Decompression Question

MossBerg590

MossBerg590

Active Member
Am I supposed to press the decompression on the heads before starting every time? I read that some people do the rear,then front. I don't but maybe that's why my starter takes 3-5 tries before it starts? I assumed it was from the primary oil leaking in the starter and so it wasn't making good contacts. Also once the bike is started, if I put my finger on the decompression bulbs, I can feel the rod inside going up and down, the front one isn't moving at all. What does this mean? What sort of problems is or could this cause? Thanks.
 
JWScarab

JWScarab

Active Member
If your compression releases are electric and not manual - you do not need to press them at all. They will open when you hit the start button, then close when you release the start button. The one going up/down doesnt seem right at all. After the engine starts, they should stay closed.
 
pauldeepsea

pauldeepsea

Guru
First your compression releases are controlled electronically. You should hear the engage when you press the run switch. You may also want to check on your starting procedure. Since you have a carb you should twist the throttle 2-3 times before trying to start, do not use the choke especially in warm weather. If this doesn't work you may need to clean the contact on the starter. Also check your battery voltage. Start with these smaller things first
 
MossBerg590

MossBerg590

Active Member
Yes I keep the battery on the tender, and Im dealing with cleaning my starter etc. Its an 06, are they electric or auto pressure valves? Yes the rear one I can feel the rod going up and down pretty fast and the front just seems to stay down. Am I losing compression from the rear one? The bike does seem to be running weird but I was assuming it was the carb needing adjusting. I dont normally use the choke, just turn the key, press off, press run, twist throttle twice and start.
 
JWScarab

JWScarab

Active Member
They should be auto, opening only when starter engaged. The experts will chime in, but I think you have a faulty rear compression release.
 
MossBerg590

MossBerg590

Active Member
Ok, so if the rear is bad, would that have done any damage riding it like that or would that only make it harder to start?
 
pauldeepsea

pauldeepsea

Guru
I really don't think it's your compression releases. Too many other things.. What is your battery reading? Volt wise ? You can see if your contacts need cleaned. The are a bright bronze color if they are clean! Check the forums there is a how to on that. Your starter could be failing . I could go on and on but you need to be more specific on what you are having problems with. Pm me if you need and I will try to help you dial it in
 
S

Sven

Well-Known Member
MossBerg590 said:
Yes the rear one I can feel the rod going up and down pretty fast and the front just seems to stay down.
Click to expand...
The one rod going up and down times with the suck of the piston going down and compression build of the piston coming up. I think that puppy is broken. Might as well change both as a set. Is this an S&S part?

Am I losing compression from the rear one? The bike does seem to be running weird
Click to expand...
Bingo! Only 3 variables and compression is it.

but I was assuming it was the carb needing adjusting.
Click to expand...
No. How are you going to adjust for the [non-moving rod] or the better running cylinder, if both use the same needle? Hindsight goes Bingo!


Replace the moving rod you feel and the weird cylinder comes back in line like a potato-potato should sound.
 
Marky-Marc

Marky-Marc

Well-Known Member
Here's the S&S PDF link for instructions for the manual ones I believe. The tool is almost a MUST, but someone said you could use an o2 sensor socket as well, never tried it. I think BrewCrew has the socket and said he would be willing to lend it out, if you send it back to him when done.....

http://www.sscycle.com/files/3213/7033/9895/51-1065.pdf

Curtis (WSW) has all the parts in stock, as do other vendors....
 
Ray

Ray

Well-Known Member
pauldeepsea said:
First your compression releases are controlled electronically. You should hear the engage when you press the run switch. You may also want to check on your starting procedure. Since you have a carb you should twist the throttle 2-3 times before trying to start, do not use the choke especially in warm weather. If this doesn't work you may need to clean the contact on the starter. Also check your battery voltage. Start with these smaller things first
Click to expand...
Since I put a Braile Battery in my ole Scooter it cranks like a "Champ". That piece of crap "Interstate" Battery was my starting issue for a long time. I thought I had a good Battery until I got the Braile,,, worth the investment.

Ray
 
MossBerg590

MossBerg590

Active Member
So what all do I need to pull off to replace the compression release? What gaskets if any do I need to buy as well. Is this the part number I would need to have everything to replace the rear? S&S Cycle Compression Release Assembly 90-4914 Thanks
 
S

Sven

Well-Known Member
Compression Release Socket Kit

And this tool.

And now a meguyveer tool. There is not that much of a torque or a way to distort the unit. Looks like a crush gasket is in place or something very shinny there. So a gasket should come with it or it's installed already.

If all you are doing is to crush that com unit on [via that gasket being crushed meaning], you could buy a 6 point box end wrench for under 10 dollars. If this S&S socket goes down and you still need a 3/8ths wrench to twist it off, torque it back on, why not a box end wrench? One of the 6 points has to land on a flat so you can tell how much it took to break it loose. I tighten it the same way it is all about feel.
 
MossBerg590

MossBerg590

Active Member
Also I can get some manual ones for pretty cheap, will these work? I searched and no one really specified a part number that will work other than the s&s ones.
 
MossBerg590

MossBerg590

Active Member
For example
[ame="http://www.amazon.com/TP-Engineering-45-4020-21-Compression-Harley-Davidson/dp/B007KPT31K/ref=pd_sim_sbs_auto_1?ie=UTF8&refRID=01FKZ9E0J90A5RHF8V3E"]500 Service Unavailable Error[/ame]
 
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