Author Topic: FFJMOORE CB550 BIG bore engine build. (Read 83075 times)

Flying J · « **Reply #225 on:** April 10, 2012, 02:40:27 PM »

Machine shop said, $65 to cut all 4 pistons. Guess ill go that route.

bwaller · « **Reply #226 on:** April 10, 2012, 03:27:22 PM »

Not much choice man, welcome to the world of searching for more....two steps forward, one back!

Flying J · « **Reply #227 on:** April 10, 2012, 03:52:38 PM »

Boy am i having a rough day. So i find out the pistons dont fit and need $65 in machine work. Then i decide to ride my 550 to take the rest of the pistons to the machinist because its the last nice day before 3 days of rain. Half way there the bike starts to surge a little. THen it starts to surge a lot. I limp it to the closest fire station (I work for the fire dept) It feels like its running real hot and the thing keeps surging and struggles to run. So now im in the station waiting for my wife to come get me so i can go get my truck. It was funny though when i rode in one of the guys said "wow that is an old bike, what year? like an 85?" LOL thats what i get for riding old bikes.

Flying J · « **Reply #228 on:** April 10, 2012, 09:23:53 PM »

I caught a ride to the machine shop from a co worker so i could get there before 5. But i had to walk back to my bike through the bum infested down town. Looking in the window of a vacant shop i saw this and took a picture. I thought it looked pretty cool.

dave500 · « **Reply #229 on:** April 10, 2012, 10:12:40 PM »

chevy grave yard?

lucky · « **Reply #230 on:** April 11, 2012, 07:41:46 AM »

Quote from: ffJMoore on April 10, 2012, 09:23:53 PM

I caught a ride to the machine shop from a co worker so i could get there before 5. But i had to walk back to my bike through the bum infested down town. Looking in the window of a vacant shop i saw this and took a picture. I thought it looked pretty cool.

When you first started this thread I was thinking, This guy( Fullbore) better get some help.

BTW...some day you will be old and be downtown and some young guy will drive by and say look at that bum. Of course that bum already knows 100 times what you know. Plus he may be a veteran and could kick your ass. Be careful of what you talk yourself into.

Flying J · « **Reply #231 on:** April 11, 2012, 09:51:13 AM »

Thanks lucky, your post are always so informative and helpful.

And your prediction of me being confused for a bum downtown im sure is spot on as well.
But the fact is that they are bums. Yes some of them may be vetrans, and many of them have mental illness. Most have a drug or alcohal problem as well. But i did not just call them bums because they are old and downtown. I called them bums because they live in tents made of tarps, #$%* on the street, piss on the wall, beg for money and drive shopping carts. There are camps full of them downtown. Almost like its infested.

As for kicking my ass. I dont think somebody who prefers to buy alcohol over food is going to have the strength to kick my ass. But even still i wouldnt fight because they might bite me and give me Hep C or HIV. They are bums and they are all down town because that is where the help center for them is. But you are not allowed in if you are drunk or on drugs. So most of them camp out on the street outside.

As for knowing 100 times more then me. Well yes i dont know what dumpsters have the best food in them or who sells the cheapest drugs or even how to cook heroin. I thinks its more of a quality vs quantity sort of thing. While I may not know as much information as they do because they have been around longer then me. I know how to keep a job, shower, and not do drugs. Those 3 things i know should help some kid from confusing me for a bum downtown in the future. Unless im down there on the off chance because i ran out of razors to shave, trip and fall in a mud puddle and tear my close while pushing my shopping cart into the store. Then i guess you could be right.

I used to drive an ambulance in town. I knew some of these bums personally. There are 2 currently who called 911 1363 times last year. And they are not isolated cases.
http://www.fresnobee.com/2012/02/11/2719079/ambulance-is-pricey-taxi-service.html#storylink=misearch
Unlike most people i have an up-close look and interaction with them. My opinion is not based on a simple observation from a walk down town.
So did you have anything of value to add, because as you stated Im going to need help.

Flying J · « **Reply #232 on:** April 11, 2012, 11:46:38 AM »

Checked the ring end gap. Checked it in a few places and they were all about .014-.015"
the search function seems to be down but from what i could find that is an ok number to start with.

jgmmgood · « **Reply #233 on:** April 11, 2012, 12:56:28 PM »

Just to touch on the item you had mentioned when installing the pistons.....I believe you had stated the larger port would be on the intake side?

Someone feel free to correct me, but I am thinking the larger port (and valve) would be for the exhaust.

Apologies in advance if I am incorrect. This may need to be double checked before you go and get piston machining done.

Flying J · « **Reply #234 on:** April 11, 2012, 01:09:22 PM »

No worries. I have missed things before so i appreciate the input. I went and looked just t make sure.

this is the intake side

bwaller · « **Reply #235 on:** April 11, 2012, 03:07:43 PM »

If this is a fresh bore then that end gap is plenty.

Flying J · « **Reply #236 on:** April 11, 2012, 04:09:13 PM »

yup its a fresh bore.
Pistons are back.

one of them still rubbed. I could make a full revolution but i could feel a little drag so i figured out which one it was and hit it with a flapper wheel and now it clears fine.

