TT350 Not XT350

Discussion in 'Thumpers' started by zerohype, Feb 2, 2008.

  1. NordieBoy

    NordieBoy Armature speller

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    About 5cm of up and down movement before I started fiddling. Now about 3cm.

    Looks like I've got decent shock bearings now which is good as they cost a shitload.

    Also, according to the fiche, it looks like there's not meant to be washers under the heads of the bolts either. Mine has them. Shouldn't be a problem unless it moves the grease paths too far out of whack.
  2. pigeyes

    pigeyes bilge rat

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    Righto, any of you blokes got a coded wiring diagram for these tt ( and/or XT) things.
    currently putting blinkers on 2 of our 350's and the yankee diagram isn't compatible.
    So if any one can steer me in the right direction for info.... greatly appreciated, got it almost sussed
    but just like to check.Appears to be individual rectifier and regulator so may have to let some of the smoke out to find
    where I need to connect things... beaudy eh!
    mick
  3. NordieBoy

    NordieBoy Armature speller

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    Little bro has a factory manual, I'll see if it has the appropriate diagram...
  4. pigeyes

    pigeyes bilge rat

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    Nordie, that would be real good if it happens and we wont tell him about those bits that went missing from his bike.:huh
  5. Lenz1

    Lenz1 Been here awhile

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    I've got a very basic wiring diagram for a TT350S that has no DC circuits.

    The TT350 I've been working on is plated as a 1999 but the VIN number says its a 1994. The magneto leads are the standard white/red and black and brown into the CDI module plus the yellow for the lights. The yellow becomes yellow/red and runs up into the light switch where it is voltage regulated to 12V AC when the lights are switched on - makes sense to keep the bulbs surviving.

    The added bonus in my case is the presence of an additional white magneto power lead. This little critter is provided for the DC requirements of horn, indicators, brake and instrument panel lights. The white lead also runs up into the light switch and is not voltage regulated with lights on (Yellow/red is switched in at this time) but is voltage regulated to 12V AC with lights off.

    The standard wiring connects the white circuit to a basic rectifier (25mm x 25mm x 6mm thick) with 2 terminals - white one side and red the other. This is the way Yamaha produce a very rough 6V DC on the red circuit for indicators, horn, brake lights and instrument lights PLUS charge a tiny 6V lead acid battery. The low weight of a smaller battery seems to be the only positive result of the 6V option.

    The big problem is when the white circuit is unregulated (lights on) there can be more than 20V AC in this circuit which when it is halved by the standard basic rectifier, produces ~ 10 V DC - this is not good for 6V bulbs, indicator senders and very small 6V batteries.

    I've ditched the 6V DC setup and used a bridge rectifier to produce DC at a nominal 12V DC. The component is rated to 400V and 35amps and cost the princely sum of $AU 5 from Jaycar (everything electronic store) The rectifier has 4 terminals with white to the AC marked terminal and the second black magneto return lead diagonally opposite. DC positive is marked with DC negative diagonally opposite.

    The 12V+ DC circuit now runs the horn, indicators, brake light and tail light. I tried a 12V car horn but it didn't fly so I went back to the original 6V horn and it tolerates the additional voltage - should be adequate for registration purposes.

    I initially had a reasonably large 100V DC capacitor wired into the DC circuit but have deleted it - it's just not needed nor is a battery.

    There is the issue of the headlight dimming significantly at low revs due to it's AC source off the magneto. It's entirely possible to fix this by converting the yellow/red AC circuit into DC with another bridge rectifier and using a large capacitor to store charge for use at low revs. I've opted to see if I can live with the variations in headlight brightness for the time being - I'm sick of working on the thing - it's time it was ridden.
  6. Lenz1

    Lenz1 Been here awhile

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    The TT350 I've been breathing new life into has at last had a test run on the road. I'm 95kg, the final drive is 14:50 and the rear shock is at max preload pending maybe a little softening of the rear shock.

    The engine has great torque through low and midrange revs. I'm looking forward to fine tuning the carbies in the upper rev range when the wet weather clears.

    Tomorrow we're off to get a pre-registration safety certificate then on to get the bike road registered.

    I'll post some pics in due course
  7. Lenz1

    Lenz1 Been here awhile

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    The TT350 is now road registered / "approved".

    Given the new rings and honed bore I've done a few intervals of hard acceleration and roll off /slow down then a little run over a mix of sealed and dirt road.

    The front end is very stable, responsive and absolutely acceptable.

    The rear suspension with the rebuilt original TT350 "De Carbon" rear shock is at maximum pre load and 5 clicks back from max damping. I think there is room for a little reduction in preload and damping which means the rear shock is definitely within operating tolerances.

    The engine is the result of 20thou off the head, std head gasket, valves refaced, shim clearances set to mid tolerance range but the big change has been the porting of the cylinder head plus new angled inlet manifolds. The original manifolds and poorly bonded rubber carbie joiners are complete rubbish.

    The end result is an engine that pulls without hesitation off a slow idle and produces major power past mid range revs. The gearing is 14:50 (std), the carbies are standard with all standard jetting and I'm 95kg. At 60% - 100% throttle the engine develops hard acceleration. Open the throttle at 100kph in 6th gear and it drives hard immediately - it was pulling VERY HARD at 125kph @14:50 in 6th gear and showing no sign of losing power / accelleration

    At 14:52 as with the 2012 450 KTM EXC, this thing will be very interesting in the dirt ..... it lives !
  8. NordieBoy

    NordieBoy Armature speller

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    I went for 10w oil in the shock and put on a better ext res.
    The damping adjuster is in the middle of its settings.
  9. NordieBoy

    NordieBoy Armature speller

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    I think my rings may be a bit shot. 300hrs on the rings and 1st oversize piston so far. It's spitting a bit of oil out the crank case breather.

