The time has finally come to install the SE 103 kit that I've had sitting in the shed for the last couple of months.
The Fatbob has got about 12,000 kays up and is due for an intermediate oil & filter change, which I will do after fitting the kit and bedding in the rings.
When I bought the bike new back in March I used "Motomans" street break in method. ....link ....http://www.mototuneusa.com/break_in_secrets.htm.........so now that I have removed pistons and barrels, it is a good opportunity to inspect the results. Below is a photo of one of the pistons I pulled out today.
There seems to be very little blow by, which of course is a good thing. I'm no expert, just a long time HD rider that likes to do as much of his own "mechanicin" as he can.
Anybody got any opinions on the condition of my piston after 12,000kms?
Another thing, I checked Cold Cranking Pressure before I started to pull it down, and got 190psi both pots. (air cleaner off, throttle wide open, cold engine)
I'm currently running Woods TW6-6 cams in stock 96" motor. According to Big Boyz calculator I should only have about 170-175psi............after installing the 103 kit with 0.030 head gasket It tells me I will get 190-195psi...........
So, if I already have 190psi now, what am I gonna end up with ?????210-215????? and will it be too high for reliability??????? Or am I missing something?????(probably likely!!!)
Cheers, Burto.
I have found the bigboyz calculator to be greatly inaccurate. There really is no such thing as motomans "secret". That information is well known. Baby your bike during break-in, and it will chew oil. Flog it senseless, and it may well scuff. Ride hard, and it will love you. It is not carbon, it is not your gauge. My dyna cranks over 190, and has done since new. It had no carbon, and I have a quality gauge. It starts easily, every time(stock motor). If you have a 103 kit you will (depending on your heads) likely also crank more than 200. There is a reason why those kits make good low end power, and for all the posts concerning shattered teeth on starters, and hard starting. The power, with the SE 255, for example, does drop off early. If you are concerned with the cranking pressure, you could fit a -4 gear, and ease the starting, as well as extend the power range(a little, anyhow). It is designed to run as it is, though. If you are using the supplied head gasket, as opposed to a .030, that will obviously have an effect, but will not be(in my view) quite as efficient in its power production squish-wise. With the .030, I think the -4 gear becomes a really good idea. You negate the extra compression, but do not lose the added benefit of the better squish. Just a thought.
Maybe when you bought your bike they where doing free 103 upgrades and neglected to tell ya...
When you are doing ccp test, if you spin the motor faster you get a higher reading.
i changed my primary ratio to a lower ratio and saw a higher ccp, then went back to stock primary ratio saw a lower ccp. same motor no changes. also saw this on race motors were they use remote starters, if you use a more powerful starter to spin the motor doing the ccp testing you get a higher reading than useing a starter that spins motor slower.
just thought i'd point this out
103 kit installed and rings bedded, oil and filter changed, have done 1 vtune so far, will do some more next weekend. Runs real good! pulls strong!........gotta be the best $700 I ever spent!
I did check the ccp after install and got 190psi, but this was before any running in, I would imagine that after bedding the rings it will be higher.
There was a lot of carbon build up on the old pistons, so you might be right Hogbag. This may have been caused by the bike running rich for a while (during tuning with TTS) and also the oil being fed back into the combustion chamber from the crankcase breather. This may explain the high ccp before pulling it down.
To overcome this problem I have piped the breathers out of the air filter (yes, to the atmosphere! just like all my previous bikes!) and also drilled out the oil return holes in the rocker arm support plate, to allow more oil to return to motor instead of getting sucked out to the air intake. Thats the theory anyway.
Too busy drinkin xxxx now, but might get another ccp test done tomorrow.
Gotta say, I think they were right when they said that the "best bang for your buck" comes from increasing displacement!
Burto.
Didnt get a chance to install clutch spring as yet.
Checked ccp today after about 140kms and got 210psi. A lot higher than I expected it should be.
Any body got any thoughts on this reading? Is it too high for reliability?
I checked again today with air cleaner off this time (210 with ac on) and got 215 psi!
I'm really starting to think that my compression tester is reading high. From memory, last year after rebuilding my evo and adding EV27 cam, I got around 165 psi. Never checked the calculater back then but checking that build now, I should have got 152 psi.
Wont get a chance till the weekend to try someone elses gauge, to see if my suspicions are correct. Mate, I reckon if I really had 215, she wouldn't turn over as easy as she does!
Berms, basically went with the SE 103 to keep it Harley for warranty reasons (although fitting it myself probably voids that anyway!) Also, seems to be the most popular choice.
S&S 106 was a couple of hundred dearer and came with less ie. air cleaner kit and HD clutch spring.
Rev Tech 107- didnt know much about em.
Have heard that at 106 ci you dont have much left for boring out if needed later. Although, with the new barrels being relatively cheap these days, why bore, just replace! Especially if you live in Bumfuck like I do!
OK, got the chance to try a mates compression tester on the bike yesterday. Got 195psi! As suspected my cheap and nasty gauge was reading way to high!
195 is spot on what the calculators told me I should have, so I'm happy now!
Anyway, aside from needing a bit more tuning to get it spot on, the bike is really pulling well! A shitload more power and torque. Gotta be happy with that! Only possible downside is that I will probably go thru tyres a bit quicker, at least until the novelty wears off!!
