Odd Running

[IgorVigor]

Hello people.

My bike is sadly (because I'm under 21) restricted to 33bhp...

Its not too bad though....just no power past 6.5k rpm :S

It runs nicely between 4k rpm and 7k rpm at which point the restrictors really kick in...

Now, the problem is, under 4k rpm :S

If the bike has been kept between 4 and 7 k rpm I can drop the revs down to almost idle, and if I dont keep it under the 4k mark, it will accelerate nicely again...

However, if I am cruising through a 30 or 40mph speed limit area, I keep the revs between 2.5 and 4k rpm...
When I then open the throttle the engine struggles to rev...and stutters and jolts...

And then its all fine again over 4k rpm
It also smells rich at times when the revs are low...

Anyone had a similar problem?
Or anyone else had a 33bhp restricted Firestorm?

I wondered if the choke was sticking on (isnt it actually an enricher on these bikes?)
Either that, or a bit of dirt in the carb...

Might have to whip the carbs off and clean them...

Any ideas?

[IgorVigor]

The restrictors arent as bad as everyone makes out...

TBH, its just like riding with a throttle that you only open to half...

The smaller intake hole causes less vacuum to be created, so the carbs never open fully....
It does make it run a bit richer though...at least it seems too :S
35mpg from it worked out over 2 tankfuls...

I think I will get a set of cans for it though....
Will hopefully lean the mix out a little bit, so better economy and sound better...

I will balance the carbs if I can find my gadget :S...

[coledog]

cant you take out the restrictors and put them back in at mot time ?

[IgorVigor]

No, I have to legally have restrictors in due to being under 21 and passed my bike test less than 2 years ago...

And its not checked on an MOT...

If I got caught riding without the restrictors, I would be charged for:
riding within breach of license
riding without valid insurance
what ever else they want to charge me for

which totals to loss of license, banned for 2 or 3 years, retest after that ban, big fines, and possible prison sentence....

[chris1bev]

LOL, But putting all that to one side...can't you take the restrictors out? , thats what i did with my babyblade and damn was it worth it! All jokes aside though a friend of mine had the 33bhp restrictors in his gsx-r750 and he had to have his carbs balanced due to shuddering...hope this helps!

[warby221]

The odd running probably down to the restrictor kit
Especially if it’s the type that uses two big washers with holes in them that sit between the carbs and the inlets to restrict the amount of air getting in to the engine
At all revs they will destroy the airflow in to the engine with turbulence at the back of the washer were it suddenly opens out and you’ll most feel it at low revs when the velocity of the air is low

[Stratman]

Even with restrictors I would have thought a dyno run could get a better set up. For my two penn'eth, don't take the restrictors out because otherwise you will be in deep doodoo if you have an accident and there is a third party claim as you won't be insured!

[chuxsta]

if i was in your situation the way i was at that age i would have taken them out and said 2 fingers to the law.. i want a hoot...

but as others have said dont take em out...
what you could do is put the big bike away till you can ride it legaly unrestricted and have fun on smaller bikes..
throttle to the stop all the time.. its part of the journey of biking..
but saying that i got more points on a 125 than i have ever got on a big bike.

although some of the pre big bikes i had were about as cool as leather elbow patches mixed with socks n sandles but looking back i had a freaking scream on them.
a race tuned rd 125. it was kinda legal... would have been in a crash.. but bugger me 100mph plus on a push bike is a rush..
got pulled my police many a time saying my bike looked unstable was every thing ok,,,, it used to do strange things over 70mph.

i see this law of riding any bike you want as long as its restricted like been able to have the woman of your dreams in bed with you, but you must use bunk beds or if in double bed she MUST wear a hair net and brown M&S underwear with knee high pop socks and have gargled cat poop mixed with pickled garlic prior to bed time.

