Intermittent Death Rev??

[TecateDan]

I took my 1985 Tecate out for a good thrashing the other day and About half way through the ride I startte3d to get some intermittent DEV REV! I know crank seals are a common cause of this but I changed them when I rebuilt the motor and have put mabey about 6-7 hours on the motor since then? I was just sitting at idle when all of a sudden it reved out of control and I had to dump the clutch and stall it out. Restarted it and took it for a quick rip and it was fine for mabey 2 hours. It did it once more later in the ride but other than that it ran and Idled perfectly. The trails were real wet and muddy but I have a stock airbox. Any body got an idea of what would cause an intermittent problem? Also what would be the easiest way to check the crank seals<<

:wondering:wondering:wondering:wondering

[shortline10]

Check your intake boot for leaks/cracks . Also could be a sticky float valve .

[dcreel]

The filter on your petcock may be dirty, dirt in your fuel tank..

[jeswinehart]

Yeah, I am with D'creel on that. I am sure he is thinking it basically was on the start of running out of fuel and was going into death rev before dying.
IMO if crank seals or intake boot was the problem it would be a consistent problem and not intermittent, especially at idle.
Might even check the tank cap vent hose for a partial obstruction,
To make a leak down test set up > http://www.3wheelerworld.com/showthread.php?96856-Make-a-leak-down-tester-for-about-20
Many other extremely useful stuff in the "WORLD class help" section

john

[TecateDan]

Thanks for the tips Guys!! I had 3/4 of a tank so I didn't even consider the fule tank but it is quite possible that I have dirt in the tank or an obstructed screen...

[tri again]

So these 2 strokes will run fast when running out of fuel?
like the old .049 little airplane engines?

I wonder why chainsaws don't do that?

Interesting.
and the danger is the machine going unpredictably fast at the wrong time
and overrevving too?

Thanks for the insights.
I had no idea.
Looked at a 250R today but never knew these were issues with 2 strokes.

[fabiodriven]

and the danger is the machine going unpredictably fast at the wrong time
and overrevving too?
.

The danger is blowing the top end from a lean condition.

Dirty screen, stuck float, and bad vent are all very plausible. I have to ask you Daniel-san... Does your carb have the little plastic skirt around the main jet? Mine fell down off it's seat and caused a death-rev with my Tecate.

Did they teach grammar at BU? I know a guy who went to Harvard and he doesn't type like that.:D

[Chazz of Blades]

I always like to think that Doc is typing in his own poetic style, like a Docku, similar to a haiku, but nobody knows the format.

[fabiodriven]

I always like to think that Doc is typing in his own poetic style, like a Docku, similar to a haiku, but nobody knows the format.

I was referring to Dan's grammar. I also came to the conclusion that the good doctor types in Haiku. Interesting that we both thought that.

[TecateDan]

Who is the "good doctor" and I was a math and science guy not a grammer person...

[Dirtcrasher]

I want a KONGO bar..................

[TecateDan]

??? what is happening to this thread I have no Idea what you guys are talking about anymore

[Chazz of Blades]

Drjoe171, "Doc, The Good Doctor, and a few other monikers" -Was a trauma doc for many years, and in my opinion one of the most interesting people on here, always learn something new from him, pay attention when ya can.

And Fabs is just.......well...............ignore him and maybe he'll go away. :P


I have no idea what Steve is talking about.

[Motorious]

I want a KONGO bar..................

I don't know what DC is talking about here either, but it made me LOL.

"INTERMITTENT DEATH REV"... Great name for a death metal band.

:beer

[just ben]

did you get the issue taken care of? I have seen needle and seats that are so worn the needle doesnt drop down with the floats,running the carb out of fuel. also if it has the plastic floats in it make sure the rods they slide on arent bent

[TecateDan]

did you get the issue taken care of? I have seen needle and seats that are so worn the needle doesnt drop down with the floats,running the carb out of fuel. also if it has the plastic floats in it make sure the rods they slide on arent bent

Haven't had a chance to look at it yet hopefully thursday I'll take a peek at it and see what I can come up with.

[jeffatc250r]

Thats weird, in the pit when we were getting ready to leave, i thought we were gonna have to tow you out. It would be better if it wasnt intermittent so the problem can be found. Me and ryan were talking about that on the way home, it seems to be a kawasaki thing, never seen it happen to a red guy. Weve seen it before and its always been green critters, we never were able to solve the issue.
You running a mikuni?

[fabiodriven]

He is running a Mik Jeff, and the problem sounds just like the one I had that I already posted. Mine did the same exact thing. We'll find out soon.

