1. Adventure Rider Print Magazine!
    We're doing a print magazine this November - 128 pages of high quality adventure riding stories, photography and interviews!

    Click here to purchase a copy for $9. Limited copies still available.
    Dismiss Notice

Rz350

Discussion in '2 smokers' started by rd400racer, May 21, 2013.

  1. mjfields_228

    mjfields_228 Long timer Supporter

    Joined:
    Sep 17, 2010
    Oddometer:
    1,398
    Location:
    Cape Canaveral, Florida
    The MF'r RZ350 Saga Continues...........

    Aquired this one in 2016 off of the Flea Market here on the -->ADV<--. The bike immediately demonstrated that this one was not going to be an easy one to sort out nor would it be an enjoyable experience.

    Got off to a bad start. I was riding it to work a couple of mornings after I bought it and it blew the headlight and dash fuse. I replaced the fuse and it blew again. Found some "suspect" areas in the fuse block and attempted mitigate it and that seemed to take care of that.

    Then the bike would quit mid stride. Like someone flipped the kill switch. Sometimes it would start after I rolled to the side of the road and cycled the key a few times. Sometimes it would not. I took it to 2 separate shops in my area and--of course--they could not get it to reproduce the issue. So I decided to try a guy I trusted a few states away! Since I frequent the Robbinsville North Carolina area I loaded the RZ350 up with a couple of others that ran good and heading up there the 4th of July week 2017. The "PLAN" was to leave the RZ with Wheeler in Robbinsville and he would trouble shoot and fix it and I would be back on Thanksgiving 2017 to pick it up. Wheeler isolated the issue to the OEM ignition module and after several weeks of attempting to source a OEM unit we elected to purchase the Zeeltronics Module. All went well with the install (so we thought) and I headed up as scheduled in November 2017. Picking up the RZ I had the biggest smile on my face ever because Wheeler showed my the Dyno plot and the bike had jumped significantly in HP numbers.......... While running up Highway 129 just outside of Robbinsville the bike shit the bed. Limped back into town and found that one of the pistons experience a burn thru of the dome.

    Wheeler claimed responsibility and said he would replace the top end and return it less aggressively.

    RZ350 did not come home in November of 2017. The repair went slowly and the OEM Head was warped now due to the first failure. Attempts to source a OEM unit were unsuccessful so we went with a Cool Head Product. I continued to call Wheeler frequently and finally he felt the RZ was ready in September of 2018. Drove up to get it and upon arrival Wheeler informed me that it need a few more hours of tuning. I checked into the hotel and came back later to find the bike had devoured another piston. Wheeler promised me that he would fix it again and get it right this time.........

    Fast forward to this weekend. I gave waiting for the bike to be ready again. I drove up Friday 2/22/2019 and picked up the bike. Came home on Saturday 2/23/2019 and have carefully put about 60 miles on the bike. Here is where it is at.....I think.........

    It is very staved for power above the 7000 RPM region. Feels like a small displacement 4 stroke spinning up--not a 2 smoker.

    It runs very hot. And when I push it even a little bit the temp gauge climbs to just below the red area. It was in in the low 70's this morning. At 50mph in 6th gear on a very flat road with no head wind in was reading between the middle mark and the Red area. Any sort of motor load or quick revving of the engine the gauge will quickly spike to just shy of the red zone.

    I don't know if it just an old crappy cooling system. Or if the timing it still wonky and causing excess combustion heat. I may punt and take it to a newly discovered old School shop in my area that I just discovered last week. Or I will just cry!!!! I've tried everything I could to get the right hands on the bike to make it right. It just is not working out in my favor right now.

    [​IMG]IMG_0579 by Matthew Fields, on Flickr
    [​IMG]IMG_0581 by Matthew Fields, on Flickr
    [​IMG]IMG_0582 by Matthew Fields, on Flickr
    [​IMG]IMG_0583 by Matthew Fields, on Flickr
    [​IMG]IMG_0589 by Matthew Fields, on Flickr
    jethrocephus and aptbldr like this.
  2. jethrocephus

    jethrocephus His Honorable Right Minister of Flying Monkeys Supporter

    Joined:
    Nov 6, 2004
    Oddometer:
    726
    Location:
    In the Bonus Round
    Man....that's a pretty awful experience! Hope you can get it straightened out, it's a beautiful bike!
  3. snarlyjohn

    snarlyjohn Human money repellant

    Joined:
    Apr 1, 2016
    Oddometer:
    496
    Location:
    Australia
    A few thoughts.. I'd be trying to set the Zeeltronic to closely match the original factory timing curve as a starting point. It mightn't be the ultimate horsepower wise but at least it will be safe and it should run reasonably well. One of the RD/RZ forums should be able to advise on the numbers but the usual brand specific forum warnings should be kept in mind ie. they usually have more than their fair share of nutjob "experts". Even a fixed (or straight line) advance curve should give reasonable performance though it'll be a bit doughy down low.

