dyno dilemma

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It's still going to be cheaper to get a good used engine.

Sean

Yeah, I think you are right, but I have another engine, see below.

I may use my original engine which has a bad 2nd gear and use the blown motor's transmission, in the original engine. Steve at Under Pressure said he would check the crank journal bearings/clearances, connecting rod big end shells/clearances, check/set the valves for any that are out of spec., new gasket/seal set, and then I need to blast the cases and re-paint the engine.

I think Sean uses stock automotive paint, not sure what manufacturer or color, I would be pretty-happy with the stock-style finish. I already made block-off plates for the exhausts (1.94") & intakes (2.125"), and just used 1/4", 1/2" and 3/4" gas or H2O hose for the engine vents & H2O spigots.
I was planning on using dried silica sand (30/65) in my pressurized sandblaster tank which is what I have been using for rust removal. I have a 220V/60 gal., 11cfm compressor, which should get it done, or I can do it at the shop, they have a much more powerful cfm setup.
 
Peak Horsepower appears to have happened at 109 mph. From there on, HP fell off like it would after 9,000 RPM on a stock motor...
So it appears that quite a few more RPM were added. Is it possible the runs were made in 3rd gear? Just a thought.... Only other
thought is like KJ mentioned with a blow O-Ring..
 
Well I can ask Steve who tore-down the engine about the oil pickup.

As for the 109 mph peak power, I really don't know how to interpret the graph other than to see what the max value is, and whether or not there are any horrendous dips in the curve.

I just watched the video I shot and it appears the bike is in 4th gear for the pulls.
 
The bottom of the chart is MPH and indicates that max 109,23 HP was achieved at 109 MPH but the RPM continues
to climb till HP has dropped way off. Post your Video for us to see, Please...
 
Engine ran good before? Now has a bad rod! I don't blame you for being suspicious.
At this point another engine might get you up and running faster. Sorry to here the bad news.
I'm not doing it, unless they sign a waiver and I watch. So, it prolly won't ever get done. I've had friends complain of their bike being over reved on the Dyno.
Steve
 
I'd use the trans from the blown engine and install into the engine with the bad trans. Won't even need to remove the heads for the work. Much simpler that way!

Sean
 
After looking at the data and the dyno sheet again, 4th gear and 109 mph is going to be around 8000 rpm. From the math, its looking like it wasn't an over-rev issue.
109.1mph - 8k rpm. (where the drop off is on the dyno sheet) < 136.4mph - 10k rpm.
 
what if it was in 3rd?

or would 110 hp on a stock vmax be pretty good in 3rd?
 
The dyno sheet I got when we ran my 94, shows a definite end of increasing RPM at
9,500. No drop in horsepower, nothing, it ends there..:confused2:

Is 3rd Possible ??????????????????????????????:ummm:
See the chart, it's close: Peak RPM would have been 12,500 + at 136 mph in 3rd
or 10,150 + at 136 mph in 4th.. If that speed is truly a factor in the chart...

http://www.vmaxoutlaw.com/tech/speed_in_gears.htm
 
Thanks,Sean that is what I planned to do. Great minds think alike! If only I had your VMax experience. :biglaugh:

I'd use the trans from the blown engine and install into the engine with the bad trans. Won't even need to remove the heads for the work. Much simpler that way!

Sean
 
Yuck man... the trans swap is kind of a pain in the ass but its not too bad. im looking to get my bike dyno tuned this spring and this kind of event scares me. i want to get the best power out of the bike but not at the added expense of a motor. i wish you the best getting it fixed and back on the road.

Oh yea, dont feel too bad about not riding it, most of us in canada are with out for a good 4-5 months usually. lol.

peace,
Evan...
 
Waiting for my web video-hosting site to say, "OK." Gonna be awhile.
 
I haven't had much luck lately w/uploads of stills. When I try to upload I have to do it multiple times before the site will accept it. I usually end-up having to do it only two at a time.

I have an AMD 32-bit chip and a dsl line.

http://youtu.be/6RvDg3NT5zo

If you count the roll-offs of the throttle, it appears as if the tech shifts it into gear initially, and then shifts it three more times under load to the rear wheel. That's what I count anyways. That would be fourth to my counting. The only exception to that is if he didn't actually shift it into another gear one of those times and I suppose that is possible, I just don't know. I didn't ask, or I don't recall asking what gear they run in, I assumed it would be direct 1:1 drive, which would be fourth gear, right?

You will also see smoke coming from the engine in the vicinity of the engine crankcase breather, apparently. In-light of the engine failure shortly (as-in "one road mile from the dyno" shortly!) maybe the tech saw the tell-tale smoke from the engine, figured, "shit, I blew this guy's engine!," and decided to call it a day before the bike lunched itself then & there.

I spoke with the guy who sat in the saddle and ran the dyno for the runs. I asked him about the smoke. His response was that it appeared to him that the 3/4" crankcase breather wasn't fully-seated on the airbox, and that was the source of the fumes.

