You can put it in from the side.
Just lever out a bush, or put a screwdriver in one side and tap out the other...
You shouldn’t t need to split the cases. Just lift the engine up in the frame till you have access...
As mentioned the diamond shape fits the pulley with the square / rectangular end as well
The grooves in the power valve aren't for O-rings, instead these fit into the ends caps as you cant refit the valve into the cylinder with O-rings in the grooves 😉
@jimmydc98 As @jimmydc98 says you would be far better off getting it TIG welded, as that would be a much stronger and more durable fix. I've used several JB weld epoxy's / adhesives and have never found them to be any good. They do not seem to stick or repair stuff as stated, so I would steer well clear of them. I have tried this stuff tho and can recommend it;
Sorry for the mega late reply on this lads, sacrificed internet for the rebuild at the time and just wanted to say (now i remembered :P) Thanks so much for all your help. got it sorted with the loctite in the end and it all worked out! really grateful for the replies. will post some bike porn soon and start getting active! 🙂
@calum old thread mate but can you use a 4fu head on a 3mb barrel? ive got a 3bn head on atm and wondering what my best option is and how much more power will i gain from a 3mb/4fu head
@challenger Typically it's Rotax Engines, TZ 250 Engines and Suzukis.
I don't recall there being any examples of road going bikes, but I read it in 2013 so a long time ago now. I have since read the collection of other tuning books he wrote, they're very good.
If the bore is OK leave it alone you just need to find the right piston. Go through an authentic dealer, also get the bore measured by an engineer so you know exactly what size you’re looking for...
Some 3bn engines have slightly different inlets, not where the manifold bolts on but inside. The internals have different dimensions that I can only guess is supposed to help flow to the ports...
@finchfocker
I know! Don’t worry! I get uppity when I drink more than 4 special brews 🤪 I was just being a dick 👃🙂 So take no notice of me after 9pm!...
We all love bikes, 2 or 4/‘s and the variety is a good thing...
@lllDennis So my rebuild consisted of Stainless as it's cheap.
I just got all the bolts for the engine from "Raceti" and that cost me £145. So it's not cheap. And I'm sure you can appreciate there are a lot more bolts than just the engine.
