RG250 migrating misfire!

[Blue Meanie]

I’ve just been told by my LBS that it’s highly likely my RG250’s motor has expired! A couple of months ago it developed a pretty severe misfire on the left hand cylinder and totally lacked any power. I had a play with it checking out the usual suspects and discovered that the coil had been botched. I managed to get hold of a replacement, stuck it on, test rode the bike and everything seemed OK. However, when I tried to use the bike a couple of days later, the misfire had returned - this time on the right hand cylinder! It was easy to tell which cylinder was misbehaving because the exhaust pipe was stone cold while the other side was running nice and hot.

Anyhow, I had to concede that in the absence of a workshop manual or decent tools I’d have to take the bike into my LBS for them to have a look at. I had a chat with the owner/workshop manager and he suggested that the problem may be with an internal crankcase seal that effectively isolates each of the cylinder assemblies. Apparently, this problem is common on RG250’s with high mileage and is terminal. Expecting the worse, I left the bike and told him not to spend more than a couple of hours working on it – just not worth it given the age of the bike!

I waited a few days and got a call saying the bike was done, running fine and I could pick it up when I wanted. Fantastic, I was back on the road. When I asked what was wrong he said it was a culmination of several little things and that he’d replaced a few bits like damaged plug caps and cleaned a few things up and the bike was running fine. I parted with $165 and away I went.

I have to be honest, when I rode away from the shop, I was expecting the bike to go like the clappers but it seemed to be holding back a bit. That said it was running a lot better than it had been!

A couple of days later I got the bike ready for a quick ride and off I went. I got 300m up the road and guess what? The misfire was back again but this time it was back on the left hand side!

Back to the shop it went. They’ve had a play with it but reckon that because the misfire is migrating from one pot to the other, there’s a strong likelihood that the centre crankcase seal has deteriorated or failed totally. In their opinion, it just ain’t worth spending any more money.

Has anyone else ever had this problem on an RG250?

Incidentally, I’m planning to put the rego on hold and have a go at repairing the bike myself. Trouble is, I know that while I’ve got the motor out I’ll want to replace everything else as well and buy myself some decent tools in the process!

What pisses me off the most is that once again, I’ll spend yet another summer fixing my damn bike instead of riding it! Bugger!

[vagrant]

Perhaps you could try for another engine from a wreckers?
Some of them do offer warranties on the engine, so if you fit it and its knackered, you can take it back.

[Blue Meanie]

Replacement RG250 motors are as rare as rocking shit! A mate from work suggested an RD350 or RG500 motor. Not really practical on a Learner licence!

Anyway, I bit the bullet and over the Xmas holiday I put the rego on hold, cancelled my insurance and set to work stripping the bike down. I decided that this will be my 'new' project for the next twelve to eighteen months.

Currently working on breaking the motor down with a view to rebuilding it. Seemed like the logical place to start.

I'll keep you posted.

[rabidnz]

mate, i think you really have to love this bike if you are going to keep it, as she is going to cause you pain and heartache! All worth it i promise you!
she may have nothing under 6 grand, she may sound like your nana couging a lung out under the powerband but its still my favourite bike ever!

End of last year my lump seized at the bigend and took out pretty much all the piston skirt, both cylinders, which lead me to find another motor, and also the wonderful people at rgv250.co.uk, their rg forum saved me !
Got the motor for 200 and a new pv controller coz mines stuffed, all shipped from north island for 240, upon inspection seemed looked after, so much so i didnt pull it apart before putting it in. Ive also got a full gasket set and 2 new pistons for when its time to do a top end, just looking for rods now!

Love this bike, can you post a pic??