I'm at the end of the road and need help please.

[chappers]

Hi,

I've had my RD350 YPVS for about 6 months, of which, it's been on the road for about two weeks. Not long after I got it it suffered siezed calipers and a leaking master cylinder. So, off with the brakes and sent to Nick Chambers who refurbed them to spanking new condition - great. New piston for master cylinder from Yamaha had that back to tip top condition after trying to fit a CB900 in its place. Lesson learnt.

So, all back together and...Nothing. Turns out there was now no spark. Checked all the usual things as per everyone's suggestions on the web and came to the conclusion it was the CDI as the coil seemed to read ok along with slow and fast windings on stator. Replaced with a shiny new zeeltronic, kicked her over and...Nothing.

After discussing with a few mates, I then changed the stator to no avail. Finally I bought a dynatec coil and...Nothing.

So, off with the carbs which I'd been trying to avoid, and although they were pretty clean, I gave them a good clean in the ultrasonic jewellery cleaner and popped them back on. Checked all of the wires an hey presto, she started.

Off I trotted to the MOT centre and then off for a ride and all was well apart from a drop in revs when pulling away. This meant I had to slip the clutch massively to get away from the lights. So, I checked the carb setup threads on a number of sites and set about making things better. Oh boy.

At this point, I bought a new aftermarket throttle cable as mine was actually too long (came with the bike). As I was going to have the tops off the carbs I thought I'd change it at the same time. Anyway, the cable I got was too short from splitter to carbs and the bike wouldn't run at all. I got a good cable from a second hand dealer (like new in fact) and fitted that. Bled the oil pump and started her up. I bled the pump by pulling the cable and left it for a minute or so with a fair bit of smoke coming out of the exhausts. She would only idle without throttle when warm so I figured there may be something wrong with the air screw setting. I set this as per the carb setup buide found on the web.

I managed to get rid of the drop in revs and she pulled away lovely. Went for a ride at 0-quarter revs and all was good. Plugs were perfect. I then went for a ride at quarter to half revs, all good and plugs looked perfect again. Then...I went half to three quarter throttle and she siezed (soft sieze). I let her cool down and then limped back home. Off with the carb tops and drop the needle a notch. Test ride, same thing. Dropped the needle another notch and...now it's really fubar'd. Will still start and idle but sounds terrible and if I give it any throttle at all it backfires and stops.

Before I go and spend another £200 on this pile of junk, can anyone point me in the right direction and let me know what I'm doing wrong. I know I now will need new pistons and a rebore but I don't want to do that then get the same problem.

I thought it may be the timing but the stator can only be in one place and it's all secure.

Can anyone help?

[johnlc]

Maybe rings were sticking or crank seals shot sucking in air but if your rebuilding you'll be renewing all the seals and gaskets anyway

[atomicstroker]

I'd stop throwing good money after bad, do the sensible thing, get someone in that really knows what they're doing. It'll be money well spent, you can watch and learn and at least at the end of it you'll have a properly running bike you can enjoy instead of growing to hate it!
I know, it happened to me with an Aprillia RS 250, never did sort it soooo -- I sold it!!!!

[cb250g5]

Nov 15, 2011 17:59:43 GMT 1 chappers said:

Off with the carb tops and drop the needle a notch. Test ride, same thing. Dropped the needle another notch and...now it's really fubar'd. Will still start and idle but sounds terrible and if I give it any throttle at all it backfires and stops.

Can anyone help?

Dropping the needles makes the bike run leaner - why do this if it's seizing?

[chappers]

Thanks for the note about leaning the mixture by dropping the needles. I was following the advice on this thread:-

www.2strokeworld.com/forum/index.php?topic=9103.0

There is a picture half way down that explains how to set things up. As I said, all was well under half throttle.

Wondering if the dynatek coils are making it run hot and causing the sieze?

I would happily get somebody in to help me with it/show me what to do (and pay) but I don't know anybody in my area (just outside Norwich) who could help. I have done everything else so far myself and am happy doing things and want to learn so don't just want to take it to a shop.

