Two Stroke Motocross
Two Stroke Motocross Forum => Technical => Topic started by: ford832 on January 24, 2011, 03:55:36 AM
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Ok, a little background first.
Way back when I bought a new RZ.For those that don't know,it's a 2t twin street bike with dual carbs.It's one downside was a lack of range(about 110 km)and,having an urge to do a little traveling,I sold it and bought a 750 Interceptor.
After I got that out of my system,I had an urge for another RZ and found a used one for sale with a freshly rebuilt engine for a super good deal.Usually,that would set the alarm bells ringing but the guy had taken the engine out and sent it to the shop I buy my parts from so I had no doubt the rebuild was done correctly.
Upon arrival,I checked it over then snapped the choke on and it started first kick.Given that the price was about half what it should be,I took a chance and bought it.
On the way home,it was running so super rich it wanted to stall at anything under about 1/3 throttle so I had to pull the clutch in and keep the revs up just to keep it going.
Above that throttle opening,it would go like a scalded cat.
Once I got home, the solution came after about ten minutes of sitting on the step slurping a brew and staring at it(beer = brain power)
Once fixed,it then created another problem that I'll get into later if anyone gets this.
Both fixes came quickly but in truth,only because I was intimately familiar with the RZ's set up due to my first one.Had this not been the case,it would have been much more of a head scratcher.
Anyone..........
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If my memory serves me correctly, the carbs and motor from that RZ350 is essentially (or very close/similar to) the powerplant Yamaha used in their Banshee quad (from '87-2006). I know the Banshee is a liquid cooled motor. .. is the RZ liquid or air cooled? Did it have oil injection or run on premix?
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You're right.Basically the RZ and Banshee engines are clones-for the most part anyway.Liquid cooled,oil injection.
It looks like this......
(http://i207.photobucket.com/albums/bb162/ford832/86rz350-ca-red-white-side-shot-300w2.jpg)
Damn,I miss my RZ's :(
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Seeing how those cylinders would have head gaskets rather than O-rings, it seems possible there could have been a coolant leak. .. I've had that before on my TRX and it made the bottom end feel boggy. . . once it got screaming up top it burned right through though. .
That's my "shot-in-the-dark" guess since I'm figuring that the obvious (simple jetting issues) weren't the problem (otherwise this wouldn't be much of a riddle)
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Nope,no engine issues whatsoever and I never had to rejet-well,not really anyway as I never changed any brass.
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the pilot jet was gummed up, the air filter was dirty, or there was a rag in the boot?
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None of the above....
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rat nest in the pipe
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Moved the clip to lean her out a little more?
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Adjusted the oil pump, switched to the correct oil, untangled the cable for the injector,......?
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Nope,nope and nope......
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I say you forgot to shut the choke after starting it :)
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Oddly enough,given my addle-mindedness-no.However,it ran just like that only I would say even richer/worse.
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the main jet came unscrewed
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No,not brass related.
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Does this guy have the little main jet in the float bowl, with a little o-ring that directs it through the needle jet?
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Power valve wired up backwards.
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Nope,nope and nope......
Now you're starting to sound like my ex wives. ::)
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Nope,nope and nope......
Now you're starting to sound like my ex wives. ::)
Or my current one :(
As for TMKIWI and Juliend-no and no.
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Were the carbs rebuilt with the engine ?
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No but the problem is carb related......
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The balance tube was not hooked up to the right carby was it ?. Instead of the fuel line.
Or the choke rod between the carby's was on wrong
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Nope.As I said,had I not been very familiar with the set up it would have proven far more difficult.Anyone give up yet(and willing to suffer the shame and abuse that would automatically follow ) :D
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I give up.
I had one back in the day but never had any issues with it.
You can roast me now. ::)
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Bugger it. I don't give up.
Was the motor rebuilt because of this problem or rebuilt because of something else.
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I just posted the answer and saw your last response so I took it off-hopefully before you saw it :D
The motor rebuild wasn't due to this issue.
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Shit.
Can you put it back up.
Then i can guess. ;).
Did you pull the carby's apart to fix it.