    14/52 is quite nice off road but with an MT43 on the back, you need to run a tooth smaller on the front just to keep the same ratio as the tyre is so tall. Not to mention 2 more links in the chain.
  10. Lenz1

    Lenz1 Been here awhile

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    He sounds a little tired Nordie - maybe time for a refresh. Maybe a new piston etc etc etc

    Trouble is it's like painting one wall in a house - all of a sudden the other walls look "neglected" then it's the room next to it When do you stop
  11. NordieBoy

    NordieBoy Armature speller

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    Just got a Sept '87 Dirt Rider mag.
    It's got a multi-page article on the White Bros TT350...

    :deal
  12. Lenz1

    Lenz1 Been here awhile

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    I've upped the gearing to 15:50 for road use and gone back to the 32mm internal diameter muffler outlet. The bike tops out at around 140kph now by the speedo (felt faster) but I'll calibrate the speedo using GPS as standard soon.

    I'm considering going to a 52 rear permanently and just changing between 14 and 15 for the gearbox sprocket with 14:52 for off road and 15:52 for the road.

    A permanent 51 rear and changing between 14 and 15 could also be useful - I know it would be OK for the road but only a run in local off road conditions will tell me if 14:51 is low enough for deep dirt. I suspect 14:52 would be just about right for the torque this thing has running a set of knobbies.

    I'm still blown away by how hard this little bike goes now from 50% to 100% throttle. A dyno run would be interesting .......
  13. pigeyes

    pigeyes bilge rat

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    Thanks for all the info blokes. got it all wired up with no probs and ready for rego.

    I'm equally impressed with how well these things go when you open the taps,
    it's great.
    I like the way the bike settles into a nice idle quickly and responds to big handfuls of throttle from an idling crawl and just bolts as it revs out.

    I can feel a motard coming on.

    mick.
  14. Ted farkas

    Ted farkas Adventurer

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    May 30, 2012
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    Hi,

    The yamaha australia website has a pdf manual for these old girls (has wiring diag at rear). Currently getting my tt 3fity 91' back to glory - having troule with ideling rough and poping back through carby - assuming its a lean problem carb boots are new and carb has been pulled part and cleaned , any ideas would be help full .

    Cheers
    Brett
  15. Lenz1

    Lenz1 Been here awhile

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    Highly likely to be running lean at the pilot screw on the primary carby. This is the screw downstream of the carby bowl. The manual says 2 and 3/4 turns out from fully screwed in but the real adjustment is whatever it takes to idle when warm and crack off idle without missing. Start the adjustment process at the recommended 2.75 turns out and go out from there.

    If it doesn't settle down you've got a leak elsewhere

    The Yamaha Australia site would have been the one place I didn't look for a manual before I started the rebuild project. The wiring diagram is helpful from the 1993 manual but the manual I've used successfully is for a 1986 TT350S - bit more comprehensive on the engine and adjustments.
  16. Ted farkas

    Ted farkas Adventurer

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    Thanks,

    I'm using a clymers manual but the wiring diagram was ords ( for there basic non compliance models) .
  17. Lenz1

    Lenz1 Been here awhile

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    Well I had hoped I would be able to live with the almost complete loss of headlight at low revs but it's neither useful or safe in any traffic. I don't just want to see I also want to be seen.

    So I have devised a cunning plan to provide 12V - 25V DC from the Yellow/red magneto lead. A bridge rectifier ($Au 5) produces the DC and a 40V 10000 micro Farad capacitor ($Au 10) provides a storage capacity for low rev periods. If the single capacitor isn't enough I'll add another. The reason for using capacitors is their tolerance of a much wider input voltage range than batteries. The yellow and white AC leads provide 12V - 25V AC depending on revs and if the regulator is switched onto either yellow or white.

    I'm gonna massage the handle bar light and hi / lo switches so the low beam is powered directly from the light switch and only the high beam is switched at the hi / lo switch. This allows both high and low beam to run when high beam is switched on and still provides low beam when high beam is switched off.

    If the light body melts we'll know not to do that again won't we .....
  18. Ted farkas

    Ted farkas Adventurer

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    Hi lenz,

    Following your posts closely, my system is straight 6v including ac for headlights, looking at diag it seems by just replacing seperate regulator to 12 v ac and adding new rectifier to 12 vdc my jobs done. I see your bridging/ rec post but cant follow exactly follw where wires should be going where eg rec is just red and white wire not shore where the black goes.

    Thanks
    Brett
  19. yokesman

    yokesman Been here awhile

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    I ran my norton for years on a capacitor alone for years,day and nite.
  20. Lenz1

    Lenz1 Been here awhile

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    This is how I would deal with your situation

    First confirm the AC magneto output voltage at the magneto power leads. A meter set to AC with the black meter lead to the black magneto return wire that is not committed to the ignition circuit and the red meter lead to the individual AC power lead/s. Record the voltage with lights on and lights off (regulator is on when lights are on) at mid range revs

    If the AC voltage ranges up to 20+V AC then perhaps 12+V DC can be produced and maintained but if the lighting coils only produce a very low raw AC voltage maybe you're stuck with a 6V system unless the lighting coils inside the magneto are replaced. If the system really is 6V AC at the magneto wires then MAYBE 12V DC can be created by branching the magneto power wire and return wire to create 2 source AC points and connecting 2 bridge rectifiers in series. I haven't tried this with bridge rectifiers before but increasing voltage by connecting batteries in series is commonly done

    So we ain't beat yet if it only pumps 6V AC but I can't give any definite suggestions until the magneto / lighting coil output is confirmed