DR750 & DR800 owners thread

Discussion in 'Thumpers' started by MCmad, Jul 14, 2008.

  1. the_sad_punk

    the_sad_punk Been here awhile

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    Rob, likewise mate, how are ye keeping? All well here if a little busier than normal:rofl
    Bike is still on the bench so as to speak:D.
    Im saving up all the pennies to bascially have the whole thing rebuilt, well apart from the head. Its an expensive route to take but that way il know its sorted once and for all bar basic servicing.
    If you hear of anone selling new oem bearings, chains, tensioners, guides, springs at a good price let me know.
    Also any upgrades that are wise to do shout! I have that first oversize piston and barrel (without cutouts but i read that ok to use?) and ive read about the later cct and a hessler spring being a good idea.
    Lastly the i think i remember Dave saying to use a later balance chain guide too...?

    Spen, the creation is looking well mate, you gona sell the pther one or start a collection like Bob?:D

    Ps Mait that piston looks great!
  2. motolab

    motolab Long timer

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    That's probably a good thing.

    Regards,

    Derek
  3. Ladder106

    Ladder106 It's a short cut, really

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    I obviously did not read the instructions well enough.

    Good thing I've not started building anything yet.

    Never even heard of gapless rings before. Why are they good....or not?
  4. motolab

    motolab Long timer

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    In Total Seal's case, the rings are two piece designs where the second ring overlaps the gap of the first. I would never want to use a gapless 2nd ring (that is one that goes into the 2nd ring groove of the piston) because the top ring needs to be pushed against its bottom ring land in order to seal, and relies on a pressure differential between the area above and below the ring to do so. I'm skeptical of a two piece design in general, because as far as I can tell, there is nothing to prevent the gasses from getting between them (meaning the top portion won't do much to help facilitate sealing). In the end, if set up properly, the ring gap on standard top rings is close to nothing during operation (that is when hot) anyhow.

    Regards,

    Derek
  5. Ladder106

    Ladder106 It's a short cut, really

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    I obviously did not read the instructions well enough.

    Good thing I've not started building anything yet.

    Never even heard of gapless rings before. Why are they good....or not?


    Taking a closer look at this, Mait, it would appear that the rings are , indeed, conventional.

    The top ring is the "torsional" type and installs with the inner bevel UP.

    The second ring is the "napier" type and installs with the "notch" DOWN.

    Does that sound correct? I'm sure I'd have discovered it eventually but it's nice to have it straight in my head now.
  6. mait

    mait Been here awhile

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    Absolutely correct!
    Top ring installs inner bevel up.
    Second ring installs notch down (to scrape oil from cylinder wall when moving down).
    Oil ring spring (the wave shaped piece) installs with ends facing down.

    Don't forget to set the 1st and 2nd compression ring end gaps! Or ask your shop to it for you.

    Gapless rings... they might work but I didn't feel like experimenting this time.


  7. spen

    spen on my arse

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    Does any one know if it is possible to get a link pipe made to fit the GSXR can onto the DR ,Anybody on here make them ??? Also if anyone has a spare can for sale PM me . thanks :norton
  8. Ladder106

    Ladder106 It's a short cut, really

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    Most good auto muffler shops will build one.

    But, they mostly use benders that reduce the inside diameter of the pipe during the bending process. This is likely OK on cars but not so nice on motorcycles.

    If you look through exhaust tubing web sites you can find mandrel bent tubing in many different configurations. 2 90 deg bends should give you all the angles that you need.

    Then just cut the bends at the angles you require to connect the pipes.

    FWIW, I started with a link pipe from a GPR silencer. This pipe was OK but was difficult for me to adapt to the Spark Arrestor that I require in the USA for off-road riding. The link pipe provided was very very close and I only had to modify the silencer end to get it to mate to the Suzuki can. Dunno if the GPR link pipes can be had seperately.

    The OD of the Suzuki head pipe is about 43 mm while the pipe exiting the square flange on the GSXR is 58 mm so some reduction has to be engineered in along the way. If you can find a pipe with the 1000 link pipe attached, this will help you start the fabrication process. The link pipe will have the square flange and pipe alreay attached and the gasket between the silencer (yes, there IS a muffler gasket) and the link pipe present. Then you can just cut the link pipe at whatever point you went to continue your build

    Be sure you get the "(x)40f0(x)" (stamped in the aluminium outer shell) pipe from the 2000-01 GSXR 1000. The 35F0 silencer from the 750/600 is also the same outside size but has just slightly smaller internal pipe size. It isn't Titanium but the weight difference it slight. This one may be more redily available.

    The use of these pipes for DR650s is likely not quite so popular in your part of the world so it's usually quite probable to find one at a breakers.

    If you haven't seen this site yet: https://docs.google.com/presentatio..._h8J2BBNkCwyuCE92fGflMOSQ/present#slide=id.i0

    Take a look since it has good information. The link pipes for the DR650 are close but the end nearer the engine has a large "UP" angle that is not used on the DR750. It may be a starting point but would be a shame to spend all that money and then cut the pipe up.

