Messages

31

Yamaha / Re: Straight cut gears DT1, where?

« on: January 26, 2019, 08:17:06 pm »

But wait there's more lol. The crank wheels are Tricker. Not sure if they're lighter but should be as are sort of hollowed out where you can't see. Thought i'd lost mine but found them recently in my short stroke 360 [325] when changing it back to the full 360 crank. Just realised i still have a rough set in my trademe listings so here's a ink if you want to look. Not sure if its these wheels or my other set but by memory i slid either the lead weight out or the alloy tube bit [think that bit] & was hollowed out behind it. So thinking the outer rim might be or must be a separate item fitted on after. Seems like a hell of a lot of trouble to go to to save weight & no doubt all added to the cost. also if i remember right the crank pin is a mm or two bigger than a DT1. They used a 360 pin & a roller cage with small rollers. well essentially just a 360 roller assembly & crank pin. as same rod ID as the 250. Sorry getting off track & lost. You'd better double check my info but nothing wrong with my long term memory--i think. Forgotten the question now.

32

Yamaha / Re: Straight cut gears DT1, where?

« on: January 26, 2019, 07:54:54 pm »

Just incase you're not aware, the gear change on the A & B has a shorter throw. I'll put a link to the two parts which are pretty obvious anyway. I 'did' have those bits but buggered if i can find them now. I never used them as i liked the amount of movement of the original DT1. My theory probably was--seeing i never use the clutch, the dogs need as much help as they can get to [Get in There] so less lever travel means less leverage. Stupid theory i know. Probably just thinking back to my Triumph Metisse that had a very long movement.
No8 in first link & No24 in the second. Reason being they changed the position of 31 so it is closer to the pivot point, if that makes sense.
https://www.partzilla.com/catalog/yamaha/motorcycle/1974/yz250a/shifter-2
https://www.partzilla.com/catalog/yamaha/motorcycle/1974/yz250a/shifter-1
link below to the clutch & crank gears while i'm at it. Intersting thing is i see they've drawn the crank gear helical like a DT! which is wrong but can see in the cluch link they've drawn it straight cut. Both 431 if that means A or B so must be right. Hope i'm not confusing everyone woffling on.
https://www.partzilla.com/catalog/yamaha/motorcycle/1974/yz250a/clutch
https://www.partzilla.com/catalog/yamaha/motorcycle/1974/yz250a/crank-piston

33

Yamaha / Re: Straight cut gears DT1, where?

« on: January 26, 2019, 07:21:00 pm »

  YZ250A & B. Had some on mine from some leftover A bits i was given many years ago. So far as where to look, they'd be as scarce as Hens Teeth. That's assuming, come to think, that your talking clutch & crank gears which i dare say you are. Cheers.

34

Tech Talk / Re: Exhaust port height on Piston-port 250 ?

« on: January 24, 2019, 02:00:18 pm »

My old yamaha service data from back in the day says DT2 trail 37mm to top of exhaust port & DT2MX 34mm. So 36mm doesn't sound too wild [me thinks guessing] Not piston port i know but!!. I 'do' have a DT1MX cylinder on one of my relics [not gyt kit chrome but cast original off the first mx in probably 1970 after the gyt kit--give me that chrome bore anyday lol. Don't have my cylinder off to measure. Anyway i've got a 360 crank in mine 70x70. I bought [a life time ago] an IT400 motor & fitted it into a mono DT250 frame. Someone had ported it & got carried away i think & with the pipe i used which was adapted from a 465 or something--big enough & long enough for the job. but the thing had a terrible roadracing type power & came on so strong & so high up it wasn't going to last long, was a pain. So added 100mm [4 inches] to the header pipe & fixed it 100%. Only guessed 4 inches as it was 'so far' off the scale i thought it's need plenty more length to get what wanted.
Meant to say--it had 192 degrees duration on the exhaust [talking the IT400 still] Not sure what they're suppose to have but was guessing it's way too much, hence the header extension because that was easiest for me--& my rough methods.

35

Tech Talk / Re: Crank bearing housing resleeving?

« on: September 07, 2018, 06:32:53 pm »

Speedy sleeve any use. Confused me reading numbers but think i came up with 3.146 [79.9084 mm] ID on the nearest size i could find on page 26. Your 6307 should be 80mm OD, so 'what's that'--too tight on the bearing to fit. Think i read they're 11 thou thick so no doubt ya bearing's not that loose in the case. good old DT1 & all related early motors have a steel piece cast in with the case, never a problem--till later motors like , oh, my yz125e or f--e i think where they started casting the case around a separate 'alloy' ring which then came loose in the case!!. Wasn't obviously visible unless you looked closely or had got caught out as some did. case was cast right up over the front edge of the ring so had to look in a couple of mm or more to see where the ring started, & with the bearing in place you could--click click click the complete thing. Not sure what the theory was but was a pain when it went wrong. Even had an RM250X "81 where 'that alloy ring' same set up--had broken into bits, so bugger it, sold it in bits to someone clever with machine shop gear.

