| Author | Message | ||
     Bentwrench |
Hi; First thanks to Badweatherbikers.com/staff/posters. I have done a lot of reading and there is almost an overwhelming amount of info here. It has been a big help. 01 Blast/5000+mi) Problem, starts fine and throttle is responsive to blip until auto choke drops to regular idle. Then it will hardly accept any throttle and will sneeze or stutter/miss if throttle is twisted . Have to baby throttle when riding to gain high rpms & then can finally go to wot. While doing a compression check I reversed the center diode and it turned over fine w/o clutch in however, upon trying to start it, it wouldn’t start until diode was turned back/clutch pulled in(this was all with kickstand down/in neutral). Warm compression check with carb boot pulled is 180. cold about same. Timing is set with timming light (warm)- 2 dots in center at 1200rpm. Plug wire & coil check out within range on ohm test. The ignition is new. New denso plug. New Batt. New dan’s super boot/clamp. New Carb with yost/48-180 jets af 2.5 turns/ new velocity stack&prefilter/new jardine exhaust & gasket. New gaskets- rocker plate&cover & pcv valve. New o-ring on intake manifold. All gounds/fuses have been cleaned. Fuel petcock tube cleaned & new o-ring. Oil/filter changed mtr&primary mobil v-twin20-50. All electrical works- all lights/signals/speedo/horn/safety switches kik&clutch. Have opened gas cap & run on vented bottle no difference. Trying to figure out if this is electrical or mechanical. Was going to replace coil/plug wire just in case they were failing when hot? Not sure if volt regulator/bank angle sensor would cause anything like this? Mechanical- was going to check push rods/pull head check valve springs. Seems like with 180 comp rings/valves should be good? Is 180 to high for stock? Not sure witch way to go elect. or mech.? FUNNY part is I have only put 150 miles on it since I got It, mostly riding around to test the latest part I put on. Not sure if this ole girl is ever going to let me ride her hard lol. I think she just likes me spending $ and fussing over her. Sorry about the long windy post. Just wanted to get all pertinent info in. Any ideas appreciated ! John | ||
| Swampy |
Welcome to the Thumper Forum Bentwrench! The Blasts like to run rich, think of it as a big old Briggs and Stratton lawnmower engine. With you saying that it runs somewhat nice when cold until it comes off of fast idle it would lead one to believe that you are probably running a little lean, possibly to the point of an intake leak, or float level being set too low. So check your boot, make sure your float level is correct, make sure you have clean primary jets, then try adjusting your idle air mixture screw like you would on a lawnmower(out 2.5 turns, and while running engine warm at idle, turn the screw in until the idle starts to change it should drop, then screw it out until it picks up again then continue until it just starts to drop, you are going from too lean to just to too rich) This is of course after you have assured yourself that you have a tank full of fresh premium fuel. If that doesn't work, change the ignition module. | ||
| Gearheaderiko |
Concur (mostly)! First: Stop digging! Its very unlikely that its a mechanical failure so dont go pulling the head apart etc. What was the last thing you did to it and when was the last time it ran right? Your post seems to indicate that you checked running after every mod, but with you only putting 150 miles on it I'm skeptical. That also says to me its probably something you did that caused this problem (no offense). Again, if you havent already messed with it, dont take it apart (IE: if you havent done anything with the top end-its probably not the top end). *180psi is excellent compression for a Blast. Nothing wrong there. *Pull the pre-filter off. Run the bike without the air cleaner and see if the problem goes away. (sounds very, very lean as swampy said) Your bike sounds like it has a very bad "Das Boot" or the wrong pre filter installed (dont cover the opening with your knee). In reality a Blast will run in all kinds of 'mis tune'. They arent that sensitive to changes in jetting, timing, plugs, etc.They usually have to be way off to be unrideable. 00' and 01' were notorious for bad modules. Keep us posted.but again, avoid the "replace everything" approach to repair. | ||
| Gearheaderiko |
Did you add needle shims? Thats also a common faulty installation. PS We've all made mistakes working on our bikes no matter how much experience we've had. If you havent made a mistake its because of 2 reasons: a) You've never actually worked on your bike. or b) You're a liar! | ||
| Bentwrench |
THX 2 both. I just put a new IGN module in a few days ago & I have been testing w/o p/filter. Boot is new but,I'll throw the new spare in & check intake manifold again. I'll ck carb float & try a/f adjst. I haven't shimmed needle yet & was waiting till ran better. I agree it seems like a air leak/lean condition. IS there an easy way to check carb float height? Like pulling the bowel and checking amount of fuel say 50% full? | ||
| Gearheaderiko |
If you can go WOT, I dont think its a float issue. Was it bad before you put the module in? "New carb with Yost?" and "48/180". Seems we had/have another Blaster with issues and the Yost tube. The Yost tube seems to make it run rich? Was installed correctly? Did it run okay after that for a long period of time? I dont know enough about it to give any advice and I only know 2 Blasters (including you) that run the Yost. What works on a twin carb often doesnt work with the Blast. An example is that if you install an accelerator pump on the Blast carb, you'll have a hellova time tuning it in. It just doesnt work. *unsolicited opinion to follow*: FWIW: unless you really know what you are doing its best to stick with stock carb jets and parts. Then we can help. But start throwing on all kinds of aftermarket jet kits, thunder slides, etc., then not enough of us use them to be very helpful. There also isnt any aftermarket "magic bullet" with the Blast carb thats going to make it into a rocket. Sure, if you know what you're doing you can greatly improve the performance just with the carb, if you know what you're doing. If you do know what you are doing, then it doesnt matter what parts you're using. We can get you close by telling you what jets and shims to run, but its still up to you for the fine tuning. Lastly, take any advice you get from someone riding a twin with a grain of salt. The Blast is not just half a twin and some mods dont just transfer onto the Blast. | ||
| Gearheaderiko |
Just read your profile: You dont still have the CA epa charcoal canister hooked up do you? Is the carb vacuum port that went to the canister plugged? | ||
| Ezblast |
Yost is old reliable tech,I concur though that the last post is 100% spot on. Note: Most modern FI mist the fuel for quicker cleaner burn as well. It also helps satisfying the EPA. If all your riding is short 15 minute spurts, then the bike will act like POS because it is always cycling through the auto-choke and the Yost tube magnifies that cycling, so if other things are not tuned correctly that also will show. That filter I suggest from OuterWears is as free flowing as it gets - after that is just raw air. I suspect most of your rides are short in duration. With the Yost tube I let it idle for a minute then go gently the first 5 minutes, then I just go! Everything's fine by then. EZ | ||
| Gearheaderiko |
Agreed on the Outerwears filter. Taking it off just verifies that you have the right one. Okay, 3 Blasters running the Yost tube! | ||
| Ezblast |
Actually a lot more Blastards on buellforums are running them as well - seriously - aside from the first ten minutes of riding due to it fluctuating with the auto choke - the yost tube performance difference is the crisper/faster carb response to input, due to a more complete burn. Most notice it right away, and like me suffer the trade for the much better carb performance. EZ (Message edited by ezblast on May 08, 2010) | ||
| Bentwrench |
Didn't have much time this weekend. Did check boot/intake & messed with a/f screw adjustment. Not much change. Tonight I pulled the yost tube and put stocker back in. 2 mile warm-up at 30 in 2nd/then jumped on it & it ran good. Will try later in wk to adjust a/f a lil better /idle/check timing ect. Putting yost in the box for a bit. LOL! THX again for taking the time to respond. I was definitely “DIGGING" !!!! |
