XJ750 trike problems

I bought the trike about six months ago when I got her home she needed work so I have cleaned the carbs ,changed the clutch, renewed all the cables, new battery , new coils new plugs . The pickups are fine , Now she was running and was being use before I got her , But at low speed she seams low on power , and holds back until about two and ahalf thousand revs, I am unsure if this is the extra weight or she is still not running right.When you give her some throttle she is off like a stabbed rat .it seams all or nothing any help would be most welcome.

 

Can you post a few more pics of how the back is attached? Is it chain to a live axle or is the something in between that takes it from chain to ujoint? What sort of gearing is it running? I'm just thinking that it takes a bit to get all that mass and weight to start rolling, then like you said it starts pulling. Is it all M.O.T.'d? Can you still get hold of the previous owner to see if he can shed any light, he'd know his build better than anyone. Just tuppence worth.

 

It is a robin relient axle which runs straight of the shaft from the gear box (she was shaft driven when she was a bike)
It is M,O,T'd haven't been able to get hold of the previous owner.I don't think he built her. She weights 260kg

 

I built several xj trikes a few years ago . No issues getting rolling ass shaft is direct drive to axle . This sounds more like a fuel problem like floats sticking in carbs or faulty coils .
Does the bike idle and start normally ?
In neutral if you raise the revs is there a sudden rise or normal ?
When you do get driving how does the engine feel , is it Reving it's nuts off and not going very fast or going normal speed that you would expect ?
Just try these to try and eliminate carb issue , coils issue or incorrect axle gear ratio problem

 

Also check that the coil leads are in the correct order in case it's fire out of sequence

 

What is the final drive gear ratio?
The Robin final drive might make it a bit tall.
Add the larger mass of the wider wheels and tires, and that will make it a bit slower at initial take-off.

 

She starts fine and idles fine revs ok .I will strip the carbs again just in case I missed something last time .

 

The main issues I had on both trikes I built where wheel size . It had a dramatic effect on engine revs and on one of the trikes I couldn't go faster than 50mph until I changed wheels to various sizes . A lot of experimenting to get close to normal

 

Found these old pics of the two xj Trikes I built many years ago

 

Very nice . she looks great .

 

After f***ing about with the dam thing I think the problem is the fuel tap repair kit on order . fuel comes out in waves , nearly stop starting .

 

Strange but sounds like the vacuum hose coming from fuel tap maybe partially blocked or kinkied. This can cause that sort of symptom

 

tank venting?

 

the rubber in the tap is badly worn away to the point that the it is not working properly .so the fuel is pulsing through not holding vacuum pressure when bike is running.

 

changed fuel pipe and vacuum pipe plus tap rubbers re-new and she seams to be running fine x