My 250r will be a 300r

[aviomech]

Just bought 300r kit for my 82 250r.:headbang: Decided to go bigger now that my trike is torn apart from the engine seize(rod bearing). Just waiting for the parts to come in(including a rebuilt bottom end). I'm also trying to get my swingarm extended 6". No luck yet finding someone that wants to do it. So my friend has a welder and between the 2 of us(30+ years aviation exp) can figure it out.:thumbsup:


I plan on getting a bigger carb, but in the meantime the stocker 27mm will have to do. I know jetting is the key to making any carb work, so where do I start for jet size?? Currently I have a 150 main jet, which I feel was too lean for the dunes and may have contributed to the prior engine seize. The service manual says a 158 main jet is stock for the carb. Should I start there or bigger?? And if so how much bigger(160+)??
Any advice would be great!!:hail: :hail: :hail:
Thanks for lookin' and I will post some pics soon.

[wild200x]

sounds great!

[Duner]

Just bought 300r kit for my 82 250r.:headbang: Decided to go bigger now that my trike is torn apart from the engine seize(rod bearing). Just waiting for the parts to come in(including a rebuilt bottom end). I'm also trying to get my swingarm extended 6". No luck yet finding someone that wants to do it. So my friend has a welder and between the 2 of us(30+ years aviation exp) can figure it out.:thumbsup:


I plan on getting a bigger carb, but in the meantime the stocker 27mm will have to do. I know jetting is the key to making any carb work, so where do I start for jet size?? Currently I have a 150 main jet, which I feel was too lean for the dunes and may have contributed to the prior engine seize. The service manual says a 158 main jet is stock for the carb. Should I start there or bigger?? And if so how much bigger(160+)??
Any advice would be great!!:hail: :hail: :hail:
Thanks for lookin' and I will post some pics soon.

I am just curious, does the 300 kit for the air foolers compete with a 100% stock liquid R? Never seen on run...

[aviomech]

IDK how it compares to a stock water-cooled. But with 300cc, it should be a little quicker. I saw a clip on this site where a stock airfooler beat some water-cooled R's. I think it depends on the rider.

But anyway, here it is with the extended (6") swingarm. It came out really nice. Also I have the rear shock lifted a bit to make up for my 290 lbs butt. Still waiting for engine parts, and I still have to do some painting before it'll be done.

[Bullonme]

:headbang: Sweet Avio:headbang:
Good luck with your build.. I liked mine the other day. I still need to do a lil carb work and when my buddy got it bored it was .008 over the piston. So it slaps. I'll be getting a new piston and bore job soon. :headbang:
Did you get the whole 300r kit. If so where did you get it???
Are you gonna run those tires on it? I have 18X9.5-8 on mine rite now. I like the way they spin when riding on trails.:burnout:

[aviomech]

I have only rode those Carlisle Stryker tires(22x11x8) in the snow(did ok). I have a set of Cheng Shin 10 paddle tires(22x11x8) for the dunes. The paddles worked great(up to the engine seize:cry: ).

I bought my 300r kit off ebay. It included the cylinder, head, new piston and rings, and gasket set. Still hasn't showed up yet. But should be here tomorrow or monday. I also have a rebuilt bottom end that I bought from the classifieds on this board. Hopefully I'll have it together in a week and ready to rock:fire: . I'm heading to Winchester next weekend with some friends. Sucks it isn't running for this weekend!!!

[Duner]

I have only rode those Carlisle Stryker tires(22x11x8) in the snow(did ok). I have a set of Cheng Shin 10 paddle tires(22x11x8) for the dunes. The paddles worked great(up to the engine seize:cry: ).

I bought my 300r kit off ebay. It included the cylinder, head, new piston and rings, and gasket set. Still hasn't showed up yet. But should be here tomorrow or monday. I also have a rebuilt bottom end that I bought from the classifieds on this board. Hopefully I'll have it together in a week and ready to rock:fire: . I'm heading to Winchester next weekend with some friends. Sucks it isn't running for this weekend!!!


Sounds like your getting things done.

Funny, I will also be at Winchester next wkend (Wednesday thru Sunday).....I will keep my eye out for ya. Wanna see it run up the hill.

