RG150 with no torque under 4krpm

[beanz]

Hi, I thought this was just an RG-thing, until talking to another owner, who said his RG was a breeze to launch.

Normally I have to rev it to 4krpm then slip the clutch quite a bit to take off, even when warm. If I accidently drop it under 4krpm when taking off, it seems to go into a defiant "I'm not gonna play fair" mood and all power dies away. If this happens, I have to back off, clutch in, and start again. Not fun in traffic on a hill!

Its my first bike, so this made learning to ride a bit of a bastard! I'm getting quite good at it now, but if theres something wrong with the bike, then I'd like to fix it before selling later this year.

A brief history: I bought it, and like most things I buy, I took it apart. New plugs, new thermostat (didn't even have one to start with!), new gear/clutch oil, fixed a broken power valve, checked reed valves, check rings, cleaned piston, cleaned carb out completely, and new exhaust pipe gasket.

There are only 3 things I can think of:
1) Ignition system not giving good spark below 4krpm
2) Carb set wrong
3) Theres a good 3mm of carbon buildup in the exhaust, which is a mutha trucker to get out. Maybe thats stuffing up the exhaust resonance (I'm clutching at straws here)

Oh yeah, and also its tricky to start. To begin with, I'd pump the kickstarter like I was pedaling a bicycle up a hill, until either I collapsed or it gave a spark of life and then slowly filled the neighbourhood with smoke and chugged up the rev-range. Now days, I give it 2 or 3 slow cycles of the kickstarter, then give 1 normal one, and it springs into life. Just wondering if thats a 2-stoke trait, or part of the problem too.

Has anyone else had these issues, or can lend me some advice?
Cheers guys
Chris

[pipeman]

Gee you must have got thing cheap I hope Just a small question did you have any parts over. Sound like it wasn't a runner when you got it.




A brief history: I bought it, and like most things I buy, I took it apart. New plugs, new thermostat (didn't even have one to start with!), new gear/clutch oil, fixed a broken power valve, checked reed valves, check rings, cleaned piston, cleaned carb out completely, and new exhaust pipe gasket.

could be sucking air in from some where did you tigthen every thing wright?
What plug did you put in it?
Broken wire some where or not connected somewhere?
Did you you change the 2 stock oil that was in it you never no about the previous owners.


There are only 3 things I can think of:
1) Ignition system not giving good spark below 4krpm
2) Carb set wrong
3) Theres a good 3mm of carbon buildup in the exhaust, which is a mutha trucker to get out. Maybe thats stuffing up the exhaust resonance (I'm clutching at straws here)


Don't worry about the carbon buidup thats the end resault of the problem and be cleaned out wiht costic sodia in a jiffy.
When you pulled it apart did you put it back together with the wright timing and setting 2 stocks can run well out of wack but and you don't get the optimun benifits.
Just some sugestions try and find a manuel online or a mates good luck.
P.S. THATS WHY I LIKE 2 STOCKS IT'S MORE THAN JUST RIDING

[FzerozeroT]

what condition is the silencer in? if it's straight thru it will increase top-end at the expense of bottom-end, and what's your gearing like? could be geared too high. my rear sprocket is 39 tooth standard, and it does about 40kph flat out in first.

[Motu]

No talk down low? - it's got no balls man!

Hard to start? smoke when it does,you done top end work to improve things? You may now have leaking crank seals.

[beanz]

Yeah, no balls at all! But the funny thing is that it has a good 150's worth bollocks above 4krpm, and even a noticible kick when the power valves open.

Yep, it smokes quite a bit when warming up, but after 2-3min riding, the smoke clears up. Pretty standard 2-stroke smokin, I think.

Was running when I got it, but no that well. Yep, had the head and cylinder off, but tightened to the correct torque settings afterwards. (Managed to get hold of the service manual). Leakin crank seals? Hmmm, didn't touch them. Will check that the crank oil is the right level.

