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Discussion Starter #1
Hi everyone,

Im a lil lost...

I have 2 250R's that I am going to make one good one ouyt of (Building the 88)

Okay... On the 88 I have a motor with a 5mm spacer plate under the cylinder so I have heard before that that means I have a long rod crank which is also what is a stock crank in a different year in a different motor (Okay... Im confused on the year juggle)

Here's the deal... The 88 needs a crank... I also have an 86 or 87 motor (not exactly sure) and I think that the crank in it MIGHT be good... Is it worth tearing into this other motor to go after it's crank?? Is the 86/87 crank what I am looking for if I want a long rod?? What if I were to just order a new crank from somewhere like HotRods?? What year do I tell them to go with this 5mm spacer plate??

Also... Way back then... Were these cranks "Tin Can" cranks such as in a new CR dirt bike or does the 88 i am working with have something special about it??

Sorry about all the questions in one post but if someone could be so kind as to provide some insight on all of this I would be super appreciative!!

Thanks a bunch in advance!!
 

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You will need to determine what year your engines are. The 85-86 engines are short rod cranks and the 87-89 are long rods. All years came with “tins”…

Having a spacer plate does not mean it is a stroker crankshaft, it could have been built or ported to require a 5MM spacer plate. It could also be an 88 Long Rod cylinder with an 85-86 piston kit…this is the likely scenario.

Post some pictures and look at your serial numbers, 86 TRX250R engines start with 1000XXXX, 87 with 8000XXXXX, 88 with 8100XXXXX and 89 with 82000XXXX…

Hope this helps,

Carlos.
 

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cases are also diff colors from year-year. 86-87 grey and 88-89 black if im not mistaken
 

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i wouldnt rely on the case color too much. if you post some pics of your engines we can tell you what cylinders you have 85/86 were different from 87-89. the plate maybe there because you have an early cylinder on a later bottom end
 

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PLAYTIME'S OVER BITCHES!!
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please keep the B.S post out of this thread. (there arent any now, just sayin)
im going to sticky this because i think this could turn into something very informative for other people. including myself.
 

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Discussion Starter #6
Hi everyone,

I am still at such a loss as to where to begin... Pics, Numbers, Colors etc... LOL

I dont have any pics "Yet" but was wondering if some of ya could look me up on Facebook and I'll gladly accept your friend request then we can all share notes that way.

If you look me up via Stuart Kaufman (look for a trail marker arrow pointing at about 5:00) I'll probably see your notif almost immediately.

Thanks a bunch everyone.
 

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Since this is going to be a sticky, it would really help to add some pics man. I urge you to do so.

(hope this isn't a BS post hehe.)
 

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PLAYTIME'S OVER BITCHES!!
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I just wanna ride!!
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As for the videos, Rusty is a very knowledgeable guy. He's a member over on atvriders. There is a lot of variables when it comes to these motors. Like Carlos said, the '86 featured a "short rod" crank, and '87-'89 had the long rod crank. The long rod is NOT a stroker, it just has a longer rod which is said to put less stress on the piston and cylinder.

When it comes to buying a crank, (I believe) you can only buy long rod cranks now. A know a few guys have a few OEM short rod cranks laying around.
 

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Discussion Starter #14
Ok... Now Im confused at to which way to go.

What exactly do ya'll think is the better way to go?? The long rod or the short rod?? I have a motor with a long rod and a spacer plate but it needs a crank and I was thinking of getting a replacement 87-88 crank (which from what I understand is a long rod) but I also have a motor with a short rod and I think the crank is good in it and now Im confused...

Should I use the Long Rod setup or the Short Rod setup??

Oh Yea... Both motors have the 85-86 cylinders (non-bridged intake port) and one cylinder looks to have been heavily massaged so naturally Im gonna be wanting to fit a piston to that cylinder but Im lost on which way to go with the cranks.

What are the pros and cons of the long rod vs short rod??

Which makes more power?? (Long Rod??)

Which is generally all around best to run for a lil woods racing and as a good bike for trail riding etc while still making arm straightening power when the trigger gets pulled?? Long Rod vs Short Rod dilemna it is it is...

Some input on this will be greatly appreciated

Thanks again everyone!!
 

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I just wanna ride!!
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To be honest, I don't think you're really going to notice any difference. I could be wrong, and if I am, someone can correct me. Like I said earlier, the long rod is said to put less stress on the cylinder and the piston. I've heard some guys say that the short rod will turn more RPM's.

Carlos, I didn't think Hot Rods still sold the short rod crank.
 

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Hmmm... Could it be that the short rod will spin up quicker for more instant power right off the bottom??
Like I said, I think if you had a 250R with a short rod crank and you rode it hard, then take the same motor and install a long rod crank and you not knowing which one was in there........you wouldn't notice a difference.IMO
 

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pretty much yea u wouldnt notice a differnce its all the same buy whichever you can afford and ride
 

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Personally I prefer the long rod 1987-1989 motor, there is no power difference but the motor doesn't feel like it's revving to the moon with the long rod. And cylinders also prefer 1987-1989. Reason for that is the bridged intake side, the piston has more surface to contact while piston is moving up and down giving it more stability with that extra bridge. Now those are my opinions and what I prefer thanks, Mike.
 
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