cb600 wont rev over 6.5k-7k ish stravation?

[Welshd1k]

Well the bike ran fine when i parked it up 4 weeks ago ish .
finsiehd my swing arm swap and forks etc goen to use it it had a miss fire so i swapped out the plugs for some new irridium ones . starts perfect will rev o the red line in neutral etc the issue :

when im riding it it will rev to 8-9k in first then the higher gears it gets to 6.5k ish and starts to judder and struggle and wont rev any higher if i feather the throttle it will build up slowly to 8k ish then start to die off. so i THINK its fuel starvation rather than eletrical .

so what ive tried :
swapped out carbs for another set with a dynojet kit installed
drained the tank and checked the fuel tap is working and vaccume is opening the tap
swaped out the coils
swaped the rectifier
fresh fuel
new fuel line to the carbs
swapped the CDI

kinda at a loss now trying to work out whats wrong with it its something stupid that im not thinking off probaly any help is appreciated
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Current >Cb600fx hornet, ns125rk90 21.7bhp@wheel<
Sold >,zxr400 h2 (33bhp kit) rd350 n1 rd350 lc2<

[P.]

Do you have a prime option on the tank?

If so, leave it on that and take it for a run. Also tried opening the fuel cap and taking for a quick run?

[Welshd1k]

No prime just on off and reserve tempted to take the diaphragm out of the tank so in the on position it fuels without vacuum . And I'll try tank open latter pissing me off lol
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Current >Cb600fx hornet, ns125rk90 21.7bhp@wheel<
Sold >,zxr400 h2 (33bhp kit) rd350 n1 rd350 lc2<

[P.]

Sure? A vacuum tap usually has On, Prime and Res. No need for "Off" as its vacuum fed. With no vacuum, fuel can't flow.

Weird one

[Welshd1k]

Certain forward is reserve down is off and back is on lol . It's weird my rd has prime /res/on lol
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Current >Cb600fx hornet, ns125rk90 21.7bhp@wheel<
Sold >,zxr400 h2 (33bhp kit) rd350 n1 rd350 lc2<

[P.]

Quick google, you are right, odd Where does your vacuum pipe go to? I know the one for my old Bandit 400 when to cyl 1 inlet.

[Welshd1k]

Cylinder 2
Cylinder 3 is the pair valve
1 and 4 are blanked
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Current >Cb600fx hornet, ns125rk90 21.7bhp@wheel<
Sold >,zxr400 h2 (33bhp kit) rd350 n1 rd350 lc2<

[Welshd1k]

Fuel cap off no difference . Sprayed all the inlets with carb cleaner and it isn't leaking so ummm what next lol
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Current >Cb600fx hornet, ns125rk90 21.7bhp@wheel<
Sold >,zxr400 h2 (33bhp kit) rd350 n1 rd350 lc2<

[bypass2]

is there a good petrol flow to the carbs if so maybe float heights. have you cleaned the carbs out.

[Pete.]

Remove the air filter and try it.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[Welshd1k]

tried with a stock filter / no filter etc no avail ...

took it up the road 300 yards was all good then nothing ... now wont even start LMAO

got spark
got fuel ..

wont even fire if I spray easy start in

so I think its slipped / timings jumped or cams fucked etc (engine has been stood 3 years idle) so tomorrow compression test if its fucked my old hornet engine will go in and scrap the current one then keep an eye out for a cbr600 f3 engine for moar power ... well high end (cams)
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Current >Cb600fx hornet, ns125rk90 21.7bhp@wheel<
Sold >,zxr400 h2 (33bhp kit) rd350 n1 rd350 lc2<

[gavcarter]

How is Battery volatage doing?

[Welshd1k]

12.4 even ran it with leads from my running landrover
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Current >Cb600fx hornet, ns125rk90 21.7bhp@wheel<
Sold >,zxr400 h2 (33bhp kit) rd350 n1 rd350 lc2<

[gavcarter]

12.4 is absolutely fine, check all earths make sure they are good. Considering the amount of swapping you've done i would test compression and double check timing as you've covered pretty much everything else so far

Odds on this is an electrical gremlin though.....

[Nobby the Bastard]

Generally, all running problems are electrical rather than fuelling but....

these days petrol is full of crap (ethanol) and will gum up carbs very quickly (3 weeks lack of usage on my FZ caused similar issues but a good blast and probably our pot-holed roads sorted the issue)

Check that the main jets aren't gummed up and that the floats and valves in the carbs aren't sticking.
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trevor saxe-coburg-gotha:"Remember this simple rule - scooters are for men who like to feel the breeze on their huge, flapping cunt lips."
Triumph Sprint ST 1050

[Welshd1k]

swaped a whole wiring loom froma known good bike still 0 thinking engine
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Current >Cb600fx hornet, ns125rk90 21.7bhp@wheel<
Sold >,zxr400 h2 (33bhp kit) rd350 n1 rd350 lc2<

[gavcarter]

Engine usually give another symptom, sounds wrong, smokey exhaust, knocking etc just something else to go along with it other than doesnt like to rev.
Of course I am not a mechanic and not even seen the bike so everyone just makes an educated guess on it.

I cant really think of an engine problem that would give you those symptoms with out any others to go with it.

If fuelling is definitely ruled out then start trouble shooting the engine

[Welshd1k]

I think the timing may be out or sticky valve or similar compression test tomorrow and theres a NICE Cbr f3 race lump going cheap that I may purchase with cbr carbs to replace should see 100 ish bhp with my full system and the carbs etc
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Current >Cb600fx hornet, ns125rk90 21.7bhp@wheel<
Sold >,zxr400 h2 (33bhp kit) rd350 n1 rd350 lc2<

[gavcarter]

Would make a good excuse for an engine swap haha,
Dive into the engine tomorrow poke around and see what you can find lol

[Welshd1k]

Yeah well I got 4 hornet engines here in various states so no exscuse not to fix / strip it
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Current >Cb600fx hornet, ns125rk90 21.7bhp@wheel<
Sold >,zxr400 h2 (33bhp kit) rd350 n1 rd350 lc2<

[cb1rocket]

New spark plugs?
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Honda H100S2 Rebuild - https://www.bikechatforums.com/viewtopic.php?t=253852

[Ariel Badger]

You engine must have some kind of advance/retard mechanism for the ignition. Is it working as your symptoms sounds as if it is retarded.
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Bikers make great organ donors, get 115 on your licence today.