Yep good point RZR a little thing like matching the ports(blue printing) is often over looked and so simple to do,, same with the cylinder base gasket they all need to be trimed/matched for good flow. A proper trimed base gasket can yeild 1-2 hp alone with matching ports ,,knife edge the intake bridge and 2-3 more hp with the bottom matched.Them motors wernt hard to get a extra 5 hp out of just by blue printing the motor from the intake to exhaust.

This should be a very nice finnished project with all the new NOS parts

Just in case you don't know how or what blue printing is ,,it's simple just get blue tool makers ink and assemble everything where the ink dosent make a imprent then it needs to go/ be matched small amount of work = big gains

Trim the base gasket to match the port openings.

Then transfer the base gasket to the case. Trace the gasket on the top of the case. Some layout dye will help.

Take a dremel with a carbide cutter and cut to the scribed pattern.

It's not to hard to do. Very worthwhile.

I dunno. Not sure I'd trust myself doing that.

I can't do it now anyway engines back together.

Next time.

If you ever want to try it, I'll walk you thru it.

I've literally just sent barrel to be ported. WIthout the crankcases being done it's pointless I take it? It's for my TZR 4DL project.

No problem, they can be done separately. There are hp gains to be made in both places.

Any 2 stroke can benefit from it. There is always a mis-match when parts are cast. When the case is not 'matched' to the cylinder, the flow becomes turbulent where the base gasket sit. There is not a smooth transition at this point because the base gasket protrudes into the transfer port. By making sure everything is matched, you get smoother flow. Smoother flow means a better charge. Better charge means more hp.

If you can do the work yourself, it's free hp

Yeah that makes sense rz

I've literally just sent barrel to be ported. WIthout the crankcases being done it's pointless I take it? It's for my TZR 4DL project.

Nice bike BTW. I'd like to see some pics of it. Always love seeing those smokers. Especially Yamaha ones.

Haha, Unfortunately It's not a 4DL bike. It's just the motor that i'm dropping into a Yamaha DT125RE that I supermoto'd using Aprilia RS125 Wheels and WR450F forks.

I've got a tasty little mod being hand made as we speak. Should look to get it on in a couple of weeks. Very excited.

That's a cool build. Kudos for the work that you've done so far.

did the port matching on the Gilera, 1 hp extra on that is like 15% of total HP

That is a massive gain drewps,,, .shall it be fit for foamys DT50 in a drag at squires..

That is a massive gain drewps,,, .shall it be fit for foamys DT50 in a drag at squires..

still got to get it registered then fit the spanny and then dial in the carb settings.

not sure if I'll go on it, I'll see nearer the time

He Jeff the bridge in the cylinder port ,,,knife edge it up about 3/16th of a inch and finnish up your porting with a 80 grit finninsh stone you will have to keep it oiled and work at a slower speed RPM wise so it dosent plug up with mettal but it more free hp. And its easier to see any low/high spots you may have created in the roughing stage basicaly your at a stage 2 port now stage 3 is all the stuff I said above

Hey Flip, I was thinking about the knife edge, but there seems to be a big debate on the RZ forum over it. A lot of the more expert tuners are saying that the knife edge was the NOT the way to go. I had always thought it was better. They are saying that a rounded edge is better. I just left it rounded as I wasn't ready to commit to the knife edge - I can always knife edge it later. Harder to put material back on than it is to take off.

I also need a 90 degree grinder. I need to get in the areas where the ports enter the cylinders. Just need to clean more of the casting flash better.

Good tips though.

ER Um we just jacked his thread ask me on your build I want to see how this turns out

Sorry about the slight hijack Stevec. All applicable points that apply to 2T's

Cheers Rez. I'm waiting till I can get my hands on a car so I can take it off the road properly.

Hi all, sorry it's been a while. The build has progressed slowly and had to stump up some cash :-(

Gearbox components went in

To be fair that was easy but I had bag and tagged everything. Next thing was to drop the crank in

I Yamabonded the crankcase half and put the 2 together and torqued up

Time to start fitting the outer components

Clutch basket on

Electrickery on

Then disaster struck

Decided to bite the bullet and bought one of these - hmmmm billet porn :-)

Hardest part was drilling off the old gear ring without wrecking everything but that was successful

Fitted back on engine

Sorry about the pic heavy post, I'll put the others on shortly

Cheers

Steve