| Author | Message | ||
     Hodakaguy |
Hello. I just bought a S1 lightning. It has the Buell race exhaust on it. I'm not sure what has been done to the carb or if there are any mods inside the engine. It likes to pop back through the carb when cruising at 2500 - 3000 rpm. Especially when cold. As the bike fully warms up it seams to dissapear and smooth out quite a bit but not fully. I've had burnt valves before on a different bike but they popped back through the carb at idle. Could I have a intake leak or be way to lean on the jetting? Any common issues with these bikes that would cause this problem? Thanks in advance for any help. Hodakaguy | ||
| Sandblast  |
I would check your intake seals for sure before you ride it again, you know how to do it- just spray some wd 40 or something similar at them when the bike is warmed up and idling, if the idle speed changes you have a leak. The seal is only a couple bucks. Somebody else might chime in and tell you a better way, if there is one I would like to know too! After you do that you'll want to check the jet sizes. Look in the knowledge vault under carbs, at the top of the page there are guidelines. If you take the bottom of the carb off to check/change the jets, replace the crappy brass screws with some quality allen heads, Al at American Sport Bike can hook you up with everything you need. (Message edited by sandblast on December 06, 2004) | ||
| Sandblast |
PS My Cyclone used to do the exact same thing you describe, and that was when it was brand new with stock everything. I changed the slow jet to a 45 and added a hi-flow air box and it never coughed again. | ||
| Captainkirk  |
My '99 Cyclone did the same thing with the *original* CV40 installed. After installing the Thunderslide kit, the problem pretty much went away completely...plus changing the main jet, which came with the Tslide kit. | ||
| Kevyn  |
S1's deserve Mikuni carb. Hang the CV on the wall... | ||
| Hodakaguy |
Would it be worth the money to have the local harley shop dino tune the carb? Should I buy a thunderslide kit first? Or should I buy the Mikuni and then have it tuned? I don't race it, just around town. Thanks, Tom. | ||
| Firemanjim  |
Save the T-slide kit and just change the slow jet first-it is way too lean.You will be suprised at how it changes the running. | ||
| Buells2t  |
These bikes are prone to intake leaks, so check for that first. Before you take it somewhere to have it tuned you might want to see what’s in it. You may already have a jet kit, or Thunderslide kit (Comes with a bigger slow speed jet), or bigger slow jet,.. If it has a kit with an adjustable needle in it then just raise the needle 1 groove; i.e. if it is on grove #3 from the top (flat non pointed end) then put the clip on groove #4. I like to tune the circuit that has the most control on the area my problem is in, so for steady throttle cruise, on a CV it is the needle. While changing the Slow jet can make the bike richer at cruise the pilot jet (slow speed, or idle jet) has it greatest control at idle and right off of idle. A Motorcycle needs a little more fuel when it is cold, that’s why they have an enrichener, or choke. A properly tuned carb may pop back when cold, especially in cold weather. When they reach normal operating temperature (usually about 10-20 miles of riding or so) they shouldn’t pop back through the carb. If you tune your bike to run great when the engine is cold it could be too rich when it is hot. These engines are not as sensitive to rich, as they are to lean, so if they are a little too rich they will run ok, usually a little sluggish. Here is a link with some good basic information on tuning a CV carb; http://www.Buellworld.com/cvcrbtun.htm I ran a CV carb with a Thunderslide kit for years on my S2, properly set up it is a great carb especially for street riding. Due to their design CV carbs can, compensate to a point for air conditions (temperature, and altitude). I currently run a Mikuni HSR 42, which in my opinion has the best throttle response of any carb. However it isn’t as forgiving for changing air conditions as the CV. Discussing carbs, and tuning is like discussing football teams, no matter what you say someone is going to disagree with you. Just my $.02 Mike (Message edited by buells2t on December 07, 2004) | ||
| Tramp  |
ummmmmm... *exhaust* leaks give ya popping, too. more commonly, in fact. the diaphragmatic compensation of the Cv will give you less 'popping' than the mikuni, and, as few seem to realize, the mikuni will give NO HP advantage over the Keihin CV. it'll just get you there quicker. when the race exhaust was installed, i'd hope the techs beefed up your pilot jet to at least a 45 if not a 48. your main is probably fine @ 185 or 190, esp. considering where in your rPM range you're having popping. i would suspect an exhaust leak (esp. since we KNOW that was f***ed with) first, then maybe an intake leak (spritz a little staring fluid around your intake area and listen for increased rpm) the most copmmonly overlooked cause of popping is the exhaust leak, but most bench-racers who get all their wrenching done by shops aren't aware of this, as the shops guys make better $$$ and take less blame by changing jets or intake gaskets. start your machine and hold your hand tightly over the tailpipe and listen for exhaust 'upstream'. a little dab of furnace cement is a great fix IF you've reset your exhaust clamps as snugly as possible..... | ||
| Buells2t |
" pop back through the carb" As far as I know Exhaust leaks cause popping out of the exhaust. (Message edited by buells2t on December 07, 2004) | ||
| Tramp |
i've seen both cause both, as the *balance* is impacted, either way, especially with such a short exhaust tract | ||
| Hodakaguy |
Since intake and exhaust gaskets are cheap I think I'll change both out and also check my jetting tonight when I get home. I'll post what I find. Thanks for all the help. Hodakaguy | ||
