Firestorm Running funny

[robby_firestorm]

Hi guys I am sorry if this has been asked before but I did try and search for the answer first.

When riding my bike sometimes it will be ok but most of the time not, if I hold the throttle at the same position the bike will judder like crouton and seem to want to hunt??

Also if I crank the throttle open it will almost die of power as if it has cut out and then kick in like the devil.

I must mention this bike has been sat for 5 years in a garage could a carb balance be the problem?

[benny hedges]

sounds like carb balance, possibly a vacuum problem, only picking up when the vacuum gets higher.
unless it's an ignition fault??

check the carbs out first tho (and air filter - might be piss wet)
a mates bike did this because a carb diaphragm was split and the slider only lifted whn it felt like it.

[sirch345]

If the carbs were not drained of petrol before the bike was left standing for 5yrs, then I'd say the carbs will need to be stripped down and given a good clean, taking care to make sure the jets are clear.

It's worth trying what Benny suggests first.

Chris.

[Pete.L]

Robby Said

Also if I crank the throttle open it will almost die of power as if it has cut out and then kick in like the devil.

I had a similar problem which turned out to be a sticking choke plunger, it would give you the same symptom as a blocked air jet, so as well as checking your carbs and giving them a good flushing I would also take your plugs out and if they are sooty or dark brown I would replace them. Running too rich can kill your plugs and even if you've just had some bad fuel go through it could still kill a plug.

Pete.l

[robby_firestorm]

Hi guys bit of a dilemma

Put the firestorm into the shop after the following was happening:

Sometimes won't tick over
When you rev it it doesn't rev all the way it sort of stops halfway and bangs and pops
While riding if your going slow it pops and back fires through the air box

I had the carbs stripped, cleaned and balanced and it hasn't made any difference. New air filter and plugs also

What else could it be?

[benny hedges]

could be any of the faults already listed below - split carb diaphragm??
could be cam timing has been set wrong or has jumped..
popping back through the carbs (a lot) suggests an inlet valve is still open on compression stroke...

assuming you've already set up carb balance, air filter's ok etc??

[tony.mon]

Hi guys bit of a dilemma

Put the firestorm into the shop after the following was happening:

Sometimes won't tick over
When you rev it it doesn't rev all the way it sort of stops halfway and bangs and pops
While riding if your going slow it pops and back fires through the air box

I had the carbs stripped, cleaned and balanced and it hasn't made any difference. New air filter and plugs also

What else could it be?

Is it these symptoms:-
Runs ok at less than 5000, but won't rev out in any gear over this- if you hold the throttle part-open it might get to 6,000, but no more.
Seems to rev ok when in neutral.
Sometime (maybe every minute or so) it'll sort of "cough" through the airbox. You can feel the pop in your nuts against the tank!
Also, occasionally stalls when pulling away, mostly when engine's off choke but not fully warmed up.


Let us know if this describes your bike??

[Phil-VTwin]

could be cam timing has been set wrong or has jumped..

+1

[robby_firestorm]

Tony yeah that is most of my symptons you know what it is?

[tony.mon]

As has already been suggested, most likely cam timing on one cylinder set 180 degrees from where it should be, if it won't rev out as I described.

Not a difficult job to sort, see the thread in Workshop about cam timing and follow it to the letter.
Fairing off.
Tank off, airbox off, carbs off, plastic shield underneath carbs off; then you can see both cam covers.

For ease of seeing where the front cylinder timing marks on the cam sprockets are, drain coolant (can be re-used) and drop LH side radiator off, and to make access easier still you can unbolt the oil cooler and lower it onto a clean rag placed onto the mudguard. You don't need to disconnect the oil cooler from the engine, just let it pivot down on its braided lines.

Now take off the covers, and follow the instructions.
Note that if you start with the rear cylinder it's the SECOND time the front cylinder top dead centre appears in the crankcase window that you need to use to set the front ones.
That's where most people go wrong; if you set it up at the first one you see you get 180 degrees out timing.

Even Honda dealers rock this one. We sorted one out at the last Workshop day.

If it's just the airbox "cough" you're getting, and the engine pulls to the red line OK, then you don't have to check or re-adjust this.