    Two strokes are a bit different to four strokes in that retarded timing can make the engine run hotter just as much or even more than advanced timing. If the exhaust duct in the barrel has good coolant circulation around it the coolant will pick the heat in the exhaust gas that a retarded spark produces. A late spark increases the EGT, and much of it goes into the coolant around the exhaust duct. It could be that in an attempt to avoid burning any more pistons the mechanic has used a very "safe" tune, rich and retarded. It would run hot and be sluggish. Also check your exhaust isn't restricted and the power valves are opening when they should be - these will both cause high temps and sluggishness too. If it hasn't been done already do a pressure test on the bottom end to rule out any leaky crank seals or air leaks in the intake tract.

    Generally a two stroke with chambers will want a fair bit of advance at low rpms (up to around 25deg) and then that should reduce sharply as it comes onto the pipe (to perhaps 16 - 18deg) and then with another further reduction on the overrev to extend the rev range a little. Be very careful not to use too much advance at lower revs though - the engine will probably feel sharper with more advance at rpms under the powerband but unlike a four stroke a two stroke will quite happily detonate with a light load and a small throttle opening if the advance is excessive, so be conservative.

    Once the timing is in the ballpark (and you've checked the exhausts and PVs) you might want to check the jetting. I posted a guide to two stroke jetting here some time ago that will tell you what to look for. I'll put up a link if I find it. Edit: https://advrider.com/f/threads/beginners-guide-to-two-stroke-jetting.1254185/

    One more thing - the aftermarket head. I'm a cynical old bastard but with good reason - I've found a lot of "performance" stuff to be absolute crap, often much worse than stock. Of course there is some good stuff out there too but I've seen a lot of stuff that makes worse numbers on the dyno or has other problems. I don't know anything about your head but it's possible it's overcooled and dumping heat into the coolant that would otherwise be used to make power. I'd also check the compression ratio of the aftermarket head - too much CR with a two stroke drops the EGT and kills the overrev power.
    aptbldr likes this.
  4. aptbldr

    aptbldr easy rider

    Joined:
    Apr 20, 2009
    Oddometer:
    1,571
    Location:
    Upstate South Carolina, USA
    Is the coolant system thermostat still in-place?
  5. rockt

    rockt Long timer

    Joined:
    Oct 13, 2003
    Oddometer:
    2,898
    Location:
    Canada
    Mjfields, that is an awesome bike and you're almost there. Don't give up. Snarlyjohn's advice is great but if you're not up to taking on the mechanical side yourself, there are still some 2-stroke guru's out there. I talked to a fine and hugely knowledgeable gentleman a few years ago who went by RGVSteve and who is in Florida. I don't have any more info. on him but if you do a google search it should lead you to one of the excellent 2-stroke forums and someone should know how to contact him. If he's not available, someone on one of the forums will be able to steer you in the right direction.

    This is an RZ500 site but they have an RZ350 area:

    http://www.rzrd500.com/phpBB3/

    I really liked, I believe it was called 2 Stroke World but I haven't been actively working on my RD's/RZ at the moment and haven't been on in awhile and can't find it. I hope it didn't shut down. Anyway, get on a forum somewhere and find some help 'cause you need to get that awesome RZ going.

    Good luck and please keep us posted.
  6. rockt

    rockt Long timer

    Joined:
    Oct 13, 2003
    Oddometer:
    2,898
    Location:
    Canada
    Just found an email address for RGV Steve. It's from 2016 so I don't know if it's still active but you could try it if you want to talk to him: rgv-steve@cfl.rr.com
  7. schoals

    schoals Been here awhile Supporter

    Joined:
    Dec 8, 2009
    Oddometer:
    787
    Location:
    Dahlonega GA
    Tony Dukas in Florida

    TDR
  8. anotherguy

    anotherguy Long timer

    Joined:
    Jun 18, 2009
    Oddometer:
    15,491
    Location:
    the hills
    Can you post a photo of the plug from the cylinder that did not hole a piston? As in focus and well lit as you can manage.
  9. TNWillie

    TNWillie Long timer

    Joined:
    Sep 18, 2012
    Oddometer:
    1,188
    Location:
    NE TN
    Sweet lookin RZ! Personally, and with the understanding that the cause could be any one of several things, I'd be pressure testing the crankcase to rule out a leaky crank seal(s). Reasonably easy to perform, in my opinion. GOOD luck!
  10. rd400racer

    rd400racer Long timer

    Joined:
    May 14, 2013
    Oddometer:
    4,613
    Location:
    Louisville, Ky
    Well, I'm finally getting back to work on my poor little RZ that has sat neglected for the past 3+ years. I started to gather parts this weekend and then it hit me that I had a problem with my head. After much discussion on an RZ site, I decided to send it to the renowned RZ guru Ed Toomey. Not only did he do the work in record time for a very reasonable price, it just looks damn sexy on top of all that. Now I'm really jacked to get this thing back together!

    rzhead1.jpg rzhead2.jpg rzhead.jpg
    Yard Sale and jethrocephus like this.
  11. mjfields_228

    mjfields_228 Long timer Supporter

    Joined:
    Sep 17, 2010
    Oddometer:
    1,398
    Location:
    Cape Canaveral, Florida
    I pulled the RZ out this morning to assess what might be going on with the high running temps. Started the bike up, ran down the street and it got hot immediately so I returned back to base. I pulled the cover off that hides the coolant overflow tank and and the over-flow tank was bone dry. I removed the Lower Case/Transmission Dip Stick Cap and the fucking Crank Case is full of Coolant -- looks like A root beer float in there.

