Page 1 of 1

Throttle transition

Posted: Mon Jun 05, 2006 12:55 pm
by Bruno
Thanks for the warm welcome everyone.
I'v only done a couple of hundred miles on my bike, a 52 plate, 35K,servo job. I've replaced the dead battery with an Oddessy and changed the airfilter whilst in the vicinity.
The bike's got a full service history, although it's almost due its 36K inspection. I bought it from a BM dealer who was closing down, so it was cheap, but no comebacks.
Now I'm getting a feel for the bike instead of just blasting everywhere I'm finding the throttle action disappointing, and i'm wondering if

1) "they all do that sir"
2) its just due its service,
3) perhaps I'm not riding it properly, or
4) if there is actually a fault.

On slow bends at low revs I am having difficulty with the transition from 'power off- brakes on' to applying a small amount of power and picking up the drive before/at the apex. Its difficult to do this smoothly without disturbing the suspension. There dosn't seem to be excessive slack in the throttle cable, but thats sort of what it feels like.
Sometimes when blipping the throttle for down-changes, the motor fluffs, and doesn't spin up properly. Doesn't always misbehave though.
At higher revs, say over 3500 revs and if you get the bike by the scruff of the neck its fine, but there's no finesse. Perhaps its just me, but I don't always want to ride it like I stole it.
Where should I look for these different coloured programming plugs or the absense of them?
I'm hoping that its just a servicing issue. I'm also comparing it to my heavy flywheel R100RS and a CB1300 Honda.

As an aside, should the brakes make a whirring noise when I operate the levers at a standstill. I assume it's something to do with the servo?
The brake are very effective at the moment, but if the ABS was removed at some point in the future, as some threads have suggested, do you still get the servo effect or do mastercylinders have to be changed?

My machine has the 5.5" rear wheel and I believe thats an option, but are there any other suspension options that may or may not have been fitted. I'm particularly wondering about spring rates 'cos I'm 17 stone in my kit (big bones don't ya know). Do the standard units have as short a life as Jap stuff.
Thanks in antisip-pation
Mark

Posted: Mon Jun 05, 2006 2:15 pm
by jltownshend
Must have been a slow corner ;-)

If memory serves, with a standard exhaust and chip nothing much actually happens until 3K+. You need to try and keep it in 3500-7000 or so...and there's a slight dip in there somewhere as well...with vibes around 4200 (motorway cruising speed).

Exhaust and chip smooths the whole thing out rather beautifully; they make a BIG difference.

Servos do make that noise (which I really rather liked on my previous), but I read a review that hated it at the lights, etc.

The sports suspension (which I think is Showa) is a tad longer (and yellow) and comes with a steering damper (though noone ever seems to know what this does...).

I can't (won't) comment on large bones, but I believe there are one or two gents who will be... :wink:

John

Re: Throttle transition

Posted: Mon Jun 05, 2006 2:39 pm
by nab 301
Bruno wrote:Thanks for the warm welcome everyone.
I'v only done a couple of hundred miles on my bike, a 52 plate, 35K,servo job. I've replaced the dead battery with an Oddessy and changed the airfilter whilst in the vicinity.
The bike's got a full service history, although it's almost due its 36K inspection. I bought it from a BM dealer who was closing down, so it was cheap, but no comebacks.
Now I'm getting a feel for the bike instead of just blasting everywhere I'm finding the throttle action disappointing, and i'm wondering if

1) "they all do that sir"
2) its just due its service,
3) perhaps I'm not riding it properly, or
4) if there is actually a fault.

On slow bends at low revs I am having difficulty with the transition from 'power off- brakes on' to applying a small amount of power and picking up the drive before/at the apex. Its difficult to do this smoothly without disturbing the suspension. There dosn't seem to be excessive slack in the throttle cable, but thats sort of what it feels like.
Sometimes when blipping the throttle for down-changes, the motor fluffs, and doesn't spin up properly. Doesn't always misbehave though.
At higher revs, say over 3500 revs and if you get the bike by the scruff of the neck its fine, but there's no finesse. Perhaps its just me, but I don't always want to ride it like I stole it.
Where should I look for these different coloured programming plugs or the absense of them?
I'm hoping that its just a servicing issue. I'm also comparing it to my heavy flywheel R100RS and a CB1300 H*nda.

Thanks in antisip-pation
Mark
The throttle action I would say is just the throttle bodies needing balancing, if you do a search you will find that you need to check the valve clearances first . I had a similar prob when I bought my bike from a dealer and thought "They all do that sir" but the difference after balancing the throttle bodies was incredible , (especially at low
speed/filtering).
Nigel B

Posted: Mon Jun 05, 2006 4:36 pm
by gus
Hi
I would say the bike needs a good tune up.
Check/adjust valves(critical to get a good throttle body balance)Very easy to do on this bike.
New plugs
Air filter clean or replace
OIl and filter
Then a session with a twinmax or carb stix to get the throttle bodies balanced.Do a search,plenty of helpful info on doing those items.
Has the fuel filter been changed?(due at that mileage)
A service should make things better.
Suspension will be on its way out,you can adjust wear out slighly but nothing beats new units.I would say you will need some different springs to suit your BIG bones.
A cat eliminator pipe and end cans help smooth things out and lets the bike breath a lot better.
gus

Posted: Tue Jun 06, 2006 8:56 am
by Bruno
Thanks for the suggestions. Much appreciated.
A service is needed in any case, and its reassuring that probably I haven't broken anything. Yet.

Ta,
Mark

Posted: Tue Jun 06, 2006 9:40 am
by Gromit
Mark - firstly, welcome to the funny farm. :)

Like the guys have said, reckon your TB's want balancing as from the symptoms you describe it's almost exactly the same as badly out-of-synch carbs ie crap at low revs/throttle openings but ok when giving it some beans.