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Discussion Starter #1
Does anyone recognize this cylinder?? It came with my R and i have no idea what in the world its off of, or if i should run it?




 

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looks like an old CR cylinder, i could be wrong here, but it also looks like a mugen cyl????
 

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It's a CR250R HPP (Honda Power Port) cylinder. I know what it is, but someone else will have to chime in to better explain it.
 

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^ correct .. its a honda factory racing cylinder ...what else are you asking ?
I beleive some had radical power valves & some didnt
 

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some year cr250r cylinders fit on 250r's, I think it was 84-90? Ftz still sells this combo, the powervalves are blocked off, unless the clutch cover is modded heavily using the cr250r clutch cover for the power valve parts. A guy on 3ww did this.
 

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the port timing is probably improved over the TRX topend. if it ran good when you took it off, i would leave it on.
 

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Discussion Starter #9
the port timing is probably improved over the TRX topend. if it ran good when you took it off, i would leave it on.
I didn't take it off... it came with the bike. i already have a cylinder on it. altho i have nooo idea where teh hell that one came from either.
 

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89 model CR250R Honda bike cylinder.

If you took a stock unported TRX250R cylinder & compaired it to the stock CR250R cylinder, the CR cylinder porting would be like an upper midrange ported TRX cylinder. Kinda play drag right straight from Honda.
You could mount that cylinder on the TRX bottom end & from the pics, looks like it was at some time because of the red high temp sealant in the P/V workings hole.
Its hard to see in the pic, but is the P/V still in place in the cylinder ??.
Pull one of those caps off the side & see if its still there.
Neil
 

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impressive. looks just like the cylinders that FTZ sells. that cylinder sure does have some exceptionally wide exhaust ports. :eek:
 

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Discussion Starter #12
Yea the exhaust ports on the pv are still in there. next rebuild im gonna run that for sure. how much doyou think its worth if it is built for my R?
 

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i have my 89 cr250r apart right now... the jug looks stock other than the transfers runing out the top of the reed cage area..... that must be newer jug or something.... everything else looks the same .... except those transfers.... thats so weird... cause that looks like a snap from inside one of these modern pro-x jugs or something , my 89 jug looks almost identical to a 86 trx cylinder ... besides the PV stuff
 

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i have my 89 cr250r apart right now... the jug looks stock other than the transfers runing out the top of the reed cage area..... that must be newer jug or something.... everything else looks the same .... except those transfers.... thats so weird... cause that looks like a snap from inside one of these modern pro-x jugs or something , my 89 jug looks almost identical to a 86 trx cylinder ... besides the PV stuff
You see, thats what the deal is with the Pro-x jugs, Allen at CT Racing designed them, did all the R&D & used the good points from other cylinders combined into one cylinder for the best output.
CR250R intake, Rotax cylinder port layout & cooling jacket with extra holding & a Pro Design type head with replacable domes.
Neil
 

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Discussion Starter #15
so do we have a verdict yet?? im still confused. I know its something off a CR. but has it been fabbed into somekind of hybrid?
 

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If all the PV workings are intact inside the cylinder, then no its not a hybred.

If aluminum plugs have been made & put into place where PV is suppost to be in the cylinder, then yes it could be a hybred. Other than that its just an 89 model CR250R cylinder.
FTZ Racing had two different versions of what they called a hybred engine. One used the older model cylinders like you have & then the other one was a 98 model CR250R cylinder. Both year model cylinders, the PV system had been removed & machined aluminum pulgs made & incerted into where the pv holes are in the cylinder.
Neil
 
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