Does anybody know of anyone in the Norwich area that could give me a hand (for cash).

[barbarossa]

My advice is to get shut and buy a Honda.
My Honda Superdream was stuck in a shed for 8 yrs - but started with a new battery and fresh fuel.
A new front tyre and she passed the MOT with NO ADVISORIES.
Only a Honda will do that.
She starts, goes and stops and does an indicated 90mph and always gives me 80-85mpg.
My Yamaha RZ250 on the other hand, has seized due to a broken oil pump cable and now needs what I believe is it's third rebuild. Mileage is 27000 or so - exactly the same as the Honda which needs no TLC whatsoever - it just gets on with it's job of helping me to enjoy motorcycling.
Remember - you meet the nicest people on a Honda and the most frustrated people rebuilding a YPVS.

[chappers]

Thanks for the advice but I do already own a honda in fact, a c90 for commuting and yes, I've met some very nice people, however, that's not really the point.

I always wanted an RD when I was in my yoof but couldn't afford one so I bought this to fulfil that need. I also bought it knowing that it would need some work doing to it and was looking forward to doing it but I didn't bank on having to rebuild the whole electrical system and engine in the first 6 months as I did buy it running.

The only thinkg I can think of that I've done wrong is that I didn't bleed the pump for long enough. If that's the case I'll happily go and buy the bits for the rebuild but as I said, I don't want to go to the expense and time of doing that only to put it all back together and have it do the same thing.

Does anybody have any technical opinions that might help or the name of somebody local?

thanks

[barbarossa]

Me too- always wanted an LC or YPVS in the 80s, but 3 kids and a mortgage meant food was hard to come by, never mind a bike !
I bought my RZ for the same reasons you bought your YPVS and I too am disappointed as the oil pump cable broke the first time I rode it, resulting in the need for a complete strip down and rebuild.
It's like finally getting Kylie Minogue into your bed - and finding she has bad breath and farts a lot.

[onewheelsenough]

Nov 16, 2011 20:53:05 GMT 1 barbarossa said:

My advice is to get shut and buy a Honda.
My Honda Superdream was stuck in a shed for 8 yrs - but started with a new battery and fresh fuel.
A new front tyre and she passed the MOT with NO ADVISORIES.
Only a Honda will do that.
She starts, goes and stops and does an indicated 90mph and always gives me 80-85mpg.
My Yamaha RZ250 on the other hand, has seized due to a broken oil pump cable and now needs what I believe is it's third rebuild. Mileage is 27000 or so - exactly the same as the Honda which needs no TLC whatsoever - it just gets on with it's job of helping me to enjoy motorcycling.
Remember - you meet the nicest people on a Honda and the most frustrated people rebuilding a YPVS.

I think the guy is after advice not a new bike part of owning a two stoke is the thrill of riding them. I dont think the superdream provides much of a thrill. two stroke do require a faif bit of messing with to get them running spot on but its worth it. If you are on your third rebuild in 27000 miles you must be doing something wrong

[nikfubar]

Hi here's my 10 cents worth

First, Dyna coil will not make it run hot, just gives you a better spark

Oil pump, get yourself some clear oil lines from Yambits, bleed the pump with the engine off, start the bike using premix then hold the wheel in the full open position & watch the oil going along the clear oil lines until completely bled.

Make sure you have no air leaks on the intake rubbers.

Carbs, if you say the plug colour is good on 1/4 throttle the pilot jet should be ok if your air screw is about 1 1/2 turns out.
The needle controls the fuel between 1/4 & 3/4 throttle, if it's seized at 3/4 you need to raise the needle not drop it. The needle should be on the middle clip if you are getting on the bottom clip you need a larger main jet.

Did you do a proper plug chop or just look at the plug after each run.

[nikfubar]

The only time a super dream would get your heart racing is if it fell over & you had to pick the hunk of junk up ;D ;D

[stanlc7189]

Honda Wet Dreams - I had two 400s in their day a CB400T and later a CB400N. I sold the CB400N for my original RD350LC - and the 'F' in fun really came on tap. No comparison! Sure, the 400N was reliable, thrashable and never missed a beat, but it was also BORING!!!! It had zero character, no charisma - just competently did the job and is the least memorable of all the bikes I've owned since 1974.

