| Author |
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Gearheaderiko
| | Posted on Sunday, January 16, 2011 - 02:19 am: | 
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Yep, sounds like an intake leak.
The WD40 test does a couple things. First it should smoke a little if its sucking the WD40 in. Second it should change the idle if its sucking it in through a leak.
You cant easily disconnect the choke and if you unplug it it will stay on. Most engines need some kind of choke when cold no matter what the temperature is.
No offense, but just installing a new boot does not eliminate problems. Many have installed it wrong making things worse. Too tight or too loose is what happens.
Covering the venturi with your hand should definitely cause a problem. |
Kauai1800
| | Posted on Tuesday, January 18, 2011 - 03:41 pm: |
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Thanks guys.
I tightened das boot screws and that seemed to help. The clamps are on there pretty darn tight now.
And thanks Gear for explaining the wd40 test - I've seen that mentioned before and wasn't sure what it referred to.
Venturi is definitely sucking hard on throttle application...and got a K&N on the way. |
Kauai1800
| | Posted on Sunday, January 23, 2011 - 05:10 pm: |
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rrr...I am getting very frustrated with my Blast.
what's funny is how if you look through all the posts on this board about the auto enricher or high idle speed,etc we all seem to have the same symptoms - that are then fixed by a MYRIAD of different repairs. That seems very odd to me.
The symptom is that the bike idles faster and faster without throttle application...that's a pretty specific problem.
The auto enrichener would seem to be the culprit - it's not sensing when the bike is warm and stays open. But unplugging it would not solve this problem, only replicate it.
As I look over threads where someone describes a similar problem (there's LOTS of them) I find it was fixed by any of these methods: tightening exhaust screws, replacing das boot, replacing carb, replacing auto enrichener and maybe others I've forgotten.
To me it seems odd that this same problem occurs over and over, very similar descriptions, and yet there's not one clear answer...or even a couple. Why is the Blast carb so prone to these issues? My old SU carbs in my Volvo work great and it's not like there's dozens of posts where the carbs are acting so "mysteriously" or whatever you want to call it.
For me, the bike idles OK, but upon cold start, w/o touching the throttle the bike idles faster and faster. After about 90 sec it does come down a small bit, but to nothing like what a "normal" idle should be. Ride it, and it will come back down to normal, but sitting at a red light it revs higher and higher...too much to ride.
I'm 99.5% sure it's not the boot because it's brand new and couldn't be installed any tighter. Spraying WD40 did not indicate any leak in that area. I've faithfully followed the advice on this board, but this one problem is coming back over and over.
It might be a torn carb diaphram, and I guess I'll open it up and see. :-(
Or it might be a busted auto enrichener, but there seems to be no way to diagnose this w/o buying a new one for $70.
Anyway, as a new rider, a new Blaster, and as a scientist who is very used to troubleshooting hard problems, I find it really a bummer that my bike is turning out to be such a black box with no clear answers. I definitely see how it got a reputation for being tricky to get running well...it IS. |
Gearheaderiko
| | Posted on Sunday, January 23, 2011 - 05:51 pm: |
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There isnt only one cause for your problem, thats why so many answers (though I find loose exhaust nuts a highly unlikely cause).
Your auto enrichener may be sticking in the on or partially on position. Unplugging it will cause it to remain in the on or partially on position.
You can test it, but that usually means taking it out. There may be other ways to test it, but I'm not the resident carb expert. However, if its not getting any voltage, thats a problem. (I'm sure you found that when you unplugged it, the bike ran very rich when warmed up and began to 'lope' at idle. If it didnt, thats an indication thats its stuck partially on/off). I also havent used a Blast carb in a long long time.
The boot can also be overtightened. That will cause the rubber to pucker or split and you'll get a leak. Since the WD40 test was done without a reaction, thats probably not the cause.
Diaphragm is easy to check.
Often times this problem will be caused by the ill advised "pull the carb apart and give it a good cleaning" advice. This can lead to torn diaphragms, incorrect assembly and parts left out.