Piston to deck height is .020.
Bwaller suggested a differance of .004-.006 so it looks like i need to have the cylinders re-surfaced to take off .018?

bwaller · « **Reply #237 on:** April 11, 2012, 05:56:58 PM »

I suggested you leave them down the hole some until you check clearances with the head. Realistically you could have them even with the deck if you've got ample clearance and use a 0.043" head gasket. Personally I wouldn't remove it all from the deck, maybe 0.005" and use a 0.014" (or 0.008 & 0.010) base gasket. It just leaves you a chance to "adjust" up or down if need be. Just 0.02 worth.

Flying J · « **Reply #238 on:** April 11, 2012, 06:09:58 PM »

Well im pretty frustrated. I have been trying to get an accurate measurement off the motor for the last few hours. I think my harbor freight gauge and magnetic base are not accurate. As i move it across a flat surface the gauge goes up. Like its moving up a slope. Not a surprise but then when i look at my cylinder on hole #4 the deck to piston height is different on each side of the piston! The cylinders were surfaced when they bored them out. So what is going on? Here is a picture of piston 4 right and left sides.

Im not sure if the cylinder is not flat or if the piston is wrong or if the gauge is wrong.

I just had a thought. Could the coating be what is giving me different readings across the same piston?

fastbroshi · « **Reply #239 on:** April 11, 2012, 06:32:16 PM »

Speaking of ring gap, has anyone ever used Total Seal rings in a rebuild of one of these old beasts?

azorsaurus rex · « **Reply #240 on:** April 11, 2012, 07:08:09 PM »

Quote from: ffJMoore on April 10, 2012, 09:23:53 PM

I caught a ride to the machine shop from a co worker so i could get there before 5. But i had to walk back to my bike through the bum infested down town. Looking in the window of a vacant shop i saw this and took a picture. I thought it looked pretty cool.

neat pic ... when i saw this it made me think of the terracotta army

http://en.wikipedia.org/wiki/Terracotta_Army

Syscrush · « **Reply #241 on:** April 11, 2012, 09:12:38 PM »

Quote from: ffJMoore on April 11, 2012, 04:09:13 PM

one of them still rubbed. I could make a full revolution but i could feel a little drag so i figured out which one it was and hit it with a flapper wheel and now it clears fine.

I would be really worried about interference happening when it's hot, due to the different temperatures and CTE for the crank, rods, and pistons.

bwaller · « **Reply #242 on:** April 12, 2012, 03:57:34 AM »

If it's only #4 better check that piston against the others. Your gasket surfaces are clean and the gasket is either new or good used? The cylinder is cinched down evenly?

It is unlikely to be the cylinder. That said I had a good guy work on one for me and whatever the hell happened actually ruined it, so crazy crap can happen.

I agree about heat expansion, clearances taken up at high rpm and your piston/crank clearance. Make sure you have enough now, later is too late. 0.050-0.060" comes to mind.

Flying J · « **Reply #243 on:** April 12, 2012, 10:03:14 AM »

Well it looks like the piston/ crank distance isnt going to matter because these FN POS pistons are total crap. I measured every piston, right and left in the bore. Then i pulled them out and check the differances from piston to piston. The pistons are cut uneven. Soos lathe must not have been centered well. So im up #$%* creek on these.

Here is the measurements in the holes.

I have 2 options, give up and go back to standard bore, or give up a ton of money and go with dyno man pistons. Im pretty sure that i can rebore these cylinders for dynomans. I bored these .001 over and dynomans require .0028. So these cylinders are at least salvageable and i wont have to pay $400 to have a new set bored if I go that route.

Greggo · « **Reply #244 on:** April 12, 2012, 10:07:05 AM »

What a flustercluck...I feel bad for you man, not that that helps. Those Dynoman kits look nice tho.

dave500 · « **Reply #245 on:** April 12, 2012, 12:28:34 PM »

if you bored to 61mm thats more than .001 over!

Flying J · « **Reply #246 on:** April 12, 2012, 12:33:10 PM »

correct. But the piston to wall clearance i had bored for my 61mm pistons was .001
Dynomans 61mm pistons require .0028

dave500 · « **Reply #247 on:** April 12, 2012, 12:44:25 PM »

ok now im with you,has yours been bored out of square maybe?

Flying J · « **Reply #248 on:** April 12, 2012, 12:54:04 PM »

No, the top of the pistons are different heights. If it was bored out of square i would expect the numbers to be lower on one side of the cylinder and higher on the other but its not.

bwaller · « **Reply #249 on:** April 12, 2012, 01:34:37 PM »

Sorry for your rough luck ffJ. It should be obvious even looking by eye at the sleeve base thickness or flange top if it was bored out of square.

Likely by the time you had those pistons corrected, you might be out of pocket what new would cost. I have heard good things about Dynoman kits. I also believe his pistons are forged, so that's the reason for more needed clearance.

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Author Topic: FFJMOORE CB550 BIG bore engine build. (Read 83075 times)