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mzunno2

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Discussion starter · #1 ·
what's up guys, I just picked up this 86 250r. The compression is pretty low. it reads about 115-120 cold. My question is do you guys think that when the compression is that low the cylinder is toast or do you think I will be ok to bore/hone it out and get a piston in there still safe enough to run pump gas. I don't have too much experience with these bikes and this will be my first top end rebuild. obviously I won't know what condition the cylinder is in until I tear it down.
Any input and advice is greatly appreciated.
Thanks guys
 
#3 · (Edited)
mzunno2 said:
what's up guys, I just picked up this 86 250r. The compression is pretty low. it reads about 115-120 cold. My question is do you guys think that when the compression is that low the cylinder is toast or do you think I will be ok to bore/hone it out and get a piston in there still safe enough to run pump gas. I don't have too much experience with these bikes and this will be my first top end rebuild. obviously I won't know what condition the cylinder is in until I tear it down.
Any input and advice is greatly appreciated.
Thanks guys
Click to expand...
OEM Honda cylinders are very reliable, almost 'bullet' proof and still the best overall option for the 250R....thats the good news IMO.

More than likely your rings or piston are worn out, or the rings can be stuck or binding in the groves, as well as the bore out of round or worn. Usually going to the next bore size, honing and new Piston & Rings, upper end gasket kit refurbishes the OEM cylinder back to like New.

As suggested; take the top end apart, fully inspect cylinder with an accurate Bore Gauge, Bore, Hone as needed to new size. If stock head, and squish heights; expect compression to rise to 165-175 lbs after fresh top end. 165/175 lbs is more than safe for Pump Gas, keep away from Ethanol Based Fuels.

Carlos
 
Discussion starter · #4 ·
acecarlos said:
OEM Honda cylinders are very reliable, almost 'bullet' proof and still the best overall option for the 250R....thats the good news IMO.

More than likely your rings or piston are worn out, or the rings can be stuck or binding in the groves, as well as the bore out of round or worn. Usually going to the next bore size, honing and new Piston & Rings, upper end gasket kit refurbishes the OEM cylinder back to like New.

As suggested; take the top end apart, fully inspect cylinder with an accurate Bore Gauge, Bore, Hone as needed to new size. If stock head, and squish heights; expect compression to rise to 165-175 lbs after fresh top end. 165/175 lbs is more than safe for Pump Gas, keep away from Ethanol Based Fuels.

Carlos
Click to expand...
Awesome info. Thanks alot. that's what im hoping for. Any recommendations on where I can send it to be bored out?
 
#5 ·
For just a bore/hone check with a local engine shop, a trusted mechanic should be able to direct you somewhere local too. I’m sure guys will chime in on other places to ship it to if that’s your only option. What’s your location? Someone may know somewhere close to ya.... if you are sending it out you may want to explore porting options & get it all done! I’m sure local guys can port too but I’d want to leave it up to someone like BDT or another reputable 250r builder!
 
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Discussion starter · #6 ·
Im located in Long Island NY. if I do have to send it out I will most likely explore all those options and have a port job done as well. How do I get in contact with BDT or other reputable 250r builders if I do opt to send it out? thanks for the help !!
 
#7 ·
If you have a local Napa machine shop there in New York they can bore it out for yah. I've had em do banshees and blasters for me with zero issues. It was fairly cheap to, just make sure u give em your new piston with cylinder. Its a option if you don't wanna ship out west.
 
#10 ·
american opel said:
imo make sure you take it to a shop that does 2stroke cylinders.dont just take it anywhere.
Click to expand...
Absolutely correct...!

mzunno2 said:
Im located in Long Island NY. if I do have to send it out I will most likely explore all those options and have a port job done as well. How do I get in contact with BDT or other reputable 250r builders if I do opt to send it out? thanks for the help !!
Click to expand...
Please don't just send it to any machine shop or shop that does not work on 2 strokes, specifically Honda 250R's....you won't get the 'Best' work for your cylinder. Lot's of good 2 stroke 250R shops around, you have a lot of options, if interested in BDT here is BDT contact information:

BDT Motorsports
8760 Helms Ave
Rancho Cucamonga, CA 91730
909-466-9152
USA

Carlos
 
Discussion starter · #12 · (Edited)
acecarlos said:
Absolutely correct...!



Please don't just send it to any machine shop or shop that does not work on 2 strokes, specifically Honda 250R's....you won't get the 'Best' work for your cylinder. Lot's of good 2 stroke 250R shops around, you have a lot of options, if interested in BDT here is BDT contact information:

BDT Motorsports
8760 Helms Ave
Rancho Cucamonga, CA 91730
909-466-9152
USA

Carlos
Click to expand...
ok great thanks Carlos and American Opel. I will do some digging into who is in my area on the east coast. if no luck I will inquire with BDT.
Thanks again guys. super helpful !! sorry for the noob questions
 
Discussion starter · #13 ·
Ok, great good to know. Thanks sandslinger. I guess once I pull the cylinder it will determine if I am porting and boring or just getting a new cylinder, In that case I will be searching for an OEM one !
 
#14 ·
There's a guy in your area I just know him off bansheehq his name is Carl, and he builds quick shees, but he also works on 250rs as well. BigMike on here knows who I am talking about and could probably give you the info. Itd save you shipping and he has a good Rep. If that dont work out yes Carlos at BDT in Cali could get yah set up no problem.
 
#15 ·
Welcome I’m in nyc as well,I had a good mechanic in a local Honda shop (20yrs at same dealer)but he recently left,he’s from out east I can hit him up on his cell and see where he’s working these days.where do you plan on riding? Calverton ?Big mike on here is from LI maybe he can recommend someone out east..pm him.
 
#16 · (Edited)
I'll second the motion, on finding a bore shop that only does small engines, mostly 2 strokes. Because they know the 2 stroke engines & how important it is to have a good straight bore with the proper piston to bore clearance.
Years ago, I use to hop around from one automotive machine shop to another to get my cylinder boring done, but it cost me enough one season to make me change my way of thinking. When it all came to a head, it cost me two class championships for the season, from poor bore jobs from workers that would rather set up 4 holes at a time, sit back & watch the machine work, than doing one each time. Lesson learned, so now I have the best two stroke cylinder bore man I have ever used & until something happens to him, his shop is the only one I'll use.
Having a bore shop close to you, can be important also, so you can keep an eye on things. Not that shipping it out for a bore & fit is out of the question though, because theres plenty of places to ship out to that can do a quality bore & fit.
Neil
 
Discussion starter · #17 ·
Sounds good., I am going to try to get in contact with Bigmike and see if he can give me Carls information. Obviously id like to stay on the island, cut the cost and hassle of shipping.
Most of my riding is upstate Ny and Calverton yes, - nothing serious or competitive.
How can I get in touch with bigmike? somewhat new to the site...

thanks a ton guys super helpful!
 
#20 ·
all you have to do is go on bdt's site and call or just send..you can also pm carlos.
mzunno2 said:
Sounds good., I am going to try to get in contact with Bigmike and see if he can give me Carls information. Obviously id like to stay on the island, cut the cost and hassle of shipping.
Most of my riding is upstate Ny and Calverton yes, - nothing serious or competitive.
How can I get in touch with bigmike? somewhat new to the site...

thanks a ton guys super helpful!
Click to expand...
 
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american opel
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