Piston connecting rod different 83-84 200x help

[Rookie]

I got a 84 200x a few weeks back and the engine is shot in it. So I got a 84 bottom end thinking I could put my 83 engine top end on it and be good. ( The 83 tranny 3rd gear slips in and out. Other then that it runs great thats why I'm taking the top end off ). When I went to put the jug on, the piston sticks above the jug at TDC. The cylinder and head are identical from the 83 and 84. I looked up the connecting rod and found out up to a certain engine number on the 83 they used a diff. rod. Well I have that engine. Its deff. shorter. Any suggestions on what to do to solve this problem ?. Thanks for any help in advance.

[Toaster556]

How far above does it protrude? I've stacked base gaskets as high as 4 thick to adjust compression or correct a shortened cylinder problem in the past. How far gone is your 84 cylinder?

[emmie357]

Can you swap cranks too?

[Rookie]

About 1/8 inch. the 84 measures the same as the 83. I've checked everything several times and come up with the same thing. I've never seen this mentioned before. Its got me stumped. I've heard of stacking gaskets but never had to before. The engine that came with it is junk. Metal chips all over the inside. I was hoping it was something simple that I didn't know about. As far as swaping cranks. I think if I was gonna do anything I would split the cases and swap trannys to the 83 from the 84 bottom end I got. I was told it was good.

[Scootertrash]

Can you swap cranks too?

Ya know, it might be just me, but...............
















That just sounds wrong....:D:D:wondering:wondering:lol::lol::lol:

[Toaster556]

Thats got me stumped too. I've been into a few 83 200X bottom ends and more than a few later models or XR200 engines, and I've never seen or had that problem with a stock engine. Maybe you have a stroker crank!:Bounce

[Scootertrash]

Yea, pretty strange

Are you sure no one tried making a Franken engine and mixed parts from another brand or engineering e?

[DohcBikes]

Measure the piston crown height at bdc and tdc. Sounds like you have a stroker crank.

[Rookie]

Well heres what I have as far as numbers go . Now mind you the way I measured this maybe unorthadox but its the only way I could think of to do it. I put a straight edge across the case and measured from the straight edge to the top of the connecting rod. 83 and junk 84 measured 56mm. Other 84 was 60mm. The number stamped on the 83 connecting rod is 448. Both 84's is 427. I don't know if this means anything but I wanna make sure I try to mention everything that I'm looking at. I haven't gotten to the piston measurement yet Dohc but I will asap. What is a stroker crank ? Better or worse ? I have no clue. Educate me please. I also looked at the pistons and they looked identical. I don't think this makes a diff. but I had the 83 jug bored 1 over. Thanks for all the help so far. Rich

[slashfan7964]

In simple terms, a stroker crank is a crankshaft with more throw that lengthens the amount of space the piston travels up and down in the cylinder. This increases displacement and can increase compression and overall power/torque. Stroker cranks are incredibly common on small block V8 engines for massive increases in overall torque output. 6mm stroker cranks are the common one for 200X engines.

[yaegerb]

Well heres what I have as far as numbers go . Now mind you the way I measured this maybe unorthadox but its the only way I could think of to do it. I put a straight edge across the case and measured from the straight edge to the top of the connecting rod. 83 and junk 84 measured 56mm. Other 84 was 60mm. The number stamped on the 83 connecting rod is 448. Both 84's is 427. I don't know if this means anything but I wanna make sure I try to mention everything that I'm looking at. I haven't gotten to the piston measurement yet Dohc but I will asap. What is a stroker crank ? Better or worse ? I have no clue. Educate me please. I also looked at the pistons and they looked identical. I don't think this makes a diff. but I had the 83 jug bored 1 over. Thanks for all the help so far. Rich

I doubt its a stroker crank. Stock stroke on the 84/85 is 58MM and I am pretty certain its the same on an 83. What I have typically seen are 6MM cranks which take your stroke to 64MM. I highly doubt someone with through the trouble to relocate the crank pin for 2MM. Sounds to me like something else is fishy.

[greenhuman]

Stroker crank.
The pin is only moved 3mm on the crank to get the 64mm stroke. 3mm up, 3mm down. it's a very good thing to have.
All the 200 rods are the same length. Some are wider at the big end such as the xr200 and some 200x's. They should have 446 on the rod. The narrow ones use shims at the big end and should have 427 on them.
The only 200 rod I have seen different is the shortened Powroll rod. Curtis Sparks used long rod strokers.

[yaegerb]

Good to know the stamped numbers. I stand corrected.

[yaegerb]

Looks like you need a spacer plate. Shortline10 might be able to hook you up.

[Rookie]

Greenhuman if I understand you correctly, the 3mm is the measurement I have for the piston sticking above the jug. The measurement I have with the piston all the way at the bottom ( I think thats what Dohc meant ) is 6o- 61ish mm. Sounds like what your talking about. I got the number wrong on the 83 rod, its 446 and has no spacers. They changed it to 427 after my eng. number. I got a pic of the piston sticking over.201179 So I guess I need A spacer ? Won't that mess up my top motor mount tho ?

[Toaster556]

Is that 60-61mm from the gasket face? Can we get a picture of the crank with the cylinder off? Id like to see the crank wheels if possible too, a shot down into the crankcase hole with your flash on should suffice.

[Rookie]

Thats without a gasket. A pic comn up shortly.

[Rookie]

201184201185201186201187

[Rookie]

I hope thats what you were talking about

[shortline10]

You have a long rod stroker crank , pretty rare , It will require a spacer under the cylinder and possibly a longer timing chain . If its to much for you just send it my way ill trade you for a stock crank lol .
Nice find BTW !

[Toaster556]

I concur. There may be an alternative piston that MAY work with the stroker crank, I'll get back to you.
I've heard Shortline does good head work, might be time to build the motor up

[greenhuman]

You can run a 1.5mm spacer with a stretched cam chain and machine 1.5mm off the piston lip leaving the centre alone. increase the valve pocket depth and you will end up with high comp piston.

[Rookie]

Wow. My head is spining. Everything you guys mentioned is wayyyyyyy past my grade scale. All I wanted was a good running stock engine. I've got some decitions to make. I wanna thank everybody for all their help in figuren this thing out. Again Thank You. Rich