A few r motor questions. For the gearheads

[ATC-RYDA]

So i have begun a small winter project of reviving another 85 R motor, and i am just torn about what type of top end i would like to go with .I first thougt i'd just snag a nice new top end kit on ebay maybe a 265 or so but after seeing some of the prices I quickly started giving the original cylinder a little more thought. The motor is a 85 so the crank is a short rod crank , now i was thinking i'd just get a mild port job done to her and use a spacer plate and go with a 87-89 style piston. My question is if I where to do that would that set up be okay ? I was under the impression that when using the spacer plate you needed a different style port job for port timing , but again after searching ebay it seems as though alot of those folks are selling kits with original cylinders and spacer plates.So if this is possible what size plate would i use ? Also would I still use the short rod or replace it with a long rod crank,what configurations work together ? And what are the size lengths of the two rods? So i can check what I have or know what i may need.Another question is I planned on getting a coolhead for the motor so what size cc dome would be in my best interest with that setup and pumpgas?

Any input and advice would be greatly appreciated as i am preparing to get some things ordered so i can get this thing off the bench and back in the bike .. THANKS !

[cr480r]

i thought the spacer was for using a '86 piston with a long rod?

[ATC-RYDA]

it very well may be , thats what im trying to figure out myself

[Jason Hall]

Yes, the difference Is the rod length. IMO you want to use the correct piston for the cylinder. I'm sure LOTS of people have mixed cylinders and pistons without problems! I just feel that Honda desighned the piston to match the cylinder change In 87. The rod length Is a little over 5mm longer In 87-89, 5.3mm to be exact. If your wanting to make a change, I would change the crank to the long rod, and use the 85-86 piston to match your cylinder. In that case, you would want a .190 thick spacer. The only time you need to play with the port timing's Is when you use a stroked crank. Just adding a longer rod does not change the stroke, just the rod Is longer not the offset of the main crank pin. The longer rod will add Torque, and thats a good thing for the R IMO.

[200xranger]

i am running an 86 motor with the 87-89 long rod crank and spacer plate just like you are saying. my piston is an 86 along with the cylinder. i have been running it since last year with no problems. i havent done any porting on mine though. my research when building my motor found that the racers in the 80s ran this set up for more low end and longer top end life. good luck!!! hope this helps

[ATC-RYDA]

Thanks guys that helps a lot .One other thing that im looking for is transmission bearings main/countershaft and drum bearings . Does anyone have these parts? Im looking for new stuff , and couldn't seem to find any on ebay. Are these parts still available from honda ?

[ATC-RYDA]

also im in need of a impeller bearing and a counterbalancer bearing ..If anyone has some or all of these parts or tell me where i can get em it'd be great ... THANKS !

[bkm]

Short rod vs. long rod, can almost as ugly as the 250r vs. Tecate thing. I personally would stick with the short rod and use the 85/86 piston. I like the way it revs and with an ATC torque is the least of you concerns, plus you don't have to split the cases. Honda went with the longer rod in the TRX because of the added weight of the extra wheel and front suspension. I don't buy into the longer life thing there are many original piston 85/86 bikes still roming around. But to each their own if you ask this question 10 times, you'll get 10 different answers. Guys also used the '86 piston in the long rod because it has more choices for an overbore vs. the 87-89 piston.

[Mosh]

The water pump parts are only available from Honda.

The large counter balancer bearing behind the gear can be purchased from All Balls.

There are 2 smaller trans bearings the number is (6203). these can be bought anywhere at Napa or other auto stores.
But get good ones..They will cost about $20 a pop. The brand was SKF. You will need them with only one sealed side, or you can remove one of the seals if they come with 2 seals.
I dont recomend anything but OEM trans bearings, but the number I listed should be ok if you buy the good ones.
They make them as cheap as 5 bucks each..Don't buy those.This will be the first time I run aftermarket bearings in a R motor. But I have to do it just to find out how good they will hold up..
Eventually Honda will discontinue those bearings, and may as well start finding good replacement parts now sooner than later.

[NOS_350X]

I would not recommend a spacer plate unless you must do it, IMO It adds too much crankcase volume, I also feel a short rod revs much better. But thats just my oppinion, My fastest bike is a short rod, but thats not a stock cyl, my fastest stock cyl is a long rod, Just depends on the proper setup. Porting will set everything more than anything else.

[leviblue]

run up to Service Specialites and talk to Ken or Rod. They have all the stuff for your R build. Those guys can really work an R motor and point you out in the right direction. Too bad I just gave-away a butt-load of bearings and other motor parts

[ATC-RYDA]

Yea i may do that levi and thanks for the advice guys , Does anyone know what type of coolhead would be best ? I think i've decided to go with the longrod and spacer just as Jason Hall had suggested ... Also i'll be running 93 octane fuel so what cc dome would work best for the setup ?

[ATC-RYDA]

Oh a couple other small items im in need of . A clutch cable stay to go on motor, and the small elbow nipple for crankcase ventilation , some nice polished ones would be great ! Let me know what you have guys or where i may be able to pick up these parts and i'll go ahead and post a wanted add over in the classifieds for a few small parts like these THANKS A BUNCH FELLOWS !

[ATC-RYDA]

Another thing , i was planning on using a v-force 3 reedcage , is that a good option for this perticular set up ? Is there something that may be a little better? Also not really sure about what size carb to run so a few suggestions there would be great as well.

As i was looking into pistons i came across the wossner kits , does anyone have any experience using those ,and how is there quality? Or any suggestions of what would be best

[bkm]

I always like using the old Boysen Rad Valve with the stock old fiber reeds(not carbon fiber). You can pick them up for next to nothing and the replacement reeds are like $20.

[ATC-RYDA]

any suggestions on a carb here ????

[ATC-RYDA]

still looking for a counter balancer bearing and clutch stat ... any one have these or know where to get em ????

[ATC-RYDA]

please !! any help and or advice would really help !


THANKS

[bkm]

I ran a 39mm pwk on my ported 250 and it loved it. But it had around 210 psi and I ran it on 110 octane. I think you would be happy with a 38mm.