do not try to put a 88 or 89 cylinder on a honda cr 250r 86 87 bottom end!

i tried even tho the shematics are the same the 89 will not bolt up to the 86 the valves are different and the ports are a little different and the stud bolts are shorter on the 86 bottom end

 

That is a good reason to not just look at the pictures, but to compare the part numbers. The part numbers are no where close of each other.

BUT DID IT RUN!?!?  lol

i tried even tho the shematics are the same the 89 will not bolt up to the 86 the valves are different and the ports are a little different and the stud bolts are shorter on the 86 bottom end

beleive me yet?

I told you it wouldn't.

That is a good reason to not just look at the pictures, but to compare the part numbers. The part numbers are no where close of each other.

 

That is a good reason to not just look at the pictures, but to compare the part numbers. The part numbers are no where close of each other.

yeah ur right,,,wander why they lie about the shamatics?

all yeah it will work most deff..i have to take the 2 studs out of the bottom end where the reeds go in..and put the 89 studs in..they are just a little longer..i just wouldnt recomend it..cause them studs are gonna be extremly hard to get out...but once i swap them and the valves  wallaaaaaaa  i will have it ring ninging;)

my father is a machinest..i have faith in him that he will get them out...very similar heads  just got to do alot of swapping parts to make it work..but indeed it will work

beleive me yet?

I told you it wouldn't.

 

beleive me yet?

I told you it wouldn't.

just have to swap out the stud bolts by the reeds and it will work..along with the valves... ;)  so nope! i don't believe your right ;)

just have to swap out the stud bolts by the reeds and it will work..along with the valves... ;)  so nope! i don't believe your right ;)

 

just have to swap out the stud bolts by the reeds and it will work..along with the valves... ;)  so nope! i don't believe your right ;)

i just would stick with original to avoid all the extra work and headachs and bottles of southern comfort lol

It won't work anyways the rack is different.

What are you trying to do? If your cylinder is shot have it replated. If you want more performance send to Eric Gore or someone like him. Why the Frankenbike?

What are you trying to do? If your cylinder is shot have it replated. If you want more performance send to Eric Gore or someone like him. Why the Frankenbike?

 

What are you trying to do? If your cylinder is shot have it replated. If you want more performance send to Eric Gore or someone like him. Why the Frankenbike?

i bought a 89 cylinder on ebay..i was told that the 89 cyl will interchange from 86 to 89.. it is a 86 bottom end..the spindle cam is a little different it bolts right up but the two studs on the reed side is two short so i will have to swap them out and put the 89 longer studs in it.. and the valves from 86~87 are the same and 88~89 are a little different..so if i swap the valves out as well it should work fine...and if you look up the cylinder shamatics on a 1986 honda cr250r they comferm that the cylinders are the same from 86 to 89..my hardest thing i ran into is the stud..this motor been sitting for a while and they are extemly tight..i am trying a little head..i double nutted the studs with a no go..so i am gonna try a stud puller,,,and put the 89 studs in..if i get them out..it will work....its just alot of headachs...u get ur hopes up and run into small problems..if i would have known i would have gottin a 86 cyl...i paid 250.00 for it..i wont give up till i get it,,,

blowin smoke yes ur right about the rack..but i can take the rack from the 86 and it goes right into the 89..honda did a very little difference..basically the 86 and 87 cyls were spring loaded with the hpp valves...88 and 89 was not..the actuator arm controls the spindle cam..on the 89  86 had no arm....so if i keep all original with the water pump and spindle cam all i have to do is swap the hpp valves out,,,change the studs and i believe it will indeed work..

thats the 86

csteel62_#7.jpg

In the future save yourself a HUGE amount of time and look up the part number BEFORE buying used parts especially on ebay.

 

Here is a decent link to decipher Honda part numbers:

 

http://www.scribd.com/doc/15050039/Honda-Part-Number-Understanding

 

Plenty of places online to look up part numbers such as this:

 

http://www.hondapartshouse.com/

 

You can also do a reverse part number lookup and see what other models or years a particular part number fits.

 

I would suggest you take your current 1986 CR250 cylinder, ship it to LA Sleeve and have them sleeve the motor and you will also be able to overbore that cylinder as necessary. Trying to graft a 1989 cylinder onto a 1986 bottom end is an exercise in frustration, time and money. The 1986 power valve was a one year only design.

 

Yes, you will hear people say you should not sleeve a motor but instead replate the cylinder, unless Honda revives a 2 stroke MX team a 1986 CR250 will work just fine trail/track/fun and even vintage motocross rising/racing just fine with a sleeved cylinder.

Edited by bigpaul

well guys for anyone who doubted me everything looks like it is gonna work..i have to now order the longer studs...i got the 88 crankcase cover mounted up with a 89 spindle cam and it works..i didnt even have to swap the valves..all i had to do is swap out the spindle cam and bushing and put in longer studs for the bottom end....its gonna work... :D :D :D  88 crankcase cover with the 88 parts...89 spindle cam bushing and follower and a 89 cylinder WILL WORK on a 86 honda cr 250 r :D i will send pics and video of it running..i love when people doubt me :p thanks for the advice guys..sometimes u gotta believe and not give up ;)  Rob*

..port timing is diffrent.

This things gonna " blow up " the first time you start it.

and the reason i got the 89 cyl is because my 86 jug was cracked

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