Power Flatspot

[jimdaworm]

Anyone know what might be causing a flat spot in my power at exactly 8000rpm and it doesnt go away until 8500rpm.

After 8500 it pulls fine and the power valves seem to kick in nicely around 9-10.

Its just really annoying as its just around the speed I normaly travel that I hit 8 in top gear and I can feel it surge and then stop pulling and then surge again.

[Racey Rider]

Surging means it's running lean doesn't it?

I'ld be asking at a bike shop.

a small 500rpm dull spot is not a big deal on a two/ , if it dies at those rev,s I'ld be trying to sort it out. But definatly surging is not good. Can lead to sezier.
See what others think.
Racey.

[vifferman]

Surging means it's running lean doesn't it?.
Yup, it does.
EDIT:
Oh. It's a two-smoker.
All bets are off then; conventional logic doesn't apply here - it's all black voodoo magic, evil mojo, and various sorts of witchery.
Time to find a tame witchdoctor or exorcist. :mellow:

[Motu]

Sounds like a broken powerband to me,not so common these days as modern bikes don't use the old fashioned powerband.I have some here,but they are old and have lost their snap,but I don't mind as it suits my riding style.Try Mitre 10,they used to have an assortment.

[Ixion]

Oath. Its a two smoker. So whaddya doing trying to run at under 8000 rpm anyway. Keep it at 10000+ where two smokers are supposed to be , and you'll never notice. Seriously. Almost.

[Aiolos]

Its your powervalves trying to decide between the closed and half open positions, and failing.
Its a real pain in the ass.

[jimdaworm]

Do you have that too Aiolos? Anything I can do about it? It didnt used to do it... or maby I didnt notice it sooo much. Its just really annoying as its just aroudn the speed I like to travel at.

Motu please explain I dunno if your joking or not!

I wondered about the adjustment that I remember seeing for the power valve actuator/servo....

Ixion if I were to travel at those rpm I would be severly braking the speed limit in top gear :whistle:

[SlowHand]

Is that lurching and other stupid annoying crap? I get that every now and then - thought it was just a 2 smoker thing? - cant decide whether to go balls to the wall or not?

[avgas]

Small mission to get those power valves working properly.
a) Run an iriduim plug
b) Take the bike to a race person, and get them to tune the valves for ya (in your case, ask for a linear power setup.
c) Run nice oil.
thats about all i remember from my ol' RG...for now anyhow

[Ixion]

..
Motu please explain I dunno if your joking or not!


Ixion if I were to travel at those rpm I would be severly braking the speed limit in top gear :whistle:

And? It's a two smoker. Doesn't understand these "ringa dinga waddya callem ding ringa speed limit dinga dinga" things.

Oh, and Mr Motu NEVER jokes. Believe him, after all, he's a professional

[jimdaworm]

Thanks for all your info! I cant find any information on these power bands moto is talking about so I wouldnt even know what to ask for :crybaby:


I run it on Shell Advance VX2 ... not the flashest oil but fully synthetic. I might try changing the plug before I try other things as it will be an easy fix if it works! :calm:

[Racey Rider]

:psst: Motu is pulling your leg about the powerband.

Yes the RG150 has a powerband, but that is a 'way the motor works' not a specific 'item in the motor'. The powerband can be 'ajusted' by changing items on the bike, (ie. exhaust, or carb size), but that is only for experts to play with and totally unnessary for you..

>Its your powervalves trying to decide between the closed and half open positions, and failing.
Quite possably just this. Is the bike getting up in the km? (20 000+ for these)
Things could be starting to wear, causing a bit of slop in this area.

The type of fuel you use can exaguate (sp) issues like yours. Are you running it on 91?
91 would be the norm for a Rg150.


If you find it doesn't run at it's best at that speed in top gear,,, don't use top gear! Cruise around in 5th if you have to to keep the rev's higher.

[Motu]

Spoil sport...

[Str8 Jacket]

The type of fuel you use can exaguate (sp) issues like yours. Are you running it on 91?
91 would be the norm for a Rg150.


