| Author | Message | ||
     Buckley |
Hey everyone. I am potentially purchasing a 99 Buell Cyclone tomorrow. The current owner gave me a heads up that the bike starts and idles fine, but after about ten minutes of driving the bike will die when you let off the throttle. The plugs are fouled after the bike dies. I am hoping to pick this up as a project bike, but wanted to check here to see if there are any major concerns before doing so. My best guess at what this could be at the moment is that the carb is running too rich after warmup, or the cam sensor is acting up. Are there any other typical factors that can cause this behavior? Just looking to get a little feedback prior to purchasing the bike. | ||
| Jolly |
Are you able to re=start it after it dies? can you keep it running by throttle application above idle or steady above a certain RPM? does it only die while riding it? will it run until turned off if left to idle? are the plugs fouling on the high speed jet or the low speed jet? are they fouling because the ignition has failed and its still receiving fuel but not burning it all? are the lugs pointing to the problem or a result of the problem?..ie plugs fouled because bike is too rich or plugs fouled because the ignition failed and its not fully burning fuel? Dying after warming up is a thermal issue, and normally points to an ignition issue, but dying after it warms up with changes in the throttle could point to a carb issue, or still yet, still an ignition issue. as an example, not really related except in terms of simple mechanics (i.e..fuel air spark combo) I replaced the carbs on a thruxton and the thing would only run for about 4 minutes then die and would not restart..... next day, it would start again, run for 4 minutes and die...what was the last thing I did..carbs...start with carbs right? always go to the last thing you monkeyed with!..., however it really presented more like a thermal induced ignition issue...sure enough the pickup coil failed at exactly the same time I swapped carbs..had to phone a shop to learn that it was quite a common problem on that bike, I was initially stumped!!!! and irritated!!!.....random..but common on that bike. so, will it restart after it dies? Can you keep it running when it starts to stumble with application of throttle? how dies it die? cough sputter etc..then die or just like a switch it dies out...? are the plugs fouled if checked before it dies? how does it run if left to idle to really warm up first? will it run about the same, 10 minutes at idle and die? can it be immediately restarted? When it starts to die can you crack the fuel cap open and keep it running, perhaps the fuel vent is clogged and its creating negative pressure and its basically running out of fuel? I've had no problems like this on any of my Buells, carb or injected, so I don't have a "hey this is common R2 this piece" piece of advice. but in answering the questions it will help lead you to the source and help others help you. what ever is going on, it sure sounds like it "should" be fairly easily fixed.... famous last words right?! good luck!!! | ||
| Phelan |
Sounds like the choke is stuck. That's just my knee-jerk gut feeling though. | ||
| Buckley |
Thanks for the quick response guys. I spoke to the owner a few minutes ago and here is what i learned: - The previous owner dumped the bike - The new owner (now the seller) was not able to get the bike to run right - He cleaned a bunch of what looked like sand out of the fuel tank, cleaned the petcock, and cleaned the carb to get the bike running decently. - The bike will start and idle fine. The bike runs at high RPMs, but when you drop to lower RPMs it starts to cut out. The seller said that he believes that the slow jet is a 45, and the main jet is around 170-180. Is it likely that the slow jet may be adjusted improperly? The other culprit I can think of that would fit the symptom would be a bad crank sensor. Aside from this, is it possible that a bad piston ring could be causing the cylinder to flood? Unfortunately I was not able to get much information from the current owner in terms of whether or not the bike can be restarted right away. | ||
| Dannybuell |
walk away, better yet run! | ||
| Alfau |
I wish someone had said that to me $10000 ago. | ||
| Jolly |
This cold be easy, but as you get more of the story from the seller, this could be a total mess!! Sand like substance in the gas tank = NOT GOOD!!!?? Original PO dumped it... Where? A beach? Why? Did someone sabotage his bike by pouring something in his fuel tank, which caused the bike to die, which caused him to crash? Or did he just crash, then....Couldn't get it running, sold it , next owner couldn't get it running right, now selling it.... What's been done to try and get it running? Have competent people been working on this or ..... Has it been to any kind of shop to be diagnosed if previous owners are "gifted" with only the basic rudimentary "skills"? As the story unfolds it gets worse..... | ||
| Buckley |
From what I have heard the first owner was just an idiot. Was driving drunk and laid it down. The second owner seems like he was alright with a wrench. Cleaned the sand debris out of the tank line and carb and got it to run alright. Im wondering if he did not adjust the slow jet correctly (maybe just turned it all the way in). As long as it isn't a major engine problem I dont mind chasing small electrical stuff. The bike is $1500 so I figure I cant go wrong. If it is a total mess I could always part out the bike to make some of that back. Would rather not go that route tho. | ||
