Hi folks,
Maybe this is just a sign of the bike's age, but I wonder what usually causes it.
Riding along, there will be little backwards jerks here and there, with the bars pushing on the hands, like maybe an occasional misfire or just one bad power stroke every few seconds. It is worse when the bike is cold, but even riding on the highway for 45 minutes I'll sometimes get a little of it. If I push to over 7K rpms they seem to go away, but I haven't been able to ride enough since noticing it to try to be real scientific about it. On the HW I thought it was some fuel starvation. In town I wondered if it was an ignition problem. On the HW it's more noticable when it happens, because they are rather large jerks and I think I can actually hear it in the engine, but in town I can't but I can feel them.
I thought I'd ask in case this sounds real familiar, and maybe someone can say with reasonable certainty what it is, and how much to worry about it. Or maybe could ask me some questions or offer possibilities.
FWIW I have original exhaust, had the engine tuned and jetted as per Srinath's prescription last fall, by our local mechanic. (I know when I work on it I will take too much precious riding time, so I prefer to throw money at problems for now, but I like to know what's going on nonetheless.)
Thanks,
Mike D.
EDIT: I think I have gotten it when the bike was on PRIME once on the HW.
ALSO I should point out that it hasn't been so easy to start in the morning lately, even when 55+F on the thermometer. Maybe unrelated.
OK sounds like lean misfire to me ... steady throttle cruise and it does it right ... then its definetly lean mis fire ... extra washer under needle ... you got 125 mains and 40 pilots and 1 washer and 3 turns ... if so check float level before taking it apart and washering the needle ...
Cool.
Srinath.
Quote from: seshadri_srinathOK sounds like lean misfire to me ... steady throttle cruise and it does it right ... then its definetly lean mis fire ... extra washer under needle ... you got 125 mains and 40 pilots and 1 washer and 3 turns ... if so check float level before taking it apart and washering the needle ...
Cool.
Srinath.
Cool. Will this kind of lean-ness likely show up on the plugs?
I forgot to mention that once, a few months ago I was riding down the interstate and the engine sputtered to a halt on the highway, and I had to pull over. (No carb work has been done since, except idle adjust.) After it sat a few it ran like an absolute champ. So in the back of my mind I'm thinking there might be a problem before the carb, but anyhow I'll check that stuff out that you wrote. Thanks.
OTOH In town, if I start her up with the choke it eventually wants to idle at like 4K+, so I release the choke gradually but maybe before she's really ready and I get some unsurprising sputtering. Your lean diagnosis could be spot-on, since when I described this jerkiness in town it was when warmed up fully. (Ditto highway.)
Thanks,
Mike D.
OK reading plugs is very accurate ... however its near impossible at anything other than Idle ...
This is the short version ...
Jetting depends on Throttle position ... so you have a problem at say 1/2 throttle ... you will need to hold 1/2 throttle till the rpm stabilises, and then hold it for 3-5 seconds to get the plugs burnt to that setting ... then Without changing the throttle setting hit the kill switch ... let the thing die and yank the plug ... OK so here is the deal ... you'll never get anywhere near 1/2 throttle and steady rpm wihtout load ... so youhave to be driving or on a dyno ... So In short ... accurate but impossible to do it that way ...
So simply put ... plug pull .. nope ... You'd have to do the experiment a few times and tell us what your symptoms are ... but hey ... its just contrilled riding and making mental notes ... easy ... anyway you should check float level, and then lift needle if float is fine ... also you make sure you're getting gas flow to carb ...
Cool.
Srinath.
Thanks Srinath,
As I often do, I had a chance to ride it to the local entrepreneur mechanic and did so, before I had a chance to check the plugs myself, since I had a short list of stuff I wanted him to do anyhow. I told him everything you told me, and he gave me a nod and said it all seems reasonable and he'll check it out. I've been pretty much a wuss lately when it comes to actually doing the work myself, but I convince myself I'm trying to help keep our local, young business owners going. Some summer when I have another bike in reserve, I'll take it all apart myself and see what's up, but with the two kids to watch/entertain that's considered severe goofing off on my part. Still I appreciated the advice and will certainly let you know how everything comes out. Someday I'm going to ride to your neck of the woods and see what kind of magic you can do for it in person! (I have a vision: new fork brace, new bars, sweet carburation...)
Later,
Mike D.
Quote from: geekonabikeThanks Srinath,
<snippage>
Someday I'm going to ride to your neck of the woods and see what kind of magic you can do for it in person! (I have a vision: new fork brace, new bars, sweet carburation...)
Later,
Mike D.
Sure thing ... come on over ... in any case its almost as easy to mail these out ... cos you show up here ... I'll make you do your own work ... mostly ... :lol: :lol: :lol: while I hover over you barking orders ... ask Davipu ...
Cool.
Srinath.