opinnions pc2000 cylinder bore

[Honda 250r 001]

First off is nykasyl that good? How many hours on a bore? I mean 200 bucks to get a cylinder niked does it really last 4 times as long? 50x4=200 to make it worthwile.

I have had this pc 2000 cylinder with a broken sleeve setting on the shelf for a while. And im finially gonna stick a sleeve in it. The problem is i need oppinnions on what size piston to use in it. Should i try to get a 66mm bore piston so i have a bunch of bores or should i go wit the duncan origininal 68.50? Another option is going with the monster 69.50 piston and niking the cylinder. Do you think this cylinder being a big bore would make more power if i would run a bigger piston? Another option i thought of is getting it niked and using a wiseco racers choice 68 piston and having a ultra long lasting bore. Can i even use a standard 250r piston or do i have to have some special duncan piston?

how much lighter is the 69.50 piston compared to the 66? would i be better off for low end having a light piston or does it make that much difference?

i assume the port work and everything is very similar on the 275 but with a bigger bore. So do they make any more hp than the 265?

Also do you guys think this would be a good set up for mx/trails? Im planning on keeping my ct 310 for top end power and the duncan as a more bottom end midrange cylinder for the winter when i ride trails...





SORRY THE SECOND SET OF 68.50's IS SUPPOSE TO BE 69.50! THANKS. IF A MOD COULD FIX THIS FOR ME IT WOULD BE GREAT.

[86 Quad R]

before i can comment on anything i'd need to know what the port configuration is on the cylinder. does it mimic the 85-86, the 87-89 or is it duncans own layout? i am not familiar with those cylinders other than they are nik'd, aluminum bore.

[Honda 250r 001]

i believe they used the 86 style piston.

Its similar to the 86, but it has no exhaust bridge, and secondary exhaust ports.

[86 Quad R]

ahhh yes i remember this cylinder now. seeing a pic of it jarred my memory...... with that skirt broken off you have your hands full and any route you go is going to empty the pocket significantly. whether you have the bore punched out and a new aluminum sleeve installed or have the same done and a cast iron installed. on top of that you'll need to have everything port matched again. theres no inexspensive way out.

i've actually had oem cr, tecate and yz aluminum nik'd bore cylinders punched out and installed la sleeves cast iron replacements with great results.

i personally would either contact la sleeve and see if they have a iron sleeve avail for the duncan cylinder(appears to be similar to the ole cr layout but, coud be wrong) and go from there. if all works out i would start with a stock 66mm bore. thats juss me tho:cool:

[Honda 250r 001]

Originally posted by 86 Quad R
ahhh yes i remember this cylinder now. seeing a pic of it jarred my memory...... with that skirt broken off you have your hands full and any route you go is going to empty the pocket significantly. whether you have the bore punched out and a new aluminum sleeve installed or have the same done and a cast iron installed. on top of that you'll need to have everything port matched again. theres no inexspensive way out.

i've actually had oem cr, tecate and yz aluminum nik'd bore cylinders punched out and installed la sleeves cast iron replacements with great results.

i personally would either contact la sleeve and see if they have a iron sleeve avail for the duncan cylinder(appears to be similar to the ole cr layout but, coud be wrong) and go from there. if all works out i would start with a stock 66mm bore. thats juss me tho:cool:

well i believe the first generation of this cylinder had a iron sleeve in it. I wonder who would have a replacement one of those though? Because when i called duncan about it they said they would have to use a blank sleeve?

[86 Quad R]

la sleeve is by far the largest sleeve distributor out there. i'd call them and see whats avail. when you talked to duncan was did they say if the "blank" sleeve cast or aluminum?

[Honda 250r 001]

well, you know im not sure! i dont think i ever asked him, i assumed he was talking iron but now that i think harder i bet he was thinking of putting another aluminum one in there. Well what should i say when i ask la sleeve? just ask if they have a sleeve for a duncan pc20000 cylinder? or ask them if they have blank sleeves?

Thanks

[Honda 250r 001]

more pics.

[Honda 250r 001]

are you serious? NO one has an oppinion!

[86 Quad R]

i've stated my experiences with aluminum bore cylinders versus iron sleeves and i've had great results. it's obvious that you have a few options. you can either a. contact duncan about fixing the existing aluminum bore or b. contact la sleeve about a replacement iron sleeve(whether it be a blank or a matched or c. contact a reputable machinist(one that knows his way around these things) and have them fix it the best most cost effective route. just how serious are you about getting this fixed? pm me!

[Honda 250r 001]

Originally posted by 86 Quad R
i've stated my experiences with aluminum bore cylinders versus iron sleeves and i've had great results. it's obvious that you have a few options. you can either a. contact duncan about fixing the existing aluminum bore or b. contact la sleeve about a replacement iron sleeve(whether it be a blank or a matched or c. contact a reputable machinist(one that knows his way around these things) and have them fix it the best most cost effective route. just how serious are you about getting this fixed? pm me!

another company i been thinking about was us chrome or somehting like that. they can replate over iron sleeves. pm sent