first post here...need some 350x help

[SWIGIN]

i mostly have the bugs worked out of putting an ascot 500 head on a 350x, but before i go buy new honda ascot rockers at over $100 each i need to know if anyone has a ascot ft500 ( single cly) or a 79-82 xr500 laying around and if you could tell me the size of the rocker shafts in ether motor.

im useing the 350x valve cover since i need the 350x head mount and the ft500 does not use a external oil line.

the 350x rocker shafts are .471 or 12mm, all i need to know is do the xr or ft 500 use the same size shaft.

if so then i can use the 500 rockers. the 350x has smaller valves and they are closer together then the 89mm bore 500 head and the rocker ajusters are only sitting on the valve stems about 1/2 way ( they need to be wider) and i think the 500 rockers would be a easy fix for this.

thanks

[SWIGIN]

hers what i got so far

you can see how much is needed to bolt a 350x valve cover to a ft500 head..... the black line is the stock ft500 valve cover area

[SWIGIN]

heres the stock ft intake valve next to the stock 350x intake valve

and since the ft head is fed oil up the one motor stud and the 350x is fed through the valve cover i had to plug the ft oil feed so oil can fill the cam lobe area like its suposed to.

you also have to drill the 4 motor stud holes in the ft head to 10mm

[SWIGIN]

lol.... heres the pics

[SWIGIN]

and here it is sitting on a 350 cly.... the timming chain area lines up pretty well and with a 89mm big bore the stock ft head gasket would go right on with minimum mods

[SWIGIN]

heres a shot down the bore...... this will work perfect with a 89mm big bore (89mm is stock on a ft500)

[250sx]

I have no idea, but I will say "keep us posted!" :thumbsup: I'm sure BlackSheep will chime in.

[SWIGIN]

ok guys.... on a nother site i found out that the xr500 does have the same size rocker shafts so thats no longer a problem

[chrisr200x]

Is this motor going into your quad or are you fixin up one of those 350X you and your bro have down there?

Welcome to the boards!

[SWIGIN]

i peiced a motor together off ebay so it will end up in the quad.

the motor im running right now has a loose sleeve (you can lift the sleeve right out) and the crank has some play but not noisy ...yet

i was just peicing a motor together since its only a matter of time till the rx motor goes and this is what im thinking of doing

[chrisr200x]

It's gonna RIIIiiiiipppPPPP!!!!!!

I rememebr talking to those guys up at brapp's house about doing this swap. I can't remember all the details tho. It didn't sound like a terrbly hard thing to do.

good luck to you on this project. I'm sure someone around here can help.

[SWIGIN]

the worse thing is getting the valve cover to bolt on right... thats the part everyone seems to forget to mention

[250sx]

how about a detailed writeup on this conversion? :D

[SWIGIN]

well so far this is ware im at, you can see what it takes to get everything to fit and bolt up properly .

if you have questions just let them fly.

one more thing......does anyone have some xr500 rockers they would like to sell? i will be getting them welded and hardened so the pads dont have to be nice.

but the inside hole ware the rocker rides on the shaft needs to be nice

[armyvet]

Hey swigin,its 2 muchquad from "the other site",i was thinking bout'doing this mod myself,i didnt think it was so involved,all i "heard" was the 350x valve top could be used.I think the ascot head uses 33mm intakes which would be a huge improvement.im curious myself to see how it turns out.

[SWIGIN]

the ft500 valves are 35mm and 30mm..... basicly the ft500 exhaust valve is the same size as the 350x intake valve :D


yeah all the rumors iv heard online made this sound like a 5 or so on a scale to 1-10. im thinking its a 9.5 since most people dont have a machine shop they can use.

i have no idea when ill have this thing running since i need a 89mm big bore to make it work(i got my mustang tore apart right now) but as i go along ill post pics.

i dont know if i mentioned this but after you finaly get the 350x valve cover on then youll find out that the rockers only sit about 1/2 way on the valve stems (they need to be wider) well i have a set of 82 xr500 rockers coming so that will be the next thing i deal with.

the online rumors never said anything about the rockers...lol

[SWIGIN]

today the head went back on the mill to move the stud hole with the arrow so it lines up with the 350x gasket.... im going to be running the ascot head gasket but this shows me where the 350x bolts go.

the hole across from the one with the arrow will be tougher to do....im going to drill a new hole down the cly just inside the original one

the tape on the cly is where im going to mill so i can put nuts on the 10mm studs im putting into the head

[SWIGIN]