Indications are the enrichener. Carb problems and electrical problems (especially the ignition module) are often mysterious. Some symptoms have one answer. Others have many causes. If you have 2 problems at once, that can really make things interesting!!!
And there are the oddball problems that few ever have, that you really pull your hair out on.
With many used Blasts sold on frustration, the fix is often simple and solitary.....but you have to find it first. Thats often made more complicated when someone has tried to fix it themselves and failed in the process. Then you now might have 2 problems!
The Blast is a very simple machine. Far less complex than many cars and motorcycles on the road today. Remember this when your mechanic seems to want an incredible amount of money for what seems like very little work!!! |
Kauai1800
| | Posted on Tuesday, January 25, 2011 - 05:08 pm: |
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Thanks for the calming words Erik.
I was just having a moment there. I admire the Blast's simplicity as you say...but there are the buggahs that get to you, ya?
I took a deep breath and decided to try re-installing the boot even though it seemed OK. After putting things together again, this high idle issue seems to have gone away. Hurrah!*
I took the bike out and rode it 10 miles or so and it acted fine.
A few hours later my new K&N filer arrived and I popped it in and it runs great. Also I installed the new MT 75s and a couple spiffy-looking replacement OEM footpegs. I'm stylin' now!
One thing I was meaning to ask...the small screw that holds the airbox cover in place (near the bottom)...I've never seen anything like it before. Does it EXPAND when you put it in and tighten it? At first I thought it had just stripped out, but I looked again and it seems like this is made to expand or something...
Thanks again for helping me out guys!
*********************************************
*ps I asked my wife who is a doctor and does a lot of critical care, "Hey if you put someone on a ventilator and they aren't coming around like they usually do, do you ever just re-do the whole thing and try again to see if that fixes the problem?"
"Oh yes, we are trained to do that first before anything else", she says.
So sounds like re-doing your "broken" repair ought to top the list of ways to ultimately fix your problem. I know this at some level, but interesting to hear MDs are trained this way. |
Gearheaderiko
| | Posted on Tuesday, January 25, 2011 - 07:51 pm: |
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The screw I think you are talking about goes into a "well nut" and is used on all the common black body plastics (not the coloured ones). It screws into a metal sleeve which causes the surrounding rubber to compress and expand. |
Ncovington
| | Posted on Friday, January 23, 2015 - 01:02 pm: |
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Is there a youtube video or anywhere I can get information on changing out the DAS boot? I have inspected it visually and it appears to be in great shape, only 2,500 miles on the bike. I am having the same high idle issues at temperature. Also, can someone please explain the WD 40 test? I have seen it referenced but did not see the description. thanks!! |
Marksblast
| | Posted on Friday, January 23, 2015 - 05:12 pm: |
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Not sure of a u-tube on it
It is a pretty easy operation.
From one who just did it. And I'm old ; -).
If that is your issue. Then I can also recommend the Super Boot from D-C Parts. ( Dan ). Which I will order shortly as well.
Loosen these screws gently. |
Ezblast
| | Posted on Friday, January 23, 2015 - 10:58 pm: |
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Holy buried answers Batman! Nice response though!
EZ |
Gearheaderiko
| | Posted on Saturday, January 24, 2015 - 05:26 am: |
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I'm not understanding either response!!
SuperBoot not necessary if you are using the stock set up. But re jetting the carb to a #45 slow jet will minimize backfire risk (most common cause of boot failure).
WD40 test: when the bike is running, spray some WD40 (or substitute) around/on the boot. If the idle changes you have a leaking boot. It will be a noticeable difference. |
Gearheaderiko
| | Posted on Saturday, January 24, 2015 - 05:31 am: |
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http://www.badweatherbikers.com/buell/messages/201 64/150578.html?1421096417 |
Gearheaderiko
| | Posted on Saturday, January 24, 2015 - 05:33 am: |
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http://www.badweatherbikers.com/buell/messages/201 64/6812.html?1419870456
Lots of good info in both links. |
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