TZR400
Moderator: rztom
TZR400
Hello - a little intro. My name is Jim and I have built a 390cc TZR. I used a pair of DT200 (3ET - case reed induction) cylinders. I am considering an upgrade to WR200 (3XP) cylinders. Has anyone on the list built an engine using a pair of 3ET and a pair of 37F (cylinder reed induction) cylinders? If the engine was not stroked it would be about 680cc's. The Crankworks stroked my crank to 56mm's but that is the absolute maximum. I read on the list where 54mm for the RZ5 motor is not uncommon?
Hi Jim,
It's impossible to find 37F, 1TG or 2LR cylinder from a DT200. It was not sold in europe.
But if a couple of cylinders could be find, it could be a very interesting mod for rear cyl., even if you mod cranks to increase stroke until 54mm. Without stroke increase (50mm), I think it could have big issues for exhaust and transferts port diagrams (designed for 57mm stroke).
Franck
It's impossible to find 37F, 1TG or 2LR cylinder from a DT200. It was not sold in europe.
But if a couple of cylinders could be find, it could be a very interesting mod for rear cyl., even if you mod cranks to increase stroke until 54mm. Without stroke increase (50mm), I think it could have big issues for exhaust and transferts port diagrams (designed for 57mm stroke).
Franck
All I can find for info, since the DT 200 was never sold in the US I can't bring it up on the Yamaha online microfiche. It isn't listed there anyhow.
here is the case reed 200
And here is a piston reed 200.
Now if anyone knows if these two motors share the same cylinder bolt pattern and bore and stroke we might be on to something. 680cc...
here is the case reed 200
And here is a piston reed 200.
Now if anyone knows if these two motors share the same cylinder bolt pattern and bore and stroke we might be on to something. 680cc...
DT200's
There are at least 4 variations of the water cooled DT2XX - 66 x 57. The 37F (cylinder reed), 3ET (case reed), 3XP (case reed - triple exhaust) and the DT230 (case reed - long stroke). The hold down bolts are not exactly the same as the RZ5. The side to side spacing is the same, but the rear studs are rearward about 4-5 mm's. The water channel at the front of the cylinder lines up well enough - no modifications necessary there. I am using a crank stroked to 56 mm and 110 mm rods. The DT200 was never sold in the US. The US got the tail end of the run named WR200 (3XP). I suspect that with a 54 mm crank and cases modified to reed induction a quite nice 750 could be built. With 34mm carbs - 140 HP should be very do-able. My 390 makes 70 HP at 10,000 RPM. Sorry - I would be inserting images, but haven't a clue how to do it.
Hey thor500 - welcome to the group, Jim!
Follow this link for an FAQ on posting pictures... Adding a picture to your post/reply
Follow this link for an FAQ on posting pictures... Adding a picture to your post/reply
Jim, being down the road you wish to travel it looks like you have found some good options (case reed and piston reed) for cylinders, but why not go with sleeving a 500 cylinder? I am sleeving some now to 64mm and at that size (2.520) the old sleeve finally came out, you eliminate any machining to the 500 cases all the water cooling goes right back on, if you wanted to you could still have power valves, if you stroked your stock crank to 54 put a 1.5 mil spacer plate under the 500 cylinder's run 795 MO Wiseco pistons you will find the piston would be right at TDC and your going to have 694cc's, run a stock crank and you'll be at 643. once you pull the stock cyl out to the new sleeve size the transfers are to low so its perfect for making a big bore and there is room for a triple port ex too. I am going to have some spacer plates made for my 54mm stroker crank and if you want I'll have some extra's made, I would think a DT 200 has some pretty lazy port timing anyway so you would have to redo that anyway and if you want to run 34's I have some intakes for 34's but they are for the stock 500 cylinders and I have a head that has removable domes for the 500 cyl. that will go from 130 to 180 PSI. and will allow a 66.5mm bore. Let us know your thoughts keep us posted
I thought hard about sleeving the cylinders, but think that the transfers are a bit small even for 125 cc's. Look at the base gasket for a late model RS125 and bottom of the cylinder for a TZR125 3XV.
Then look at the base gaskets for the 2MA - top and DT200 - bottom.
It seems to me that the extra displacement of sleeving the stock cylinders would indeed net more HP, the additional transfer area of the 200 cylinders would better leverage the added displacement.
Then look at the base gaskets for the 2MA - top and DT200 - bottom.
It seems to me that the extra displacement of sleeving the stock cylinders would indeed net more HP, the additional transfer area of the 200 cylinders would better leverage the added displacement.
The TZR engine I built with the two DT200 cylinders nets out at 70 HP / 10,500 RPM. The port timing is unmodified only corrected to accommodate the 56 mm stroke (standard is 57). The ports are internally "cleaned up". The exhaust port allows for 200 degrees of duration with the PV full open. I start to open the PV at 5000 and it is fully open by 6000 RPM. I think the TZR gearbox would allow a narrower power band. I suspect that the TZR reed valves have a bit more tip area than the RZ5 reeds. Can TZR reed cages be fit to an RZ5? I like the idea of a 140 HP RZ5 motor.
Changing the TZR motor to accommodate the DT200 cylinders was not easy.
The cases needed to have the rear studs moved rearward and additional aluminum added to provide a bigger foot print for the big cylinders.
Of course the stock heads were not really a practical consideration.
The cylinders were a bit too wide to sit side by side. First they had to be machined and then the water passages welded shut.
The PV connection is special as well. (Sorry no pic of that!!)
The head is cut from billet with dome inserts.
With this project I was hoping to get to 80 HP at a piston speed that provide reasonable reliability on the street. I am still running the Jolly Moto 250 pipes, but think that a better pipe design and a bit more exhaust time area will get me to that magic 80 number.
The cases needed to have the rear studs moved rearward and additional aluminum added to provide a bigger foot print for the big cylinders.
Of course the stock heads were not really a practical consideration.
The cylinders were a bit too wide to sit side by side. First they had to be machined and then the water passages welded shut.
The PV connection is special as well. (Sorry no pic of that!!)
The head is cut from billet with dome inserts.
With this project I was hoping to get to 80 HP at a piston speed that provide reasonable reliability on the street. I am still running the Jolly Moto 250 pipes, but think that a better pipe design and a bit more exhaust time area will get me to that magic 80 number.
Very nice project.
Have you seen
http://www.rgv250.co.uk/forums/index.ph ... dt200&st=0
I wanted to do something similar with the TS200R cylinders, chopped up YPVS +4mm stroker crank and an RGV engine, but time, money and life got in the way. <sigh>
Have you seen
http://www.rgv250.co.uk/forums/index.ph ... dt200&st=0
I wanted to do something similar with the TS200R cylinders, chopped up YPVS +4mm stroker crank and an RGV engine, but time, money and life got in the way. <sigh>
Two stroke lurker