200 cylinder to small block conversion?

[EddieStone]

I was interested in doing this for my chop as it's an easy bolt on increase in power. One problem is finding an untuned 200 cylinder. If it's stage 4 tuned there's a possibility that you can break into a port drilling out the stud holes.

It's a neat and cheap solution for increasing the capacity of a small block engine, but future tuning options are limited.

[shocky]

I have done loads of these including a 200 Rapido and a Autisa short stroke !
Use a 150 head and get it reprofiled or it wont line up to the bore correctly !

I've had bash at this myself,well,not all me,I had a mate do the lathe work,but there looks to be an overhang of the mag side transfer port,is there a way you overcame this,or did you not have this problem?

Thats been my main concern ive though about machining3 mm from the base and adding a packer with a tapered transfer port but then its just getting complicated

[HxPaul]

Why not get a 200 kit for a small block motor.

[shocky]

Why not get a 200 kit for a small block motor.

Theres a massive diffence in price from the budget kits to the GT, BGM, RT, CASA OR MUGGELO ones x 3 at least , im asking becose im working with a friend (motor mechanic and scooter rider for 30 years) on his engine his previous 185 kit ran like a dream for over 5 years but he wanted more after a stone entered the carb andtrashed the top end .
a 200 kit was sourced which had been fettled by the dealer all looked about as ok as these later kits do
however it will not run or even jet in properley dispite having changed the carb for 3 working ones off 2 diffent makes the cdi unit the stator the seals and now a new mecrace crank !!! .
So a known running top end has kindly been stripped of a friends engine fitted and works amost perfectly on out of the box jetting, we refitted the 200 and pressure tested it and it s leaking around the studs the 175 held pressure for over 10 mins , we were looking for a low cost viable option for his scooter without having to go the LI150 bored to 175 cast option or trying to get a proper tv 175 ora decent gp 150 as they seem to be like hens teeth

[HxPaul]

Complete small block cast iron 200 top end.
http://www.ebay.co.uk/itm/161963309906? ... EBIDX%3AIT

[shocky]

Complete small block cast iron 200 top end.
http://www.ebay.co.uk/itm/161963309906? ... EBIDX%3AIT

Thanks for that but the quality ofthose is unknown and you might ge thit with shipping tax and im guessing the chance of retuning it if its faulty is pretty low

[Lamaddict]

I would think those Indian kits on eBay have had the stud holes drilled out and the neck of the barrel turned down to make them fit into a 150 casing. I've only ever done this conversion myself, so someone in Indian might be able to do a better job of it than me in my garage etc.