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You TM riders are a just a bit too slow :P
I didn't actually have to take them apart-not really anyway,but I did have to do something to them.
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Thats the second time you have said "not really".
You either did or didn't
Stupid question but: Is it possible the carbs were on backwards ?
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Thats the second time you have said "not really".
You either did or didn't
Stupid question but: Is it possible the carbs were on backwards ?
Well,not really but you're getting warmer.There,that's three times :D Give up yet?
I'll put it this way,and it pretty much hands it to you,but I never took the bowls off.
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The slides were back to front.
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Yes indeed.While you typically can't do that,the RZ carb bodies and slides are a mirror image of each other(which lines up the guide pins when the slides are turned 180' and installed in the opposite carbs)-I expect for the fuel hook up as well as access to the slide sight windows/adjusters.Having,in effect,zero cutaway on the slides gave an amazingly rich condition,even worse than with the choke on-which sort of relates to an earlier discussion on idle settings and the effect on low speed jetting.Anyhoo....
At this point,having just bought a crappy running RZ with a rebuilt engine for half price that was fixed by 10 min of thought and five minutes of work,I was feeling all warm and fuzzy so I decided a test honk was order.After various "cunning stunts" I returned home,parked it,and went to bed-secure in the knowledge I had a flawlessly running bike.
The next morning,I geared up,swung my leg over it and proceed to kick the guts out of it but no start-or even a kick for that matter.Thinking maybe a buggered kill switch,I checked for spark and found lots.
Coffee in hand this time as I still planned on riding,I though for about five minutes and worked for ten and was back in business for good with no more issues.
The problem was............
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Your right. Even round slides do not fit in either way because the location groove and idle adjuster groove are different.
Well most of the time. ;D
I'll think about your other problem later i must get back to work. :(
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Yeah,it's almost bedtime for me.I'll ck in tomorrow.You should have it by then :)
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This discussion brings back memories of my motorsports business and some of the problems we tackled.Case in point:"A regular customer brought his multi cylinder street bike in for it's annual spring tune up.The work was done,the customer came to pick up his bike and after a little chitchat he was on his way.The next morning he called me and said every time he banked sharply left the bike would stall.He would coast to a stop,the bike would fire up instantly and everything was fine until the next left hand corner".
The bike was dropped off and we checked EVERYTHING and everything checked out.Took the bike out and sure enough,the first hard left and the bike just shut down.I've learned that many times it's best to let a problem rest for a while before tackling it again so I parked the bike on it's centre stand (the side stand had been removed) and went on to other things.
Later that evening I was staring at that street bike wondering what demon had possessed it when I noticed something.The air intake faced rearward and under the plastic I could just make out part of a rear frame cross member.It was a steel channel with the open end facing upward.I looked closely at where the centre part of the channel disappeared under some plastic and I noticed an object.
It was my 4 year old son's wooden train.This toy was the exact width of the frame rail and somehow the little guy had put the toy in there without me noticing.The air intake was on the left side of the airbox and during a hard left that toy train would roll down the frame rail and get sucked up against the intake snorkel,shutting down the engine.When the engine stalled and the bike was righted,the toy would roll back to the centre behind some plastic! :-X
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Turn on the fuel dummy. ;D ???? Sorry. Happened to me.
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Ha. This reminds me when I accidentally put a smaller slide in my 38mm pj carb, and when it finally started.. :o
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yes you do get some weird & wonder problems to solve at time.
I had a 150hp DI outboard a few years ago that the owner complained of a miss. It was only 6 months old.
We checked everything on the motor from your basic compressions to everything on the fuel system & Ignition circuit to the EMM.
We tested it at work in the tank & river tested it.
Could not fault it at all.
The owner took it back and rang me to complain the miss was still there.
So I went out on the water with him out of the local port and about 1/2 mile out there was the miss. ???
We drove around for an hour and the miss was only at 1 spot.
After talking with the owner some more he finally said yes this is the only spot it happens. No where else. >:(
It is very hard at times to get straight answers from people at times.
I talked to the council and found out there was a under water power cable there.
Any way the power cable was screwing with the EMM and causing the miss.
