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02 Sep 2019
Your admin has not been on the site much as of late as my main computer apparently seized up :( I have had limited access, but will be back soon. Thanks. Mako
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TOPIC: DT175 Premix Ratio

DT175 Premix Ratio 01 Sep 2019 14:29 #11

  • Kosmo
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KennyV wrote: I like the piece you made for your throttle cable, good idea and nice work! The one thing I did do on my 250A was try and make it look like something isn't missing. I made a plate to cover where the oil line went in and a 8mm straight thread pipe plug with same thread pitch (I wish I could remember the DIN number) for where the cable went.


Nice, looks very clean!! I will have to do something similar for mine. Currently I have a piece of fuel tubing that I inserted into the oil cable hole and then threaded a 6mm socket head bolt into. I don't know how well it will seal so before I take it out for any serious rides I'll make sure it's done properly. And thanks! I hope to remake it out of ABS (will resist higher temps seeing as the cable is right next to the exhaust and engine) and also in black so it stands out less.

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Last Edit: by Kosmo.

DT175 Premix Ratio 01 Sep 2019 14:31 #12

  • darinm
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That a great insightful reply Mark. Something I'll think about more in the future.

As my CT2 is a rider that's never been rebuilt outside of a new top end 2k ago, I tend to use whatever two stroke oil is available at the time, I figure even the cheap stuff is at least on par with what what used in 1972.

I'm resigned to rebuilding the engine at some point and don't stress too much because of that. Those clean throttle cable modifications sure do look nice.

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1972 Yamaha CT2 175
1972 Yamaha RT2 360
1972 Suzuki TS 185 Sierra
1995 Suzuki DR 350

DT175 Premix Ratio 01 Sep 2019 15:53 #13

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I wouldn't say you are screwing up with your oil. Lucas is good stuff too. The Lucas I've seen is rated for air cooled two strokes. I'd run it but at the recommended 50:1. Might actually be better than Yamalube? My main point was that because Yamalube 2R works great at 32:1 doesn't mean ALL oils should be used at that ratio.

When not using the pump there are many opinions and experiences with oils and ratios that are "right"... and people can get angry if their "right" way is challenged.

(For example, the only big end rod bearing failure I ever had was with one of the first synthetic "lean oil mix" oils... Bel-Ray MC1 at 50:1 way back when... 1970's... I haven't used Bel-Ray MC1 in anything since. Others swear by it.)

One of the things I love about these old bikes is that rarely there is only "one right answer". For example, and a little off topic... many people have failed with LED headlights on the stock system... yet DVM found a way to make one work on his CT3!

Bottom line when you start modifying is you often have to take the role of a Pioneer breaking new ground... When making changes that can affect jetting (switching to premix can be one of them) the only solid rule is you have to give the engine what it needs... the modifications are often easy... the fine tuning is what makes the difference between a great running bike and a so-so running bike.

Have fun! :Buds

P.S. Yamaha doesn't make oil... they have it made. Years ago Yamalube was made by Citgo. The formula and actual manufacturer has probably changed over the years. Funny thing is when I was racing desert for Triple E, Ed swore by Citgo oil so that's what we ran. It was cheap and we went through a lot of it. More recently, I've run the WalMart SuperTech 2 stroke injector oil that comes in the gallon jugs and it works great in the autolube systems... low carbon build up, low smoke, and engine seems to run a long time without noticeable wear. I agree that most "modern" oils are better than what these bikes had when new so it's pretty hard to screw up picking an oil. :Buds
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1963 YG1-T, 1965 MG1-T, Allstate 250, 1970 CT1b, 1971 R5, 1973 AT3MX, 1974 TS400L, 1975 RD350, 1976 DT175C, 1976 Husqvarna 250CR, 1981 DT175G, 1988 DT50, 1990 "Super" DT50, 1991 RT180, 2017 XT250

DT175 Premix Ratio 01 Sep 2019 16:01 #14

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Nice job KennyV... Looks very clean!

(I'm pretty sure the oil pump cable fitting thread is 8mm x 1.0... a little unusual thread but not impossible to find.. European cars like BMW and Mercedes sometimes used the finer 1.0 thread pitch)

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1963 YG1-T, 1965 MG1-T, Allstate 250, 1970 CT1b, 1971 R5, 1973 AT3MX, 1974 TS400L, 1975 RD350, 1976 DT175C, 1976 Husqvarna 250CR, 1981 DT175G, 1988 DT50, 1990 "Super" DT50, 1991 RT180, 2017 XT250

DT175 Premix Ratio 01 Sep 2019 16:14 #15

  • Giancarlo124
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If you are running a stock carb with stock jets then run the recommended ratio. If you are planning to run something different then you need to re-jet.

If no one is running your setup you are just going to have to try stuff and figure it out for yourself.
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The Oil burners: 1973 DT-250, 1966 YM-1 305, 1966 YSD3, YZ-105

DT175 Premix Ratio 02 Sep 2019 10:49 #16

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You can't be too goofed up Kosmo because you are still smokin' and not broken!
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DT175 Premix Ratio 03 Sep 2019 21:19 #17

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Snglsmkr wrote: because you are still smokin' and not broken!


haha I like that, gonna start saying it :D

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Last Edit: by Kosmo.

DT175 Premix Ratio 04 Sep 2019 01:41 #18

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Your engine does not have the same materials as new bikes that can tolerate 50:1 ratio! Get autolube working, you won't have to worry about downhills lacking lubrication as you do w/pre-mix. Pre-mix even @ 32:1 is probably not enough for continued WFO operation. Your using good oil at least, plug issues are tuning related, I sometimes run pre-mix (from 2 stroke equipment) in 4 stroke stuff (just to use it up faster) no smoke/no issues at all. 2 strokes smoke because they don't burn all the fuel they injest, thats also why they don't have twice+ power even though a two stroke's complete cycle is 360 degrees vs 4 stroke of 720 degrees.
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Last Edit: by liferbiker.

DT175 Premix Ratio 12 Sep 2019 14:28 #19

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KennyV wrote: I like the piece you made for your throttle cable, good idea and nice work! The one thing I did do on my 250A was try and make it look like something isn't missing. I made a plate to cover where the oil line went in and a 8mm straight thread pipe plug with same thread pitch (I wish I could remember the DIN number) for where the cable went.


For those who choose not to use the auto lube and want to plug and cover the openings, the straight thread pipe plug DIN number is 9029 and it's 8 x 1.0. And I used an aluminum crush washer to seal it.

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71 Z50 Minitrail
72 RT2
74 250A
78 XT500E
06 F650GS Dakar
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