CB750 scrambler project
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@Louis-DT-WR you're probably right on it only needing one cable but U.S DOT requires two by law incase the spring fails or throttle slide sticks. Contrary to their name they don't actually push, when you shut off throttle the push cable actually pulls the throttle closed. As for the dtr having single cable maybe they weren't sold in U S.A or maybe that law comes in for bikes of a certain size/power. My 1989 nc30 had two.
And yes it is a breather pipe, they sometimes are routed back into the carb manifold so any nasty emissions are burnt off. Hope this helps. -
@markus-w great thanks but I have a dt200wr which was sold in the US and that wasn't push-pull.
The carbs to have slots for two cables day + choke cable.the CB 750 doesn't seem to have that breather pipe, but on this cbx750 it does.
Brains hurting from all the learning on this build haha.
I'm happy the rolling chassis is done.
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@Louis-DT-WR my thirst for knowledge has got the better of me I've just done a bit of googling and apparently it's only four strokes have 2 cables because the extra vacuum created by a 4 stroke can cause the throttle slide to flutter and jam against the side of the body. That seems to me the most logical explanation so far.
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@markus-w possible. The other thing with this engine is why does it have 2 oil fillers caps
️ 1 says (don't open) but that's the sprocket side.
In some pictures I see that's where the dipstick is on some bikes. My dipsticks on the clutch cover side like most bikes.Haynes don't do a cbx750 manual.
Just going to persist working through all the small bits. -
So the carbs were very similar but not correct.
So I started again
parts are taking so long to come from overseas
All new float bowl gaskets, diaphragms, o-rings and rejetted.
Powder coated partsStainless steel Allen cap bolts
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Finally my bar clamps came, 3 weeks.
I've got the controls, grip, master cylinders on. Front brake operational.
Choke and throttle cables.
Front headlight on the number board (not finished yet) more to add to it.Pro taper contour bars.
Rear fender (when pulled out, it's a shovel! (Entrenching tool))
Slowly making progress.
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@Louis-DT-WR i like the shovel rear fender adds character
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Been driving me crazy how the seller of the engine said it was from a cb750 but appears to be a cbx750 engine (much older + hydraulic clutch) rc17/17E
But the engine apparently had only done 12k
Also looks very new for something that would be 40 years old nearly.After a lot of research the Japanese did a later 2007 LTD with the Rc17E engine when looking at the part numbers for the upper crankcase on this models parts diagram it confirms this.
This is a super rare models engine, + hydraulic clutch optional extra. On an import!But it will work perfectly for me, just ordered the correct pulse generator.
Writing this down for future reference because I'll forget. -
Started on the looming and electrics.
Repositioned the coils to clear the fuel tank.
Little jobs like that take a lot of time getting right.My holster on the headlight number board is all part of the walking dead style bike. It definitely wouldn't be ridden with that on it
even though I'm trained on glocks , this is just a replica.
Only used for pics
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@Louis-DT-WR this looks amazing, well done
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Working through the electrics. I've got my rear indicators and tail lights sorted.
I made a CDI holder to relocate it.
Fuse box and indicator regular relocated.
Front lights, indicators and horn on.
Ignition barrel relocation plate made.
Just sorting a battery box and the battery is on order. I can't fully test what connector goes where until the battery comes.
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Well I put the engine in alone which was a very heavy task
killed my back haha. Lining it up with the mounts while the bike was leaning again the bench. (You can't fit the engine when the chassis is on a bike lift)Got my battery box mounted with the lithium battery. Its so light! I thought it was just a empty case!
Carbs on + filters and cables. Fitting the carbs was tricky, the rubber manifolds are so hard. I'd replace them but £150+vat for 4 and they're not cracked.
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I even have a engine lift but it would have needed an offset cradle made up to clear the frame
