New Project (Gwyns old bike)

[deano123]

as i bought it

this is as i bought it from gwyn but had ar silencer fitted as the rsv one needs re weld on the bracket. Needed a complete engine rebuild as it was making some very strange noises. Also cdi needs repair as powervalve also didnt work

started to strip is down

stipped down

exhaust has many big dent in so im going to blow these out will provide more photos of how i do this when i get to it (basically block both ends off, pressurise it , heat up the dents and most of the time they come out)

rsv exhaust

while the enigne is in bits ive decided to do some basic porting work to start with
which basically blue print the enigine to how it should have been from factory. As these enigne like most are formed from casts it usually means lots of lots of imperfections are left in the casting. These imperfections are the rough feeling you see on the outside of the engine.

What we are interested in is removing this but from the air pathways eg, transfer ports,inlet port and the crankcase (where the crank sits) also to some degree smoothing out the exhaust will also help a little but your main gain is from the others.

First thing that needs to be done is the port matching. This means matching the transfer ports to the crankcase. So bolt the barrel down to one side of the crankcase show below (make sure barrel dowl is in place)

[deano123]

you then need to rub your finger between where the bottom of the barrel meets the the top of crankcase or you could call it the gasket face. You will find a ridge and this is not good for air flow and needs t be removed, what you need for this a good rotory file or dremel, mark where the metal needs to be removed on either the barrel or case. Start of slow you dont want to remove to much metal or leave big scores in the metal and these will be hard to remove without removing more metal. Below is what my case looked like after id been over it with rotory file.

crankcase matching

After you have done this do the same with the other side.

Also take not that the base gasket will also have to be trimmed when fitted to the motor as it will overhang , it overhanges even on standard cases!!

Next step is to polish all the ports to speed up gas flow!!

[Active Rascal]

Good stuff!! Lots of pics will be great. I thought the transfer ports should be relatively rough to ensure the fuel mixes well?

[deano123]

some beleive this to be true its called the golf ball effect (pimples in a golf ball aid it through the air) but in reality it doesnt work , look in any race engine that has been tunned and you will find smooth ports. Also tried it back when i was road racing 250 MZ's on the track. As i rode for one of the tunners, so gathered and picked up alot through the years of racing them. Now racing 09 triumph daytona 675 at BSB.

Any way the smoother you can get the ports the quicker the air and fuel will flow resulting in more power through rev range and increased throttle responce.

next stage and more photos to follow

[Active Rascal]

Cracking stuff! Keep the pics coming....

[deano123]

Right now for the port polishing

Get yourself down to halfords and buy what they call the wet & dry project pack, intails a few sheets of paper of different grades. Start off with a low number paper like 300 or 400 with water thn move up the grades untill you finish on 1200 or something by this time depending on how long youve spent on them should be nice and shiney. My advice get the wifes best towel over your lap sit in the living room and watch the footbal oh and a can or larger. This can be a long and boring process depening on how well you want them.

[deano123]

[deano123]

bit more work to do to the transfer ports on the barrel but you get the picture

Right now got better pic so you can see what needs to be done transfer wise on the barrel

in the black square is the imperfections left over from the cast and these can easily be removed , but those pits or small holes in the red saure cant be removed without to much work and and not worth the effort will take days depening on size.

[back off road]

looks like the cold dark winters nights are fully booked

[deano123]

did it over xmas , just about done now, just waiting on bearings and bits from honda to turn up now