Erratic performance 5,000 rpm

zixxer · Post by **zixxer** » Wed Nov 05, 2008 7:00 pm

hello lads.

I've spent a fortune trying to track down this problem and its driving me insane.

The RR fried on the bike and took the battery out with it. I replaced the RR, this time using the nice big Yam R1 unit. The bike was running again but at about 4,800 - 5,200rpm when she is held at constant revs she is jumpy and struggling. she will pull out of it easily and takes off but when held at this rev range she acts horribly.

At first I thought carbs, so I gave them a thorough cleaning and made sure everything was ok. it made no difference.

so then i thought that maybe the throttle position sensor was fried when the RR unit packed in. I ran the test on the TPS and found it was actually damaged and replaced it with a new one.

this made some difference but the bike is still erratic at the same rev range. also, when you drive her hard and let off the throttle and then open it up again she takes a second to kick and then takes off.

it only happens when the bike is well warmed up.

its driving me absolutely insane and any help would be seriously appreciated. i hope i did an ok job of describing it.

Stratman · Post by **Stratman** » Wed Nov 05, 2008 10:17 pm

How new/old are the plugs? The plug leads may be suspect. I'd check them out and the plugs next.

zixxer · Post by **zixxer** » Thu Nov 06, 2008 9:43 am

hiya Stratman, thanks for the suggestion. However I firgot to say the plugs are brand new. When I bought the bike I serviced her straight away (new oil, filter, plugs etc) and i stuck in a pair of those iridium plugs. I even took them out and then bought a set of the standard NGK ones and tried them but no difference.

stormingjoe · Post by **stormingjoe** » Thu Nov 06, 2008 10:26 am

sounds like weak mixture, carbs go out of sync well easy, but might be worth just checking all leccy connections

Post by **sirch345** » Thu Nov 06, 2008 10:27 am

If you've not already done so, check the connections between the spark plug lead and the plug caps. Stratman found he had a problem there iirc. he just cut off 6mm or so of the lead and re-fitted it.

I do wonder if you have some sort of a problem with the ICU (ignition control unit) seeing as you found the TPS to be faulty. But normally the ICU is very reliable so it may not be that.

Just a thought, not long ago another member found he had damaged one of the ht coils by turning the engine over with ignition switched on without having the removed spark plug in it's cap earthed on the engine.

I presume you've balanced the carbs

Also how many miles has the air filter done

Chris.

gilson · Post by **gilson** » Thu Nov 06, 2008 11:31 am

I got caught out recently when I took the tank off and put a vaccum tube on the wrong inlet. It's well documented but a bugger to realise.

However, this does affect idle and most of the rev range, although a mate of mine did several track sessions running like this.

The best way to explain it is looking at the petrol tap under the tank, there should not be ANY tube attached to the downward facing 'connection'. This connection lends itself to the small tube, but it actually should fix behind the fatter petrol tube on the right (as you look at it).

Not sure if this is your problem, but it could be and it's a very easy check and fix.

Good luck with it all!

storminateacup · Post by **storminateacup** » Thu Nov 06, 2008 1:08 pm

Did you reset the TPS

zixxer · Post by **zixxer** » Thu Nov 06, 2008 5:52 pm

thanks a million for all the suggestions guys, your the shot.

Well I took them on board and checked the hoses from the tank but its not that as its on exactly as it is in the manual.

How do you reset the TPS? I adjusted it until I got the correct readings on the multimeter is all?

I'm going to invest in a new air filter as I don't know what mileage is on the one it and a set of leads and new plug caps too i guess.

i never mentioned she is a high miler, with 47k miles up on her clock. saying that though she was very well looked after as the linkages on the back shock had been well maintained and greased etc. things like that i thought would be the give away with a bike that was treated badly.

storminateacup · Post by **storminateacup** » Fri Nov 07, 2008 10:31 am

zixxer wrote:thanks a million for all the suggestions guys, your the shot.

How do you reset the TPS? I adjusted it until I got the correct readings on the multimeter is all?

With multimeter so thats alright then

zixxer · Post by **zixxer** » Thu Nov 20, 2008 5:29 pm

hello lads, I'm still having this problem. since the last post i put in a new air filter and no difference. i had her out today and put up about 100miles and she is bogging down continously now. she pulls on through thr revs no rpoblem but when held at a constant rev she is jumping like mad.

its driving me up the wall as i need the bike as daily transport.

zixxer · Post by **zixxer** » Thu Nov 20, 2008 5:40 pm

i forgot to mention also that my bike is missing the PAIR valve from the airbox. It was never on the bike since I've had it and its only for emissions control so i never really considered it an issue. but i'm running out of ideas about whats causing this missing/bogging-down problem and i'm starting to wonder could it possibly have something to do with it?

Post by **sirch345** » Thu Nov 20, 2008 6:04 pm

We do seem to be running out of ideas

Have you checked the vacuum pipe along its length from the petrol tap for any splits

Also have you checked the valve timing

Chris.

PS. This link could be helpful for you to make sure your pair valve has been moved correctly, if you've not already seen it. I see there's a mention about the vacuum pipe or pipe's etc in there:-
Click on the 'VTR1000f' at the top of the page then 'performance and mods' then you'll see it:-
http://home.nycap.rr.com/ghlbo/index.html

bikerpiker · Post by **bikerpiker** » Thu Nov 20, 2008 8:46 pm

As above vacuum pipe ,...so far ive never had the tank removed on the 'storm,but on my ex Triumph Daytona the routing of the vacuum pipe was absolutely critical , as when the tank was put in place the pipe could so very easily get pinched between tank and frame

I had symptoms very much like yours ,albeit at lower revs ,the pick-up coil /sensor was prone to fail ,so check that as well,if you havnt already...i bought a new one and even it was out of spec , also my coils gave an in-tolerance reading when cold, but were way out when hot, to find this out i set up a remote petrol tank ,so i could check em instantly without having to remove everything and therefore giving em time to cool

Squiffythewombat · Post by **Squiffythewombat** » Thu Nov 20, 2008 8:47 pm

what cans have you got on, have you have it rejetted or anything? i had a VERY similar problem with mine when going back to stock cans from arts with the different jet setup!

chuxsta · Post by **chuxsta** » Thu Nov 20, 2008 9:12 pm

i get similar on mine,
even after i have just changed the plugs for the DP9 iridium's, new airfilter, new oil and oil filter, so i have ruled out those as the cause..

what makes it even more strange is its intermitant...

is yours the same?
or do you get this performance lumpyness at 5k revs every time your out?