Benelli 250 2C

[Lotus54]

I took it for a longer ride today- ran great!
I found out why cold start was poor- the cable going to the ‘splitter’ that opens both of the starter valves had broken.

I need to get some 3mm screws to bolt down the handlebar switch, a few other little things and ready to put some miles on it to break it in.
I turned over 5,000 miles on the speedo.

I forgot to take a picture on the ride.

[Lotus54]

Great day for a ride up the Elwha (and other places)

[Lotus54]

The throttle cable adjuster had broken. I’m going to replace the throttle and splitter with a two-cable setup, but in the meantime, I made a new adjuster. The knurling is not very good- but it is functional

[John H]

Knurling takes some practice to get a perfect pattern. What brand is the throttle?

[Lotus54]

Tomeselli.

I’ve done a lot better knurls before, but this was a different tool, different lathe and different material.

[Lotus54]

I got a dual cable Tomeselli throttle. This is not the desmodronic type that many modern 4-stroke bikes use, but both cables are pull to open.
I made up both cables from some Venhill kits I have. The throttle is quite a bit lighter without the splitter (and old upper cable), smoother also.
I then made up the ‘top’ cable for the two enrichers on the carbs. It had broken in the spitter. So now I can just pull the lever on the handlebar for cold starts. It starts really easily with that active, but not won’t start without it. I was just pulling on a cable until I got it fixed- much better now.

I got one new silencer in from Germany, that is all they had. But it does replace the rustier one. I will keep looking for a right now, but will start working on cleaning up the old ones really well and see about rechroming. The baffle system comes completely out.

[John H]

Tomaselli accessories are always high quality unlike some Amal items. I like the idea of changing to twin throttle cables
all the way too.

[Lotus54]

The manual has a very slow breakin recommendation. On this one, mostly the pistons (rings) that would require it. Tolerences are fairly snug so I don’t want to push it.
I have a spare headpipe, so I think I will weld an O2 sensor bung on it and go ride it with my readout box, so I can verify mixture. I think that is the most important on a 2-stroke, get too lean and it gets hot and…

[John H]

I know what 'lean' does to 2 strokes, put the wrong gas in the Lawnboy last year and stuck it. How do you adjust the oil mix on the Benelli 250?

[Lotus54]

The Benelli is pre-mix. I’ve been using Motorex full synth 2-stroke at 50:1
My KTM 300 called fro 60:1, my Beta averages about 88:1 (oil injected).

With the oils in 1972, they called for 5% - but even back in the later 70s, I ran much leaner (I think 40:1) with the oils that had come out.
BUT, I want to make sure not too lean. That will kill it a lot faster than lean oil (well, from what I’ve seen). Plus oils avaliable now are very good.