carbon in front but not rear Help?

[Bigbass]

I did a winter rebuild of 650cam with 640 springs
port and polish heads
zero decked and diamond cut
new rings and wrist pins
new triple x carb with thunder jet ( I told him I had the radius pipes when I bought the carb.
swtiched from big radius pipes to short fuelies with torque cones I purcahsed seperatly( I have not changed jets since the pipe change )


Here is the question I was adjusting the carb and noticed front pipes turned blue really fast. The back pipe never changed color. I got the carb set fairly close where it responded okay for now. Ran the motor for a total of 30 minutes on the stand . I have not riden it just wanting to get motor right before i ride.

I pulled the pipes off to make a mount bracket for the short pipes and noriced there was a ton of carbon on front pipe but back pipe had none.

What would cause the front to build carbon but not the back. Did I not get Valve adjusted right or do I have a ring problem. Do I just need to adjust carb. The motor makes no niose and seems to run great. The lifters had tick before the build but now there is no tick at all.

Do I need to just put the radius back on. The motor starts and runs great but when I het throttle I do notice black smoke in front pipe and not rear. I would appreciate any suggestions. If it is a carb adjustment then what would cause it only to be in front cylinder.

I want to learn everything about thise motor so any suggestion would be great,

 

[Ridgeback05]

your mistake is your pipes they dont even run them on pro stock drag bike put a set of 2into ones

 

[Bigbass]

I a think they are called fuelies. They are short and dump between the mptor and tranny.

I did a compression check and both are even they have 152 psi.

I am not familiar with a S&S 117. This is my first one to rebuild. Would you mind neducating me as to why one cylinder has more carbon than another? If compression is same in both what is the difference. I understand what you are saying about pipes not for max horse power and such. I am not a fan of the 2 into 1 exhaust. I like the looks of the two seperate pipes. If I go back to the radius pipes will the carbon problem go away.

 

[MARV]

check to make sure you dont have an intake leak.

start with fresh plugs

then adjust the carb

also 152 psi is dirt low with zero deck and 650 cam
check that again as mine is 200 + psi.

if your looking for power then, like RB05 said, lose the short pipes

 

[Bigbass]

I checked it again. I could not get around to hold carb open. With carb closed the compression is 172 psi in both front and rear. As I said I was not able to hold the carb open. I have the bars and stuff off.

This started with me using our local S&S dealer to send in the jugs and heads to have them diamond caut and zero decked.
He said he had trouble finding someone that knew what zero decking was. He said he talked to man named Wolfe at the factory and I gave hime my engine serial number. He said they zero decked it and all is good.

I never gave him any measurements from the cylinders. He said he thinks they knew it by the serial number.
With only 172 psi I am curious if it really got zeroed. I am going to put radius pipes back on and have my brother hold the carb apon and re check it. I have not checked it after it ran. My compression checks have been done on the motor being bone cold. I am going to warm it up and hold carb open and re check.

 

[beezer]

Zero decking cannot be done to a set of cylinders that are shipped to a shop--measurements must be performed on the engine they are from--ya might want to check some other clearances,such as coil bind as your runnin a .650 cam with .640 springs.

 

[Bigbass]

I guess in my haste to explain this I did not go into full detail. I used the local S&S dealer to ship them back to the S&S factory. They were diamond cut and supposedly zero decked. I do know they were shipped to the factory and returned from the factory because I seen the invoice from S&S. Just wondering though if the zero decking really happened. The invoice showed where they came back from but did not see the work that was done to them on the invoice.

When they talked to Wolfe at the factory he was familiar with what I wanted done and said he needed my serial number and would take care of it.

 

[MARV]

you can angle a piece of solder into the combustion chamber then have someone turn over the motor by hand to figure the deck height minus the gasket which stock is .040

 

[mobsta]

i was told by s/s that the compression is checked on a hot motor,not warm but hot,just sayn

 

[Bigbass]

I thank all of you very much.

Mobsta, I wasn't thinking at the time I posted this about the compression. I am going to get her finished and run it and then check it.

Marv, I also thank you very much sir. I never thought about trying to measure it thaty way but will try it this weekend.

You guy's are all awesome thanks/

 

[snypr]

Just my 2 cnts for your understanding. Zero Decking is also known as Compression Height which is the gap between the top of the piston in relation to the flat of the head. The accurate way or way that I was taught was done with heads off and a set of torque plates. Then the distance is measured from top of piston to top of cylinder at TDC. As others stated you cannot send anything out ot have it decked unless you know how much your going to shave off your cylinders unless you do as I have and use single layer steel cometic gaskets to reduce height .045 and a piston with a taller CH distance.

I also agree with BEEZER on the coil bind as I have had that issue with a HD 113" motors that were cam'd up. Bottom line if you want looks deal with it, if you want performance then go 2 into 1 for exhaust. Poor exhaust can kill all the money spent on decking, heads, etc.

 

[Vegas]

All this zero decking talk is great but the engine is hardly broke in and even compression should mean relatively even burning cylinders. I agree with Marv, check for a vaccum leak. What air cleaner is on the bike?

 

[Bigbass]

I am running the spike for now but after I save a few bucks I am going to get the dual S&S.

 

[Vegas]

That's why your cylinders aren't burning evenly. I've seen it first hand on my 05 mastiff.

 

[john sachs]

Just-a-quickie.
"0" deck,or the distance between the piston crown and the top of the cylinder,influences the area known as the quench,or squish.This area plays an important role,
Compression height is the distance from the center of the wristpin to the top of the piston crown.
S&S cylinders can be altered,usually,without actual measurement,as S&S has records on each engine they ship.Aside from this,the 117",and 124" S&S EPA motors all have specific,over length cylinders.
I've done quite a few,(I do it in the heads on 117" motors)without having the whole engine here,and they have ALWAYS been right on. :2thumbs:
John