November 2010 18
I said goodbye to Mazatlan.
I knew I’d love Mazatlan, and finally it was the next stop. I still needed to rest and recover a bit, and would rather do it in Mazatlan than up where I was. The few hundred miles to get there was difficult with only a couple fingers to work with.
So i recently purchased my first motorcycle a GS1000 and as you are aware this is a big bike and should easily do 100mph but its topping out at 70ish mph, what could be causing this? I did notice it backfires al ot also. I have changed the plugs and cleaned the K&N air filters well i did last night and still have not had a chance to see if that helped, so I will when i get home, but I am looking for suggestions on that issue.
thanks, great site you have here very informative.
Note from Reader:
As you open up the throttle, the gas/air mixture in the carbs changes. You have 4 carbs and it sounds like you need to get them synchronized. The backfiring indicates too rich a gas/air mixture.
If you’re running a K&N filter and especially if you are running an aftermarket exhaust, it may just be running way too lean. Do a plug chop. Find a gentle upslope, run the bike in 5th gear, full throttle up the hill. After 10 seconds at full throttle pull in the clutch, kill the engine and coast to a stop. Then pull out the plugs and look at their color. I bet they are white (lean).
Though it could also be a synchronization issue as mentioned by millknee – though you would also have erratic idle if this were the case. It could also be an air leak in the manifolds, or valves that need adjustment.
Hello,I am at wits end ,We can not figure out the problem…hitachi carbs just rebuilt..Bike will still stumble and run on 1 cylinder,also gas getting into the front pipe and shoots out when started.The bike has new Jardine rumblers and carbs have been rejetted.Sometimes will run on 2 cylinders but then go back to 1,could this be electrical or carborated….Please I welcome all responses..Thanks in advance!!!
I assume your valve clearances are in check? Is your timing off?
What kind of compression are you getting on both cylinders?
The hospital stuff isn’t much of a story. The ambulance dropped me at a small hospital in town where where I got some x-rays and was attended to by a couple doctors who didn’t seem to have much experience or training. I left with a cast on my left hand and a splint on my right and hobbled out to the street and caught a taxi. He brought me to the nearest hotel where I crashed for the night.
The next morning was fairly rough. I was incredibly sore and swollen all over. My knee, ankle, hands, and in particular my ribs were troublesome. I’ve had bruised/cracked ribs in the past so I’m used to the feeling, but that doesn’t make it any more comfortable!
I just removed and cleaned the carbs in my Honda CM450, it was sitting for 12 years. It was my first time doing this, the info on this site really helped a lot…
The good news – the bike started right up! Ran just like it used to!
The bad news – when I turn the petcock on, fuel starts leaking from the carb vents & drain hose. As soon as I turn the petcock off it stops leaking. (When I first put the carbs back on and turned the petcock on, it took about 5 seconds to start leaking, but now it leaks right away after turning the petcock on).
Any ideas on how I could troubleshoot?
Well, I took the carbs off again and re-cleaned the float needles, even thought they looked clean. Then I realized, when I put it together last time, that the accelerator pump assembly wasn’t right… I had put a rubber boot inside the assembly, when it supposed to go on the outside.
Congrats on the fix. If a bike is leaking fuel out the carb it can really only be a couple things. Either the float needle is dirty, worn, or gummed up or the floats are set too high so the needle never gets pushed closed. Both are simple fixes!
I was more or less tracing the main road and hopped off sporadically when I spotted a fun dirt road. I didn’t have a map which was somewhat of an issue, but my limited fuel range was more of a concern than proper directions. I had planned on heading into Creel but the nighttime temperatures were dipping to 40 and below so I knew I’d freeze since I didn’t have any cold weather gear. Instead I hugged the ocean and continued south.
The temperature variance was huge. Scorching hot in the sun during the days, and cold as soon as it got dark. So when the sun disappears I pull off the road and make sure I’m geared up with everything I have.
I’ve heard many people recite the “Don’t drive at night in Mexico” mantra many times. I never paid much heed, partially because of my own stupidity, and if I need to be honest, my bravado as well. On this particular night I had a rude reality check.
So I cleaned my carbs and put them back on the bike. As the bike is running I hear a loud intermittent clicking sound from the carbs, and the bike almost stalling at each one. I’m sitting there pulling my hair out, trying to figure out what was wrong. It was obviously the carb valves, but why?
Then I realized, when I took the carb off, I had to remove the crankcase breather hose, and I plugged the hole in the crankcase to keep dirt from getting in the engine.
So I unplugged the hole and problem solved!! Hopefully this post will keep someone else from making the same mistake!
Hahah – Nice! Let that engine breathe!
I couldn’t even tell you how many similar stupid mistakes I’ve made over the years.
Hi. Read your article about Carb cleaning/boiling. I was wondering, will the boiling method clear up the little Carb Circuitry passages in the body of the carb? Have you ever tried?
Sure – that’s the whole point!
Boiling in lemon juice isn’t any sort of magic formula, but it DOES do a great job of breaking up gunk inside the carbs.
It’s always a good idea to check internal passages by blowing air through them, or shooting carb cleaner or wd-40 through them with a straw. If you have stubborn passages you can force fluid through them with a syringe. Or give some more extreme techniques a try, like the boiling. If you have access to an ultrasonic cleaner toss them in!
There are lots of different methods. I’ve disassembled and soaked many racks in chem dip. I’ve also done the boiling with different solutions. It’s also well known that a soak in Pinesol does wonders. Pick your poison – none are a magic solution, but all are great tools for aiding in getting old grungy carbs back into service.
I had an oversize Clarke gas tank overnighted to meet me at the border so I’d have more than a 90 mile range. I was thrilled when it arrived, but wasn’t sure how I was going to take it anywhere.
So I promptly got to installing it on the road outside the UPS station.
Wouldn’t you know it. The tank didn’t fit.