More possible Exup woes

[1967fazer]

Just a quickie, this subject has probably been done plenty of times before but, after fixing the gearbox and putting the engine back in my gen1, every thing seems ok apart from the fact that it won't rev above 8000 rpm!, any suggestions would be greatly apreciated

[MadDogMcQ]

Stay below 8000rpm  :rollin :lol

(Sorry)

[eddie]

check airbox for obstruction, throttle cables not adjusted correctly, exup cables in wrong way ,rubber boots  to carbs not air tight.

[InTheY2K]

I'd go for the obstructed air intake. Cloth, map, rain gear, plastic bag or anything stored under the seat that can get sucked in at high rpm.

A classic cause for irritation :-)

Cheers,
Sascha

[kebab19]

Another vote for something under the seat too near the airbox intake

[1967fazer]

Stay below 8000rpm  :rollin :lol

(Sorry)

Ha ha ha you're not the only one to say that! It tops out at 120mph now (which probably isn't a bad thing) on a private track of course!
Thanks for those suggestions, will start with the easy one (airbox) and work my way toward the rest. Incidentally, it doesn't 'alf pop on the over run, not sure if that makes a difference?

[eddie]

it doesn't 'alf pop on the over run, ......................fueling problem maybe ..carbs need adjustment ?

[ghostbiker]

sounds like an air leak somewhere, check the intake stubbs are sealed and the exhaust isnt blowing.
thats the poping im talking about, i would think it would take a hell of an air leak to stop it reving out, so as said above blocked airbox/filter is most common cause.

[tomlinscote]

Isn't popping on the over-run a symptom of unburnt fuel going bang in the exhaust? If so may be your bike is running too rich, maybe 'cos of restricted airbox etc.
I once had a mk2 escort whose autochoke decided to come on when I was going down the M4 it run like a cow, not revving out and a popping like a good 'un, until I hit it and it turned off again!!
Also isn't this the popping on the over-run what some gen2 guys miss hence they fit the FCE, well maybe thats one of their reasons??

[1967fazer]

So I had a go at setting the Exup correctly today, as there was no obstructions around the airbox and, hey presto, instant healthy bike again! Total transformation, the exhaust is quieter, it'll rev well above 8000rpm, it feels gruntier and it doesn't pop and bang as much on the over run!
Can the Exup being badly adjusted really make such a difference?

[b1k3rdude]

Can the Exup being badly adjusted really make such a difference?

Yes, as it wont be opening correctly at the required rpm's. Also when you set the exup cable freeplay it would be no more than about 2 millimeters (http://www.cartestsoftware.com/fz1/exupmaintenance.html)

nb. after 7 posts  no-one mentioned the obvious straight off, eg the bloody exup and or its cables... If Falcon or some of the other requlars were around they would have set you straight with thier first reply.