[TecateDan]

Oh man!! Two towes in one day now that would have sucked! I'm hoping it's something simple but it will be hard to know if I fixed it until I go riding again unless it's the carb issue fabio is talking about because I'll be able to see that right away.


Thats weird, in the pit when we were getting ready to leave, i thought we were gonna have to tow you out. It would be better if it wasnt intermittent so the problem can be found. Me and ryan were talking about that on the way home, it seems to be a kawasaki thing, never seen it happen to a red guy. Weve seen it before and its always been green critters, we never were able to solve the issue.
You running a mikuni?

[Dirtcrasher]

A fine young gentleman brought us KONGO/CONGO? bars to begin our day with where we registered our trikes...... :D

[TecateDan]

Oh yea!!! The one I ate was still warm when we were getting registrations and Delicious


A fine young gentleman brought us KONGO/CONGO? bars to begin our day with where we registered our trikes...... :D

[fabiodriven]

Well, Dan just left here and it was the problem that I thought it was. Yes, I am just that friggin good.

[dcreel]

Well, Dan just left here and it was the problem that I thought it was. Yes, I am just that friggin good.

Just curious.. did you run to the computer to tell us, or did you strut? lol

[jeffatc250r]

I find this very odd. Was it something plugged in the carb, or stuck float?
Ill stick to my keihins if thats the case, death rev is not welcome unless its me making it happen, thats just flat out dangerous.

[jeswinehart]

I am gonna go out on a limb here and say it was the little plastic diffuser thingy~ma~bob that once removed can almost never be put back in properly, as he stated before.
What the heck are them things for anyway ?

[just ben]

I am gonna go out on a limb here and say it was the little plastic diffuser thingy~ma~bob that once removed can almost never be put back in properly, as he stated before.
What the heck are them things for anyway ? its a baffle to slow sloshing around the main jet and its not possible to just fall off. more likely fell of when the bowl was being installed and went unoticed. I dont know if they do what they are soppose to,I have had many miks without them and abunch with them any all ran fine so who knows

[fabiodriven]

its a baffle to slow sloshing around the main jet and its not possible to just fall off. more likely fell of when the bowl was being installed and went unoticed

Wanna bet they can't just fall off Ben? How many times do you think I've dealt with this to know off the top of my head what the problem was gonna be?

The float bowl in no way comes anywhere near contacting that skirt. The skirt is made of plastic and has 4 wimpy little tabs that distort from soaking in gas for years and years. They expand just a little bit and the 4 tiny fingers pull away from the ridge that they're supposed to clip on to, thus dropping the skirt directly on top of the pit that the main jet sits in and sips out of. The pit gets covered just right by the skirt and limits the amount of fuel that can enter that little pit. End product? Intermittent death rev. This is not theory, this is fact experienced more than once from a 7 year multi-Tecate owner. One who happens to have had many, many carbs apart many, many times. Please do not second guess our mechanical abilities.

What was that you were saying Ben?

[fabiodriven]

I find this very odd. Was it something plugged in the carb, or stuck float?
Ill stick to my keihins if thats the case, death rev is not welcome unless its me making it happen, thats just flat out dangerous.

I've made reference to the problem twice already Jeff.

[TecateDan]

I have not ridden mine to see how this affected it but I was with fabio when he removed his plastic "thing a ma bob" and saw it fuix his death rev on the spot and never come backso I am very cofident this is infact the problem.

[just ben]

Wanna bet they can't just fall off Ben? How many times do you think I've dealt with this to know off the top of my head what the problem was gonna be?

The float bowl in no way comes anywhere near contacting that skirt. The skirt is made of plastic and has 4 wimpy little tabs that distort from soaking in gas for years and years. They expand just a little bit and the 4 tiny fingers pull away from the ridge that they're supposed to clip on to, thus dropping the skirt directly on top of the pit that the main jet sits in and sips out of. The pit gets covered just right by the skirt and limits the amount of fuel that can enter that little pit. End product? Intermittent death rev. This is not theory, this is fact experienced more than once from a 7 year multi-Tecate owner. One who happens to have had many, many carbs apart many, many times. Please do not second guess our mechanical abilities.

