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WELL...NOW WHAT

Started by harley#1, August 25, 2019, 06:35:32 AM

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harley#1

Hey guys. I done a 107 on my 09 classic recently and have some concerns i hope i can get help with. 107 je 10.25 pistons,stage 2 acr  heads,83 cc. .40 HG. was told comp should be around 10-6. stock TB and injectors, CR 575 cams.heat cycled then dyno tuned. got almost 5ks on it. bike works good.It does spark knock a tad now and then if i lug it to low when hot. it uses 2 dots of oil on the stick every 5 or 6 hundred kms. checked intake by the guides for oil found none, plugs are clean and grey/white so i check the compression when warm. to my amazement 235 front and rear. did this twice, same. guage is new only used a couple of times but ill get another and check again. way to much, especially for the cams.  what do i do now. maybe this is the cause of oil usage. i could use some direction. thanks.

FLDavetrain

 I've used those cams many times and 10.3 is high end of what they like and that advice comes from the cam designer himself. You're probably over 10.6 and you probably have pre detonation going on even where you don't hear it. I would swap cams, plenty of good ones in the range you're actually in.
currently 510ci on tap

harley#1

thanks for the reply. Ill probably hear it for using those cams so what do you think about the compression no. what low/mid cam would you suggest. thanks.

FLDavetrain

First I'd get hands on another compression tester to verify. If you're at 235 psi warm then cold would put you sub 230 which would give you around 11.3 static working backwards from 230psi. So you're know compression being suspect I would confirm compression and go from there on cam options.
currently 510ci on tap

Rockout Rocker Products

I went through this same kinda thing... 230 PSI+ with a 57 cam, head work, 110 kit. Wasn't supposed to be but it was. From suggestions here I changed to a T-Man 590 cam that, due to late closing should drop the compression. Not a bit lol. Great cam but nothing changed. Sometimes the calculators just don't match real world results.

I ended up doing logs & running them through My Tune a few times, making corrections until the pinging went away. FWIT my pinging wasn't at WFO... rather at slow throttle roll on at highway speeds.

Good luck in the hunt  :up:
www.rockout.biz Stop the top end TAPPING!!

1workinman

Quote from: harley#1 on August 25, 2019, 06:35:32 AM
Hey guys. I done a 107 on my 09 classic recently and have some concerns i hope i can get help with. 107 je 10.25 pistons,stage 2 acr  heads,83 cc. .40 HG. was told comp should be around 10-6. stock TB and injectors, CR 575 cams.heat cycled then dyno tuned. got almost 5ks on it. bike works good.It does spark knock a tad now and then if i lug it to low when hot. it uses 2 dots of oil on the stick every 5 or 6 hundred kms. checked intake by the guides for oil found none, plugs are clean and grey/white so i check the compression when warm. to my amazement 235 front and rear. did this twice, same. guage is new only used a couple of times but ill get another and check again. way to much, especially for the cams.  what do i do now. maybe this is the cause of oil usage. i could use some direction. thanks.
I was told that 200 psi is the target but I am not a tuner . The oil usage I recommend running the machine a few dots lower say no higher than 4 dots low on the dip stick hot .  Or even a tad lower .  I also suggest that some of those cooling fans to help keep the engine cooler works on both of my  money pits Harleys . I avoid riding when its hot over the high 90s and avoid stop and go traffic , big towns ect . I got stuck in those places and just killed the damn thing and waited then started up and went on hate that crap . I use the best fuel I can find . I don't lug or short shift and now both bikes have a deeper gear in them . I installed a 49 tooth evolution billet basket and that I think will help in may ways including what you suggested although I never I think experienced the knock event . I noticed that short shifting and how weather are a bad mix for the knock event . But a 235 and lugging seems to me a sure fire way of getting into that problem . I not a tuner but I think that a mixture that is richer and very little timing would be needed . I have oil temp gauges and I use them and they will tell you a lot if your interested . I noticed that even 2 up riding can elevate the temp on motor . Yea I know that seems a simple things lol  For now if it was me I sure want to ride in cool weather avoid the stop and go traffic if possible use cooling fans use 93 fuel and run the oil level down some to may be half way hot .

dsvracer

it seems to me whom ever set this up did not use the correct formula.  compression is a simple math test. IMO it is the pistons that are the problem, that and the heads were milled to a 83 cc. to correct this you will need to use a different piston with no dome, a thicker head gasket and possibly making the combustion chamber a bit bigger, or just make the combustion chamber a little bigger. any questions just ask.dsv

838

Not knowing the dome volume of the pistons and assuming it was calculated correctly. Could the cam be a tooth off?

