350X Front End on 250R

[JohnR.]

Has anyone here done this? I remember reading here a while back that back in the day the hot flat track set up was to run a 350X front end (triple clamps, forks) on a 250R because it will greatly decrease the amount of rake in the front end. I've been toying around with the idea of trying it and I've got some extra 250R and 350X trips and forks to play with. So far I've taken the tapered bearings off the bottom of one of my 250R trips and tried to put it on the 350X lower trip but the shaft that it slides down on has a step up about 3/4" below the threads. It fits perfect just above the step but the step is too big. I'm guessing my choices are to either have the step machined off or get a set of aftermarket tapered bearings for a 350X and see if they will fit in the 250R frame. If anyone has any input on this I'd love to hear it.

Thanks.

John

[Tri-Z Pilot]

Decreased rake? I'm pretty sure its an increase. 250R's definately turn better than an X. Leading axle setups are for increased stability, while trailing axles help with a lower turning radius. If you still want to ge through with it, you should be able to just swap the stems, and may need some steering stop mods. I'm not sure of how different the stops are on the frames/tripples of those models.

[Louis Mielke]

Actually i believe that with the change to leading axle it actually negates the change in rake. So effectively,

leading axle on 350x = rake built into 250r tripples

By swapping the entire front end of a 350x onto a 250r there should be little to no change in rake.

[Dirtcrasher]

I thought that the 350X rake was in the frame and the tripples are a straight shot and the fork tubes are in line with the neck.

The 250R it's built into the tripples. So I would assume that if you used the 350X tripples on the 250R that you would have decreased rake?

Just my thoughts......

[Louis Mielke]

Technically I think your right and if we wanted to split hairs I think you're definitely right but for the sake of usage I believe the rake in the frames are similar if not exact and the difference in the rake is in the tripples.

The 350x has no rake in the tripples with leading axle,
the 250r has built in rake in the tripples but trailing axle.

Swapping the fronts you should see very little difference in handling as far as steering is concerned. Obviously we all know that the liquid 250r front ends are much better suspension. I know Jason Hall has done some pretty extensive research in this and I believe that's where this information is coming from if I'm remembering correctly. I'm sure he'll chime in eventually.

So literally if we get out the measuring tools your right DC but effectively its not much difference.

I won't pretend to know this as earth ending fact but I feel confident enough with my inverted fork adventures and chatting with Jason that this will hold pretty true. Of course in 2 or 3 hours Jason will come in and tell me I'm remembering wrong and I'll be happy to eat a big plate full of crow. lol!

[The Goat]

And what if you ran it trailing axel on the 350x. Thereby decreasing rake even further. Suspension means a lot less on a flat surface... like dirt, or.... ice.

[JohnR.]

Great info guys. Keep the input coming. Maybe I'll just mock it up and see where it ends up. I can just measure from the swingarm bolt (or any fixed location) up to the stock front axle at ride height and then just rig the 350 triples in there and find a way to keep the stem centered while I take the same measurement. That'll give me some idea of where I'll end up before i make myself crazy with it. What I'm also wondering is let's just say that the leading axle on the X makes it a wash, will that completely negate the rather large decrease in rake that I'll see in the forks themselves?

Looking at Honda microfiche online it appears that the 84 250R had a trailing front axle and if I understand correctly, the same diameter forks as a 350X. Maybe I need to use the X trips with 84 R forks to get the desired decrease in rake? Once I get away from 350X's or liquid cooled 250R's my trike knowledge goes down to almost zero so please bear with my lack of knowledge on this stuff.

John

[Tri-Z Pilot]

You can run a leading or trailing axle with any bike, just moove the forks to the opposite side and turn them around.

From the sounds of things your gonna want to run the 350 tripples with a trailing axle to get an effective rake decrease.

[JohnR.]

Well its been a few weeks but I haven't given up on this. I got the shafts out of the triples today at work. Since ice season is over I can take the R apart and take my time with it. I'm hoping to mock up the X triples and forks with a front tire on them early next week. I'm need to see where the forks are in relation to the gas tank and where the tire is in relation to the pipe. Then, if I have room to move the wheel back further still, I can consider going to the 84 R forks in the 350X triple clamps. I'll post an update with some pics when I have some pics worth posting.

EDIT: It looks like an 86 200X is also a trailing axle type set up. Can someone confirm if these forks will fit in the 350X triple clamps? Something must be different about them since the seals are a different part number between the two of them.

John

[JohnR.]

Bringing this back from the dead. I had a few minutes tonight to get the R front end out of my R and try the X front end on it by putting a 250R steering stem into 350X triples. It took 5 degrees of rake out of the forks but the leading axle leaves plenty of room for even the stock tire. Although I really don't want to run it with the X forks flipped around to make them into a trailing axle just to make sure I have clearance between the tire and the pipe before I go out and get a full 1984 front clip. I have to figure out if I can get my 350X or 250R front caliper, hub, rotor, etc... to work on the 1984 250R front end. Any more input anyone?

[JohnR.]

