I have a 72 Interstate. Late last year I had it running good and then stored it for the winter. excited to ride it all summer I went to start it and it ran sluggish and bogged around 4000is rmp. I was told its probably a pilot jet. I took apart the carbs and cleaned them, used a guitar string to clean pilot jet, new o-rings and gaskets. Put them all back together and went to start the bike. It started but the same thing is happening and now I have fuel spitting out the RH exhaust. Is it still a carb issue or should I be looking elsewhere? Thanks.
Whats the problem?
- Thread starter blipJC
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running elect ignition, plugs have about 15 hrs of use, fresh gas and good flow, choke open and closed no help. changed needle settings, no luck. Just changed alternator and rotor a few days ago. That was the only change from last year. I had better luck getting it running last summer after sitting for 29 years.
Double or triple checked ignition timing with a strobe, inc verifying it advances with more rpms ?
jamesp has a longish running thread here with the same problem - won't rev over 4500 after standing for a long while.
He seems to have been through everything 2 or 3 times, still same result.
Is someone selling gas that won't rev ??
Although cleaning out carbs and ensuring the jets and passages etc are clear sure is a mandatory 1st step.
And also that no fiberglass tanks are involved....
jamesp has a longish running thread here with the same problem - won't rev over 4500 after standing for a long while.
He seems to have been through everything 2 or 3 times, still same result.
Is someone selling gas that won't rev ??
Although cleaning out carbs and ensuring the jets and passages etc are clear sure is a mandatory 1st step.
And also that no fiberglass tanks are involved....
I don't know if the alternator is woking. haven't had a chance to ride it and test it. is there a simple way to check with the bike running and a volt meter? I thought they don't produce a charge until 4000 rpm ish. I changed them because last year the batterie would die after an hour or so of riding and the bike would stall and wouldn't start w/ elect. ign. until I charged it. Last year I changed the wire harness and all the elec., all new cables, front and rear brakes, rebuilt the carbs. new seat and exhaust. Basically rebuilt the whole thing except. motor and trans.
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Would it be too mean to suggest checking everything you handled and changed? If hi beam brightens on blip then charger is good enough to over come even a poor battery after mid 2000's. A dead unchargable battery will not let ya even start till disconnected. Some are lucky enough just new plugs solves roughness. A carb leak shows up same as over tickling mostly dripping outside of engine so to see fuel out exhaust - implies lack of ignition.
Not mean at all hobot. Last thing I changed since it ran good was the alternator and rotor. Maybe the batterie is no good. I will recheck all my wiring tomorrow and see if that is a problem. There is no one left around here in my city that knows anything about British bikes, and no one will touch anything other than a Harley. The closest place is 900 KM away that will even help me with parts and advice (other then here), so when I need a part I have to wait close to a week for delivery. I have done everything myself so I could have made a mistake. I had better luck getting it running last summer after sitting for 29 years.
blipJC said:
Put a volt meter across the battery and start the bike. At 2000-2500 rpm you should see the voltage start to come up. Run it up to 4000-4500 and you should see a steady voltage at something around 13-13.5V (or more depending on your alternator/regulator set up).
Will the bike hold a steady 4500 rpm in neutral ?
Greg
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it is POSSIBLE that you are not getting fuel flow at the higher rpms you say you are having a problem achieving
maybe the tank gas cap's little air breather got plugged over the winter
try opening the cap and then in neutral see if you can increase the throttle until the rpms keep going up past your 4000 problem area
maybe the tank gas cap's little air breather got plugged over the winter
try opening the cap and then in neutral see if you can increase the throttle until the rpms keep going up past your 4000 problem area
I have not tried to put in in gear since the carbs were taken apart and cleaned. I will check with a volt meter as Greg suggested. When I tried to run it last weekend it would idle good at 15k and rev up to about 40k then stumble back down to 25k and idle fine again, when I had it in gear it had no power and and with throttle wide open would not go past 40k rpm and a top speed of about 40 mph. After about an hour of 2 min trips and 5 min of idle between trying to dial in the carbs the batterie would not have enough juice to start it again when it stalled. After an hour on the charger it was good to go again, but with the same results. Today after all I did it has same issue but with fuel spitting out the RH exhaust. No fuel was what I was thinking last weekend and tried with the cap open and closed, but why would it be spitting out the exhaust now? I am starting to think its the batterie and carb adjustments. It boggles my brain and feel like shipping it off and spending thousands of dollars to get it sorted, just to do it all again next year.
