Ämne: CBW-250 Tuning :)

[strepto]

Hi!

I just wanted to share a project that I'm working on with you guys.

The SMC-250 (Barossa, Derbi, bladibladi) is becoming increasingly more popular in Europe because its road-legal. I have one myself, and its really a great ride - but it is still just 20 horsepower (if even that) and 250 CC.

Durin the past month, I've had quite a bit of contact with Wiesco about making a bigbore kit for the ATV.

These are some of the parts we've choosen for the project:

Wiesco 58mm 12.4:1 Pistons w. Hasting Rings









Upgraded valvetrain w. bigger lobes on the camshaft. Camshafts will be a regrind from the OEM piece. Lift and duration not yet published.





A new CDI system is also needed, because the timing on the CBW-250 is really fucked up. It uses 10 degrees BTDC @ 1500 rpm, and a static switch to 26 degrees BTDC on 4000 rpm. We will be making a scalable map based on the results of the increased compression. A knock sensor is also in the works.

Also - I can already provide headwork for the CB-250 engine. Using either single or dual carburators - we can improve the headflow significantly. I am waiting for a head from SMC to flowtest now on our flowbench. It will be really exiting to see the numbers. I expect the head flows like a bloated old grandma - but with some work, we should be able to see some gains.

Also - we're looking at the possibility of using a JG Edelbrock 40mm carburator for the upgraded exhaust system, to ensure good flow. This added with a portjob, and it should yield some good results! Our aim is 35 horsepower.[/img]

[bayern]

Nice post  :idea:
And welcome whith more good posts :wink:

[EbbE]

Nice :wink: but it sounds REALY REALY expensive, but its`s about time someone loked into the possibilitys of a major horsepower increase on the cbw 250. Keep upp the GREAT work!

[Anonymous]

Thanks guys!

The thing is that is isnt really that expensive. A complete engine build, with new sleeves, bore, portjob and new pistons and rods, are about 5000 SEK, or approx 450 EURO. The sleeving process is the most expensive part. The two pistons are approx 50 EURO each. the trick is to find an entire Kit we may use.. And thats my challenge

[strepto]

Okey I just got off the Phone with Wiesco in USA, and they will be able to custom manufactor pistons for it. However - I need information, and maybe you guys can help me out.

I need pictures and engine specs from the cylinder head, the engine block. I need this to figure out which sleeve design to use, and how big the bores can go. It doesnt seem like the thin edge of the cylinderwall, towards the chain, leaves much leverage for larger bore, but a stronger sleeve will compensate for that. Wiesco is still looking into alternative rods and cranks.

[Fyrhjulingpunktse]

How nice!

I think You should contact the SMC importer in Sweden, JIAB.

http://www.smcatv.se

I know he is searching for bigborekit to the CB250! I think he can provide You with what You need!

[strepto]

[ <- Edited -> ]

[smcatv]

Hej, Tord,

Du skrev: "I talked to them. They have little interest in the project. "

 
Vi har aldrig talats vid om detta, vad jag kan minnas?

Jag är klart intresserad av allt i tuning och tillbehör till SMC, satsar mycket på att ta fram häftiga tillbehör.

[strepto]

Vet du - det er mitt fel! Jeg sendte to mail om prosjektet, og fikk begge tilbake fra Mailer-Daemon som havnet i mitt spam filter. Beklager! Jeg skal sende dem på nytt i dag, og så kan dere få se!