Now, bear in-mind I have owned this bike since it was 1 yr. old. This is not the original engine, I replaced it with a used engine of unknown mileage this past year, and had only run maybe five tanks of gas thru it before I decided to dyno it. Up to that time, since I had installed the 'good used' engine, it ran perfectly. About the only thing that it did was run a bit rough at idle in (for FL) cold weather, as-in the 40's F. Above or coming-off idle and accelerating through the rev band, it ran perfectly. No hesitation, no spitting-back through the carbs, no backfiring out the exhausts, no excess smoke coming from either the intake or exhaust, nothing. It would pull hard to redline and I infrequently ran my original engine or this to redline repeatedly, as-in flogging the engine. I as a rule, don't do drag-race starts (what's the fun in that w/a VMax?) and never speed-shift. I granny-shift, rolling out of the throttle while I clutch the bike and select the next gear, but on-occasion, I will go full-throttle as the clutch engages. Not excessive slipping of the clutch, just make sure the clutch is fully-released and then a snap of the throttle WFO until the next shift.

Actually, there were three runs as I recall, this is what I recorded. I count three before the end of the video. The last one has the smoke coming up from under the carbs where the first two pulls seem to be more exhaust-origin.

0:17 clutch engaged
0:37 run #1 begins
0:45 left side exhaust smoke

1:25 run #2 begins
1:34 smoke

2:07 run #3 begins
2:15 smoke
2:30 carb area smoke

I am having trouble getting the video to upload so I am going to look at the stickies for help. OK, after searching the site, I haven't found the instructions for loading a video here, so I guess that means using a web-hosting site. I'm trying that now.
 
Something happen while it was on the dyno and your right about the smoke. I counted the shifts and I would say 4th gear. I hope you get it up and running again soon.
 
I agree with the count. 4th gear. But I noticed the R's were higher with each pull. not too bad, but higher. I too noticed the smoke, more significant on the left after pull #2, and out of both pipes, after the 3rd pull.

As for the video uploading, On youtube you have the video set for "only for people who have the link." I think that disables the ability to imbed the video.
 
Wow, that does appear to have done it. I think you are right that the guy suspected damage. I don't think he did anything wrong though. I think that engine was headed that way anyhow and this just nudged it over the edge. Take what I say with less than a grain of salt as I'm not a mechanic. The damage may have been minor though, prior to the ride home.

Sent from my Galaxy Nexus using Tapatalk
 
Wow, that does appear to have done it. I think you are right that the guy suspected damage. I don't think he did anything wrong though. I think that engine was headed that way anyhow and this just nudged it over the edge. Take what I say with less than a grain of salt as I'm not a mechanic. The damage may have been minor though, prior to the ride home.

Sent from my Galaxy Nexus using Tapatalk

It is certainly possible the engine was on its way out prior to the dyno, but it never gave me any indication that it was. It didn't smoke during use, it didn't 'rattle' or labor to start, it didn't run hot, nothing. I ran Motul oil in it and was careful to run at least one tankful of gas thru it before I did anything which could be considered 'spirited,' and even then, there were several heat/cool cycles since swapping the engine in before that. After each use, I inspected the exterior lines and cases for any fluids, weepage, misting, etc. and there was no indicator of problems.

Well, it happened, and now I have my machinist friend doing some stuff for me to make the bike suitable for reassembly. No, no overbore, stroker, nothing like that. Once the engine (the original engine, which has a bad 2nd gear) is in-place and working, I will see what the case is with the bad #'s 3 & 4 rod(s) motor, if the case is affected on the thrust surface, and if the crank cap is bad, and the crank bearings and other crank/rod bearings show any evidence of damage from debris in the oil as the engine went south. Maybe I can start looking for parts to do a budget hot-rod build, but for now I would just like to get this together again for use.



As soon as the engine developed the knock, that was it as far as damage. Shutting it down at that point probably would have made no significant change in the level of damage as I understand it, from what Steve at Under Pressure told me. The (worst) rod and crank were both toast, and the adjoining rod was probably bad because of the damage it sustained from its neighbor, just not w/2 mm of big-end freeplay yet. For purpose of comparison he showed me a Falicon KZ1000 racing crank which he had recently gotten back after lending it to a racer, the bearings showed evidence of 'scuffing' on the outside of the races from not being solidly secured by the saddles when the racer assembled the engine. Steve did not assemble it. The locating pin was crushed, the guy evidently had the pin out of place when he reassembled the case halves, he failed to ensure it was located properly in the hole. In use, the bearings were able to 'walk' back & forth slightly, causing the scuffs on the bearing exterior radiuses. He said it was a $4500 crank.
 
The Dyno Runs were good , all in 4th gear and not over-reved.. Just musta been a weak part I would guess.. Still Sucks for you Fire-medic...

Good Luck with the fix...

Dave
 

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