Jump to content
Sign in to follow this  

XR600 RFVC Engined Honda CRF 600 Supermoto project!

Recommended Posts

So here it begins!

Basicly i want to build a supermoto that i can road register and ride daily without having to worry about the high costs of running a motorcross engine on the road..

Some of you may be familiar with me already as i started a post a few weeks ago about what engine should i try and fit into a spare cr125 frame i had knocking about.. I had some good ideas sent my way but i wanted to keep the bike Honda engined and prefably have atleast 500-600cc.

http://www.thumperta...ine-conversion/

I did abit of research on various motocross engine conversions and there wasnt much out there, ive seen a RXV with a ej6 engine so that made me believe anything was possible!

Then i found the crf/xr440 that has been mentiond on here a few times so i decided i was going to do the same but with the 600 motor!

http://www.youtube.com/watch?v=2EYgwgdk8uI

Any way, a RFVC xl600 engine came up cheap with loom, carb and exhaust, so i snapped it up and decided that this will be the beast that we will fit to the cr125 frame.

I made the trip to collect the frame and it wasnt untill i got there that i realised how massive the engine is compared to a crf450 and im not even going to talk about the back breaking weight! But not to be put of once ive commited to something i bought the engine and began the project!

The engine isnt pritty, its been painted 3 or 4 times but i have most of the paint of now

DSCF3782_zps5156e7ae.jpg

DSCF3783_zpsa6a5216d.jpg

So the next step was to cut up the 125 frame to see if it would actully fit in!, so i took it upto a friend who builds alot of bikes and he got it tempory fitted into the frame in the correct position so i can build it up as much as i can before we go any further to see if its actully do-able

DSCF3786_zps42ce717f.jpg

DSCF3789_zps0abeadbd.jpg

DSCF3791_zps00e3b25d.jpg

DSCF3792_zps882d1308.jpg

I think it fits pritty well considering the size of it!, the next challange is to come up with an idea for the carbs. The xl600 orignaly came with twin carbs, there just isnt enough room for them, its very close mind, the carbs with fit in the frame without the manifold but with the manifold they will need some modification..

DSCF3793_zps6a2acb26.jpg

DSCF3794_zpsb2190310.jpg

with manifold

DSCF3796_zpsd49c17b4.jpg

DSCF3797_zpsc782299b.jpg

without manifold

DSCF3798_zpsd65af060.jpg

DSCF3799_zps6d8c5ec8.jpg

DSCF3800_zpsf7bc6f15.jpg

DSCF3801_zps7449f8c1.jpg

DSCF3802_zps1b16a9bb.jpg

I think the only realistic option is to run a single carb like the xr650's.. but would this mean chainging my duel carb head to a single carb one?

Edited by McGoo 69

Share this post


Link to post
Share on other sites

Ive also got an Aprilia RXV swingarm for this, and i know that to fit it to a crf frame you have to mill abit of the swingarm, but from what ive read about other rxv swingarm conversions you dont have to take alot of "meat" of the swingarm to get it into a crf frame but it looks like i may have to take abit more of for it to fit into a cr125 frame, what do you think?

i dont want to modifiy the swingarm too soon then find out this conversion wont work then ill be left with a RXV swingarm thats only useable on a cr125.

DSCF3812_zpsbba40c01.jpg

DSCF3813_zpsf471c751.jpg

DSCF3815_zpsd0d02cf7.jpg

And heres the money shot! 👍

DSCF3806_zps1f534320.jpg

So thats basicly how far ive got for now, im curious to hear any concerns or ideas for this project as its a bit of a one of so any useful ideas or input would be appriciated!

thanks for reading if you got this far :goofy:

Matty

Share this post


Link to post
Share on other sites

Well... I have an sxv.... with a.... Blown head gasket.

Look up project kxf300exc on here.

Is that an xr or XL motor I'm thinking XL because I don't see a kicker.

I hope your good with at tig welding aluminum.

I wish you luck with this project my friend.

Share this post


Link to post
Share on other sites

Looking at your dark marker on your left side frame for cutting the frame rail in order to allow clearance for the decompression cover... Remove the cover, remove the valve! Get rid of the cover and make a nice flat cover that might be able to fit inside the frame tube without cutting it! It will work fine.

Swiss

Lot of work to go! I like your swingarm.

Edited by Swiss

Share this post


Link to post
Share on other sites

I'll go out on a limb and say we never see this running. I don't base this on your skills as a builder/fabricator, but simply on the many, many threads like this that never get completed. I hope you prove me wrong!