The silencer: non existant. One of the past 12 owners thought it may be a good idea to rip all the mesh out. Makes it nice and loud, but didn't realise it affected performance. Why? Its just a straight through perforated pipe, so why does the existance of sound deadening material around it matter? (Not that I don't believe you, just wondering why)

As far as I can tell, the timing on these things cannot be tweaked. Its all static inside the dynamo housing.

[pipeman]

Yeah, no balls at all! But the funny thing is that it has a good 150's worth bollocks above 4krpm, and even a noticible kick when the power valves open.

Yep, it smokes quite a bit when warming up, but after 2-3min riding, the smoke clears up. Pretty standard 2-stroke smokin, I think.

Was running when I got it, but no that well. Yep, had the head and cylinder off, but tightened to the correct torque settings afterwards. (Managed to get hold of the service manual). Leakin crank seals? Hmmm, didn't touch them. Will check that the crank oil is the right level.

The silencer: non existant. One of the past 12 owners thought it may be a good idea to rip all the mesh out. Makes it nice and loud, but didn't realise it affected performance. Why? Its just a straight through perforated pipe, so why does the existance of sound deadening material around it matter? (Not that I don't believe you, just wondering why)

As far as I can tell, the timing on these things cannot be tweaked. Its all static inside the dynamo housing.

GOT TO HAVE BACK PRESSURE FOR THE EXPANNISH CHAMBER TO WORK BRO

[beanz]

Right.... so you reckon the missing mesh is affecting the backpressure?

The pipe comes out of the expansion chamber, then theres the join, then the muffler section. Inside is a straight-through pipe with holes all through it, around which is the outer casing. I'm guessing theres meant to be mesh between the perforated pipe and the outer casing, to deaden the noise, but as I said, its not there anymore. The bit I'm having problems with, is how the existance (or non-existance in this case) of the wire mesh can affect the backpressure.

Good thinking tho. I have a friend with an RG too, so I might swap the mufflers to see any change. Thanks for your help.

[beanz]

BTW, my rear sprocket is a 48 tooth... quite a few more than your 39 tooth sprocket, FzerozeroT!!

So, if 39 is standard, the 48 will lower the gearing, and give more torque, not less.

[mini_me]

2) Carb set wrong

does it idle ok?

maybe have a look at the low speed jets on the carbs, i know of a similar problem with a zx6r and he cleaned out his low speed jets on his carbs and it more or less fixed the problem.
m/m

[Racey Rider]

Firstly - I had a RG150 before my KR.
They are a small two/ motor, which have to be rev'ed to get them moving.
I used to rev to 6000rpm or more off the lights.
Or for more fun, make every red to green lights change a "race start" and pratice getting the right amount of clutch to match 10 000rpm.
The guy that says "was a breeze to launch" is ether a very skilled RG rider, useing over 4000rpm with out relizing it (I'm trying to be diplomatic), or just plan out 'ing you.

Here's my thread on cleaning out the expansion chamber:
http://www.kiwibiker.co.nz/forums/showthread.php?t=1872

I think the muffler is suppost to be straight through

[Two Smoker]

Dont worry about the mesh in the exhaust, it doesnt really change the performance of the RG....... I also use about 6k worth of revs to get it off at the lights, but it will quite happily do 12k slip the clutch off the lights too.... But as RR said, quick take offs require about 10k......

Just bring it too Puke this Saturday and ilol check it out

[beanz]

Cheers for the ideas guys. Yeah, I'll try to bring it to Puke on Sat, just to make sure I'm not moaning about normal RG quirks.

[VivaVee]

Hi

I had an RG150. I wouldn't expect it to do anything under 4k. I never attempted a gear change unless I had > 8k on the counter and I ride like my granny. It was a revelation to get a 'lazy' 750 that in comparison could pull a tree stump from anything over 2k. Well 3k without killing the clutch.

So try to get a ride of another RG150 before you strip it apart trying to 'fix' the 2-strokeness.