Messages

Bought a third set for $76.00 and got a $40.00 refund on the 2nd set, so I paid $96.00, $37.85 and $76.00, $209.85 plus tax for 3 top ends. I haven't dial bored any of them yet, just put them on the shelf for now. I did notice the external portion of the casting above the T2 ports will need to be built up with weld for serious porting. Mark, the drop of several mm below BDC in the liner at T2 won't be a problem, in the 70"s we would intentionally lower it under the impression it helped torque, oh well, times change.

I hope I didn't waste my money but I just bought a second set for $78.69. How can I pass that up?

I just took a chance and bought a set. Late summer or fall I'll see how they like some porting and a decent spray of nitrous. I already have a crank built with Banshee rods and ceramic bearings, 39.2 carbs, big reed cages and a couple spare bottom ends just laying around and a pair of Pro-Flo pipes hanging in the dyno room. I'm in the process of messing with a 400 frame and building a long arm with struts so I'll have a place to put it. There is a 1/8 mile drag strip close by to run it. Hey, even if it blows up while testing on the dyno the cost won't hurt too bad. 

If you are still looking for heads I have a pair of R5 high compression and high torque that CC'd at 20.5cc each, $100. plus ship. All fins and chambers are good. Outer fins need rubbed on and then fresh paint.

I think I have a matching front fender with questionable paint condition. Also have quite a few engine parts, frame etc. Also, I can give you porting tips if you end up going modified.

Did you pressure test the engine prior to starting it?

I use multiple engine/porting programs daily. I started in 1993 with SAE's attempt to rewrite Blairs into dos then Tom Turner made them his TSR's programs and I got them as soon as they were marketed (maybe 1995 or 6 or 7, don't remember) then got Mota, never liked it, then numerous others. I still use all of them except Mota because each one has something to offer. In early 2007 I leased ENGMOD2. This program is the best I'm aware of but the damn thing will drive you out of your friggin mind playing "what if", it is not for the beginner and most new users give up, start with a couple programs that are not as good but will get you exposed, yes they may have faults but will teach you some basics until you're ready to advance.

I have been using a Motion Pro 2 stroke pressure tester for 20 to 25 years and hundreds of times. Last Friday it failed to create pressure, the check valve was just plain wore out. Monday morning I called to order a replacement part. Larry Snyder in tech, one of the nicest guys you could ever deal with, instructed me to email the warranty dept., bottom line is after decades of use, hundreds of times, Motion Pro has shipped me a replacement free of charge and no shipping charges. Thank you Motion Pro.
John Ritter

Noguchi built some great pipes. I'd love to have that one for my RD60

**** Single and twin persons have been selected. Thanks to those  that inquired.

I'm looking for 1 person to tutor doing their own Stage 1 cylinders in their own garage with their own tools. I'll take you through step by step at your pace up to 3 months. Most Q&A must be by phone, I'm not going to be a pen pal. I'll supply some written instructions, diagrams, print outs, examples etc. We will cover modifying the intake ports, reed valves, liners at transfer entry, transfer ducts, transfer windows, boost ports, exhaust ports, pistons, squish clearance and angles, head cc's, compression, timing etc. If you intend to modify the heads, you will most likely need an outside machining source.
Selection of who I help will be made after discussing your project. Message me through the forum.
My input and time are free but you will need to donate $25.00 or more to support the forum before we start.

Yamaha Enduro Singles, If you have an air cooled single, any size, that you would rather do, I'm open to discussing it.
John Ritter

 

Oxford, I was raised in PA and put thousands of miles in trail and woods riding 1st on a 73 DT250 and multiple years of Yamaha MX & YZ bikes 125,175,250 and 500cc. The 1975 DT175 is one of the best looking Yamahas from that era and weighs about 50 pounds less than the DT250. 50 lbs at the end of the day is a killer but it is also 7 or 8 hp down on a 250 which shows on steep long hills. Dragging a bike back on course after you blew a turn that is packed with an extra 20 pounds of mud needs to be considered also, assuming you are doing mostly trail riding. My 2 favorites for trails were modified 1976 YZ175 and the 1974 SC500 but in the 70's and 80's we didn't have as many regulations then.

Joe, I was only suggesting a possible build combination, I have to pass, I'm finishing up odds and end customer jobs, not taking on anything new. I have several personal projects of my own I'd like to see completed. One is a stroked GT80 for our RD60, a very intense 175 drag engine, revamp the current 175 drag engine for nitrous, reassemble our RD400 land speed engine and dyno build pipes for it, finish the land speed FJ1100 chassis and build a 400 bottom with sleeved and injected R5 with a  Procharger engine and my son reminded me Monday I promised him a 522cc build for our street RD400, I better live to be 100 because at the rate I'm going it will take until then.

rearwheelslider, we have a RD400 that is ported and piped and our street engine runs modified VM28's. The roads in my area our somewhat hilly and twisty and the 28's work great.

JR, last year when we discussed this if I remember correctly you were adamant about using the R5 bottom and exactly 410cc and finishing in 2nd place was out of the question, this required bore/stroke/rod changes, dyno time, crank balancing etc making for a costly build. Now that I see you are allowing a 400 into the mix a much more logical build is possible, by the way, do not short rod the 400, go 120 or maybe 122 to 125. You are running in the dirt and a short rod might cause wheel spin, you need to hook up right out of the hole. My first thoughts without studying it would be 2R9 cylinders @ 64.75mm bore, crank build, porting, 40 Lectrons, 6 petal reeds etc.

Might want to consider the rod/stroke ratio if for street. You would be going from an already 1.85:1 to 1.77:1, no problem on a well maintained race setup. Just a thought.