2 more pics from today


i threw it together to see how far off the top end studs would be.... the inner 2 look fine but the outer 2 will need spacers.

oh..... and the 350x timming chain is the right length too

[SWIGIN]

im haveing a real hard time finding the m10x1.25 studs i need (95mm long) MSC and mcmaster carr have nothing except cheap all thread with no rating.

but i think i finaly found a source......400ex cly stud #5 is 10mm and 92mm long.

i just hope its like most other 10mm bolts or studs and is 1.25 thread pitch

anyone have a 400ex or have worked on one and can verify the thread pitch on the cly studs? (a lug nut off most bigger bikes are 10mm x 1.25 if that helps)

[Gdkarma]

WOW, this is a pretty brave project! Keep us updated. I have to give you credit for jumping in and being determined to make this work!:headbang: :headbang: :headbang:

[SWIGIN]

thanks

like iv said, iv heard about this swap since the late 80s but never could find anything about the swap other then hearsay and rumors.

im hopeing that this thread sticks around since it shows one way to do it with 100% proof it works.

if anyone has info or the old dirt wheels mag (this is where i read of this back in the day) please jump in.... id like to see how they did this back then.

[SWIGIN]

ok now i have more parts to play with

in the first pic you can see how mutch wider the xr500 rockers(left) are then the 350x rocker (right)

and now with the 500 rockers in the 350x valve cover (they fall right in with no mods) they line right up with the valves.

[SWIGIN]

i also got my hands on a early xr500 top end gasket kit so now i can show with the drilling of 1 new hole how nice it will be to use off the shelf gaskets fop this and not have to cut up a stock 350x head gasket or order a custom one for big bucks.

the sharpie is pointing to the new hole, it will be just inside of the stock hole

the 2nd pic just shows the gasket on my new xr500 sleeve and the 3rd pic shows how the new sleeve is to tall but a lathe will fix that

[SWIGIN]

tonight i went to HREATV and i cut the xr500 sleeve down but i left it a 1/16 long since with the stroker the piston will be going farther down in the hole.

then we bored old cly for the new sleeve

[SWIGIN]

ok i finaly got my 400ex stud in from honda and heres what it looks like.

i still need to throw the cly in the mill to clean up the area i hacked at with a cut off tool.

in the first pic you can see how short the stock studs were...they only went to the first air fin or so. i wanted more meat so thats why i went with the 400ex stud.

the short stud will also get replaced with the same length stud and the cyl will be cut out just like the other side

[SWIGIN]

in post 18 you can see how long the outer 2 top end studs are.....well i found out that 250x ,250sx, 250es, 300ex are all shorter then the 350x studs.

so heres some pics of the 250x studs in...the one will still need a spacer made but it looks alot cleaner this way.

[350XBigbore]

Looking good and I was also thinking about building one of those but thats alot of work.

[SWIGIN]

yup it is but i dont mind....my buddy has a machine shop i can use so its bin no big deal so far

[350XBigbore]

Yeah i also have access to a machine shop so it maybe a project once I ride the one I am finishing up now, I'll decide. Later

[SWIGIN]

ok heres the last group of pics... i think im finally done at the machine shop...lol

first pic just shows the spacer need when useing the shorter 250x top end studs. with the 250x studs the left one is perfect

2nd pic shows the threaded boss or insert we used in the head to run a longer 8mm stud in the front of the head.

the stock stud had a 12mm base so thats the reason for the insert

[SWIGIN]

these pics just show the notchs i had to mill into the cly to get to the studs to put nuts on them.

the ft500 and the xr500 uses the same notchs but i used longer studs.... the 500 studs only go to the first air fin and seemed a little cheesy.

well thats it as far as getting everything to work, not a easy thing to do but it is posible.
its just not as easy as all the rumors make it sound and i have found no pics or fine details on how to this at all.....till now.

so get to it guys...lol

[Mohgarr]

Hi there,

I'm currently tackling a similar project here myself. It seems to me that it would
be much easier to modify the FT500 rocker cover with external oiling lines and
cam bearing grooves that try and fight the 350x. Either way it will take some
time at the machine shop or VERY carefull hands. On another note... Does anyone
know of the possibility of using the FT500 crank/rod assembly in the 350x? Thanks
for the info.

