Engine strip and re-build

[Bill Black]

Hello to all
I have bought a Dual twin and am in the process of stripping it to assess damage , it was seized and from what I see it probably happened not long after it was bought ..... the speedo shows less than 1200 miles and from the condition of the cycle parts i would say that's probably right , I am having to resort to some extreme brutality to get the barrels off .... i would say it was left with plugs out for years i tried removing the studs to get the barrels moving and have managed to remove all bar one which sheared off just below the barrel face , i can now see the crank is also locked up with corrosion as well .....
So what can i expect when it comes to trying to get it going again at the least I will need two barrels , pistons rings and a crank can they be gotten and what will i expect to pay?  I live in Ireland so if anyone in the UK has parts can they reply as well ?

Regards
Bill

[ddog71]

Try ebay seller "bsaddict" in the UK ; "bridgestone", "swapmeetman", "nancysgreatfinds" in USA. What you can't find in the UK then your best alternative will be ebay seller "bridgestone". His name is Richard Clark and he started this Bridgestone forum. Great person to deal with.!!!!  Best of lick.... Tim

[Redrust]

If I remember right Richard has all the things you need to get the bike running but the price is the problem. I priced out both jugs at $1300 US new in box parts. The crank I believe is around $500 US if I got all the parts and had it rebuilt but I don't know about a new one. New ones don't come up on eBay often. You might want to look into recoating the jugs if you have access to that and maybe a rebuilt crank. Do some looking around at what's available and don't worry if its gonna take a while to get it going. Bridgestone's are a labor of love. Good luck

[ziggy stardust]

Try contacting Mopar5426 in the U.S., he has a good number of used parts for sale, his name is Gene.

Z

[Bill Black]

Thanks Tim and Red rust .....
I managed to get the barrels off last night , excuse the brutal approach but the barrels had seized on the sheared off studs on top of everything else and i had to cut one stud with a hacksaw flush with the crankcase and the other i had to slice through the barrel to sever it ....... then pound away with a hammer !
I decided that if i could manage to avoid wrecking the crankcase then that was good enough ,
Barrels :

Pistons :

Crank 1 :

Crank 2 :

End result :


Next to split the cases and see what I can salvage from the crank ....

Regards
Bill

   

[dcr]

Is it just me, or are most of the dual cylinder engines found seized? I don't see many posts on 50's, 60's, 90's or 100's with stuck engines, but there are plenty on the 175's and 350's.

Is this a product of engine materials, or some other anomaly?

Dan

[mqtsteve]

drc, I have three 90's that were all stuck when I got them.  They weren't as bad as Bills.  Steve

[slawsonb]

Yup, Bill's appear to be very high on the "stuckness scale". We probably need Colin to weigh in on this, but these appear to be above my 9.7 cylinders.
 
...bert

[Bill Black]

Hello again
given the amount of water and rust present in and around the crank I am thinking this bike seized not long after it was bought and then seeing how as almost all the red parts have completely faded to silver ( the undercoat ?) it was left outside somewhere sunny in the US ...... with the plugs out , over the years water has made its way down into the cases .. the clutch and gearbox internals are spotless and the gearbox oil was clear and clean , I am hoping I can salvage as much of the crank as possible and have asked Richard for a price on two conrod kits and all new mains and seals .... I will update with pics. when I strip out the crank

I would love to get a spare engine but shipping from the US is a bit expensive but maybe it will end up my only option .... time will tell

Regards
Bill

[Bill Black]

Well i managed to split the cases and even though it all looks like something from the bottom of the ocean ...... it has come apart surprisingly well , the cast iron ? disc valve covers are a bit pitted as are the inner faces of the crankcase but they should polish up OK I am hoping , and I may be  able to save some of the crank......

photo's :

cases:



Crank :

[slawsonb]

Wow! Quite the swamp in there. I don't think I have ever seen algae growing in a crankcase. 
Did the big end bearings still move on the pins?
...bert

[bsforever]

I just have to say, that is very humorous of Bill to say it looks like it came from the bottom of the ocean ( i sure had a laugh out of reading that one!!! ) lol... engine parts from the Titanic?   Looks extremely corroded  ... bsforever

[dcr]

Here is a quick motor shot of the 1966 175DT i picked up today. More to follow in a separate post but here is what happens when a hammer is the only tool used to solve the stuck piston problem. What was this person thinking?!?!

[slawsonb]

My one of my parts bike cylinders looked like this (not quite as bad, but close) and the guys who did the repair and replating we able to fix the hammer marks and resurface the deck-looks like new, so if you can unstick the piston the cylinder might be salvageable.
...bert

[Bill Black]

Managed to split the crank with a hydraulic press in the tool-room at work after giving it all a clean up with wire brushes in the drill and I will be able to save the main parts  , it all came apart surprisingly well .......

All the pieces :



What I will need to replace :


Now to hunt down the parts .......

Regards
Bill

[Bill Black]

Ok so some major progress has been made I actually found a person fairly near to me who has a treasure trove of new and second hand parts ......
I now have a good second hand crank , and a set of 200 cc barrels and pistons .... along with lots of other little bits like tank rubbers a tool box , gaskets , small end needle rollers and more

One question is can 175 heads work on a 200 ? or will i need to machine them , i can see i need to get the crankcases bored out

Regards
Bill 

[ziggy stardust]

So who is this person with a treasure trove of new and used parts?

Z

[Redrust]

No 200cc heads and cylinder will not work on a 175cc case half. The opening for the cylinder is different slightly enough to make it unable to fit. If you had a 200 case top then you can use the 175 bottom case half I believe.

[OldSwartout]

If you had a 200 case top then you can use the 175 bottom case half I believe.

Caution:
The top and bottom case halves for all the twins are a machined matched set and shouldn't be interchanged. All the bearing bores that cross the horizontal splitline and all the vertical surfaces were machined with the case halves clamped together. If the case halves are mixed, there can be mismatches that will fail bearings, cause leaks, etc.  There are actually match numbers stamped on the upper and lower halves.

[Bill Black]

Thanks for the replies I can see the case matching numbers stamped above and below the join line near the back sprocket area so i can see and would have assumed cases are paired , fitting the 200 cc barrels is just a matter of milling out the opening to allow the lower spigot of the barrel in ..... , has anyone machined a squish area into 175 cc heads to suit the 200 cc wider bore ,
The guy with the parts is John Kiely who lives in Stillorgan County Dublin , he may even be a site member .......
Regards
Bill