What was that you were saying Ben? I guess I misunderstood what you were saying. I took it as the baffle coming off and lodging under the float restricting fuel being let into the carb which there would be no way for it to do that unless it was broken enough to get past the jet tube. Although I believe it would affect performance if it simply dropped down and were constricting flow to the main jet it wouldn't affect it at an Idle since the carb would or should be operating on the pilot jet not the main at all. I assume thats when dan was having his trouble since he said he had to dump the clutch to shut it down,which tells me he wasnt moving when it happend and wasnt on the main jet.that would lead me to believe the bowl didnt have enough fuel it it to submerse the pilot jet or possibly Dan left out a small detail such when he was stopped he gave it a quick rev or something and the slide didnt return for some reason. I dont doubt your mechanical albilities but on a properly tuned carb I doubt your theory. If you take a minute to think about how the carb works you may doubt it too. So thats what I was saying ...since you asked

[fabiodriven]

That's a good point about the pilot still having fuel Ben. Like I said, I've seen this happen many times before and I know it's going to fix his problem, but with the pilot still submerged..... Hmmm.... I'm gonna have to think about that one.

[just ben]

It would affect it if the needle were set too high or if the needle and the main were not compatible (too big of a jet for the needle)and it were idling off the main jet since there is more vacuum to the main than the pilot. Its hard to diagnose these old machines they have been around so long who knows what have been done to them and alot of times you cant read the numbers on the jets or needle. when I have problems with a carb them are the first parts I replace so you know for sure what you are working with. Even when you can read numbers people get bright ideas like drilling out jets instead of spend 3 bucks to a jet. Its really tough to troubleshoot or tune a carb with variables like that. If the baffle dropping down is causing that problem then there are other issues going on. I think you would agree

[TecateDan]

I got the carb from Jeswineheart who is usually pretty through with all of his stuff so I immagine no drilling of parts and I just put a new jet in so that should be fine and I know that the slide was NOT stuck. Just out of curiosity and please no yelling about keeipng the bike pure (Fabio) is their a Keihn that would be a direct swap for the Mink? On a seperate note I'm going ot look at another Tecate on Monday! It's a beater but has a lot of good parts to scrounge up and hang onto

[dcreel]

Dan, I've had a 41mm Mikuni flat slide on my Tecate for 25 years that I know of with no problems whatsoever. The little plastic piece was removed from the carb before I got the Tecate. My point isn't to start a whose better Mikuni or Keihin but just to say that they can be very reliable.

[TecateDan]

Dan, I've had a 41mm Mikuni flat slide on my Tecate for 25 years that I know of with no problems whatsoever. The little plastic piece was removed from the carb before I got the Tecate. My point isn't to start a whose better Mikuni or Keihin but just to say that they can be very reliable.

Were you able to still use the stock Airbox. I love to drive in puddles/mud/rivers...etc and running the stock airbox is an absolute must for me?

[dcreel]

Were you able to still use the stock Airbox. I love to drive in puddles/mud/rivers...etc and running the stock airbox is an absolute must for me?

I'm not sure I use either a UFO airbox or a K&N filter and wrap off the carb. I've never tried to see if it will fit a stock airbox.

[just ben]

I know swinehart wouldnt basterdize a carb but I I doubt he bought it new and has probably been through many hands. your carb is probably fine, spend a few bucks to do a proper rebuild on it rather than spend cash on a different carb and have to start from scratch tuning that one. atleast with the stock mik you know all the parts it should have stock.(in the manual) P.S I was really looking foreward to coming home from work and reading fabios smart ass reply after proving his theory wrong and nothing! I'm disapointed in you fabio lol. BTW I wasnt saying that its impossible, just not logical the way a carb is suppose to function

[fabiodriven]

I have no issued admitting when I make a mistake. Although you did make some good points, I'm not convinced there is anything wrong with the carb. It certainly doesn't need a rebuild, this much we know. I know it seems illogical that blocking the main would cause a death rev, but it does. I don't think it is showing any faults or wear in the carb, I'd be willing to bet a brand new Mik would do the same thing.

[just ben]

I was working on a 40mm mik earlier that has a brass baffle instead of plastic and there is no way for it to drop down. Just for kicks I took the jet access bolt off the bowl while it was together to see how close it(the baffle) to the float bowl. it sits right on the bottom of the bowl. I havnt checked yet with a plastic one but I think if it werent at the very bottom of the bowl it wouldnt function for its intended purpose. I may have an old float bowl I could cut in half to show its position when properly installed

[TecateDan]

I was looking around today and I believe (but could be wrong) that this part is actually a Needle Jet Holder not a Fuel Slosh do hickey. At least that is how Bikebadit has it listed. Not that I am going to buy a new one but list is 48.89 for that little part. If that's the case is shouldn't matter if it is removed as far as driveabiltiy IMO.

[fabiodriven]

Just for the record, the bike never hasn't death-revved since removal of that thing.