| Author | Message | ||
     Rayycc1 |
Help please. I recently picked up a very low mileage 2010 blast for my wife to ride... It was used in the riders edge program years ago and had been parked since. My wife replaced a fork tube and changed the oil... And then she cleaned the carb...5 times... Couldn't get it to run right so I cleaned the carb myself... Using guitar strings to go thru the passages... Compressed air... Carb cleaner... You name it. The bike starts and idles ok... But when you go to try and ride it it starts to fall in its face at low throttle input. If you twist harder it takes off and runs like it should... But again falls on its face at low throttle input. I've cleaned thousands of carbs in my day without issue but I'm still thinking it's got to be a carb issue? Is there anything else it could be? She's ready to ride this thing and getting tired very quickly of uninstalling and reinstalling the carb. Any words of wisdom? | ||
| Gearheaderiko |
1st. STOP messing with the carb, it probably wasn’t even dirty in the first place and they rarely need “a good cleaning”. That being said, since you had it apart, were the jets not clogged? What were the jet numbers? Is the idle mixture screw still capped off from the factory? Is it a California model? | ||
| Rayycc1 |
Well... Not a Cali model... Yes... Still capped... Didn't look at jet numbers but yes they were dirty and the gas that was in the bike was 9 years old... It definitely needed cleaning | ||
| Gearheaderiko |
Any modifications to it at all? Did you change the spark plug? I would. They don’t last 10 years unfortunately (wired, but true). Slow/pilot jet should be changed to a #44 or 45. Uncap the idle mixture screw and turn it 2 1/2 turns out. Blasts are notoriously lean. This should put you more in the ballpark of a good running Blast. Check reassembly of the spring and “spider” piece and make sure it’s seated. | ||
| Rayycc1 |
Changed the plug... Black as hell... Definitely running too rich. Currently jet is a 42... Where do you get jets for this? Harley? Thanks for the help btw. | ||
| Missionbolts |
I'm just a bit concerned about the idle mixture screw being turned out an additional 2-1/2 turns from where it is at the moment! Shouldn't that be 2-1/2 total, counting from when it's lightly bottomed out? And is there any possibility the auto-enrichener is a little bit off? That gets highly under-appreciated for how much it can mess up your tuning efforts. It modifies the vacuum signal going to the diaphragm in order to raise the idle speed when the enrichener is cold. If the enrichener is set too aggressive, it's possible your throttle can open too much just as you begin to crack it open. At wider throttle positions, the idle vacuum port doesn't make as much of a difference like it does when the throttle is closed, due to it being located right where it can get the most airflow at closed throttle When the carb is working right, you will note the engine likes to run really fast the 1st time you start it, and if you let it idle a minute or so, you'll hear the engine suddenly drop down to a more normal sounding idle speed. That's the enrichener closing off the vacuum port that adds extra vacuum to the diaphragm, thus letting the throttle ride lower | ||
| Gearheaderiko |
Yes, 2 1/2 turns total. Since the carb has been apart so many times the idea is to get it to a good running baseline or a point at which I know it will run well if there isn’t any problems. If the AE is not damaged but malfunctioning, the bike will either run well cold or run well warm. At this point I’m concerned that carb has been reassembled improperly or is missing a part. In many cases taking the carb has created many many more problems than it has ever solved. Almost exclusively the only problem is the slow jet gets clogged. They all run lean from the factory and current fuel exacerbates this. CV carbs are very simple and “a good cleaning” is only necessary in the harshest of conditions, but they are apparently very easy to mess up if taken apart. “Do not take the carb apart to give it a good cleaning”-They’re going to put that on my tombstone!! | ||
| Gearheaderiko |
You can get jets at Harley, maybe. A #45 slow is factory on carbureted softails. But they might all be fuel injected now, hence Harley may not stock them. Jets are available from Bike Bandit or Dennis Kirk among other places. They are the same jets used in any CV carbed Sportster or “Big Twin”. | ||
| Gearheaderiko |
https://www.denniskirk.com/cycle-pro/no-44-pilot-j et-for-hd-keihin-carbs-20733.ph17206.prd/H17206.sk u I prefer a #44 for a bike with stock exhaust. DO NOT buy a “jet kit”. This will only compound your problems. | ||
| Mnscrounger |
These two guys, (Gearhead and Mission),talked me through figuring out a similar problem on my bike, they are geniuses in my book. The symptoms you describe are very similar. It was a simple fix but took me forever to find. It's possible you are not the first to ever be into that carb. I would encourage you to check to make sure your needle jet is not installed incorrectly like mine was. It may not solve your problem, but it narrows the search for a solution. http://www.badweatherbikers.com/buell/messages/201 64/864435.html?1593098438 | ||
| Missionbolts |
Oh yeah, forgot about that one! Sometimes, you have to start from scratch on a carb & this means going back to the full out exploded view and really looking at what they are attempting to show you A 'floating main needle' will really mess with your head! And will stump any expert who would never think of putting that in wrong I know enough about CV carbs & standard carbs to know better than to claim they are bullet-proof. There's many failure points. #1 is gas going bad from sitting & gumming up the works, or alky gas getting the float bowl full of water after sitting over winter Which reminds me of my #1 complaint about the Blast CV carb - no drain screw! There's a place where it could have been. One of these days, I might just JB Weld on a drain port with a plastic sight tube. Quick & easy to deal with, no threads to fail. Just hang the tube up above the top of the carb. Kinda like my other mod, where I drilled a hole in the airbox lid so a straw from a can of starting fluid will aim right into the carb, avoiding the need to tear into the bike when I just want to get & go! | ||
| Mnscrounger |
Yeah, the Keihin exploded diagrams leave a bit to be desired in the way of detail. I put mine together wrong I think 6 times before we found that. I've done the starting fluid hole on my lawn tractor, but I value the motors on the Buells too much to deliberately allow unfiltered air into them. | ||
| Missionbolts |
yup, even the 'Blastards' think I take things too far out there! I also drilled a hole in the gas tank cover so a screwdriver has a straight shot at the idle speed adjuster. Changed the fork fluid to a 20W without consulting anyone on if that would be wise or not. Thinking about drilling a hole in the rear shock and JB Welding a threaded bung, so I can change out that fluid too. Chopped the cow-catcher off my muffler and bashed it upwards into a rock & log friendly skid-plate. While I was at it, I cut a pipe inside the muffler so it flows straight through & added some 1-1/4" holes because it wasn't loud/fast enough. And my bike throws random bolts at cars every now & then. So don't follow too close behind me! If you hear a traffic accident coming down the road, that's just me out for a ride. I swear that muffler rattles in every possible direction! Weird, just realized I've put more holes in this bike than actually fixed anything on it... | ||
| Mnscrounger |
"If it ain't broke... you're not tryin'." (Red Green) | ||
| Ezblast |
OMG!  |
