Bultaco M49 Tuning

How to make the old Bulto more competitive:

Footpegs more backwards and down

the brake lever needed some adjustments too, more down	modified in the 80ies with Montesa 348 pegs and 2008 with Sammy Miller Pegs (Hebo)

After successfully fitting an Oko Carb 24mm from ebay Taiwan to my Honda TL 250, I always was wondering, what a more modern carb would improve the old Amal 627 on my M49.

I found in the internet at inmotion.co.uk a Mikuni manifold. Great and quick deliveriy from David Renham at Bultaco.co.uk. Highly recommended !!

I had to dremmel a bit the rubber, as the Amal nuts did not fit, but then it worked. Also the gas cable was ok and fitted.

Ok, but how to fit the air box with a sealed connection? I went to the do-it-yourself market, sanitary and found a 50mm flexible plastic thing.

I also bought once a Montesa rubber and hat another rubber, so I coult make a connection to the small airbox, Of course, a bigger and better airbox could improve the breathing, maybe later.

original, but new Amal 627	Oko 24mm with Mikuni manifold and Montesa rubber
how to connect to the airbox? Cut the frame??	no, the local Do-it-yourself shop had a sanitary flexible plastic, 50mm
first success, everything fits and its running

I kicked the beast and it was running on 45 slow, 120 main, 1 1/2 screws mixture, clip on 2nd from top. Ok, so far, so good, but it was 20.30h and my neighbour was peacfully sitting in the garden with guests.

Next is to go with the jet-set to my training ground and try different jettings. Can I improve the risk of stalling in steep downhille sections?

16 July, warm summer day

I spent 2 hours in my training ground, optimising the Oko carb. I went down to 42 slow, but could no more adujust, so back to 45. Then went down main form 120 to 115 to 110.

I'm quite happy now with 45 slow and 110 main, clip on 2nd positiont from top, air screw 1 3/4. Pulls good, can accelerate in hills after slowing down. Next will be to compete a club trial and check the spark plug for the colour.