OK. The 1983/1984 250R did have a trailing axle but it looks like it was basically accomplished by switching forks similar to the 350X external design and swapping them side to side. The brakes are on the opposite side as they were on the X and the brake line runs down the back of the fork which would also be a by-product of swapping the forks side to side in the triple clamps. The 200X is like that too all the way up until 1987. I didn't want to just swap the forks to get that result but it looks like that's the way it'll have to be. I'm going to try to make time to go back out there tomorrow evening and try that quick. I hate it when I do something stupid like that and overlook something so obvious. Keep your fingers crossed for me. :D

[Thorpe]

Wouldnt it just be easier to relocated the neck angle 5 degrees? (dont get me wrong, parts interchange is sweet...)

[JohnR.]

Maybe it would be if the frame was going to get blasted and coated anyways. If this is something that can be done with basic hand tools it makes it do-able for a lot more of us. Not to mention that when I get back to the dunes in MI again I'll want my 250R front end and geometry back for obvious reasons. Not getting out there tonight. Maybe tomorrow.

John

[audioworks04]

I dont know about basic tools, but could be done easly with a porta band or just a hack saw and a mig welder with some gussets or reinforcing plates.

[oldskool83]

86 200X are the same size as 83-85...they are all 33mm.

[JohnR.]

I agree but a MIG is definitely not something the average guy has around and the ability to make a weld solid enough that I would trust it to keep my front end from breaking off is something I'd leave to someone who really knows how to weld.

[jonathandexter]

OMG!!! build a bigger engine and get on the brakes faster to win Gheese, sorry but don't you thing Honda would have tried tested all this crap..... WTF.
Sorry bro but SLAP!

Jonathan

[JohnR.]

First of all, I am not your bro. I don't know you, I've never had any interaction with you so why do you think its going to be OK to come into my thread, talk trash and then call me bro?? I'm guessing by saying "don't you thing Honda would have tried tested all this crap" you are attempting in broken English to say "don't you think that Honda would have tested this set up". I don't know what they tested but I do know that (like everything on any mass produced vehicle) the stock set up is a compromise and since the vast majority of these machines were going to be used in the woods and on the MX track they set the front end geometry up to favor those conditions. My R only gets used when flat tracking on the ice so a front end with less rake will make your steering more responsive on a flat surface while sacrificing its ability to suck up bumps. By your reasoning there is no point to modifying anything because the manufacturer has already done all the testing and made the machine the best it can possibly be in all situations. :rolleyes: If you have something constructive and topical to add please feel free to do so, if you're just going to revive a thread from 3 months ago to talk trash about my ice trike from a place that has never seen snow please keep it to yourself.

Thanks.

John

[MudBug]

First of all, I am not your bro. I don't know you, I've never had any interaction with you so why do you think its going to be OK to come into my thread, talk trash and then call me bro?? I'm guessing by saying "don't you thing Honda would have tried tested all this crap" you are attempting in broken English to say "don't you think that Honda would have tested this set up". I don't know what they tested but I do know that (like everything on any mass produced vehicle) the stock set up is a compromise and since the vast majority of these machines were going to be used in the woods and on the MX track they set the front end geometry up to favor those conditions. My R only gets used when flat tracking on the ice so a front end with less rake will make your steering more responsive on a flat surface while sacrificing its ability to suck up bumps. By your reasoning there is no point to modifying anything because the manufacturer has already done all the testing and made the machine the best it can possibly be in all situations. :rolleyes: If you have something constructive and topical to add please feel free to do so, if you're just going to revive a thread from 3 months ago to talk trash about my ice trike from a place that has never seen snow please keep it to yourself.

Thanks.

John

SLAP! :lol:

Just one question, by switching to a trailing front axle, your sterring radius is smaller? Would this better for trail riding?

[JohnR.]

For trail riding you don't want to reduce the caster like the 350X front end would regardless of any change it would make in the turning radius. Having more caster makes the front end work better when hitting things like logs or large rocks. More caster will allow the tire to move up and back when it encounters an obstacle. Stock, the R has a trailing front axle and the X has a leading front. When I get back to fooling with this again I'm going to try swapping the forks left to right and running the X front end as a trailing axle set up. What remains to be seen is if I will have enough clearance between the tire and pipe if I set it up this way.

John

[Mosh]

OMG!!! build a bigger engine and get on the brakes faster to win Gheese, sorry but don't you thing Honda would have tried tested all this crap..... WTF.
Sorry bro but SLAP!

Jonathan
I just went through all 6 of your posts, and only 1 post had any real relevance.
For you to come on a new forum and spout like you do is just a little over the top.
Dont try so hard to "fit in" by "forcing your way" in and I am sure you will have a lot better time on this forum.
Just a friendly piece of advice.

[aldochina]

OMG!!! build a bigger engine and get on the brakes faster to win Gheese, sorry but don't you thing Honda would have tried tested all this crap..... WTF.
Sorry bro but SLAP!

Jonathan
what a dill!! I thought it was an interesting thread

[Tecate 50]

I agree....JohnR keep us updated on the build!