 http://www.waikatobearings.co.nz/file/anytime4e796e5b88a5a/open

36

Tech Talk / Re: Coil Ohms Readings

« on: July 20, 2018, 10:04:14 pm »

https://www.partzilla.com/catalog/yamaha/motorcycle/1978/yz80e/c-d-i-magneto-yz80e
Wouldn't have thought only 2 coils in the flywheel unless there's a lighting coil left in there but looks like i'm wrong looking at a cdi box on ebay but if i was stuck & you're getting ound 350 ohms out of the brown to earth then a simple cdi box off a yamy scooter would work where by [did it on my 490] i happened to have a passola scooter typical simple box & think i hooked the brown from source coil to the black/red in the box. White/red [not white/orange think you said so must be a faded red stripe] from stator goes to 'that' in the box. Orange to plug coil. Don't think there'll be a black but if there is then earth it but don't earth any black/white as will be kill switch--stops it when earthed. Worked for me. Plus another trick that worked was simply using the source coil [brown in your case] & hook it to an RG50 or LT50 JR50 plug coil which is a cdi box combined. No trigger coil needed. Only two terminals on the coil & one is the kill wire terminal. Did that on a DT125LC with a destroyed pulser coil when screws fell out of lighting i think. In 'that' case i didn't even have to alter anything as timing was ok & ran faultless till kids grew out of it. YZ490 never suffered but probably without the brown & two coil set up maybe the timing doesn't advance or retard as much as it does originally--or does the extra coil boost the spark at high revs, i don't know--just ran like a normal arm stretching 490 & retarded for starting so all good. Looks like maybe only one terminal in so there'll be a branch off that for kill switch just to short the source coil.
https://www.ebay.com/itm/Ignition-Coil-With-CDI-for-Suzuki-JR50-JR-50-/221913131546
Funny thing is--looking at the YZ80E stator on partzilla it looks like the second coil has no windings but shows a wire going to it. Anyway, if you have a red then it's got windings. Resistance won't be anything like the 350ohn coil & maybe 100 or so guessing. Hope that's not too confusing but sure confused me trying to proof read it--gave up lol, keyboard misses letters.

37

Wanted / Re: 1974 CR250M crankcases

« on: July 17, 2018, 01:21:25 pm »

Oh bugger. I broke two conrods in mine back in "74 in the days of no conrod kits & had to buy a complete crank. luckily for me Honda paid each time--or supplied all the parts. I'd had the cylinder off regularly after the first disaster but still got me. Big end revolved smooth & felt like new but don't think each time it was a bigend issue--it just broke the rod[Got sick of being revved to the limit]. first one happened when they started 100 bikes in probably 3 rows at the winter series down Otaihanga Road Paraparaumu [yes a real place name for you aussies]. Lap scorers though their pencils & paper away after a lap so stopped it & divided it into ods & evens & a final. Lead the pack at the end of the start straight & BANG [fk it], stepped out sideways locked up & took the weight on my right leg. Not broken but black & blue lying on the couch thinking--send me another motor [& leg]. Honda said go around the corner & get a new one from the opposition [CZ & Honda--we were Yamaha & Honda at Tim Gibbes]. New bike felt so damn good in every way as old one was getting baggy although probably less than a season old. Anyway--Eventualy the same thing happened after quite a lot of meetings. Pretty certain i whizzed the splines off the output shaft where the sprocket runs too. Still liked it--i think!!. Anyway--forgotten the subject--oh yeah & i feel ya pain. ps, they had bobweight flywheels like an old villiers eh?, why i don't know but would've been better with full flywheels in my opinion. just too snappy light flywheely. Wonder if the MT250 has full wheels & are interchangeable. Umm, if your case damage wasn't from a rod--then i've worn out my computer ink typing lol.
Edit, just re-reading it sounds like tis a rod or same end result.

38

Tech Talk / Re: Alluminium disc rotors, your thoughts?

« on: July 12, 2018, 12:24:32 pm »

Reminds me of about 20 years ago when my son bought home his first roadrace bike--an NSR250 turned into an RS250 with go fast bits. I took it for the obligatory thrashing down our road going far too fast & trod on the rear brake. Think it had those sintered bronze type pads & instantly ripped the disc to bits & packed it all up against the pads & locked the wheel solid. Was bloody lucky to escape from going sideways down the road. Had to carry it onto the trailer for the short trip home. Of course he said what the %^&* are you doing using the rear brake lol.

39

Yamaha / Re: just trying photobucket to see if it works, not realy knowing what i'm doing.

« on: July 07, 2018, 12:04:27 pm »

Thanks Hoony, i'll give it a go. Not very computer savvy. What happened to P/bucket, did they just give up. I had issues [just me i think] with everytime i made a move on pbucket i had to confirm my email again just going from page to page--was bloody frustrating--said a confirmation will be sent to email but just carbled long list of numbers & things, nothing sensible arrived, & nothing to click on or type in as such. Doesn't matter realy. I'll keep trying when i have time.