| Ratbuell |
The jets are either right, or wrong. They aren't adjustable. Your idle mixture screw should be 2.5 turns from being lightly bottomed - turn it all the way in gently, then back it off 2.5 turns. If it runs fine and sounds good when it is running, I wouldn't be afraid of it. If it makes noise, consumes oil, or smokes when running, I'd be more cautious. It sounds to me like a simple tuning issue. | ||
| Harleyelf |
Sand in the pilot jet? That would let the bike start on the choke circuit but then die when nothing but the main jet was supplying fuel to the motor. "Dies when you let off the throttle" is a major clue - indicates the main jet circuit works but the slow jet does not. Clean the carburetor or get a Mikuni. It might also be as simple as bad intake seals. | ||
| Akbuell |
At $1500, go ahead and pick it up. I'll take it off your hands if you don't want to fool with it. Not that I need another bike, but what the hey. The last thing messed with was the fuel system, so that is the place to start, esp given the fouled plugs. Could be float level, clogged air passage, improper reassembly or adjustment, ect. Careful inspection and assembly should reveal the issue, and a simple fix. | ||
| Jolly |
It certainly sounds like a fuel delivery problem... I never clean jets, I just buy new ones, it's simple and guaranteed, and I'm always making an order anyway... So a few new jets when I'm trying get a carb working... Easy! Everything points to the slow speed jet as stated above.... Still must be more to the story though on why two previous owners couldn't get it running... "Could be" a 1500.00 bike, a few hours of work, rebuild carb, new jets.... Replace fuel line, filter, flush tank... And you're done!! I've bought worse!!!!!! | ||
| Dannybuell |
ethanol, oxygenated gasoline puts weird crusty barnacles on the inside of the carb. If the needle or more likely the seat has crust on it the flow of fuel may be too great. the Keihin CV is a sounds like a POS. Add a Mikuni HSR42 and a dyno tune to wake the bike up. | ||
| Buckley |
So I picked up the bike this afternoon. I only had a small amount of time to play around with it, but was able to get it started after I cleaned the plugs (didn't have a chance to buy a new set yet). I only ran the bike for about a minute, but I pulled the plugs after and they were soaked with fuel. The bike has a 190 main jet and 45 slow jet. Just as a check I turned the idle mixture screw out 1 turn as opposed to 2.5 turns, thinking this should cause the bike to run lean (as a sanity check). Oddly enough the plugs were still soaked with fuel when I tried to get the bike to start. My tinker was cut short by the battery running out of juice however. I plan to charge the battery overnight and play around with it more tomorrow. Any foreseeable reason why the bike would be running rich even with the idle mixture screw turned out only 1 revolution? Would this point towards the float level being off? | ||
| Rjn |
Take the carb apart and clean it. Then you rule out a lot of " what ifs" IMHO  | ||
| Ratbuell |
Yep, clean it personally. Sounds to me like there's a bad gasket, or the float needle isn't seating, allowing the bowl to overfill - which means gas is going around the jets, not only through them. I run CV's on all my carbureted Buells with zero issues. If you're one of the guys who buys into the "CVs are crap, you have to have a Mikuni to get it to run right"...send me your CV. I'll put it to good use. | ||
| Imadog |
I think I am with Phelan on this one. Seems like the choke (enricher) circuit is messing up. Get all new gaskets, including the intake and Carb to intake gaskets. Clean and rebuild it. There is a lot of info on the Keihin CV40 here and on the web. Check everything for cleanliness and operation. | ||
| Dannybuell |
Keihin carbs are great fun to work with, 185 and a 42 is a good place to start. the CV slide and slide rails gum up with varnish soak them well. CV Slide rails? Using a thin microfiber type polishing cloth some polishing compound, and a popsicle stick you can make the frame rails shine too! Moving to a dynojet thunder slide (plastic) does not eliminate the polishing chore for the slide rails. (Message edited by dannybuell on November 24, 2014) | ||
| Jayvee |
I suggest new Intake Seals while you're at it... | ||
| Buckley |
I havn't had much time to work on this yet, but I did throw new plugs in after having adjusted the slow jet to a lean position (as a sanity check). As expected the plugs burned white. Pretty sure they previous owner just had the slow jet out WAY too far. I plan to dig into it much more on Friday however. | ||
| Ratbuell |
Pretty sure they previous owner just had the slow jet out WAY too far. That's NOT the slow jet. It's the idle mixture screw. The jets are either in...or they're loose. No adjustment on the jet. Please...for sanity's sake...get a manual so you know what you're adjusting. | ||
| Buckley |
Haha sorry, typo | ||
| Jolly |
any updates? hope its just a clogged slow jet, and your idle mixture screw is now set right and it runs perfectly! | ||
| Buckley |
Had some time to work on it more today. Luckily this was an easy fix. After setting the mixture screw to 2 1/2 turns outward the bike ran great. The float looked to be set correctly and everything is cleaned now as well. Thanks for the input on this one guys. |