Pop-pop2

I have those cams in a 103 @ 10.3:1, ported heads. My compression is 210 psi.
I am ASKING - what about a 2 or 4 degree offset key to slightly retard the cams ? Wouldn't that lower the compression enough to help get rid of the detonation ?
Pop

harley#1

Those pistons are advertised as 10.25.1 . with my 83cc heads and ,40 HG and those cams my ccp is still 215 cold so i think the pistons are bigger than advertised. talking to guys who know thier stuff a flat top 10.0 pistons should get me down to 10.3.1 and my ccp around 200 which is what im looking for. does this sound right?

838

I'm pretty sure Those je (10.25:1) pistons are +2cc dome. with a .040 head gasket and 83cc heads you are at like 10.85:1 or 215ccp with the 575.

838

Lots of other cams work real good at 10.8

rigidthumper

If measurements are correct, you should crank ~205.
If the cam to crank timing was off 1 notch, your CCP would be ~230 cold, little higher warm.
If the cam to crank timing is correct, you have smaller than 83 chambers or .030" head gasket or both. A Woods-8  or SE 251/259 work well at that CR.
Ignorance is bliss, and accuracy expensive. How much of either can you afford?

harley#1

well.. there is another problem which ties into this thread. I thought with more miles it might tighten up .with around 5k on build it uses 2 dots of oil every 5 to 600 kms.It was heat cycled then dynod when new so i have no choise but to tear down even if i wanted to change cams which would be the easy way out. Ill buy from a proven shop so not to have this problem again.bike work to good to be a tooth off, the tuner would have caught this right off.So i will get flat top pistons with .40 HG . hopefully this will fix things.

Don D

Do yourself a favor and measure the CCP now as a baseline.

harley#1

I did that and cold it is 215, hot 235

Don D

I think you are on the high side of 10:1. With it apart before making any decisions or buying parts consider measuring the heads, and check the deck height. With just a 2cc dome that could be cut. This can be fixed as mentioned by others and I don't think any parts, other than gaskets, need to be changed. Do not worry about pulling the jugs and going back with the same rings. Do not hone or re-ring it. You will likely choose a .040hg and after this the calculators will put you in the 10.3 area which is fine.

harley#1

thanks don. It is coming apart as we speak. I don't know if you herd of murch motors. He is only 80 miles from me and we spoke. he is well known and respected here so we are coming up with a plan. shaving the dome off the piston is a good option and see whats up with the oil usage.

Don D

I am probably one of the few that actually have torque plates for a merch, yep I know about them. Good luck.

kd

It's Merch and they have been around and in and out for a long time.  There's been some changes but my info is they have managed to keep the quality standard their business was originally built on.  You should be OK with them for what you are doing.  After all, they are just down the road too.  Do a search on Merch engines and read some of the company history so you know a little more about them.
KD

hogmandon

I have 4 1/8 in Pistons in an all bore I did that had 2cc domes on them. As per Dons advice I cut them flat, no problems with them all in18,000m. Bike uses 1 qt in 5,000m I don't see it or smell it so I will leave it alone. When it was a stock 88in it didn't use any oil but it also had no power

harley#1

apart and at murch. crank rods are to tight and you can feel little bumps on the rods when turning over. going to rebuild. cyl look good, no score marks just normal light scratch marks.going to torque plate and measure. pistons look ok but rings look small,thin. compared to stock.lack of spring grip on oil rings probably the problem. going to cp pistons.

Don D

Have the skirts coated. Line2line