My project

[tbus93]

[ATTACH]undefined[/ATTACH]] just recently joined the trike Mania I got the bike for 1300 (got hosed more wrong found out after buying) I currently have 1300 in the bike it runs good but has a leak at the crank case gasket I want to put a big bore on it what do you guys think?

[dustrunner]

welcome, looks pretty good 2 me...it's a bummer when ya can't find the blem's in their driveway huh....

[tbus93]

Carrier bearing was almost gone new forks carb needs rebuilt or new one doesn't allow it to idle Paul turner pipe has a small crack and hole in it

[RIDE-RED 250r]

Well, it still looks like you have a good starting point to build a really nice R.

But a bit of advice.... Before you go upgrading to a big bore, you will want to do a full tear-down and inspect and freshen up. New crank bearings and rebuilding the counterbalancer are a must for such a build. Plus, unless you plan on just going 310 or bolt-on 330 you will have to tear it all down anyway to send the bare case halves to a builder to be bored for the big bore cylinder.

Something else that is highly recommended is to replace the old cast counterbalancer carrier with a new billet unit. (that is if it hasn't already been replaced).. The reason for this is that the 27 year old cast CB carrier gets fatigued with age and use and can crack and/or break apart. This will cause major damage to your bottom end.

Another good thing to do to ensure a reliable big bore is to have your crank rebuilt. And have it rebuilt with either an OEM rod, or a Hot Rods rod.

Other things to inspect for wear and to make sure are in good working order is the transmission and clutch. You don't really need any special heavy duty transmission components for most big bores (under 75hp ballpark), but you want it to be in good serviceable condition to handle the extra power you will be putting to it. It may also be prudent to have all the transmission bearings replaced if you have any doubt as to their condition and serviceability...

I know it seems like alot, just giving you the best advice I can based on personal experience and advice from some of the best 250r builders in the business, IE shops and other owners who have been around the block...

Welcome aboard!!

[tbus93]

I have a guy I plan on building my motor I just want to do the 330 esr kit and have him port it i hear esr port jobs are wack thanks for the heads up on the counter balancer can't decide if I want to go with a long rod for a stroker yet want it to be bbad

[pantera1975]

I went with a 330 esr top end and a 88-89 long rod style hotrod crank. That way if needed I can put on my original top end if I blow it. I had BDT motor sports do 2 of my motors. Complete rebuild inside and out.

[RIDE-RED 250r]

The long rod does not make it a stroker... To be a stroker, you have to run a stroked crank.. That is a crankshaft that has been modified to increase stroke by re-locating the crank pin farther out on the radius of the crank tins.


And if you run a plus size stroker crank, you MUST have the cylinder ported for the stroker crank and run a spacer.

Word of warning because I've been there.. Pretty much all of the heads that come with pretty much all of the big bore cyls have straight up spark plug orientation ad opposed to the stock head where the plug is angled slightly. With the ATC's, particularly the '85 there is little clearance between the spark plug and a part of the frame. You will have to run shorty plugs, or get the smallest, most compact sparkplug cap you can find. Running the stroker and spacer plate will add to this issue. Don't get me wrong, it is workable.. It can just be a bit of a pain finding that perfect sparkplug cap that allows you relatively easy removal and re-installation of the plug cap. I went that route as opposed to the more expensive and less abundantly available shorty sparkplugs.

[tbus93]

My uncle has a stroker 310 big bore trx 250r I love the pull that thing has not 100% sure what I want to do yet trying to slow down my spend rate right now even debated the 500r

[pantera1975]

Either way I know where you can get motor matching big bore numbers for your ATC

[tbus93]

Want to get new shrouds before I put decals on them old maier shrouds are ugly

[JasonB]

Welcome to the boards, theres some great info in here, thank for clearing a lot if that up for him ride red 250r!! I think the price wasn't too bad, sucks about the leak but good job catching it before you ran it lean and burned up. I love my 310esr motor but have also heard great things about bdt

[tbus93]

I liked the price when I bought didn't expect to be putting a new carrier bearing 165 moose racing and 265 on forks there polished and look great sucks I have to replace my Paul turner pipe going to buy my uncles fmf pipe for now until I build my big bore then figure out what I like just have to top off the tranny fluid before I ride it everytime no big deal just Quaker state 10w 40

[tbus93]

Also doesn't leak while I ride just if it sits for awhile

[JasonB]

Don't know if I missed it but what's wrong with the Paul turner? Would never replace anything but a stock pipe with an FMF lol

[tbus93]

The pipe has a crack in about 2 inches long right after the first bend of the pipe and a 1/4 inch hole I came off a jump pretty hard and think I bottomed the bike out and caused it don't know if it can be fixed I hate fmf but a new pt pipe is running about 400 new not looking to put something on until after a rebuild