    Clearly a bad gasket or one of the cylinder faying surfaces is warped. I have NOT pulled the top end apart to figure out where the leak is and if there is any possible piston/ring damage.

    I am not nearly skilled enough to go after this myself. $10000 total burned so far (price of the bike plus the multiple trips to the shop in the last two years). I am emotionally beat over this because I simply wanted a run about bike--nothing special--not show bike. This bike was fucked from day one.

    Going to park it and decided in the next few months whether to cut my losses and move on or take another run at it with more money and different mechanic.
  12. rockt

    rockt Long timer

    Joined:
    Oct 13, 2003
    Oddometer:
    2,898
    Location:
    Canada
    Hey MJ, I can feel your pain through my computer screen. These 2-strokes can be a hair-pulling experience. BUT... if mildly tuned, once sorted, they don't require much, if any continued fettling and... they're FUN. Plus your bike is a beauty. So before you give up, at least talk to one of the good 2-stroke guys and get an opinion. Personally, I don't think your bike is far off. You might not have to put much more into it to get it right. If that's the case, you'll be glad you kept at it.

    Good luck!
    jethrocephus likes this.
  13. mjfields_228

    mjfields_228 Long timer Supporter

    Joined:
    Sep 17, 2010
    Oddometer:
    1,398
    Location:
    Cape Canaveral, Florida
    Question for anyone familiar with the RZ’s motor. If it is a clutch seal or water pump seal that is the cause of my viscous leak, is that an easy item to replace that does not require too much engine disassembly?
  14. dpforth

    dpforth no inline fours

    Joined:
    Oct 22, 2010
    Oddometer:
    1,109
    Location:
    YQQ
    IIRC there's a coolant passage behind the clutch cover that would be worth looking at. But, I may be thinking of my old DT200.
  15. mjfields_228

    mjfields_228 Long timer Supporter

    Joined:
    Sep 17, 2010
    Oddometer:
    1,398
    Location:
    Cape Canaveral, Florida
    First things first.......I drained the oil/coolant volume to get that shit out of there. I used the air nozzle on my compressor to blow are thru the fill plug to try and vacate the cases the best I could. I let it sit and static drain for about 2 hours occasionally tilting the bike side to side.

    I am still not sure if I am going to tear into the clutch case first chance I get or explore other options. CAUTION:: If you look at these photos for more than 30 seconds you will become very sad which may result in you calling in sick to work in the morning!!!

    [​IMG]IMG_0722 by Matthew Fields, on Flickr
    [​IMG]IMG_0723 by Matthew Fields, on Flickr
  16. dave0

    dave0 Been here awhile

    Joined:
    Sep 23, 2012
    Oddometer:
    228
    Location:
    there
    From those photos I'd say you've got a broken impeller shaft or impeller gear. And a bad shaft seal. That's the only way to get coolant into the gearbox. All that is under the plastic cover on the clutch side.

    This was a somewhat common issue when racing. The combination of no antifreeze coolant, cold temps, and enthusiastic riders broke quite a few water pumps. If not caught in time would over heat the motor quickly.

    Check that and check your compression. Hoping your lucky .
  17. oic

    oic Business is ALWAYS personal

    Joined:
    Sep 6, 2014
    Oddometer:
    2,164
    Location:
    Directly under the earths sun.
    Any luck getting it straight?
  18. mjfields_228

    mjfields_228 Long timer Supporter

    Joined:
    Sep 17, 2010
    Oddometer:
    1,398
    Location:
    Cape Canaveral, Florida
    I tore the RZ apart last Saturday with a complete set of new Water Pump parts ready to go in. The Impeller shaft looked good, the seal and bearing looked okay but there are some fatigue cracks in the side cover casting around the impeller housing. I don't know if they are simply an artifact from when the seal was originally pressed in or due to over heating at some point or bad casting. Since I cannot be sure if these contributed to the leak I opted to order a new side cover and will refresh that as well.

    [​IMG]DSC_3794 by Matthew Fields, on Flickr
  19. Ant24

    Ant24 n00b

    Joined:
    Mar 7, 2019
    Oddometer:
    7
    Location:
    li ny
    Hi, love the thread.
    I just finished bringing my 84 Kenny Roberts back to stock ( I was installing an Airtech fairing on it, but eventually didn't like the look), to go along with my rider 72 H2, and a 71 H1 basket waiting for a rebuild. Can I ask what kind of pipes you are running? I have a set of old microns on it I would like to change out and like the look of yours.
    Thanks, I now have to get back to reading the thread.
  20. oic

    oic Business is ALWAYS personal

    Joined:
    Sep 6, 2014
    Oddometer:
    2,164
    Location:
    Directly under the earths sun.
    Looks like you have it surrounded! I hope that takes care of it for ya. I have sworn off anymore Ducatis and almost KTM as I prefer to just ride it without worry, but your RZ is one I think I could deal with the BS to ride around.