RG150 powervalve issues

[richiewendt]

I have an RG150 with 13000km on the clock. Have been doing a few big trips (hamilton - Auckland few times, Hamilton to Mangiwhai heads, etc) and a few hundred km ago the power dropped of a lot. It seems like the power valve opens up at 8000rpm like it should, then the power drops off at just over 8000 and then kicks in at 9000 again, absolutely noooo guts whatsoever in this gap. Which is really annoying cause 8000rpm in sixth gear is just under 100kph (or 120 according to speedo) which means I either go below the speed limit or push the limit a bit. Feels like the power valve closes and opens again betwee 8200ish-9000rpm. Why?? Could it be the electronics or what?

It rides like normal besides that, same power above 9000rpm and below 8000 and I don't thrash the sh*t out of the thing.

Any ideas?

[FruitLooPs]

That does sound strange, it normally has a hole in the powerband before the valves kick in but it should be smooth from there.

They're spose to open about 7800rpm I believe, so they might be sticking for whatever reason. It's not difficult to get in there and check it out, so i'd recommend you do that. Check their overall condition too while you're at it.

13,000kms man thats pretty fresh as RG's go! Mines pushing 56,000

[neil_cb125t]

I raced mine for 3 years, had a prob with mine valves slotting, they are a 3 piece unit with the middle segment have a locating pin. this pin is in a hole in the valve segment. that hole can slot or widen meaning the pin moves forward and backwards. You Follow? This means the valve does open all the way, and can move forward and back on its own. Not good for racing or road riding. I had mine fixed by a gunsmith, for a doz beer. new valves $350.

Ive puled them apart so many times its not funny, also know haow to make em go allot FASTER than standard. any q's just ask.

[richiewendt]

Will pull out the powervalves, may answer a few questions. I have the manual for the bike, that helps too.. Interested in the get more power out of them side though... Tell all!

[neil_cb125t]

All my improvements were done to race her, These bikes are bullet proof if you run them in good and run good oil.
Well where to start.
The things to do is simple, getting them checked on a dyno was the $$$.

Take your expansion chamber off, there's an internal "skin" for noise baffling etc. Get that removed, you have to get the whole can opened up. Then remove the aiffilter and airbox lid. the airbox lid needs to be taken too with a grinder. the air intake is a pipe that is about 100mm long, grind it of so there is just a hole with no pipe for the air to travel thru. Leave the filter out, Then rejet the main jet to a 180 jet. I went frm 26 RWHP to 32.5 RWHP on a dyno. I ran this setup racing for over a year, never blew up never have to rebiuld it, i had re ringed it before the mods.

There is other ways, taking a layer of the headgasket off, raising compression, porting the head { which i wouldn't look at } They do a 175 piston kit im pretty sure too.

I modified the rear shock to raise tha back end so i wouldnt drag the pipe on right handers..

The list goes on, hope this helps I pulled mine appart so many times it wasn't funny.

[richiewendt]

Considering I'm quite a novice at things, I would only look at a bigger piston... Nice little power increase considering you didn't muck around with the porting!! Mind you, you stiff that up and I doubt it would be too cheap/easy to find a new barrel in decent nick...