Evo top end pulldown with pics

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Evo top end pulldown with pics

John.R
6 years ago

Hi guys, a while ago I posted about my Evo smoking a little when warm. Well now that its out of rego and its winter, I decided to have a bit of a look.
I have never worked on a Harley, and I'm not a mechanic by any means, so please bear with me if I'm missing anything obvious, or I've done something goofy.

Engine is an 86 with unknown KM's, but has been pulled down before (has KB pistons in it)

I did a compression test, with good results, and did a leak down test that showed the front cylinder (the one thats smoking) down slightly compared to the rear, but not super bad (it was around 20% at 11psi (shitty tester isnt accurate higher, for comparison rear cyl showed 7.5%, so big difference). Audibly, I could hear a slight hissing out of the timing hole, for both cylinders. And for the front, I thought I could hear a little bit out of the intake but nothing obvious (like when the bike wasn't at TDC and I could hear it out the intake clearly).

I thought that it could be in the intake or exhaust valve guides, as it only smoked once warm, and mainly on vacuum, when the revs where dropping or at idle.

Now that I've pulled it down, I've noticed the cylinder has really odd marks on it, nearly like an adhoc, deeper cross hatching mark? It can be felt by the finger nail which isn't good.. And given the formation of carbon on the piston, its exactly what the factory manual indicates oil getting past the rings/cylinder would show.

In my head, I thought I was up for a head reco (front and rear to be safe) and I also wanted to put a cam in it, and depending on the piston/cyl, potentially put new pistons in it with higher compression. Turns out the piston in it is already 40thou over.

Now that I've seen this cylinder, Im thinking new barrels, new pistons (something higher compression), either a EV27, 46 or Wood W6 cam? Will the heads likely need to be reco'd? Do they even look like the culprit still, or would it be the cylinder?

bloodog
6 years ago

Thanks for the post I never get to see this stuff

paulybronco
6 years ago

John photos are often difficult to get a true indication from but certainly the score/scratch marks on the cylinder are of concern.

binnsy
6 years ago

Strange way for a score mark to appear on a sleeve I would've thought, its like it was done when it was honed years ago or something. Would've thought if it was scored with a ring it would've been straight up and down the bore...

speedzter
6 years ago

The honing stones have picked up some sort of contaminant when honing and scored the bore.
Regardless of that issue, you likely need new oversize pistons, and a re-bore to suit.
If you are super tight on money, maybe a ball hone and a new set of rings would get you a few more km's, but not recommended .

speedzter
6 years ago

A nice 85 cube option esp' if you want a compression bump (note, you may need a cam change to suit ) :-

http://www.nrhsperformance.com/ekitevbt.shtml

perthhog
6 years ago

What speedster said in regards to hone mark As for heads just get any reputable machine shop to service them
Not worth the the hassle of doing it yourself set evo heads about $350 to $400 maybe slightly more if thay
Have to replace the guides , I run Wisco in one of my evos 10.1 with a ev3 And ignition , you may want to upgrade
Your ignition too if you go up comp and cam And check your lifters ,breather gear too if you don't upgrade the
Breather gear whist your there at least replace with a new Oem one and depending on which cam you may not
Need adjustable push rods

brash
6 years ago

Don't get to see too many Evo's torn down to their undies because it was pre internet and the things just go for fucking ever!

Can reccomend the EV27 cam, I had one in my evo hardtail chopper, went really good combined with the SE ignition.

speedzter
6 years ago

If you are looking at 10.5:1 + , for cams, look at the EV5 or if you build the heads, a Tman 590 will smoke it !!

Baloffski
6 years ago

J thanks for motor porn, I too have very little knowledge of engines, you're giving it a good go..
Well done for what you've completed, achieved, and for sharing.

tussuck
6 years ago

No Stock holes...Folks just drilled em out. I cut down an allen key and it works sweet, but I still have to drop the front motor mount.
I have pulled my old 86 Evo apart many times s yell out if you need any thoughts or help!

Adz69
6 years ago

This is a really informative thread. It's great to check out the pics too. I like the cut down allen key tool...necessity is the mother of invention.

John.R
6 years ago

Heads dropped off to local shop today, he'll go through em let me know what needs to replaced, no hurry on em though. I just need to give him the valve seals when I get my gasket kit.
Any preferences between Cometic and James? It had a james kit in, withno dramas, but hear Cometic is just as popular?