40

Yamaha / just trying photobucket to see if it works, not realy knowing what i'm doing.

« on: July 06, 2018, 08:48:33 pm »

http://i1276.photobucket.com/albums/y476/gasgirlings/PIC_0022_zpsimuigw3n.jpg

not doing it right as think only a link will arrive to click--which is better than nothing.

Don't ask, looking at pic think i was compressing an xt125 mono to get the top clip out. Did drill the base on an angle to insert a valve but main problem was the gas had got past the gas piston Oring & mixed with the oil turning it into a pogo. Actualy i think it ended up a compromise as long after the gas had got past a stuff tin cup piston Oring courtesy of a scuffed internal bore from the cheap arse gas piston--i found the flap that stops dirt heading up forward from the back wheel had got inverted [for many years probably] so was folded forward & it wore through the weld on the shock body till it leaked oil. Hairline crack in the weld from year of polishing by the flap. Piss me off that did, but i'd assembled it as a straight oil shock, full to the top minus the rod displacement & worked almost perfect--perfect for the farm bike anyway. So no gas & can only feel the piston above the oil if ya lift it up by the tail a couple of time quickly but was ok riding it--So, just gave it a scratch & soldered it without dismantling, well put it in the vice tilted the other way to 'just' clear the oil away from that end., worked well. So, everything you wanted to know but too afraid to ask--or glad you hadn't.

41

For Sale / Yamaha CS3E parts for a 200 twin if anyone remembers them!!. Cylinders & Heads.

« on: July 01, 2018, 06:54:50 pm »

Have a pair of cylinders & heads on standard bore size. Will put them on TradeMe soon & put a link up here. Ok not vmx but still old Yamaha. These were before reed valve arrived on Yamahas. They have the rear transfers just as slots in the side of the liner but they still went well despite that. Great days those & remember assembling these models new & the heading of around town to give it a run [damn good thrashing lol], never went past 1/3 throttle Boss, as you instructed.

https://www.trademe.co.nz/Browse/Listing.aspx?id=1684776887&ed=true

42

For Sale / ITk/YZ465h combo. rough as a bears arse & goes like a cut cat.

« on: June 30, 2018, 09:09:34 pm »

May as well show this too--my overpriced vmx bike. Had it for more years than i can remember. Couple of not very good vids up there, or a live link with the pics plus a link lower down.

https://www.trademe.co.nz/Browse/Listing.aspx?id=1674162291

43

For Sale / YZ250A & B Crank Wheels.

« on: June 30, 2018, 09:03:00 pm »

Pair of crank wheels as seen. Few marks here & there & lead bungs are loose. Taper & keyway are good. Case in the pic doesn't go with it at the mo, so just the wheels.

https://www.trademe.co.nz/Browse/Listing.aspx?id=1681508712

44

For Sale / YZ465 piston & ring etc plus selector drum, star & roller arm.

« on: June 30, 2018, 08:57:09 pm »

Have a couple of YZ465 bits on TradeMe NZ if anyone is interested. Might need them if my overpriced IT250K/YZ465H combo doesn't sell.
Piston & rings 4th over. plus gearbox selector drum. Came with a gear cluster off ebay many year ago & used the cluster in my 4 speed 490K. Actually that's a point--how'd i end up with this left over. Better have a think. Probably what happened was the custer came with drum only so had to get selectors that came with a drum, hence left over. Sounds convincing!!.

https://www.trademe.co.nz/Browse/Listing.aspx?id=1681508696

https://www.trademe.co.nz/Browse/Listing.aspx?id=1683799279

45

Yamaha / Re: 125 G-Banger Project

« on: June 30, 2018, 01:42:15 pm »

Great work you guys do!!, i'd be bloody hopeless at restoration work, can do the mechanical stuff but dodge the cosmetics as much as i can. Anyway--28 years ago when i had one new--just be careful with the floating rear brake as over time & probably many over tightenings of the axle the spacer through the brake plate got swollen by a few thou & suspension got stiffer with more compression & rebound damping feel until it went down & stayed down after fixing a puncture on the day. Tightened axle & it was stiff to push down & had to pull it back up. Panic to the start line so backed it off a bit & it worked so raced like that for the one race. Then during the week i went looking & that's what i found. Can't remember now if i eased the brake plate or the spacer but would be whatever was the easiest option at the time. Ma.n i loved mine & had it on Alky [methanol] a lot of the time. Hey one think, not a criticism but just an observation--looks a bit like its been over backwards a few times & subframe might be tweaked up under the seat although can see a pic of the frame which doesn't look that way, maybe guard mount, maybe my bad eyesight, maybe aftermarket guard---anyway--. Had a 465G as well but that's another story, damn scary one.
Might have to eat my words there as most of the pics on the net the guard's stuck up in the air--not all but most.