Amongst the various spare bits I have is a bottom end from a electric start DT125. Purely as an intellectual exercise, would it be a practical "mod" to swap the bottom end? (A thought experiment, if you will, to keep us entertained in this time of plague boredom.) Personally I think I'd rather keep the original matching frame + engine number, that and a 175 isn't that hard to kick over.

So the list of changes I think it would need is:

• Swap over barrel (and carb, bolt into frame, all the physical stuff)
• Maybe a different kicker
• Definitely a different shifter
• 12V battery, regulator, rectifier
• 12V bulbs throughout (and there are quite a few!)
• Coil, points?
• A whole new loom?
• Maybe a different oil tank if the basket behind isn't big enough for the battery (lithium-ion might be a "cheat" as they're smaller)
• Anything else?

Phew! That seems like a lot of work

If you are talking about a true DT175... 1974-on... Then you'll have to add "make and weld new engine mounts to frame".

Aha! So the frames between the 100/125/175 are not all the same for the 76/77 era?

Hello Easy-X , you may find that the 125 crankshaft with its unique end to attach the dynamo will fit in your 175.

Not exactly.

Yamaha Enduro engines were "detuned" versions of their production motocross bikes.

In 1974, there was a major re-design of the 100/125/175 platform engine... major changes were that the clutch mechanism went internal instead of in the side cover, internal shift-shaft mechanism was made more complex, and the stator diameter went from 130mm to 120mm, and the rear lower motor mount was made a lot shorter.

All the 1974 DT Enduro models got these "upgrades" (shift mechanism change seems like a "downgrade" to me).... Except for the starter/generator versions of the DT125.

In the USA, all we got was the starter/generator DT125 from 1974 to 1976. Other countries got a "kick start only" DT125 which as far as I can tell got the "upgraded" bottom end.

(The Oceania AG175 was an outlier as well... it appears to have kept the pre-74 design even though it was not a starter/generator model... it is possible that other models in other countries kept the early design too.)

For the USA and much of the world, the medium displacement 1969 to 1973 enduros (HT, LT, AT, and CT) and the 1974 to 1976 DT125 (sold only as a starter/generator model in the USA) had the following "first generation" engine mount layout:



The USA 1974-76 DT100 and DT175 (and "kick start only" DT125's in other countries) got the new "second generation" design with the shorter lower rear engine mount:



There was no 1977 model DT125 or DT175 in the USA... In 1978 through the last US year of 1981, the USA got the new monoshock DT125 and DT175... (no more US twinshock for the 125/175...) The DT125 and DT175 monoshock engines were upgraded to a "third generation" bottom end design which was a detuned version of the 1977 YZ125. No electric start version for the monoshock models.

The USA 1977-83 DT100 remained twin shock and kept the "second generation" bottom end design... this basic engine came back to the USA with the 1990's RT100 dirt bike.

Jeez... have you ever considered writing a book. Your knowledge never ceases to amaze me, Mark

So in essence, the 1G0 125 bottom I have is hang over "older" tech than the 1G1. That makes sense Bit like how the Golf Mk2 came out but the convertible version was still really a Mk1 with a body kit.

Hehe... I'm now fully armed to bore the pants off my local bike nerds, thanks very much!

Thank you for the kind words... I spent a lot of time trying to figure out the differences between the various 125 and 175 models over the years.... while they are slow by modern standards... all the Enduros are... I say the 175's still pack the most "smile per mile" of any of the models. Light and fun with the same or better power to weight ratio than a 250 Enduro.

I don't know as much about the UK and European models... but yes, I've seen DT125E** 1G0 parts lists from as late as 1979 and it's basically the same bottom end as the first 125 Enduro... the 1969 AT1.

**In the USA, the letter at the end of the model designated the year... "E" was 1978. In other countries the "E" at the end of "DT125E" designated it as a "electric start" version rather than the "kick start only" twin shock DT125 model that we never got in the USA... the E had nothing to do with the model year like it did here.

Suzuki TC185 [high/low farm bike early "70's] had electric start. Worked well but was a very large armature & stator [field coils], think even larger than the first AT1 piston port model electric. Later DT125EA [we called it] in "74 went smaller in the starter/generator but the one i had worked great so maybe they improved it by then & might start your 175 [if you can cobble it all together]. I haven't quite got 'that' bored yet in lockdown lol.

Yeah the Suzukis are harder to keep track of, perhaps due to a) selling less overall and b) making more changes by the year and model, making them really hard to keep track of I.E. the 1972 Suzuki TS185 has chrome fenders, while the 1972 Suzuki TS125 has plastic fenders, yet the 1972 Suzuki TC125 has chrome fenders. Their 125 is a different from Yamaha who used the same frame for their 125/175cc bikes. The Suzuki CDI is only 1971-1972 too, it changed from '70 and again at '73. I guess a good thing for us Yamaha fans is that their "efficiency" of repurposing parts makes life a lot easier - especially considering the "performance" advantage of all these bikes vs each other.