[aviomech]

Well my trike will remain a 250r until next week:( . Needed to get a hone job on the 300r cylinder. So I put my 250r head on to go ride this weekend. Got the frame painted and engine installed.

But now I need to pull the motor to put in my old gearshift spindle, seens how the 83 spindle is too short for my 82 gearshift:doh: . I will keep trucking and maybe be able to ride this weekend!!:burnout:

Will post pics soon.

[aviomech]

Got my 300 bigbore back and it is back together, ready to rock.:headbang: Wasn't able to ride last weekend(didn't have jets to tune the carb). Still waiting for jets to get it tuned in. And looking to get some 300r graphics. But it is all together. Here is everything that was done:

*300 bigbore
*Rebuilt bottom end
*+6" on swingarm
*Painted frame and swingarm
*30mm Mikuni(off Kawasaki H2) installed
*Boyesen Reeds

Pics coming soon!!!

[aviomech]

here it is!!!

[Gdkarma]

Looks GREAT! This will be the first time to run the new motor? What size carb are you running? Your list says 30mm, but I imagine you probably are running bigger than stock aren't you?

Make sure to get some action photos!:headbang:

[aviomech]

I ran it with the 250 cylinder on it last friday, but the jetting was off. So I ordered a jet kit. Then my 300 bigbore came in, so I installed it. But have not ran with new cylinder.

The stock carb was a 27mm. I got three 30mm carbs for free from a friend that had pulled them off a Kawasaki H2 motor. I pulled apart all 3 and rebuilt 1. Nice to have extra parts for the same carb. Just had to order some jets for it.:thumbsup:

I'm heading to Vegas this weekend, so it will be jetted and running next week. Hopefully I can win alittle cash to start building my 86 250r!!

[Gdkarma]

Sorry about that.............I thought the stock carb was like 32mm. I think that I went with a 34mm on my 83R, and so it seemed odd that you had a 30mm. It's been a while, so I've probably got something confused:doh:

Be sure to let us know how it goes!:headbang:

[aviomech]

The 81-82 had 27mm carb, 83-84 had 30mm carb, and I think the 85-86 have a 34mm carb.

The 2 reasons I went with the Mikuni carb 1. it was free!! 2. 30mm is better than 27mm!! Personally, I would like to have put a 32-34mm Keihin, but I would have to buy another intake boot( I got a 30mm intake boot when I bought an 83 reed cage), and spend money on the carb.

So hopefully some time early next week I will have it jetted and ready to go.

[3razors]

Looking really nice. But a 30mm carb will act like a rev limiter compared to a 38mm which will really make that engine come to life. You can use an intake boot from a FL350 oddessy to fit a 38

[aviomech]

Thx for the info 3razors. May look at doing that in the future, but I want to start focusing my cash on my 86 250r build. It sucks only having one trike together, when it breaks, I have nothing to ride. So I'm trying to get 2 running, then start the little upgrades. Although I did go a bit further than just getting the 82 running.:D

[3wheelergod]

Where did you find your 300 kit?

[aviomech]

Got the 300r kit off ebay. Had to get it honed for piston fit. Bottom of cylinder sleeve was broken (not mentioned in ad):slap: but luckly it is low enough not to affect piston travel.:thumbsup: Still would not have paid as much if I knew about it.:( I will probably resleeve it if I pull it again.

[aviomech]

Just saw this one on ebay for $299. Looks in good shape with a couple used pistons. No takers yet. But he is willing to take reasonable offers. I wouldn't give more than $200-225 without a new piston and rings.

[3wheelergod]

I have an extra cylinder that is already at 72mm, the biggest wiseco makes for them so I was looking for a piston, sleeve, and head gasket for one. What mm is the 300 kit? Maybe I can find a different piston that will work!

[3wheelergod]

I've been looking at your pictures and I notice that your head has 7 bolts! My 1981 250r and the extra top end I bought BOTH have 6 head bolts, WTF?