Share this post


Link to post
Share on other sites

Well... I have an sxv.... with a.... Blown head gasket.

Look up project kxf300exc on here.

Is that an xr or XL motor I'm thinking XL because I don't see a kicker.

I hope your good with at tig welding aluminum.

I wish you luck with this project my friend.

its an xl i belive and it does have a kicker

i wont be doing the welding my friend does that and hes built a fair few bikes/frames etc

Looking at your dark marker on your left side frame for cutting the frame rail in order to allow clearance for the decompression cover... Remove the cover, remove the valve! Get rid of the cover and make a nice flat cover that might be able to fit inside the frame tube without cutting it! It will work fine.

Swiss

Lot of work to go! I like your swingarm.

id like to remove as much of the engine as possible but i dont know much about the rfvc's except there bulit proof.. i have a feeling ill regret taking the decomp of mind,

I'll go out on a limb and say we never see this running. I don't base this on your skills as a builder/fabricator, but simply on the many, many threads like this that never get completed. I hope you prove me wrong!

you could be right, im not saying this conversion is possible, im just giving it a go, it was ambitious from the get go but if im going to do an engine conversion i may aswell do it properly! haha

im here for ideas to get around any problems during the build, i just wanted to get the mock up out there so i can see peoples thoughts or concerns, the only thing i have lost is a spare frame.

Share this post


Link to post
Share on other sites

How about no carbs? Go EFI with Microsquirt.

i have thought about fuel injection but it cannot be cheap?

do you have any info on microsquirt

Share this post


Link to post
Share on other sites

i have thought about fuel injection but it cannot be cheap?

do you have any info on microsquirt

No, I've got a older car I'm going to to an EFI conversion with Megasquirt, but don't know enough about it. But here's some info. http://www.diyautotune.com/catalog/microsquirt-c-35.html Search the web. There are a few Microsquirt conversions.

Share this post


Link to post
Share on other sites

That big Honda motor would be a great candidate for MicroSquirt injection... I imagine it will be very tolerant of running while the air / fuel maps are getting sorted out. You'll just have to find the appropriate throttle body to run. That would be awesome!

-Tom

Share this post


Link to post
Share on other sites

well if your buddy can tig weld he could probably make a full tubed intake for it. i have seen this done on cars and i see no reason for it not to work here.

Share this post


Link to post
Share on other sites

No, I've got a older car I'm going to to an EFI conversion with Megasquirt, but don't know enough about it. But here's some info. http://www.diyautotu...quirt-c-35.html Search the web. There are a few Microsquirt conversions.

yes im familier with megasquirt etc but i didnt realise you could do the same to a motorbike engine funing a carb.

That big Honda motor would be a great candidate for MicroSquirt injection... I imagine it will be very tolerant of running while the air / fuel maps are getting sorted out. You'll just have to find the appropriate throttle body to run. That would be awesome!

-Tom

its a possibility for sure, just an expensive one, im going to look into it

well if your buddy can tig weld he could probably make a full tubed intake for it. i have seen this done on cars and i see no reason for it not to work here.

yes i can make a tubed intake, that isnt the issue, the issue i have is that i assume id need equal length manifolds for each port else it will run shite..

you do realize you have like 35 hp max coming from this motor, right?

more than that its atleast 40hp when new but i dont see your point?

Share this post


Link to post
Share on other sites

more than that its atleast 40hp when new but i dont see your point?

Just use a 450F motor instead. Far more available power/torque with less vibration too. 40HP stock on a XR600 or XR650L did/does not happen.

Share this post


Link to post
Share on other sites
I think the only realistic option is to run a single carb like the xr650's.. but would this mean chainging my duel carb head to a single carb one?

It would be most straighforward to use the whole top end from an '88+ XR600....cylinder, head, cam valvetrain, chain, etc. '88+ engines have 9mm head bolts while earlier ones have 8mm. You could use just the complete head assembly if you had some stepped alignment dowls and head bolt bushings made.

40HP stock on a XR600 or XR650L did/does not happen.

It did with the twin carburetor engines.

Share this post


Link to post
Share on other sites

It would be most straighforward to use the whole top end from an '88+ XR600....cylinder, head, cam valvetrain, chain, etc. '88+ engines have 9mm head bolts while earlier ones have 8mm. You could use just the complete head assembly if you had some stepped alignment dowls and head bolt bushings made.

cheers for the info, i knew it was possible.. this is the sort of info i need. ill keep my eye out for a xr600 top end

if yo know of any conversion guides send them my way

thanks

matty

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×
×
  • Create New...