rg250 engine problems

[rcpboy]

the old bike has been dragged out of the shed, given some new oil, fresh petrol and a new chain and clutch cable. and it idles nicely and when not under load, will rev freely through the entire range.

i have not fitted a new battery yet (old one poked). Its a 1984/ 5 RG250.

the problem is when taking it for ride, it won't go past about 4k without bogging down. If i feather it on the choke, i can get it too pull through, and when it does, it will run through to red line. more often though it bogs down, like it's only running on one cylinder (but its not - though maybe intermittently).

we adjusted the mix, and made it richer by 1/2 turn - made a difference, but still the same issue. seems to be more of a left hand cylinder issue.

it's got platinum plugs, old - but they seem fine; probably next on the list to replace and see if any improvements.

Any ideas? i don;t think it has power valves or anything? not sure though.

[eelracing]

Could possibly be fuel related,check that its flowing well at the petrol tap and give the carbs a good clean out while your at it (how long has it been sitting in the shed?)as old fuel may have scummed up and could be causing a blockage somewhere or floats sticking open/shut.Get those new plugs in at the same time too.See how you get on.

[rcpboy]

how long has it been sitting in the shed?

10 years...unloved and unused. so was expecting a few issues; remarkably though it's been pretty straight forward.

the gas is fresh, the left carb has been blown out; will pull the right tomorrow and have another crack at it.

thinking about it tonight, it must be to do with the main jet, as it's at about that point in throttle (1/8th ish) when the trouble occurs.

cheers

[gammaguy]

its a 2T

carburetion is king

grab the carbs

take em off,strip em and rebuild em.

enjoy:done:

[rcpboy]

cool; is it worth looking at new (bigger) carbs? fuel is flowing well - just checked all that. the standard air box has been taken off (taken off a long time ago - pod filters fitted)

what's the 2T designation? the type of engine?

the only problem to raise its head is the pitting on the forks - oil everywhere...need new forks...

[DEATH_INC.]

Does the battery have ANY charge? Dunno if the RGV is the same, but when I bought my RZ500 it had a shit battery and wouldn't rev past 1/2 revs or so, new battery and she was sorted :)

PM Rodders , this guy can tell you EVERYTHING about rgv's....

[CookMySock]

Replace the plugs.

Steve

[eelracing]

10 years..

thinking about it tonight, it must be to do with the main jet, as it's at about that point in throttle (1/8th ish) when the trouble occurs.

cheers

You got me confused coz i would have thought 1/8th would be just off idle and if ya probs are around that area you should be lookn at the pilot jet?

The main jet will only affect carb performance at 3/4 to wide open throttle.

Another thing with two strokes (2t) sitting for a long time it can cause the rubber crank seals to perish and allowing oil(gearbox side)and or air leaks into the crank and richening/leaning off of the mixture.But as she screams through to the redline maybe you are ok on this.

[rcpboy]

yeah - sorry - the 1/8th thing is me guessing and postulating, rather than thinking. no load - will scream through the rev range, with load (i.e., my fat arse on it), will go to about 5k on both, and then bogs. Its at that point if i feather the choke, i can nurse it through the flat spot and it will scream through to the redline.

when it was put in storage, the exhausts where plugged, oil in the bores, and blocked the carbs. always dry stored (carport for a couple of years which ruined the forks, but it was the front that got wet).

got new plugs the other day, and about to order a new battery to get rid of electrical issues.

if still a problem (and guessing it will be) then carb rebuild. Where can i get a kit for these flatsides? cheers

[rcpboy]

would it be the reed valves? i'm assuming it has them?

[The Pastor]

Is the exhaust clogged

[rcpboy]

nope; doesn't seem to be. clouds of smoke to start with, and then a couple of decent blats when it was warm cleared them - maybe the cans. will have a look in the weekend.

[eelracing]

the standard air box has been taken off (taken off a long time ago - pod filters fitted)


Ok this maybe the reason for the flat spot around 5ooo rpm and im assuming its between 1/4 to 3/4 throttle openings. You can try changing the position of the clip on the jet needle.Lower the clip therefore raising the needle which will richen up the mixture and see if there is a difference when you take it for a test run.

have you still got the airbox by the way?

Aint two tangers fun

[rcpboy]

maybe - it'd been like that for a few years, and had been 'fiddled' with post air box removal and went fine. i'm starting to think crank seals. or reed valves. either way - it could be an engine out.

going to put in plugs in this weekend, new battery, check carbs again, check fuel lines; after that - electrical, and then engine out.

love the 2 strokes; it runs at least so not all bad; just an issue with either fuel or electrics. could be the stator playing up. though i had that rewound (on one side) at about 25k kms. bike has 27 on it now, so..maybe / maybe not that. cheers

[glice]

heres a manual

http://www.rgv250.co.uk/forums/lofiversion/index.php?t28378.html

[gregh]

Have you had any luck sorting your RG?
Ive got one that Ive fitted 1mm OS pistons & rings, its an 84 with no power valves.
It runs OK but is real weak in the mid range , 1/4 to 3/4 throttle, then when the revs get to around 6500 it takes off - smoke & noise everywhere.

Im going to try raising the needles, at 1mm overbore its nearly 5% larger so maybe running lean
Also I'll have a look at the electronic air valve, it bleeds air into the carb emulsion tube, but cuts off at about 6500rpm
good luck

[ready4whatever]

depends why it was parked 10 years ago. if it was parked going and fine. then it wouldnt be the engine seals would it