[aviomech]

Hondaline 300r heads have 7 bolts and the cylinder is ported. The stock 250r heads have 6 bolts. My 300r cylinder was around 77mm. If your cylinder is 72mm you are running just 2mm over stock cylinder(70mm). 72mm bore = 262cc. 300r is a whole 'nother critter. A Hondaline 300 kit is a different cylinder, head and piston. It was sold as an accessory kit for the 83-84 250r. But will also work on 81-82 bottom ends.

[3wheelergod]

So is it a different cut on the squish angle on the head also? I can bore mine and port the hell out of it myself, now I need to find a 77mm piston with the same deck height and pin location and I can make it work, I can make my oown head gasket out of copper also, I just needed bore size! Thanks. I just did a tecate motor with a Rotax sleeve and piston in it at 78mm, so this one should be a breeze, cause it has a HUGE sleeve in it now, so I only gotta bore and port instead of make my own sleeve also! Thanks bro!:thumbsup:

[aviomech]

You must have a huge sleeve to be able to bore it out to 77mm. Kustom Kraft a company I found online, http://kustom-kraft.com/hondakits.html, does a resleeve and bore but they only go to 290cc(about a 76mm bore) for the 81-84 ATC 250r. But they charge $495, and an old 300r bigbore kit goes for around $300. And if your doing it yourself, you might want to ask someone with more exp than me on how much you can bore out the cylinder. I'm sure there are more than a few exp guys:oldfogey: here that have punched out their 250r motor:bash: .

[3wheelergod]

I have measured it and I can safely bore it to around 76mm. It has a thick sleeve, anyways, I can have L.A. Sleeve build any sleeve I need. I had them build my tecate sleeve blank and I cut all the ports on the mill, then bored my tecate out to 84mm then sleeve her down to 78mm (3mm each side), so I'm sure I can just do the same with this one! I just needed the bore measurement for the 300 kit, I'll do the rest, maybe have them send a gasket though, I dont want to buy a whole piece of copper and program the plasma-cam to do it! Thanks for the info.:hail:


Do you know how many horses the 300 has? Or supposed too have?:confused:
I think I'll dyno both of my motors just to see what mine has?:headbang:

[aviomech]

Let me know what you come up with. I don't have a clue at what hp the 300 puts out. I wanted to dyno mine but the cost and waiting a month to get my trike in really pushed me away from getting it done.

Anyway, sounds like you got a plan!

[aviomech]

Looking really nice. But a 30mm carb will act like a rev limiter compared to a 38mm which will really make that engine come to life. You can use an intake boot from a FL350 oddessy to fit a 38


I thought the oddessy came with a 35mm?? Isn't a 38mm too big??

I'm looking for a bigger carb. Question is, what carbs will fit in my stock boot(30mm carb) and what boot will work for carbs between 34-38mm??

[3razors]

The oddessy boot will stretch to fit a 38mm, might have to heat it up a lil bit by boiling or another method but it will work. If ur looking for perfection you can also match the intake boot to the carb by sanding it out to a 38mm.

[aviomech]

Well here is my trike ready to rock:headbang: !!! Put a 200x headlight on and painted the tank. I also got some 300r decals on there thanks to James(Bullonme). So here is how it looks.

[Duner]

Looks good. Did you have any additional port work done to it? If not, take it to Piranha Pete and let him work his magic. You should look at getting a custom fabed pipe at some pt too.

[200x_Basket]

where did you extend the swinger? between the carrier and the shock or between the pivot and the shock?

[aviomech]

On the 82 250r, the shock mounts are on the bottom of the carrier. So I chopped the mounts off, and cut 2" in front of carrier(giving enough room for overlap). Then I got 8" long rectangular pieces(I think the were 2x4) and overlaped each side by an inch. Then I squared it up and welded it. I actually drilled a hole thru the extension and put a high grade bolt thru to mount the shock. This raised it up a bit, but I'm a heavy guy so it settles in nicely when I'm seated.

[Gdkarma]

Looks great! When do we get a ride report? Did you score a bigger carb yet?

[aviomech]

Haven't got a bigger carb yet. But I did get a stock Keihin for cheap. The Mikuni was giving me a hard time trying to jet it. I still have the pyrometer hooked up(in pics) just haven't got around to taking it for a run. I'm hoping to get it ready by next week, so it will be ready for Winchester.