Recently had a set of SE heads put on my bike, and long story short, I need to install a set of Compression Release's.
Dealer says they need to send the heads sent out to have a hole machined in them to accept the CR.
Had the tank off over the weekend and I noticed that there on the top of the heads, a machined hole (with thread) approx 3/4 inch deep already there. The hole is blocked, but I was wondering are they already set up to accept the ACR, and all I have to do is drill thru to open them up to the compression chamber?
If so, what size hole is required and can I do this myself with a drill press?

Thanks!

 

ozzie,

What kind of compression do you have ? What did you do besides the heads ? I put Short Block Charlie heads which are the same as the SEs on my 90 ultra with .030 head gaskets with 5 over flat tops with a EV 27 cam and I don't have cr's on mine.

To answer your question....... Yes you can do it with any drill as long as you dont hit the threads already there. I would take the heads off, drill with maybe a bit 2 sizes smaller and install the compression releases. Put new head gaskets and reinstall the heads.

This is just my humble opinion and i have been know to be in error on occasion. I am sure someone with more knowledge in this area will have some input soon.

later.................

 

Since the rebuild, I am having starter issues.

If it tries to start on a compression stroke, it will lock up and not turn over. I have replaced the starter, battery,solenoid and cables. This is the last resort!

Turns over no problems with plugs out.

Even tried removing the plug wires to see if it is a timing issue. Still same problem.

Going to put in CR's now ....

Running 10.5 : 1

I think the hole I was referring to earlier is a temp sending unit mount. Will pull the heads tonight and see.

 

I may be way off but i think you have a starter issue or something. always thought CR came into the picture at 11:1 and up?

But then again 10.5:1 isn't that far from 11:1 so who knows.

 

The holes through the head for the compression releases is 1/8", the main body of most after market ones are 7MM. Be careful you don't get any metal inside the engine, you can grease up up the drill to catch the chips. Just don't let the bit get too hot. I would take them off though. Hope this helps.

 

Heads are coming off this week!

Hopefully this will help / solve my starting issues

 

Been running my ported SE heads at 10.5 to 1 with a V-Thunder EVL 5015 cam @.585 lift for over a year now. Turned over and fired up just fine with the stock starter, so no need for compression releases.

Before you rip everything apart, what cam are you running and what is the cranking compression? Could possibly be your cam timing causing this problem.

 

Running an Andrews EV27 Cam.

Yesterday was a classic example:
Hit the starter and it locks up. Complete shut down of all electrics with the load. Put the bike in gear and rock it past the compression. Hit the starter again, and even with the volt meter now reading 10v it spins right over and starts.

I changed the starter, solenoid, battery, cables and relay as this was the same symptons the stock items gave me. ground is good, and I have no issues spinning it with the plugs out.

Now, I could have a bad second starter, etc, but I have had 2 techs check my timing and both say it is ok....

I really don't know..... just trying to solve this rather annoying issue

 

Ozzie,
The 27 is a good cam, but does build alot of cranking compression when turning over. Before I did the mods to my engine the starter was working harder than it does now. There are alot of guys running a 27 that do not have the problem you are seeing. Before you do all that work and pull the heads, check the load and continuity on the battery, the starter and ALL of your connections. Just because they look good does not mean they are. I also replaced my stock battery to ground strap with one made out of welding cable wire. Also added a second main ground and one from the voltage regulator directly to the frame.

Methinks that you have an electrical problem.

 

Here is what I have done......

Put a new ground cable from battery to frame.
Ground from frame to primary
Ground from frame to starter
Ground from starter to solenoid

Extra ground from regulator to frame

New positive cable to solenoid

New cable from solenoid to starter

new cable from solenoid to main breaker

Have I missed anything?