Totally bummed out

[dij0674]

Well, I'm not really sure what to do next. I've rebuilt my max from the ground up. completely rebuilt the motor 180 miles on it, took it to a dyno shop and had 3 pulls. the results are bad. 9500RPM on the rev limiter.

1. 108 hp.
2. lean condition is off the charts
3. oil smoke from the exhaust during the runs

the rebuild was stock, the machinist said all piston / cylinder clearances were in spec.
it looks like the rebuild didn't fix the issue, that I had in the first place (#3 cylinder looked like a stop sign with a mic).

anybody know if a lean condition will cause oil consumption?

leak down test is less than 5% on all cylinders.

The rebuild consisted of:
Machinist Checking specs on crank, heads, cylinders, block deck, and rods.
Hone the cylinders, new stock sized pistons, rings.
Brass bushings in the conn rods.
drilled thrust surface for more oil flow on the mains.
New bearings throughout the motor.
Valve job, flowtest the heads.
Arp head bolts (60 lbs)
Undercut trans.
5th gear change for less rpm on the highway.
Jet kit for carbs. -- I think I need to tune the A/F needle to deal with the lean condition.





DIJ

 

[tugla]

do you remember what the compression was on all four? did you do the cams or anything, valves are set correctly are they?

how about the carbs, what are the jets and air jets set at? what kind of exhaust to you got?

seems a stocker with a marks 4-2 system can pull up around 117-119hp so i would assume a stocker would do 108-114 maybe, so you are not that far off if yours is all stock.

 

[dij0674]

The cams are stock.
The valves are intake .005 - .006 and exhaust .010 - .011
I seem to remember the compression being close to equal on the cylinders and in the 150 range.
I have a marks exhaust with 12in cans and a Dyna 3000 ignition.

 

[Rand-5107]

Post your dyno slips. Off the chart lean air fuel ratio doesn't really tell us much. Also have your carbs been gone thru? Are the carbs and vboost seated correctly in the rubber connecters?

 

[dij0674]

one sec have to send myself a pic of the sheet.

 

[dij0674]

here's my dyno sheet.

http://www.vmaxforum.net/album.php?albumid=679&pictureid=5280

the carbs have been rebuilt, the rubbers on the intake/carbs/vboost are all new and seated correctly.

 

[Rand-5107]

It looks like there was a loose wire or something wrong with the air fuel meter setup. I'd ask your guy for another pull but slower ramp up to take a better look at what your ratio is through the whole range. I had a Kerker with a stock can and made 108 hp. I changed to a Mark's 4 into 1 and went up to 117. All stock carbs.

 

[dij0674]

good point, would oil burning affect the reading? if so, seems like it would show rich not lean.

 

[Rhoy Carter]

You might also want to put a few more miles on the bike, 180 miles on a fresh motor probalby will not seat the rings well enough to stop the oil smoking. The guys on here can tell you what jets to use with your set up.

 

[dij0674]

I used this procedure

http://www.mototuneusa.com/break_in_secrets.htm

a very knowledgeable vmax builder told me this is what he uses.

according to this article the rings break in, in 20 miles or so.

what do you guys think? is this accurate?

 

[one2dmax]

Most of the time rings do seal well enough to not smoke in those short miles. I would suspect the valve guides or seals at this point. The a/f readying is very suspect but if accurate you need a lot more fuel!

Sean

 

[dij0674]

this may explain my 40+ miles a gallon :-|

Changed my needles to as rich as they go. going for a ride to see how it feels.

 

[Patrick78]

Can that graph be accurate? I mean if he's making 108hp can it really be that lean or did something malfunction during the pulls?

 

[dij0674]

Well, I just finished a quick 15 mile ride after making the needles as rich as I can...Damn I love this bike. Its stumbling when I hold it at 4K and there seems to be some hesitation at 2K to WOT, but going from 5K to WOT and you better hang on to the bike. Could I be to rich at this point?

 

[sdt354]

Well, I just finished a quick 15 mile ride after making the needles as rich as I can...Damn I love this bike. Its stumbling when I hold it at 4K and there seems to be some hesitation at 2K to WOT, but going from 5K to WOT and you better hang on to the bike. Could I be to rich at this point?

That cylinder that was shaped like a stop sign. What did you mean by that? Out of round? How much? If It got honed only, I'd check the compression again before fixing the carb (fuel) problems. Just my 2 cents. And, can you post the readings.
Steve-o

 

[dij0674]

That cylinder that was shaped like a stop sign. What did you mean by that? Out of round? How much? If It got honed only, I'd check the compression again before fixing the carb (fuel) problems. Just my 2 cents. And, can you post the readings.
Steve-o

I had two machinist check the cylinder, both of them said the mic measurements showed edges in the cylinder, and you could actually see lines from the rings running vertically on the cylinder. I have pics if you'd like to see them.

I'll check the compression today, and post the numbers.

is it possible to have good compression / leak down, and still have oil control issues with the rings?

Sean wants me to check the valve guides and seals, are there any tests for these? that don't involve pulling the motor/heads?

thanks for the reply.

 

[sdt354]

I had two machinist check the cylinder, both of them said the mic measurements showed edges in the cylinder, and you could actually see lines from the rings running vertically on the cylinder. I have pics if you'd like to see them.

I'll check the compression today, and post the numbers.

is it possible to have good compression / leak down, and still have oil control issues with the rings?

Sean wants me to check the valve guides and seals, are there any tests for these? that don't involve pulling the motor/heads?

thanks for the reply.

Yes there are, I'd message Sean about the valve and seal teat. The leak down test tells you that the cylinder may be good at TDC only. Compression? do it again please.And post. 150psi for a new motor is nothing I'd be happy with. But I'd think if all 4 were 150 it'd run ok. I'm 180 all around with 32k on the motor, and not carboned up inside. Did the machinist suggest boring the worn cylinder?
Steve-o

 

[sdt354]

pm sent

 

[dij0674]

Well something is very wrong...here are my compression readings as of today. 190 miles on the motor.

Engine Cold:

Dry:
Cyl 1 - 100
Cyl 2 - 110
Cyl 3 - 130
Cyl 4 - 110

Wet:
Cyl 1 - 125
Cyl 2 - 125
Cyl 3 - 145
Cyl 4 - 140


All of my spark plugs look dry at this point. But I'm not digging these compression readings.

DIJ

 

[sdt354]

Well something is very wrong...here are my compression readings as of today. 190 miles on the motor.

Engine Cold:

Dry:
Cyl 1 - 100
Cyl 2 - 110
Cyl 3 - 130
Cyl 4 - 110

Wet:
Cyl 1 - 125
Cyl 2 - 125
Cyl 3 - 145
Cyl 4 - 140


All of my spark plugs look dry at this point. But I'm not digging these compression readings.

DIJ

Compression is too low for a new, broken in engine. Pm'n ya.
Steve