If you find it doesn't run at it's best at that speed in top gear,,, don't use top gear! Cruise around in 5th if you have to to keep the rev's higher.

Sorry to jump in here Jim, but RR do you think that my KR would run better on 91 then say 96 or 98? . . . Or no different?

On a side note I have found it quite hard getting used to keeping the revs up too. The KR is sure different to the mighty GN, im usually sitting around 7-8000 revs around town, should I be keeping them higher? . . . .

[Ixion]

Sorry to jump in here Jim, but RR do you think that my KR would run better on 91 then say 96 or 98? . . . Or no different?

On a side note I have found it quite hard getting used to keeping the revs up too. The KR is sure different to the mighty GN, im usually sitting around 7-8000 revs around town, should I be keeping them higher? . . . .

Probably no difference running a ringa-a-ding-ding on 91, but if it did anything it would be an improvement. No point in high octane on a two smoker. Keep the revs as high as they'll go. You gotta wring the neck off a two stroke. And being a two stroke, the revs won't do any harm (they will wear out quick of course, but that's cheap to fix)

[Racey Rider]

Wow! Thats quite a statement. :spudwow:
Please note the first word - PROBABLY - as in, 'He dant know!'
and then to say - >No point in high octane on a two smoker. :oi-grr:
Please put thy fingers back in thy pockets before thee embarrasses thyself futher Ixion!

Your bike is designed to run on 91. and as long as it doesn't detonate on 91 (and it shouldn't), then 91 will give you the best power, fuel burn, enconmy, and may help it start easyer.

But high octane IS useful for 2/'s. I use high octane in my race bike, because it needs it. Not because someone thought I should, Not because it's more expencive so Must be better. But because I have proved that 91, in my bike, under my race conditions, at my track, will detonate and seize My motor. :crybaby:

You don't have to 'wring the neck off' a modern 2/ with oil injection for commuting. Yes give it a good burst now and again, but keeping it at high revs is only neccary if you want to be in the 'full power/go fast' bragade.



Do a KB search on the word Octane. theres been heaps written about it.
or heres (http://www.kiwibiker.co.nz/forums/showthread.php?t=15050) another post about it.

[marty]

Sounds like a broken powerband to me,not so common these days as modern bikes don't use the old fashioned powerband.I have some here,but they are old and have lost their snap,but I don't mind as it suits my riding style.Try Mitre 10,they used to have an assortment.

i thought 'powerband' myself, but after deeper thought, it's probably one of the two weights, more than likely the long weight. they always give trouble in 2 strokes. i'm sure someone on here has one hanging around somewhere..

[Racey Rider]

O Piss Off you 4/ Bastards :mad:

sorry about the language, not what I'ld usually say,, but theres a time and place for everything!

[Str8 Jacket]

Cheers Racey,
Have put 91 in today and am hoping that my bike may actually start a little easier now as I have had a few issues with it starting. Though in saying that it is kinda hard to kickstart a bike with a bung knee! :crybaby:
Is your KR kickstart only or do you have an electric starter as well? . . . .

[Racey Rider]

No they are all just kick start.

It should start easyer on 91. Useing 96 or higher is affectively changing the timeing of the fuel burn, (96 burns slower (appartly,, haven't actually seen it with me own eyes)) , so can cause hard starting unless motor is setup for that fuel.
4/'s are more tolerant of different conditions and fuel octanes.

Let us know ether way if you notice a differance.
We all learn from each other.

[Str8 Jacket]

Let us know ether way if you notice a differance.
We all learn from each other.


Will do, at the moment sometimes when I start it just dies, I try revving it a bit but it just kinda goes "glug glug . . . blurrr" and then dies. Makes it very embarrasing if there's a few peeps around!

[Ixion]

Wow! Thats quite a statement. :spudwow:
Please note the first word - PROBABLY - as in, 'He dant know!'
and then to say - >No point in high octane on a two smoker. :oi-grr:
Please put thy fingers back in thy pockets before thee embarrasses thyself futher Ixion!