Shouldn't happen but sometimes these things do.
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bad crank seal???
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bad crank seal???
Nope.
The train thing and cable are too funny :D
Some things almost make you pull your hair out.
I remember quite a number of years ago I had a customer who complained that his car lost power at times-especially on hills.He had it in three times and I could never find anything wrong with it.He eventually realized that it only happened when he had his utility trailer on.
I told him to bring it back with his trailer though I couldn't see how light wiring would have any effect on driveability.
Anyway,it turned out that his ball was one size too small for his hitch and because it was a light trailer,when he hit a hill and accelerated it would rack back and forth some.The knock was picked up by the knock sensor on the engine and the ecu would retard the timing-causing his loss of power.
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Ah bugger to late to say the reversed slides (ask me how I know). a good one I found was a a bike that started and ran , sometimes, back fired others and then refuse to start. A broken woodruff key.
A good article I read written by a long time mechanic, customer brings in a gixxer 1100 and says it has a bad vibration at 220k's, tells him to ring in a week, customer ring says it will be ready on monday, customer arrives bike has not moved , "Did you fix the vibration?"
"No reckon just stick to 219k's in the future", customer arcs up and tells hime he's extended his life by a week and a half.
Another time did full rebuild on a multi, comes back in a week with a seized engine , cam cover off and obvious no oil getting to the top, start stripping it down, mechanic notices something blocking a oil gallery, gets it out and it's a small triangular piece of brown glass, customer goes mental, about the same time his best mate rocks in walks over sees the bit of glass on a tissue, " Ah that's probably a bit of that beer bottle you smashed when you put that engine in. Told you to flush it out"
Thinking the vaccum hoses on the petcock not correctly installed?
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Nope.The above is too funny.The key brings back memories of a nissan sentra that would start good,then not,backfire,then not,run good,then not.The key on the crank was good but it had beat out 1/8" either side from centre on the crank pulley so the timing would be all over the place.Bah,I hate cars........
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broken coil wire? where the sparkplug cap screws into it?
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No.
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out of gas?
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:D No
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flooded?
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Made up symptom just to mess with us? :D
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Maybe :-X :D
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lmao
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fouled plugs from the previously rich condition
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Nope.
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oil injection if your still using it.. ;D
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Nope.
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powervalves?
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Nope.
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reeds? low compression? My friends banshee would do this when the carb flooded.
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Were the plugs wet ?
The beer bottle incident reminds me of a job in the UK years ago.
A guy brings in his new to him Lancia Delta HF Integrale with loss of power. It was 2 years old.
Do some tests and find it has no turbo boost.
Pull Turbo of the car and it is toast.Housings ,shaft & impellers beyond repair.
So I fit a new turbo and proceed to bleed the oil lines.
After flatning 2 battery's and no oil coming out of the turbo dump hose I start to wonder whats going on.
So I took off the braided oil feed line from block to turbo.
The block end of the hose had match sticks jammed into the line. :o
Turns out the guy bought the car 2 days before from a car yard & only test run it around the block.
The car obviously had blown turbo seals so to stop it smoking the car yard blocked the oil feed to the turbo.
The turbo lasted just enough for the test run & the drive home. >:(
The car yard was sued and lost their license.
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No,none of the above.
That story reminds me of the guy that brought his car in for a noisy transmission.He'd just bought it a couple weeks before from a used car place and was sold as a 4 spd.Once I got looking at it,I realized it was a 5 spd but fifth had let go so the used car place bought a 4spd knob and screwed it on ;D
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LOL. Could of sworn it was reed/carb related, cdi?
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Nope,but who said it wasn't carb related?There,that's your hint of the day......or is it?..... :D
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forgot to tighten the caps on the carbs after fixing the slides
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Nope.Anybody ready to give up,hang your head in shame and all that? :D
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no, but soaking that bike with gas and setting it on fire sounds good right now, lol
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You could give me the motor since it is plague with a mystery problem. ;D
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water in the bowl
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I am guesing a choke related problem.
The bike went first time because the motor was flooded because of the slides but now you have given it a run it's not getting enough fuel cold.
