2003 Honda Hornet 600

[Enzo200500]

This is the first bike of my friendly tree surgeon.

It gets to about 6-7k then refuses to rev out any further.

It has some crappy straight through tailpipe fixed on, with no baffle.

Would this cause the bike not to pull over 7k max?

There are no restrictions in the inlets, and the throttle does open the butterflies fully.

The tailpipe is caked in soot, like it’s running rich, but the choke does work ok.

Any ideas before I tell him to come and get the shitheap?

[srad34]

Is it hesitant and stumbling or just dead stop at 7k?

I doubt even a crap can would stop it revving out….

I would start with checking carbs settings, fuel filter condition, maybe a fresh set of plugs and check coils as sounds like a needs a bloody good service to start afresh

Edited August 13 by srad34

[Enzo200500]

It pretty much hits a wall and sounds almost ‘crackly’ from the exhaust.

The bike is a bit of a dog being perfectly honest. So I don’t know whether I want the potential grief?!

[Thunderbolt]

It’s not breathing, the question is why?

Fuel or airflow?

It’s not getting one or both.

Do the easy stuff first, air filter? Carbs, are the slides lifting all the way?

Blocked/restricted fuel flow? Tank breather?

Exhaust completely gummed up?

Choke???

[jaycee]

Idiotic thought warning;

Would a crudely restricted 33bhp version of this perhaps have a rev limiter?

[Enzo200500]

That was exactly our first thought!

I have checked the inlets with the borescope and the throttle butterflies open fully.

Unless it’s in the ECU?

[jaycee]

19 minutes ago, Enzo200500 said:

That was exactly our first thought!

I have checked the inlets with the borescope and the throttle butterflies open fully.

Unless it’s in the ECU?

That's exactly what I was wondering too. How would you know though, unless you had a good, stock ECU to compare with?

[ssray]

Don't think it would be restricted via the ECU, this is the restriction kit

https://rawpowermotorcycles.com/product/restrictor-kit-35kw-honda-cb-600-f-hornet-2002-2003/

[David W]

Enormous restriction washers in the headers?

[jaycee]

Have you had the carbs off? I had an SV650 that had restrictors below the carbs.

[Rick448]

Fuel pump maybe, or tank breather pipe blocked, kinked? 

Edited August 16 by Rick448

[El Gringo]

Has it still got the snorkel attached to the airfilter cover?

We had one in years ago that had had it removed and wouldn't run properly

[CMSMJ1]

Does it have the standard clocks / speedo etc?  Older Hondas can have a 5.5k limit if it cannot detect the speedo