vinyl tubing and the reason I used that size was because I needed a bunch of it and it was cheap. The 1/8" ID tubing was a bit on the small size for hooking up to adapters on the intake of the bike but it worked. Scott

 

Did you try adjust the pilot screws again now that you have the tach hooked up properly?

 

Not yet, I normally don't mess with anything until I have some time off on weekends. The only reason I've been home all day today is because I took the day off due to a back injury so I basically just went out there to hook the tach up and give it a try and then came back inside. Besides I still want to get another vacuum gauge first.

 

As I read on web, they say, first sync ur carbs with vacuum gauges then tune ur pilot screws, today im starting make shopping list DIY vacuum gauge and tomorrow starting to build it. On the weekend I will sync and tune them. But Im not so sure about cleaning them again. I've cleaned them 1 month ago but I was using with untuned carbs all the time after cleaning. And in this month my bike stopped 2 times while riding and took 1 min to make it start again. I will check R/R on this weekend too as Ern said.

 

So what is the process for adjusting the pilot screws with a vac gauge, I just spent 60 bucks on the tach for this purpose lol I hope it works for me.