[Wicky]

I agree with chuxsta - Instead of lumbering around on a castrated VTR (what on earth is the cost of your insurance?) why not have fun on an old retro 28 bhp 250 superdream

Even this must have a better bhp/weight ratio than your restricted storm (cb250n Weight incl. oil, gas, etc: 186.0 kg (410.1 pounds - FireStorm dry weight 192.0 kg (423.3 pounds)

http://www.realclassic.co.uk/250superdream1.html

or even, if you can find one, a cute VT250F (43hp/Dry Weight (without fluids): 146 kg (321.9 pounds) - just add a sack of potatoes on the back ;)

http://freespace.virgin.net/simon.r.bromley/index.html

[IgorVigor]

Firstly, the restrictors are definately staying in...

I will balance the carbs ASAP, hopefully that will make it a little better....

As for the "get a smaller bike", I already thought about a 250, but I'm too big
I've had my fun on smaller bikes though...

I owned a slightly tuned TZR125 (1989) with a race pipe...it was fun....but soooo small for me
I passed my bike test and rode a 1997 Honda CB500 (restricted) for about 3 months, until the head gasket blew, which I then replaced.
Even that felt small for me

Then I got a Honda Vigor 650 (Like the SLR650), which was fun, but used a bit of oil, so traded it in for the Firestorm...

I love the Firestorm, so even if it is castrated, I dont mind too much...
Its comfortable, torquey, great handling, and is a nice size for me.

As I said, I will balance the carbs, and see how it goes from there...

[sirch345]

Firstly, the restrictors are definately staying in...

That to me is your best bet, even though it must be tempting to remove them. You sound like a young guy with a mature head on your shoulders. That bhp restriction was brought in for a very good reason.

I know some of you will be thinking I'm being an old fuddy duddy by saying that, (well the old bit is probably right ) but remember "Them that live longest see most"

I expect it is the restrictors that are up setting the carburation as already suggested, but giving the carbs a balance can only help,

Chris.

[IgorVigor]

Thanks timbo, thats exactly it....

I find the Firestorm much more comfortable due to my size than small bikes...
And as you said, the restrictors dont affect the bottom end grunt much at all....

Basically its just like riding the firestorm without ever opening the throttle to more than half and dont let the revs exceed 6k rpm...
Thats pretty much what the restrictors do.

(I know its not quite that simple, but oh well... )

Thanks for the input....
Going to raid the shed for the carb balancer (homemade )...if its still there :S

EDIT:
Its very tempting to remove them, but tbh, its not worth the risk in my opinion :S
I have managed 1 year, so its not hard to manage another....
The only thing I do think is unfair, is car drivers have no restrictions....

They get the same maximum of 6 points for the first 2 years, but no car restriction :S
Shouldnt the government restrict the cars a bit?
There are a few rich kiddies near me, who passed there test just before they were 18 and go from their instructors car, a 1.1 petrol or 1.4 diesel etc, and their parents buy them a 10 year old Subaru Impreza 2.0L turbo! :O hows that safe!

And as for the mature head on young shoulder, thanks....
Its nice that someone thinks that...
Normally its just "Oh hes 19, so he's and idiot"

[IgorVigor]

and more worrying is the amount who get the subaru's and cars like that....
and arent insured!

from what I heard from a friend of the family (ex traffic cop) only about 1/2 of the "chavs" are actually insured...
mind you....a small percentage havent got a license!

[chuxsta]

from reading your posts you give the impression your rather tall and struggle finding a bike to fit your size

so i found this,, i think its an import but might be right up your street.

[IgorVigor]

Haha!

Thats good, I like that....

I think it might understeer though ;)

On a more serious note, I'm not overly tall (6 foot 2), but I am built like the proverbial outhouse
Used to play a lot of rugby, Tight head prop...

So smaller bikes arent comfortable...
I could pick my old TZR125 up and walk off with it, so I did look daft on it....
Probably something like this:


Thats why the firestorm is the bike I chose...
I sat on a ZZR250, which were about the biggest 250, and it wasnt good :S

Thanks for the input people...