Still trying pin down a pair of nice cylinders, otherwise it looks like ill probably just end up with the S&S replacement kit, which comes with 10:1 pistons anyway. Only problem is ive gotta wait till my parents go to the states in a month to get em.

perthhog
6 years ago

Ok I'll throw it out there good going with your made tool , evo softails have a hole in the frame for the said bolt as do the
Aftermarket kraftech frames , I had a chuckle at what Dave said about the bolt getting lost down into frame I remember
Back to when I had one of frames re powder coated and had the frame at hm blowing out all the excess sand that was
In the frame from being sandblasted before I started to assemble it back together and a rocker cover bolt come
Flying out of a frame hole lol And snapon and probley others do make a spanner for the rocker cover bolts I'm lucky
I grabbed one years ago of flebay

tussuck
6 years ago

Both James and Cometic are good gasket kits. I tend to go with James but that's mainly habit and availability... The key thing with either set of head gaskets is to follow their instructions and not the ones in the harley manual (I buy the MLS ones which are basically a laminated one and so have different torque needs)

John.R
6 years ago

Opened the cam chest up on the weekend, and surprised to find a TP engineering steel breather gear...
Even weirder is that is has no screen on it. Luckily the bore is std size and in good nick, so the S&S one has been slotted in.
Not surprised to find the stock cam in it though haha. I think I've decided on the EV46.
Ill swap the bearing out soon, its already got a Torrington in it which is good, but just swapping out anyway.

tussuck
6 years ago

Looks good!. I run an S&S valve breather so do not have to worry about syncing any timing slots. You could 'time' the hole and resize it to be 100% with the piston downstroke but its a bit wanky for almost no gain.
Suggest you press off the old gear from the cam and press onto the EV46 as then you do not have to worry about setting the correct gear lash etc (and its bloody important to do!). Its very easy to do.

Also dry fit the cam and make sure that the inner most cam lob DOES NOT hit the inner case (there is a lip in there at the back). For my EV3 I had to grind out a small section to provide the clearance. Just pull the old cam and put in the new one and see if you can turn it a full 360 degrees by hand - if the lip is there you will feel it thats for sure.

Finally make sure you buy the correct gaskets! there are 2 types that look almost identical but if you put the wrong one into an early EVO it will piss oil out everywhere when you start it up (do not ask how I know this one ,, lol)

tussuck
6 years ago

Yep, that's the right James top end Gasket kit (it comes with the washers for the covers so you do not need to order them separately) - the MLS ones are pretty bullet proof (I run the same on my turbo engine without any issues)
Measuring the gear backlash just did head in - I know its not complicated but in the end it was easier to press off/press on the gear...lol...plus a good excuse to buy a Hydrolich Press for the shed. The local Dealership will do it for you as well, but charge $50 for the time.

Double check ALL the threads on the cam cover as well - I had 3 of them stripped out and had to replace with TimeSert inserts - the best I have come across plus the kit works on the primary cover bolts as well.

I stripped all clearcoat off my cover and polished the alloy up until it shone like chrome! Once its done right and coated and looked after it lasts for years (unlike the clear which all stripped off on the front side from the road chit that got kicked up)

Remember to use chitloads of Assembley Lube when putting it all back together again.

Here is the right style Cam Cover Gaskets to use (https://www.jamesgaskets.com/product/jgi-25225-70-xf/)
Here is the wrong style gasket although it does fit okay it will piss oil out everywhere (https://www.jamesgaskets.com/product/jgi-25225-93/)

tussuck
6 years ago

Oddly enough they are not 'keyed' per sec but there are marks on the cam and gear that line up like a key.
So long as the new gasket is 100% the same as your old one your good. Its not the material of the gasket nor the holes as they are the same. Its the 'extra' bit of gasket material on the inside on the larger circle. One has a small section of gasket material in the bottom left of the gasket and for the older Evos thats the important bit (I think I worked it out once that its to do with top breather vs bottom breather systems and in my case the old 86 Evo is a bottom breather.

Topics

Evo top end pulldown with pics

Evo top end pulldown with pics

John.R

bloodog

paulybronco

binnsy

speedzter

speedzter

perthhog

brash

speedzter

Baloffski

tussuck

Adz69

John.R

perthhog

tussuck

John.R

tussuck

tussuck

tussuck