Yamaha Tz250L classic race bike

[weeksy]

https://www.ebay.co.uk/itm/Yamaha-Tz250 ... Sw79Vf8i-W

[Yorick]

Looks cool, but horrible to ride for the vast majority.

[Skub]

Purdy.

[DEADPOOL]

Amazing machines, very difficult to get the best out of one. Hard as nails, like riding a very high speed plank.

[Skub]

If you have 15 minutes to watch,this clip from Kirkistown in 1989 shows an old workmate of mine Gary Cowan using a 250 Yamaha to good effect against the big bikes of the day.

[Le_Fromage_Grande]

The 350 I had a brief spin on had a similar power band to an F2 tuned LC engine, wasn't massively better handling either, not sure what model it was, the frame was the YPVS shaped frame, so probably an F or a G, mate had a Rotax 250 engined Armstrong that was peakier, that was like a light switch for power delivery.

[Newey]

I wonder if anyone ever used a Champion spark plug in an TZ or an LC for that matter, i mean out of choice and not necessity??

[Le_Fromage_Grande]

I wonder if anyone ever used a Champion spark plug in an TZ or an LC for that matter, i mean out of choice and not necessity??

No, they were shot plugs, NGK every time, B8ES in a standard LC, B9ES in a tuned LC

[Newey]

First road bike at 17 was a Yamaha RD125 twin (JOT 320P ) even remember the number plate without a second thought, first ride out in the evening we ended up in the New Forest direction and it blew a hole in a piston, turned out, if true or not but was told that Yamaha put in NGK 7 plugs for running in purposes, no more problems with a 8 or 9

[Potter]

I rode stuff like that back in the late 80's and early 90's because it was all I could afford at the time, I was also eligible for Forgotten Era races if they were holding them at the same meeting because my bikes were so old

I have fond memories but they were hard to get the best out of, and that's when I only knew how to ride two strokes, I don't think I'd ever ridden a four stroke.

If you were used to four strokes and you got on that bike you'd think it was broken until you worked out how to use the power.
That happened to me when I bought my LC in 2012, I'd had two decades on four strokes and I honestly thought the LC was broken during the first mile of riding it because it was cold and the throttle didn't seem to do anything other than make it chug along spluttering.
It took me a good few rides to get used to a two stroke again and get my throttle control back.

[Le_Fromage_Grande]

It's a skill I'm going to have to relearn when I get my YPVS on the road, apart from a few off road bikes I haven't ridden a two stroke in 30 years.

[Yorick]

My Husky has bags of torque and it's insane when you dial in full noise

[Le_Fromage_Grande]

My Husky has bags of torque and it's insane when you dial in full noise

All the modern(ish) off road competition two strokes I've ridden have been like that, but I'm sure you can remember power valves aren't like that, they have much simpler power valve arrangements, 20 year old KDX200s have at least 3 stages of power valve and digitised ignition which makes them a lot smoother than the old 80s bikes.

[Yorick]

My Husky has bags of torque and it's insane when you dial in full noise

All the modern(ish) off road competition two strokes I've ridden have been like that, but I'm sure you can remember power valves aren't like that, they have much simpler power valve arrangements, 20 year old KDX200s have at least 3 stages of power valve and digitised ignition which makes them a lot smoother than the old 80s bikes.

Properly tuned bikes don't need to have knife edge powerband.
I bought my first race LC350 almost new with only 1 race meeting. Beckett tuned and engine was great. Even used it on road when necessary.

Then in 3rd season I bought a full F2 system from Beckett which he built for someone to do the Manx.
Almost TZ power with LC power spread. Awesome on tighter tracks. Many wins and outright lap record at Flookburgh

After my gap to go travelling, my pal bought me a Beckett YPVS F2 that another pal built for 88 Manx.
That was road friendly and I took it to Spain mid season as my CB900 fucked up.

[Scotsrich]

I had a mate that used to club race 250's and 350's

Although they would be earlier than that version being the mid to late 70's.

The outstanding memory I have of that is him swapping jets at the track if it was wet/dry/damp/hot/cold to try and get the best out of the motor.

[Potter]

The outstanding memory I have of that is him swapping jets at the track if it was wet/dry/damp/hot/cold to try and get the best out of the motor.

They needed a lot of fettling if you wanted them to run right.

In contrast when I started racing a four stroke it cut prep time down to pretty much zero and the only maintenance was washing the flies off the screen occasionally. It was so much easier to ride too.

Motocross was the biggest difference, when you're fresh out of the gate you want to be on a two stroke because it's light and you can wring it's neck, but three-quarters of the way around when you're absolutely knackered a four stroke is just so much easier to ride.

[Le_Fromage_Grande]

Properly tuned bikes don't need to have knife edge powerband.
I bought my first race LC350 almost new with only 1 race meeting. Beckett tuned and engine was great. Even used it on road when necessary.

Then in 3rd season I bought a full F2 system from Beckett which he built for someone to do the Manx.
Almost TZ power with LC power spread. Awesome on tighter tracks. Many wins and outright lap record at Flookburgh

After my gap to go travelling, my pal bought me a Beckett YPVS F2 that another pal built for 88 Manx.
That was road friendly and I took it to Spain mid season as my CB900 fucked up.

The only bike I've had with a really pronounced powerband was a 1980 air cooled YZ125 that had been tuned for Bavins (Yamaha off road dealer in Norfolk), it was great fun to ride but if you dropped out of the powerband you had to keep changing down gears until you found it, this was in 1988, it was as fast as the newer bikes I was racing against, but nowhere near as smooth, and if you dropped out of the power it was like putting the brakes on, club motocross races were 2 x 20 minute races and by the end of 20 minutes I was knackered - after 40 minutes the bike was knackered and needed a new ring just to run without spluttering.

I bought a 1986 KTM 250 to replace it, and that was the opposite, smooth power all the way through and no real noticeable power band, it was also a bit on the slow side and similar age Japanese bikes were faster, lighter, easier to ride and handled better (and also didn't have White Power USD forks that kept blowing seals)

On the road I had an F2 tuned 350LC with 26mm carbs and Microns that was pretty smooth but I think the small carbs and exhausts were limiting the power, I then mad the hideous mistake of buying a 1979 GSX750ET, that didn't have enough power to haul it's fat arse, so that went for a 350YPVS, which I then had a Stan Stephens stage 2 tune, which gave it another 10mph top speed but no noticeable loss of mid range, I then put a set of Lomas pipes on this, which shifted all the power up above the red line, which gave it another 10mph (top speed 135 indicated) it was still quite smooth though, certainly better than most of my friends bikes at the time, but I kept the airbox which helped a lot