Hey guys, it's been a while since I've been on the forum as I've taken a long break from working on any ATV's. Well, I'm on a couple again and have an issue with properly ID-ing a Moto 4.

Was told it was a 1989 250 (YFM250W). However, after doing some parts searching, etc, I'm not so sure it's not a 350cc (YFM350ER)

Here are the Chassis and Engine VIN / Ser #'s
Chassis: JY42HT009HC004706
Engine: 2HT-004706

I have a full set of service manuals covering all Moto 4's from 1985-1995 from 200cc up to 350cc. However, Chapter 1 of those manuals give locations and VIN's / Ser #'s for both chassis and engine, but none match the numbers on my ATV. I've google searched and get mixed results. Figure I'd reach out on the forum and see if anyone can assist.

Oh, also of note, this unit has 3 dash lights (Reverse, Neutral, Oil Temp). Best I can tell, the 350 was the only one who had the Oil Temp Warning light according to my manuals, but when I bought a used 350cc exhaust, it did not fit the engine head exhaust hole connection(was too big).

Any clarification would be appreciated. I try to research all I can before posting any questions, but am at a loss ion this one.

Thanks Guys!
Roger

 

I had both the 250 moto4 and 350 Moto4 (Big Bear). The 250 has the low range/revers shifter lever down low by the left foot peg.
The 350 had the lever up on beside the left front rack.

Another easy way is the 250 has a small chassis while the 350 has a Mid size chassis.

Top pic is the 250 Moto4 the Bottom is the 350 Moto4.

 

VIN code shows it to be 1987.

 

No matter, they did zero changes to those ATVs until 1993 . They ditched the low range sub tranny which kind of sucked.

 

Thanks guys. Just out of curiosity, how'd you decode the VIN? I tried a couple VIN decoder sites, but they did not find it. I've verified I have the digits correct. I would think the manuals I have would have has the info somewhere. So, it appears to be a 250cc based on the shift lever location, but it doesn't appear a 250 was made in 1987 based on Microfiche I'm looking at for parts. 1987 only list a 200cc and a 225cc. Also, I'm not showing any of the 200-250cc models having the Oil Temp light system as mine does. I only see that in the 350cc's? Now more confused than ever......lol. I can never seem to have something that is simple I tell ya!

http://www.mrcycles.com/oemparts/#/c...atv_1987/parts

 

This is the site I used.

Copy and pasted your number into it.

 

Maybe you have the very first Yamaha Moto4 which was just a 3 wheeler with 2 front wheels added on as a after thought. You can,t mistake those they had a real odd looking front end.

I think the 225 and 250 are the same motor and Yamaha just rounded of the number later on.
Don,t worry about little dash details those can be different. I had a Yamaha 350 Bruin (Canada) with a speedo and I ment a person with a U.S 350 Bruin and it did not have a speedo but was the same ATV.

 

Definitely not that adapted 3-wheeler, but I suppose it was some engineers good idea at the time...hahaha. Comparing to your pics of your 250 and 350, mine is definitely the 250. Looks identical to your 250 except it was red and someone painted it black at some point.

When looking at Microfiche and wiring diagrams, some of what I have match the 200-250 stuff (engine/chassis parts specifically), while wiring diagrams seem to match the 350. Just makes it tricky chasing down wiring issues when I don't know with absolute certainty which diagram to follow. I appreciate both your inputs.

I have a weird electrical fault that rared up yesterday that I need to chase down. that's what got me to post this thread to start with, so I could confirm which diagram to be tracing out......lol. I should start a new thread for that to explain in detail.

Roger

 

I'm fairly sure Yamaha casts the engine capacity onto the cylinder, just below the fins. We used to maintain one of the "converted" 4 wheelers, I don't think it had any suspension, certainly one end was rigid, it gave a very hard ride when off road.

 

Had another look at the block to see. Only ID marks I find other than already mentioned is at the base of the fins on the case (left side next to the shift lever). 59V01 and under that is V-1.

I guess the 2HT-004706 on the right side of the engine case is only a Ser #?