:confused:

[MONSTER X RIDER]

wow:shocked: , Great job on the build and right up! I cant wait to hear how it runs. I was wondering if you could list the usable parts for a 350x 500 build? year, make, of the Honda 500 parts tha work? Im pretty intrested in doing a 500 coversion myself and want to start gathering parts. Also after doing your build, would you be intrested in maching another? If so, Please let me know. Thanx!!!:hail:

[SWIGIN]

Hi there,

I'm currently tackling a similar project here myself. It seems to me that it would
be much easier to modify the FT500 rocker cover with external oiling lines and
cam bearing grooves that try and fight the 350x. Either way it will take some
time at the machine shop or VERY carefull hands. On another note... Does anyone
know of the possibility of using the FT500 crank/rod assembly in the 350x? Thanks
for the info.

:confused:


i have no idea on useing the 500 crank in a 350 but i highly doubt it would go right in if at all.

and i stated someware why i used the 350x valve cover.....but another reason is on my 350rx (quad) i dont have the room for oil lines on top of the cover and it just seemed easyer to use the 350 cover

[SWIGIN]

wow:shocked: , Great job on the build and right up! I cant wait to hear how it runs. I was wondering if you could list the usable parts for a 350x 500 build? year, make, of the Honda 500 parts tha work? Im pretty intrested in doing a 500 coversion myself and want to start gathering parts. Also after doing your build, would you be intrested in maching another? If so, Please let me know. Thanx!!!:hail:



yeah i cant wait to get it running ether but my daughters car got rear ended and my mustang needs a tranny so this is on the back burner for awile.

but this does show how i made this all work and everything works well

[xcracer160]

man this thing oughts rip **** or bust

[Troll]

Great project!!!.................. :hail:

http://www.bmi.net/~trikegodtroll/pg7.htm
http://www.3wheeler.org/vb/showthread.php?t=4340&highlight=Ascot+500

[SWIGIN]

i got an update....my buddys 460cc (350x ported head not the ascot head) has bin runing for a month now and he's had 3 clutchs in it so far.

the 350x clutch wont hold...he has all NOS parts with new factory steels and so far hes tried factory fibers with barnett springs, barnett clutch with barnett springs and ether a ebc or a vesrha and the only one to hold for a hour was the all barnett setup.

he just called me as i was typing this and it seems he machined the stock basket and inner hub to take another steel and fiber disc (witch is the same nuber of discs the ascot has) so we will see if it holds now.

but with a slipping clutch it smokes all my other buddys race preped modded 450 quads

[SWIGIN]

the 7 fiber disc clutch didnt hold ether.......this cant be this hard

[350XBigbore]

What mill stroker crank does he have, I am about to buy a stroker crank for my big bore 350X and would like to know how to make the clutch live also. Who still makes the best stroker cranks for these old beasts now besides Powroll?

[SWIGIN]

Powroll... period

they only offer a 6mm crank witch is 460cc with a 89mm bore

as far as the clutch im not sure that the extra disc is needed......he called micky dunlope and he said he used to get custom clutch springs made just for monster motors and that you shouldnt be able to pull the clutch in easily with the right springs even with a easy pull lever.

he also said that HD springs are junk and only ment for stockish motors

we are looking onto getting some springs made or seeing if springs from another bike will work

i'll let you know what we come up with

[SWIGIN]

ok.....i put a bathroom scale in my shop press and at 1/2 inch compression stock 350x clutch springs are 53 pounds

i think id like to try some with 80-100 pounds.....any help would be great

[SWIGIN]

stock springs = 53#

new vesrah and barnett spring = 75# each

old barnett spring = 73#

so the 4 new barnett springs that are letting the clutch slip is putting 300# of presure on the clutch.

we found some aftermarket dual valve springs that acording to R&D will fit and they have 120# each...so thats 480#

this should work

[350XBigbore]

Cool, LMK when you get those new springs on the bike and working. I am going to buy a Powroll 6mill crank for my bike and a 12.5 compression piston along with some additional portwork. Do you know what size valves you can stuff into a 350x head?

[SWIGIN]

normally they just go 1mm

[350XBigbore]

Where can I buy bigger valves that fit the factory 350x head?

[SWIGIN]

call tcracingengines.com

i never wanted them and have seen tons of them bend (weaker then stock)

thats why im doing this ascott head swap.....but they have 5mm bigger valves and the stems are way fatter

[SWIGIN]

it seems the springs will work...or at least they did in a test run today.

we will see how they are after a few rides but the springs he ordered were back ordered so he got the next closest ones and they are 150lb instead of 120lb.

so thats 600lb clamping force and the clutch is not that bad to pull....luckily when you get to the stage of needing this kind of spring the motor dont need a lot of clutch work to get around the track

[Goat]

5mm larger valves from tom carlson? Does he still try to rape you on the prices?