I wish I could say that my current LC thrills me just by keeping me in suspense as to the next time it will go 'bang', but it doesn't. Thirty years on and it's not like my original LC. I had confidence in that. Never let me down. I did 12000 miles a year on it and toured two-up abroad. Wouldn't dream of doing that on this one. It's a 30-year old bike, BUT and this is the point - it smells the same, sounds the same, looks the same (gorgeous) and the grin on my face when I ride it is also the same, even though I have my hand hovering over the clutch at anything above 7000rpm. I get as much of a thrill riding that as I do my GSX-R750K5 - for different reasons of course!

[chappers]

Thanks Nikfubar.

I'll get the oil lines, great idea.

For the plug chop, I ran the bike at the throttle setting and then hit the kill switch. Pulled over and took the plugs out. I think that's what I should be doing?

I didn't think the spark would run hot but a chap at work thought that might be happening so it's good to get a third opinion.

So, I'll get the oil lines and pistons. Do I need to take engine out and strip the whole thing or do you think I'll get away with just taking the top end off which I believe can e done on the bike?

BTW, I had a superdream back in the day. Definitely not a hear racer!

Cheers

[Deleted]

stick with it chappy, get help if you need and when its all good you'll be laughing

[nikfubar]

Yeah you can change the pistons with the engine still in the bike, fiddly but do able. Hopefully you haven't damaged the crank. Don't forget to stuff rags into the crankcase before you lift the barrels completely off the pistons incase you have broken rings, don't want anything dropping down there.

Plug chop, you need new plugs, run it at WOT, kill switch, then you look at the colour of the insulator a few mm up from the base. Think this is why they call it a plug chop as the easiest way to see it is by cutting away the plug thread with a hacksaw to expose the insulator.

[barbarossa]

Thanks for the feedback.
I haven't had the RZ for 27000 miles - that's it's recorded mileage when I bought it. I was told it had had 2 rebuilds by previous owners - now it needs a third due to the snapped oil pump cable.
And I know Superdreams aren't fast and furious like 2-strokes - it just seems strange that one old 250 ( CB250N ) can be so reliable and another old 250 ( RD/RZ ) can be so much aggro.

[nikfubar]

Your oil pump cable snapped fella try running the super dream without any oil & I wonder how long that would last

[cb250g5]

It is possible to break a superdream as well, I bent one of the forked rockers that opened the 2 inlet valves, so one valve stuck open & said hello to Mr Piston......

A superdream is an appliance, whereas a 2-stroke is a proper bike.

Get it built & set-up properly & it will be as reliable as a Honda. In the last few years I've ridden an F2 round France & taken my Hybrid to John O'Groats from Sussex, including 3 track sessions at the festival of 1,000 bikes on the way back. No problems apart from an exhaust hanger shearing, and I'd made that, not Yamaha.

I'd pull my hybrid out of the garage tomorrow & go anywhere, without any more reliability worries than any other 30 year old bike, 2 or 4 stroke.

[Fingermaus]

Well I'm gonna try with a bit of support for you chappers.
I road my ypvs all This year(I keep wanting to say last year)
I bought it in february with 28000 miles, leaky fork seals and no MOT. New plugs, forks seals,pumped up the tyres,carbs cleaned,a slap on its arse and fingers crossed was all I did.
I have thrashed the living shizzle out of it all summer and it's not missed a beat.
I even went to the lakes camping on it, on a 200 mile round trip.
[a href=""][/a]

All I'm saying is to stick with it.These bikes can be reliable, you're in the right place to get great advice, and once its sorted(which it will be) it's all worth it.

[rabbit57]

I agree,stick with it mate.Bought an f2 with 40,090 on the clock 6 months ago and have only managed to do 50 miles due to a charging fault but some of the most enjoyable miles I've ridden.She absolutely flys.Am working on problem at the moment as I get time but sure she will be 100% soonBest of luck with yours.Cheers Bob.