| Steveford  |
Take a good look for a crack at the header collector and mushroomed header flanges/boogered exhaust ports, too. We use talcum powder for checking for exhaust leaks. If you're going to do something, you might as well make a mess! | ||
| Tramp |
talcum powder- why the sam hill don't i use that? i use soapy water if the exhaust isn't already hot, buut talcum powder's the way to go. | ||
| Hodakaguy |
I removed the carb tonight, its all stock. 42 pilot and 195 main. The plug on the mixture adjustment had been removed and it was set at 1 1/4 turns. I think I may install a thunderslide kit in it. I think the previous owner may have had a different carb on the bike and replaced the stock carb to sell it. The bike has the buell race exhaust, race ecm, and carbon fiber free flowing air cleaner on it, I find it hard to believe they did all that and didn't touch the carb. I may wait untill I do the carb changes before I change out the intake gaskets as they may be fine. What tool do you use to remove the allen bolts on the intake manifold? Thanks for the help. Hodakaguy | ||
| Tripper  |
You have to cut down an allen wrench, or buy a special from American Sport Bike. | ||
| Bluzm2  |
Hodaka, Put in a 45 pilot. It will help BIG time! (Message edited by bluzm2 on December 08, 2004) | ||
| Captainkirk |
Hodaka; There's your trouble! Somewhere in the race kit instructions for my M2, I remember reading that with the race header and pipe installed along with the CF air cleaner, you would definitely have to rejet. I solved that by throwing on the HSR42 at the same time...which I now need to(go figure)...rejet.  | ||
| Tramp |
being the 42 pilot's still in thar', you probably need to drill out and back out your mixture screw, as well. usually 3.5 turns out from deadstop. don't even worry about your intake/exhaust gaskets, and don't install any thundrslides just yet. first rejet and run it, so you'resure of what's happening in thar'. you might even wanna backfit a 190 or 185 main.... | ||
| Hodakaguy  |
Thanks, I think I'll pick up the 45 pilot tonight after work and reset the air screw and try that first. I'll let you know how it turns out. Thanks for all the help. Hodakaguy | ||
| Tramp |
hey- what can i say? my first fullsize bike was an 'ace 100', then a 'super rat', then a 'combat wombat'. | ||
| Hodakaguy |
Well I installed the 45 pilot tonight and set the mixture screw at 2.5 turns out. Wow what a difference. It now warms up a lot faster and idles with the enrichner off in just a short time. The popping seams to be gone and its a lot smoother in the 2500 - 3000 rpm range although its not quite perfect yet. I'm going to check the intake track for leaks on friday just to make sure they are good. Thanks for all the help on the problem! PS: I've been into hodaka's for years. At one time I had 18 of them, they are great bikes and can be a lot of fun! | ||
| Firemanjim |
Tom,you are up there in Hodaka land anyway,right.My brother has an Ace 100 and 2 Steens Hodakas,one with standard fork one with an Earles. | ||
| Tramp |
"steens" you're getting me misty, jimbo. I remember some cooooooooolaas minibikes that came w/"steens" engines in '69 or '70. my parents both rode hodakas, and i inherited my mom's old ace 100 when she got her combat wombat and my feet could touch ground on it. my dad had a super rat for trail, which my brother inherited after we lost dad. fun bikes. 'pabatco' | ||
| Hodakaguy |
I live not to far from Athena Or where they were distributed. They pop up for sale around here every now and then. All I have left of my hodakas right now are a couple engines and some spares. I'd like to find an orange tank super Combat again. They were all a lot of fun. Remember their ball bearing trans? Thanks again for the help. Hodakaguy | ||
| Captainkirk |
Sigh.. The Ace 100 was the first "real" dirtbike I ever rode.... | ||
| Tramp |
odd seems many hodaka-rats grow up and get buells..... howzabout ossas? 'member the pioneer? my dad used ta race with the king of ossas in the states, 'al snooop'. good guy, had a shop, also sold hodakas. | ||
| Bluzm2 |
"Ball bearing tranny" Wow, I've not thought of one of those for a long time. I rebuilt a Wombat and a Super Rat a number of times. My buddie was VERY hard on them. I've been keeping my eye out for a "Chrome toaster" for a while now. | ||
| Tramp |
you mean the pabatco tank or the bmw /5 slabsider? | ||
| Hodakaguy |
Well after the jet change it ran worlds better but was still a little rougher than I like in the 2500 - 3000 RPM range. This morning I changed the exhaust gaskets out and now its running even better. Its a lot smoother in that range now so I assume one was leaking. I was going to do the powder test on the old ones but I had a set of the new ones sitting on the bench so I just changed them out. Thanks again for all the help. Here's another one, I just sold a Greeves trials bike. Whens the last time you've seen one of those? I really like the vintage stuff, the Buell is a break from my normal bikes but a whole lot of fun  Hodakaguy | ||
| Tramp |
loved the greeves. big brother was an ot rider. i had some rickmans. | ||
| Sandblast |
Hodaka guy, one more thing, if nobody has told you to do this yet you really want to make sure that you dont have the old 6R12 sparkplugs in your bike, they are too hot. The new ones for all Buells, are 10R12. Get those or the equivalent. | ||
| Tramp |
GREAT point, sandcrab! | ||
| Hodakaguy |
Thanks for the tip. I checked them tonight when I got home from work and they are the 6r12 plugs. I'll pick up the 10r12 plugs this week and get them installed. I ordered a Mikuni for the bike, everyone that I've talked to that has one seams to love it so I'm looking forward to getting it on the bike. Thanks again for all the great advice! Hodakaguy |