    Oddly enough, this silencer has no detectable (to my butt dyno without any gas analysis) effect on the bikes standard jetting so there's not much mucking about there.
  9. spen

    spen on my arse

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    If i can make something up rough i can get it made in Stainless. I had a look at that site using the GSXR can on the 650 looks good ,
  10. jurvooss

    jurvooss Adventurer

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    Sep 30, 2011
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    how does the de-comp lever works on my 1990 dr800, currently my engine is on the bench and if i pull the lever mounted on the head it stays in that position. is that good? or does it has to go back on its own..!?

    i never had it started before, so idk how it works while running.

    thanks,:D
  11. mait

    mait Been here awhile

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    Yes it should stay in that position. It will go back when the camshaft turns.
  12. jurvooss

    jurvooss Adventurer

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    thanks mait, another step further!:clap
  13. jurvooss

    jurvooss Adventurer

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    :norton i have powdercoated my frame and all the little attached plates but do i have take the paint away where i place my coils so it grounds?
  14. Bob Herr

    Bob Herr Oilpatch University Graduate

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    Finally got around to putting the 42 tooth rear sprocket on my 88 DR750. Also replaced the worn out rear knobby with a Kenda 761 dual sport tire. Took my first ride with it today and I like the result. I ride all paved roads and usually have a 60-90 minute ride on interstate to get to any thing curvy. Motor now turns 3600 RPM at 100K/hr and the bike is really smooth. Motor turns 4250 RPM at 120K/hr with just a slight buzz in the pegs and bars. The torque of that 750 is really something!!! The bike takes off easily from a stop with out having to slip the clutch much and there is no engine bog. Haven't tried to pull a steep hill yet but there is no need to shift down on gentler hills. Just a little throttle roll to maintain speed. Motor just seems to be loafing along. I have had a KLR650 and a F650GS single and they seem to really be pulling hard at 70MPH. I am thinking this is going to be a really smooth bike when I get rid of the front knobby and maybe add a set of bar weights.

    I had comments from some of your fellows when I inquired about this last year so I thought I would just report back the result. - Bob
  15. robmoto

    robmoto Long timer

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    It should ground through the thread on the bolt that holds it in place on the bracket, but these brackets may need grounding where they touch the frame on both sides of the frame .
    Use locktite when replacing or you will be sorry .
  16. spen

    spen on my arse

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    Only if you want a spark
  17. Silent Hunter

    Silent Hunter Been here awhile

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    Hi sad Punk,
    I am interested in the header, but will it fit the older 41 DRs made in 1990?
    Mine is a SL model that has the Big750 body but the 800cc engine.
    What's your bike's make?

    Now on to the lithium battery part. :evil

    I got a Shorai Lithium ion battery (the biggest model- LFX18A1-BS12) and it won't fit into the battery compartment if I were to put it in the right side up.:rofl

    But there was plenty of room if I slot it in side ways, with the -ve end at the bottom of the battery compartment and the +ve end at the top.:clap

    Cranking power is significantly better when compared to the lead batteries. I got at least 12 good cranks out of it before I noticed a drop in power. But after that the battery got weaker fast. Got another 6 or 7 cranks before the battery was too weak to do a proper crank.

    The standard lead battery can only give 6-7 good cranks before it runs out of juice.
    Bad news when the bike won't start and I was troubleshooting the carb.

    I ended up push starting for every turn of the screw.
  18. the_sad_punk

    the_sad_punk Been here awhile

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    PM sent Silent Hunter.
    The shorai battery is something im considering buying for one of the bikes. Let us know how you get on with it. Did you buy thier charger for it too? I believe you cannot use a standard trickle charger on it?
  19. Silent Hunter

    Silent Hunter Been here awhile

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    I got mine from the local dealer.
    I goggle the local dealer address and number from the Shorai main website.

    The guy just started business in Singapore and I was his first customer!:rofl
    The dealer Kelvin wasn't ready for business until April. But I ordered mine from him anyway, so he did an early bird order for me and a few other people who called in and gave us a 5% discount.

    If you are getting a Shorai battery, it is best to find a local distributor. That way you get the 1 year warranty after the purchase.

    As for the charger, I just bought a generic one from this guy from eBay.

    http://www.ebay.com/itm/320715017864?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649

    Used it once to recharge the Battery after the battery went flat from my experiment on how many times the battery can crank.
    And once again after I tuned the carb. Works ok so far. Charging time is a bit long. Roughly 5-6 hours for a flat battery. 3 hours for a partially discharged battery.

    If you are getting a non-Shorai charger make sure the charger DOES NOT have the de- sulphurication mode.
    That mode will charge the battery above the safety voltage.
  20. robmoto

    robmoto Long timer

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    Anti Gravity, is the lithium battery I use, its about at least 50 percent smaller than the stock one and about a third the weight, it has about 130 cranking amps from memory.
    The instructions say that the battery operates best if the bike don,t start to leave it a few minutes before cranking again as the battery will heat itself and give out more charge the warmer it gets the better cranking .
    Silent Hunter if your battery and the size of it rather large too, and starting to die after 7 cranks maybe you got some troubles with starter motor brushes in the very near future :lol3. some thing don,t sound good to me :deal.