bogging/backfire

[cobrasneverdie]

Good day fellas, I have finally got my bike running. I've been riding it for a few days. I have owned the bike for a year. I am a student so money kind of slows me down in terms of parts and rebuilding things, that coupled with lack of knowledge and lack of garage. Anyways I don't know much about how well this bike is supposed to sound and ride. I definitely know that I need to tweak things here and there.

So this has happened twice already, sometimes the bike backfires, sometimes it's boggy. This morning was slightly cold, I fired it up. Usually takes me 2 kicks to get her going, took a while. I was about halfway to work when it died on me. It was boggy started to putt. I waited a little bit, kicked it and it ran. I headed to a gas thinking maybe I'm running out of gas but something tells me it wasn't the case. But What I'm going to do is check my cam tensioner, valve clearance, check my advance rod, and check the carbs.

Sometimes I get around riding and there are no problems.

*additional information:
1976
ignition: pamco, coil: green monster, pma
I installed a rebuild kit on the carb last year. Never got around to checking bowl clearence (a friend of mine helped me put it together, he said don't worry about it as he eye balled it, I am worried now). I also have not checked the slide jet needle
I also have not performed a proper compression test yet.

 

[5twins]

If you installed rebuild kits in your carbs that included needles and jets, that may be the cause of your problems. The kits usually contain incorrect jet sizes and the wrong needle. Put the stock jets and needle back in. Stock sizes for your '76 carbs would be a 122.5 main, 25 pilot, and a 4M1 needle set in the middle or #3 slot. I think the rebuild kit for your carbs comes with 135 mains, 27.5 pilots and a generic Y-22 needle that is several MM too short (which would make it way too rich).

 

[retiredgentleman]

You should measure the battery voltage at 3000 rpm. Perhaps a load test of the battery also.

 

[cobrasneverdie]

hey 5twins,

I will have to try and find them now, I stupidly thought hey this new kit is going to solve my problem. I think I have them somewhere though, I hope at least. You said that it would make it too rich, I saw that one of my plugs was a bit more charred on one side. Would this be because it is too rich?

I'll have figure everything out once I have time. Thanks for the quick reply.

Also while you're here, do you know what wrench size both bolts to change the oil are. I tried to look it on my manual but I was unable to find it.

 

[cobrasneverdie]

I got the bike without a tach, and it's a new battery.

How do I go about checking without a tach?

 

[Brian902]

1 1/16" wrench if you don't have the metric size.

27 mm

 

[cobrasneverdie]

Thanks Brian

 

[5twins]

Just rev the bike up to medium or mid RPMs. That should be about 3 to 4K. The charge rate should climb from around 12 or 13 at idle to around 14 volts as you rev the motor. No increase in charging rate indicates you have a charging problem and you'll need to start checking things to find it.

If by a "charred" plug, you mean black, then yes, that's an indication you're running too rich. If only one side is like that, it could be your buddy's "eye ball" float setting. He must be a pretty good wrench to be able to do it that way, lol. Float settings are pretty critical on these carbs. Many times the floats are twisted or tweaked and sit at different heights side to side. You need to measure both sides to discover that. The spec for your carb set is 25mm ± 1mm. I use a 6" steel rule graduated in MM on one side. I place it on the far side of the floats and sight directly across the tops of them. You must look straight on at them like this or your reading will be incorrect due to the parallax effect .....

Here's the same floats viewed from the wrong angle and as you can see, the reading is way off, like by 2mm .....

 

[cobrasneverdie]

thank you so much! I appreciate it a lot. I'll have to go in and check this out.