Topic: no wonder it seized up!

[mcpuffett]

dropped the oil and filter off my 1970 750 that had seized up on me last october yesterday and this is

what i found

[Bob Wessner]

Yipes!

Do you mind if I move a copy of this pic to the "You Think You Have Problems!" album in the Gallery?

[DammitDan]

Did it get driven into a river?  Sheesh!

[mick750F]

   :oYuck!!!

[mcpuffett]

i have'nt had time today to get the engine out of the frame, all the sludgey stuff is gritty and horrible

and theres bits of black plastic in there as well,

this engine has been sitting for quite a number of years in a frame etc but outside under a cover ,

so my guess is when i started messing i have disturbed a lot of rust and sedement and this is some of

it, i will keep you posted on what else i find and how i get on ,       mick.

[mcpuffett]

hi bob , yep no problems please post it there, the oil filter in the picture had only been in the engine

for about 120 miles  ,     mick.

[Bob Wessner]

OK, done, saved for posterity.

It will be interesting to see what else you find.

[toycollector10]

You're scaring me man.

I drain my oil tank about every 300 miles in between full oil change/filter change because the oil gets so black and dirty so quickly. I thought it was because the bike runs rich and soot was blowing past my rings.

I have good oil pressure, it pumps up out of the oil return OK in a healthy stream but I have never had a gauge on it so can't be 100 percent sure it's good.

I think I'll drop my pan off too. First, find a gasket.......

[Bob Wessner]

Don't forget that each cold start-up you are using a good deal of choke and running rich until warmed up so I don't think the oil will stay pristine looking very long.

[750goes]

I just lost my breakfast - that is so ugly in there...

Did you check your oil in the tank  - was it discoloured - what was the history of the bike...

That oil filter looks like mine did when I changed it - I reckon it must have done 100,000 miles before I changed it..

the black plastic is probably the cam chain rollers disintegrating or primary tensioner

 

[aptech77]

 

[MRieck]

Well...at least there aren't parts of a conrod or the crank in there. It can be rebuilt.

[wardmoto]

I think that a DNA test might be in order....correct me if I am wrong, but that appears to be a squirrel...

[mcpuffett]

the engine has only done 28,000 miles but it has been sat outside for unknown years under cover

before i bought it as a parts bike , i had it running briefly after buying it 2 or 3 years ago and since

then it has been garaged, 

last year i needed the engine (which is a f1) so i set about getting it going again changed the oil and

filter, new points and condensers etc, had some carb issues with cleaning etc and running pods,

changed oil and filter again before doing road tests,  just got the bike running pretty sweet and had

done about 120 miles of little rides while trying to iron out problems and this happened ,

my own fault really i should have dropped the sump and i would have found this and maybe

prevented any mishaps , the engine was running strong so i think it will be worth rebuilding i intend

to strip it completley and clean everything and replace what ever it needs ,

i have never rebuilt one of these engines before but i recentley stripped a k7 engine down that was

seized so i know what the insides look like , will keep you informed on my progress and no doubt i will

be asking questions when i get stuck , right i'm off out to pull the clutch and rotor off while the

engine is still in the frame  ,    mick.

[bryanj]

You will probably find its the cam that has picked up in the towers with the oil jets blocked

[mcpuffett]

hello Bryan, you were correct that the cam had seized in the carrier  , here's a picture of the damage.

[mcpuffett]

i have just about stripped the engine down , just got to take off the points plate and split the

casings , everything that can rust has done so the engine is covered in rust particles and old oil ,

up to know it has come apart ok and looks in good shape underneath all the muck,   ,  mick.

[supersport_CB400F]

Bummer Mick……but looks like that engine needed to be taken apart and cleaned anyway! 

Cheers

Dave

[mcpuffett]

Hi Dave, yeah i know i was humin & arrin about doing this myself  , but now i have started i'm

enjoying doing it  , dave silvers will be getting a shopping list this week  ,   mick.

[MRieck]

You will probably find its the cam that has picked up in the towers with the oil jets blocked

Appears to have "picked up" and layed down Bryan.

[Terry in Australia]

Geez I wish I had a buck for every time I've seen engines like that Mick, I'll never be able to estimate some peoples capacity for stupidity. How somweone can keep running an engine when they know how filthy the oil is, is beyond my comprehension.

I bought my wife a cheap used Hyundai car the year before last, and the "oil" was black, so I asked the PO when she'd had it last changed, and she couldn't remember? I've changed it three times since then, and I can still see baked on black crap in the rocker cover. If anything, it's a testament to how good modern engines are, if they were built like our old 750's they wouldn't last very long at all!

You're scaring me man.

I drain my oil tank about every 300 miles in between full oil change/filter change because the oil gets so black and dirty so quickly. I thought it was because the bike runs rich and soot was blowing past my rings.

I have good oil pressure, it pumps up out of the oil return OK in a healthy stream but I have never had a gauge on it so can't be 100 percent sure it's good.

I think I'll drop my pan off too. First, find a gasket.......

I'd be doing a compression check too mate, if your oil is getting that dirty so quickly I'm guessing you've got blow-by problems............. Cheers, Terry.

[mcpuffett]

G'day Terry hows it going?, i've learnt my lesson next time i come to use a engine it will be sump off and lets have a look inside first  ,    mick. 

[Terry in Australia]

G'day Terry hows it going?, i've learnt my lesson next time i come to use a engine it will be sump off and lets have a look inside first  ,    mick. 

G'Day Mick, I'm good mate, and yeah, drop the sump plate and pull the oil pump screen off and give it a clean too, it's quite scary how much crud can lurk in there. Also, if your sump plug hole has been "helicoiled" you should drop the sump, most helicoils are longer than the original thread and sit proud of the drain channel, thus blocking the debris from exiting when you drop the plug out.

If you need any good used bits let me know, I've got cams, cam towers, rockers, rocker shafts etc in good condition, and probably a little cheaper than Dave Silver. Cheers, Terry.

[bryanj]

Mick, If you find me a strter gear i will do you a great deal on some used but excellant towers, camshaft and rockers!

[mcpuffett]

cheers for your comments fellas , Bryanj your gear will be in the post tomorrow & thanks for the offer

of the cam and carriers but i already have another set,

i managed to split the casings today but not before i had 1 10mm stud snap on me & 1 gudgeon pin

was welded in had to use blow torch and WD40 to shift the bugger , after i got it off i noticed

that i had bent the conrod even though i had supported the piston with wood  ,

so my first question is does anyone know if a k7 conrod will be the same as a f1? as i have a spare

crank with rods out of a k7.

i have also been on to Dave silvers to price up a complete gasket and o ring set also a complete oil

seal set , cam chain, primary chains but he does'nt have all genuine parts?

complete gasket & o ring set pattern £39,

complete oil seal kit pattern £19,

primary chains 2 of oem £39,

cam chain pattern £15

has anyone had experience with the pattern parts mentioned ? Den? Dave? Bryanj? Sam? ,

i will post some pictures tomorrow   ,    mick.