Need some help on a low HP/Low comp 1441 build.....

[BusaBD]

I have a friend with one of the mystery 1441's with power lose also,his was built by a very reputable engine builder on eastcost, all good parts and fully cnc'd head and matched cams . It ran great for a few times at track then it lost about2-3 tenths and 5mph,and once in a while the power will show back up.He can tell when its on or off , more off lately. I had split the cases  last summer to check the main & rod bearings by his request motor was clean, after motor was re-assembled went to track it was on he ran 8.90's  ,the next time out 2 weeks later 9.20's off again same 60 fts though. Still have no idea why.

[Abusive]

I have a friend with one of the mystery 1441's with power lose also,his was built by a very reputable engine builder on eastcost, all good parts and fully cnc'd head and matched cams . It ran great for a few times at track then it lost about2-3 tenths and 5mph,and once in a while the power will show back up.He can tell when its on or off , more off lately. I had split the cases  last summer to check the main & rod bearings by his request motor was clean, after motor was re-assembled went to track it was on he ran 8.90's  ,the next time out 2 weeks later 9.20's off again same 60 fts though. Still have no idea why.

Could have something to do with the fueling, maybe a clogged fuel pump or fuel
Iine.

[Pat Dietrich]

Been there but it was usually caused by air conditions. Was the air the same both times?

[Pat Dietrich]

Damn...it has compression...prepare for liftoff.......it's gonna fly for sure....

Wondering if im hurting it by running pump fuel??

[mountainmotor]

Thanks for posting- been wanting to see 2mm numbers . George's 1507 with 445I @ 105 was like 240 or so.

So here are my cranking #s from Couple days ago
255
260
263
265

[mountainmotor]

Wondering if im hurting it by running pump fuel??

Could be, especially in hot weather.

That spark knock shakes the rings and never even hear it . There's got to be a point it's upset in there but not totally rattling them.

The on the verge of -- kinda thing.

[BusaBD]

I have a friend with one of the mystery 1441's with power lose also,his was built by a very reputable engine builder on eastcost, all good parts and fully cnc'd head and matched cams . It ran great for a few times at track then it lost about2-3 tenths and 5mph,and once in a while the power will show back up.He can tell when its on or off , more off lately. I had split the cases  last summer to check the main & rod bearings by his request motor was clean, after motor was re-assembled went to track it was on he ran 8.90's  ,the next time out 2 weeks later 9.20's off again same 60 fts though. Still have no idea why.

Could have something to do with the fueling, maybe a clogged fuel pump or fuel
Iine.

Nope covered it sent injectors out  for check and sonic cleaning ,came back clean had no issues with them.put a upgraded fuel pump in for whenever the nos is turned on. Lines were all checked also.

[BusaBD]

Been there but it was usually caused by air conditions. Was the air the same both times?

That was what he was told by the original engine builder and we verified it not being the issue because it was actually hotter out 1 time and the bike went a 9.0 and the 2 weeks before it was better air and only went 9.20. All this hp lose was verified by a dyno when it run 9.20's it was losing like 20 hp ,a 1441 making only 197 hp   

[Pat Dietrich]

Mine lost around 7hp once and found out the stacks were not sealing on the throttle bodies. Took the spacers out and redynoed and it was back.

[Pat Dietrich]

So what did it dyno to begin with? Also on mine last year the head gasket never sealed. Have him look at the plugs and see what they look like.

[6002abusa]

Before the build the bike made 186. The plugs are pretty new CR9E's and look good.

[Pat Dietrich]

Before the build the bike made 186. The plugs are pretty new CR9E's and look good.

Sorry, meant after the bore kit.  In the beginning before the power fell off when he ran 8.90? Also what was mph @ 8.90 and what is mph at 9.20?

[ZX-ALAN]

Thanks for the feedback guys....  I am pulling the motor out tonight and pulling the jug to have a looks.... I will definitely take pics and post them.  I will also leak test the head..... I am quite certain that the valves are gonna leak like stuck pigs....BUT I dont think that is where the missing HP is at....  The fact is, this motor should have 220psi+ cranking pressure when cold and it is barely 200......  Even if the Gen 1 dished intake valves hurt the compression ratio by .3-.4, we should STILL have way more then 200 psi cranking pressure IMOP...


MY PREDICTION...

I will pull the head and jug.... the cylinders will look great, the rings will look fine and still have plenty of tension.  I predict the head is gonna leak past the valves a decent amount because this head was not lapped....(the shop that assembled the head says this is not necessary on a fresh valve job  )

I will likely run an old, dull ball hone through the cyls ever so lightly just to help break in a fresh set of rings on all 4 cyls.  We will lap the valves until not a drop of solvent comes out (because this is how I do them when I build the heads myself and never have problems).  I will likely go back to a .005 base gasket to tighten the quench back to .038-.040.  And freakin pray this thing makes atleast 210hp...

I will say I still have my doubts about any of this being an actual problem but.....  Gotta try something...

[6002abusa]

I don't expect to find an obvious answer either. I have my fingers crossed though.

[6002abusa]

Well, we were surprised to find some excessive wear on the exhaust cam. One of the lobes looks to have lost an estimated .010"+. The corresponding bucket is dished in a perfect circle where the lobe makes contact. I estimate to depth of the wear to be about .015". There is another bucket with minor wear on the intake side. The corresponding lobe on the intake side does not have wear that is obvious to the eye. The rings all look good and move freely on the pistons. There is not evidence of damage or wear on the cylinder walls. I'm calling the shop that supplied the the cams and assembled the head later today. I'm going to speculate that the weld build up is not as hard as it should be. I could do some hardness testing if it comes down to it. I would assume they post weld heat treat these cams. I forgot the memory card that has the pictures on it. I will add them later.

[mountainmotor]

Make sure the retainer to guide had enough clearance so not to repeat knocking a lobe/bucket down next go around.

Another thing , the motor was so weak i'd double check the grind number on the cams while apart.  The springs were new and the spring for the job, correct ?

I guy would think the top end would have made some noise and even some engine miss here n there.

I don't think it was oil related but never the less, can you post or PM what oil was in there ?

[6002abusa]

The springs are APE 65#. They were not bought new for this build but they are pretty new.

[6002abusa]

Here are some tear down pics. Notice the wear on the buckets and the cam lobes

[mike46]

Retainer to guide problems?

[Rossco]

I have seen several hard weld cams do that thru no mechanical/clearance issues, just the hard weld imperfections letting go. Web MIGHT repair/replace them, cant hurt to ask them.
That said, you still should check your retainer to guide/seal and also spring bind clearance (very much doubt the latter).
It's easy enough to check your cam lift, just measure from lobe nose to base circle then subtract the base circle from that.

The damaged cam and buckets aint robbing big horse power.
The dyno used has some comparable motored busa runs on it to compare?
Did you recheck your cam timing before the teardown?

[6002abusa]

Yes cam timing was checked. The dyno is the same one I have been on several times.

[mike46]

In that (sorry) 6th pic the outside edge of valve relief looks hit.

[sportbikeryder]

You definately have some cam or clearance issue.
What were the opening and closing numbers of the cams, and also if they were BTDC, ATDC, BBDC, ABDC, etc.

[6002abusa]

Those are questions for Alan

[6002abusa]

Still waiting to hear from the guys that assembled the head to tell me what is gonna be covered. Im not getting much from them. I will hold out on telling the story just yet. Let's see how it works out.