Home › Forums › All Things 750 Twin › Projects and Progress › Progress Reports › Doh!!!
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8th January 2017 at 12:04 am #13898KennySParticipant
Thought the lower crankcase might have been ok, but no, it’s got a hole in it as well.
Lots of bits to play with, if they fit.One of my rods is damaged, but there are 3 more. Some of the pistons are damaged, skirts or tops, but there are 2 with no markings, 2 with STD stamped on top and 2 with 2 stamped on top.
One of the heads and barrels are black coated, it looks like a manufacturers finish and then it’s been filed to give bright marks.8th January 2017 at 4:40 pm #13883Evil TwinParticipanthi Kenny
been reading thru this
mmmm
its a mess
I have seen and fixed worse
ok
do me a favour
check the gasket on the oil pump
they do blow
then oil pressure obviously is lost and its usually shell bearings
crank etc that cop for it 1st
its a easy fix in time no worrys
if you turn the engine upside down you will see both bottom end conrods and bolts
and nuts holding them in place
if your luckyeee
I say that lightly,(worse case scenario )conrod and piston are sitting at tdc on the one that’s become detached.fingers xrossed
hope its minimal damage11th January 2017 at 9:59 pm #13899KennySParticipantHi Evil, it’s way past that, both cases are damaged, one piston and rod are wrecked, oil pump damaged,Cylinder barrel damaged, crank journal damaged. I might salvage the cylinder head, gear clusters, that’s about it.
But all’s not lost, I’ve stopped sulking. Thanks to KK for coming up with a B engine. And thanks to Phil for the tea and sympathy. It’s gone from being a big balance bike to something resembling a motorbike. Surprised myself by getting the motor in on my own, and still having the right number of fingers and toes. Just need to connect up the electrics and see what happens.
11th January 2017 at 11:13 pm #13848KaptainkwakKeymasterWell you have been busy.
If you need help with the electrics shout up. We will do what we can
12th January 2017 at 12:29 pm #13884Evil TwinParticipantlol ooops bit behind was I Kenny lol,glad your getting sorted then
12th January 2017 at 9:57 pm #13900KennySParticipantAnother small hiccup, for being lazy. Tried to fit the carbs, but the rubbers on the B engine were much bigger diameter, so took them off the G. Are they different size carb bodies on the models.
Hot wired the ignition to a battery and kicked it over. It did fire occasionally but wouldn’t run. Now I remember why Kawasaki fitted starter motors.
Found the points weren’t closing every time. It looks like so much corrosion on the cam. Cleaned it up and reassembled and will try again tomorrow.
Went to fit the exhaust but the left hand port has had a repair and a 10mm stud fitted in one side. Not sure yet whether to try and re-thread it to 8mm or try and drill the collar to 10mm. It would have been easier to re-thread the stud before I installed the motor. Still smiling.12th January 2017 at 11:38 pm #13849KaptainkwakKeymasterIt looks like your playing the 750 twin characteristic game.
Don’t worry we are on it and normal service will be presumed . . . eventually
19th January 2017 at 11:12 pm #13901KennySParticipantCarbs are the ones that came with my bike. Choke is hidden behind the fuel tap. Stripped them and found solid blockage in the tee piece to the left carb. Cleaned them and rebuilt but still won’t start, right hand carb flooding. Stripped them again and found petrol above the diaphragm. Not too sure how these carbs work and where the fuel and air passages go, so don’t know how it got up there.The diaphragms aren’t torn.
A little bit of light relief, I cleaned up the brakes on the little Honda.20th January 2017 at 1:28 am #13865MichaelParticipantHi Kenny,
these are the BS34 carbs of the LTD models. Only one single “Throttle opener wire”.
Mounted in a B with stock fuel tank and fuel cock, you may cut a bit of a half of the plastic knob away to pull the choke completely. That will avoid contact with the fuel cock.
They are 34mm and only fit in intake boots from the LTD models, which seems to be already fitted. They will simply fall off from the intake boots for the BS 38 mm stock carbs.
I treat these carbs to be better than the stock ones, be happy !
There is a matching carb kit from Dynojet if you like to use single pod air filters like K+N, which I highly recommend, when this is the case.
Some technical information and a lot of pics about the BS34 carbs rebuilt can be found here:
http://www.z750twin.de/vergaser.htm
Use your web-browser capabilities to get it translated.I know these carbs quite well 😉
Any question ?Take care to close the vacuum pipe connectors of these BS34. They are not needed for normal operation with the standard (non-vacuum) fuel cock of the B. Most simple way is to fit a tube from one connector to the other. Important is no fresh air intake through these “wholes”.
Remove the carbs, give them a clean (just simple clean to be dry again) and try again. Typically you don’t have fuel above the diaphragms.
Maybe I have misunderstood something and you have to explain it again or show some pics 😉
Cheers, Michael
20th January 2017 at 1:40 am #13866MichaelParticipantAhh, in regards to a previous posted pic.
The upper pair are the intake boots of a BS38 carb (stock with the B models), the lower shown pair seems to be the intake boots for the BS34 carbs (stock with LTD models)
Carbs and boots must match and in general both work fine with our Twins.
I like the BS34 more 😉
Less complicated !Cheers, Michael
20th January 2017 at 6:52 am #13850KaptainkwakKeymasterHi Michael
Thank you for your interest and input.
I have been speaking with Kennys and giving him support. I can confirm Kennys is using the 34mm carbs and carb rubbers and the vacuum pipes are blocked off. I also believe he has an aftermarket fuel rap fitted which is making the problem worse but we are looking at ways round this.
He does have the option of putting it all back to original.
20th January 2017 at 1:24 pm #13867MichaelParticipantHi KK,
good to know that !
I use the BS34 on my B and they work fine.
May post a pic of the “reduced” choke knob.
Cheers, Michael
27th January 2017 at 8:37 pm #13902KennySParticipantHi Guys,
Didn’t get much more done before I had to go back to work. Our internet connection out here in the North Sea is pretty poor.
I did strip the carbs again. Last time I couldn’t get the pilots out so I soaked them in WD40 for 3 days and finally got them out. They appear to be blocked but I had nothing fine and stiff enough to try and clear them. They were quite badly damaged where the screwdriver slot is. I haven’t taken out the needle jet or the mixture screw yet. I did try cleaning the pilots to find the size but it’s difficult to tell. I tried searching for jets for these carbs but didn’t have much success. Does anyone know where to get overhaul kits for these carbs. I’m wanting gaskets, jets, float needle valve. I did notice on Michael’s link that his original needle has multiple grooves, mine only have one choice of needle height.Cheers,
Kenny
28th January 2017 at 12:27 am #13851KaptainkwakKeymasterHi Kennys
Cheers for the update.
The way you describe your findings confirms your carbs are from a CSR. They were set to meet USA emission regulations and also to be ‘Tamper’ proof. Tamper proof being that the carbs could NOT be adjusted as there was a plug over the mixture screw and the needle could not be adjusted. However the plugs can be removed and adjustable needles can be fitted. Alternatively the needle can be raised by inserting small washers below the circlip.
As far as refurb kits are concerned my first port of call would be
If they can’t help then so far it’s the dreaded fleabay
28th January 2017 at 10:05 pm #13903KennySParticipantThe mixture screws are visible so the plugs must have been removed already, I suspect someone has already tampered. Or, judging by the rest of the bike, my carbs may not always have had those needles.
When I was sorting out some of the other ‘SPARES’ I found one of the clutch baskets has only 4 posts, the other has snapped off flush. How do you do that? -
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