Your bike is designed to run on 91. and as long as it doesn't detonate on 91 (and it shouldn't), then 91 will give you the best power, fuel burn, enconmy, and may help it start easyer.

But high octane IS useful for 2/'s. I use high octane in my race bike, because it needs it. Not because someone thought I should, Not because it's more expencive so Must be better. But because I have proved that 91, in my bike, under my race conditions, at my track, will detonate and seize My motor. :crybaby:

You don't have to 'wring the neck off' a modern 2/ with oil injection for commuting. Yes give it a good burst now and again, but keeping it at high revs is only neccary if you want to be in the 'full power/go fast' bragade.



Do a KB search on the word Octane. theres been heaps written about it.
or heres (http://www.kiwibiker.co.nz/forums/showthread.php?t=15050) another post about it.



Yah, cos your racer is a racer. As you yourself say, road going two smoker should run fine without detonation on 91 . Two strokes have an effectively lower compression ratio than four strokes. Unless there is evidence of detonation, high octane is unlikely to be necessary. It probably won't help. Probably cos two strokes is idiosyncratic and can't be sure that it won't run better on 95 without trying it. So , probably.

For me, I've never found a two stroke that has the same low rev torque as a 4 stroke single - especially a cooking ne like the GN250. If you find one, let me know.

[Aiolos]

Bah. Who needs torques down low? My bike is fine for commuting and much, much better than a GN on the open road.

[Motu]

For me, I've never found a two stroke that has the same low rev torque as a 4 stroke single - especially a cooking ne like the GN250. If you find one, let me know.

Um...a trials bike? They are made for nothing but torque,so long as the throttle is open the motor will never stop,ever.They will sit on the sidestand idling in gear,just turning the back wheel.

[Ixion]

Um...a trials bike? They are made for nothing but torque,so long as the throttle is open the motor will never stop,ever.They will sit on the sidestand idling in gear,just turning the back wheel.

Uh yeah, and a Scott Super Squirrel could pull a side car. OK, correction. Excluding the Scott, road going sports two stroke.

[jimdaworm]

I have only been running it on high octane 95-98 as I am sure someone said it would be better... but if 91 will be better 91 it is! Its cheaper :niceone:

I dunno if its a fuel thing though... as I think I have always (In the 3 months I have owned it) had 91 in it.

I was wondering if maby it was a carb thing as I only noticed it after a couple of weeks ago nearly running out of fuel... I went to clean/replace the filter but it doesnt seemt to have one!

Completed my CBTA Full license course on wednesday so full license here I come and a bigger bike... :devil2:

Who wants to buy my bike?

[Jamezo]

Who wants to buy my bike?

me! though I've only got $300......still saving lol

OMGWFTBBQ would certainly be interested, he's a little farther along the way.

but we're both on the look out for decent RG150s.

ps. is the RG150E the regular model? is there anything else even?

[Aiolos]

The E is the only model avaliable in NZ.

[sels1]

Completed my CBTA Full license course on wednesday so full license here I come and a bigger bike...

Good on ya mate

[jimdaworm]

Hey if you want Jamezo or OMGWFTBBQ wants your welcome to come round and have a look at the bike and take it for a ride.

Although I am not quite ready to sell it yet. I need to find me another bike first :niceone:

Thanks sels1. Its good to see your still riding St8 :drinkup:

[Two Smoker]

Hey if you want Jamezo or OMGWFTBBQ wants your welcome to come round and have a look at the bike and take it for a ride.

Although I am not quite ready to sell it yet. I need to find me another bike first :niceone:

Thanks sels1. Its good to see your still riding St8 :drinkup:

Your powervalves are stuffed. And you need some new ones im sorry... the power valves have three sections to their opening and it sounds like your second section is worn (common on these bikes after 20000kms) $600 for a new set i think :crazy:

[jimdaworm]

Its done about 30k and apprently already had the powervalves done. Bummer if your right... although it still has bottom and top end power...