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They had the idle mixture screws wound right out trying to get enough air with the lack of a cutaway?
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No,no and no,though setting it on fire would have been an option-lol.
TWKIWI is the closest-it's a choke related issue.There,that's hint #2.
Anyone ready to give up now and admit their mechanical spasticity? ;D
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No ,no and no
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no
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dual carbs means two chokes with a linkage device,
the choke linkage was backwards so on was off
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Nope.
Come on,you know you guys want to give up-I won't say anything-honest ::) :D
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outline the symptom again?
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Good spark,no start.
Brought it home running like crap,15 min later after slide fix,started it and went for a ride.Came home and parked it.The next a.m.,kicked it 15-20 times-nada-not even a kick.
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You don't think it was the guy doing the kicking. :P
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It's entirely possible-though not as likely as it would be now-I was much younger then :( :)
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clip on the needles at the very top, excessively lean, too lean to start
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Nope. :)
There's no shame in giving up though.Well,actually,there is-deep,painful,unimaginable shame.Just say the word though... :D
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>:( ARRRRRGH!!!!!!!!
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;D ;D ;D
I feel your pain-but not your shame :o :D
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No shame here only frustration. I have run out of ideas, having never owned a twin, I reluctantly give up.
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Ok,Ill wait for TMKIWI to give up and thereby also concede that YZ's are vastly superior to TM's.Once he does,I'll post the answer :)
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a good one I found was a a bike that started and ran , sometimes, back fired others and then refuse to start. A broken woodruff key.
That would be my RMX, yes? :P
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I don't know if that's gonna happen Ford, I haven't ridden the new YZ250, nor the new aluminum framed TM, but I rode the steel framed ones. The TM had Ohlins forks, and despite not caring for the bars, loved the TM. it felt like my KX does now that I got my suspension revalved
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I didn't necessarily say it was,I just want him to say it!Hahahahahaha
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lol
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Ok,Ill wait for TMKIWI to give up and thereby also concede that YZ's are vastly superior to TM's.Once he does,I'll post the answer :)
I can not tell a lie to all the good people here.
You can tell us tho. :(
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P.S i hate trying to diagnose problems over the phone.
People never tell you everything.
Bring the bloody thing in and I will fix it. Not your problem. ;)
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That's close enough to an admission for me(wife says I see things how I want to see them :) )
Anyway,the float bowls were on the wrong carbs.
You were right in that the only reason it started before was because the slides were in backwards causing an excessive rich condition.
After I fixed that,the bike was still warm so no choke was needed.
The following morning,when I needed it,it had none.
The choke system on the RZ,like most 2t's,is,of course, an enrichener circuit.On the RZ it is on the left carb only so when you pull it on,it opens the passage in the body which is mated to an passage drilled in to the edge of the bowl down to the bottom of it.
The right hand bowl is identical and has the same passage but the hole has a plug pressed into it from the factory so no fuel can pass through it.
Though I had rejetted and changed reeds and whatnot on my first RZ,I had never really noticed the set up of the slides or bowl at the time.
However,me and a buddy decided to go on a couple hour rip one day(first RZ) and I gassed up beforehand and picked up dirt(I've never not run a fuel filter since)
Anyway,our 2 hr trip turned into an 8 hr trip as I had to stop 9 times,take the carbs apart and give them to Rob to stuff in jacket and go find a garage somewhere in the boonies to blow it out.While I waited,I had nothing better to do but poke around at things.Though I cursed it at the time,it was good to know when I bought the second one.
I think that's the only stumper I've got-other than "why the H did I get married anyway?" :)
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Trap for young players that one.
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oh yeah do I ever know the tale, pie for breakfast, lunch and dinner, til the ceremony, then the bakery closes mon - sat.
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Only riddle here is how that shop makes a profit :o
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Reminds me of a joke:
"What's the world's most effective contraceptive?"
"Wedding cake!" :-X
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Reminds me of a joke:
"What's the world's most effective contraceptive?"
"Wedding cake!" :-X
its also the most fatting food in the world!!! :D
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bwahhh hahaha