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- It boggles my brain and feel like shipping it off and spending thousands of dollars to get it sorted, just to do it all again next year.
Hm likely you're only one so far too. Something hanging up R carb float or maybe it leaked to sink but never heard nor found fuel out exhaust no matter how many times kicked w/o starting. Good looking but internal bad fuse. Kill button resistance intermitent. HT lead shorting. Powder coat in way of good earth. i've jumper-ed off auto battery to make eliminate bad battery factor. Air leaks at intake or exhaust. Rest of life should be a breeze after figuring out your Commando. Flick at trigger wires with key on, just for good luck ritual.
You may well be right about a bad battery along with a poor carb adjustment at this point. I'd start with a couple of new plugs. I bet the ones in the motor now are pretty black and the right one fouled totally. If the battery is off and you've been chasing that with carb adjustments, they are probably out of kilter now too. A crap load of years ago, well before computers, let alone forums existed, my Boyer equipped Mk3 was acting similar to yours. I knew the battery was iffy but it never crossed my mind electronic ignition, unlike points needed good voltage right up front. A few hours of kicking and swearing, revving and adjusting carbs, and stalling, I used a good car battery jumped to the bike wiring while, for about the tenth time, the bike battery was out and on charge. Damn thing started easily and settled to an idle that was now easily fine tuned with the pilot screws. And with it's very own new battery ran fine.
For sure good battery. Two new plugs. Pilot screws out around two turns. Give it a whorl.
For sure good battery. Two new plugs. Pilot screws out around two turns. Give it a whorl.
I can get bike running by charging the batterie or hooking it to a good extra car batterie. Once I tickle the carbs it will start within 4 kicks, if it stalls I have to tickle them every time to get it running. The problem happens when the bike is running, when I had the carbs apart I checked the floats - no leaks, check the height, seems about right (1/8 inch from the top).The plug was a little fouled but all I had to do is wipe it down and looked ok. I will change them just to make sure, as well as get a new batterie. There is no fuel out of the exhaust when I try to kick it over, only once it is running.
A
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Hi thread starter.
Re your comment: "...Just changed alternator and rotor a few days ago. That was the only change from last year..."
If your bike starts with a fully charged battery and then dies after an hour of riding and won't restart until you charge the battery again then your charging circuit is the problem. The battery will be drained by the elect. ignition until spark cannot be sustained (faster drain with lights on). Since the last thing you touched before the problem began was the stator/rotor therein is the logical resolution.
Ta.
A greater AmpHour battery means you can ride longer until it too goes flat.
Re your comment: "...Just changed alternator and rotor a few days ago. That was the only change from last year..."
If your bike starts with a fully charged battery and then dies after an hour of riding and won't restart until you charge the battery again then your charging circuit is the problem. The battery will be drained by the elect. ignition until spark cannot be sustained (faster drain with lights on). Since the last thing you touched before the problem began was the stator/rotor therein is the logical resolution.
Ta.
A greater AmpHour battery means you can ride longer until it too goes flat.
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gjr said:
That's the sort of thing to do immediately after fitting a new alternator. Why was a new alternator fitted?
At least check that the headlight gets brighter as you rev off idle.
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You may have two issues .... one fuel, one electrical.
Your fuel issue may be fuel starvation at 4K plus rpm's. Check the fuel screen(s) in the fuel petcock(s) and banjo fittings. Since you report it ran well a year ago, it rules out improper main jet size, but it would do well to check these as well.
I defer on the electrical issue.
Slick
Your fuel issue may be fuel starvation at 4K plus rpm's. Check the fuel screen(s) in the fuel petcock(s) and banjo fittings. Since you report it ran well a year ago, it rules out improper main jet size, but it would do well to check these as well.
I defer on the electrical issue.
Slick
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