Putting a different motor in a frame? [Archive]

hmurphy

25th May 2009, 22:18

My friend and I had never ever done this sort of thing before and we managed ok. We had to learn to weld using an arc welder. As long as your frame is steel (makes it easier) all you need is some scrap steel and a welder (MIG or arc, MIG is much better). It all depends on what frame and motor really. The motor needs to fit in nicely so that you don't need to modify the frame a whole lot (just modify the engine mounts really), and the motor needs to be positioned so that the front and rear sprockets line up.

If you haven't done this before and you have the tools to have a go, give it a shot. But TAKE YOUR TIME!!! You don't want a badly mounted motor, things might fly off the bike... like the chain or the motor itself if you are that unlucky!

The only experience I have with this was mounting a TS125 motor into an RGV150 frame which was quite easy really, but was a LOT of work because I was very inexperienced with the tools required etc.

What motor and frame were you looking at anyway?

Skunk

25th May 2009, 22:33

For Buckets you just need to do a good job of it. There's not many engine/frame combos that are standard really (mostly FXR150's and they don't count anyway). Talk to you local Bucket guys and I'm sure someone will help you out.

I've done several now and with a welder and some thinking and planning it's quite easy. Cost me about $20-$50 in bolts, gas, etc.

TerraRoot

26th May 2009, 02:17

get your self one of these bars

<img src="http://terraroot.neoneoism.com/wp-content/uploads/2009/04/0415image005.jpg"></img>

and set it against the chain wheels, as long as the chain run is straight don't sweat the rest.

LBD

26th May 2009, 05:03

How hard is it to get a motor in a frame that it wasnt made for? I'm guessing I would need to see an engineer? any idea of cost?

Mate it all depends on what you are attempting and what vintage. ie a 748 in a kdx 200 frame may be a challenge.

so..
Is frame designed for HP and weight of motor?
Was frame designed to use engine as stressed member?
Can you position primary sprocket in line with rear sprocket?

The rest is just a basic ?...Will it fit?

saxet

26th May 2009, 09:57

As LBD says..Can you line up front and rear sprockets...Use the straight edge and take your time to be sure it,s lined up..don't forget to consider what might be in the way e.g. suspesion linkages etc.

nudemetalz

26th May 2009, 10:14

My advice is to MEASURE MEASURE MEASURE !!!!!!!!!!
See if the bloody effing motor will actually fit into the frame without modifying the frame so much that you ask yourself why did you bother in the first place.
A four-stroke single will not go into an RGV150 frame very easily........ :no: :eek:

Buckets4Me

26th May 2009, 13:20

I've seen several rgv50's with honda 100's in them
and even a lonchin 150 :)

Skunk

26th May 2009, 14:05

A four-stroke single will not go into an RGV150 frame very easily........ :no: :eek:

I've seen several rgv50's... ...even a lonchin 150 :)You mean there's more than one nutcase out there? Who would've thunk it... :confused:

LBD

26th May 2009, 15:10

You mean there's more than one nutcase out there? Who would've thunk it... :confused:

Ungineers are by nature automatically included in the Nutcase contingent...and I know we are several on this site....

YellowDog

26th May 2009, 15:19

I would advise caution here. Actually getting the engine mounted is not the problem. It is how everything else hands together. If the engine is more powerful than the frame can handle, there are other tjhings to worry about. e.g. Brakes & dampers.

If you are swapping for a similar power output unit, then it shoildn't be a worry.

Skunk

26th May 2009, 16:06

YellowDog

26th May 2009, 17:02

Fair comment. I don't think 15Hp will kill anyone.

caseye

26th May 2009, 17:10

Will if it hops outa the frame and lands on their ead!
Give it a go mate, like the others have said, measure and align things and it'll all go fine.
If this was a road bike then all bets are off unless you really do know what you are doing/ Frame design,engine weight,frame flex,engine rigid or rubber mounted, integral frame component or not, all these things then come into play.
have fun an get someone to check what you have done if you are not sure, can't hurt to have a sceond opinion.

Yow Ling

26th May 2009, 17:51

The best thing I think you could do, is tell us what frame and what engine u thinking about, many people have spent hundreds of hours of their employers time figuring out what fits and what doesnt. some fits are easy some not, almost anything can be done. FXR engine wont fit in a RG50 frame easily, most other things will, I know this because somebody tried. Most things have been tried. Some things will fit and be lame (AX100). People know just ask

nudemetalz

26th May 2009, 18:07

I've seen several rgv50's with honda 100's in them
and even a lonchin 150 :)

Granted, but it's still a bastard of a job !!

DEATH_INC.

26th May 2009, 18:18

As said previously, what are ya putting in what? Most things are possible, it just comes down to how far you're willing to go.....

Buckets4Me

26th May 2009, 18:20

aha has anyone put an rg50 in a fxr frame ?????

<_<

Buckets4Me

26th May 2009, 18:21

Granted, but it's still a bastard of a job !!

thats why I got someone els to do mine lol
but it wasn't hard just needed checking and re welding lol

SHELRACING

26th May 2009, 19:47

I've done a few replants, great fun. Before you spend any money measure up, plan it out in your head especially the engine mounts, and exhaust if it's a 2 stroke the exhaust is really important.

As said before alignment of rear wheel sprocket and engine sprocket is probably the most critical consideration.

Tell us what you want to fit into what, someones almost certain to have tried it.

Rick 52

26th May 2009, 21:07

I'm doing a ER125 in a CR85 frame and the swinging arm bolt is the same diameter as the engine that makes it very easy to mount but lowering the bike could be tricky, has anyone cut upside down forkes ?

glice

26th May 2009, 21:22

Right. I guess I should have mentiond that at first. I'm looking at putting an fxr motor into an rg250 frame, so I'm pretty sure it would fit.
I dont have a welder. has anyone payed to have it done?

gav

26th May 2009, 23:55

Is it an early RG250? Good luck, you'll need to cut and modify the frame to fit, the motor doesn't appear to fit without cutting the frame.

glice

27th May 2009, 14:45

Is it an early RG250? Good luck, you'll need to cut and modify the frame to fit, the motor doesn't appear to fit without cutting the frame.

Oh ok, its an 85 I think. Havnt got it yet, was just wondering how hard it might be.

nudemetalz

27th May 2009, 16:15

One thing you want to look at is being able to strip the top end and barrel with the crankcase still in the frame.
We had to machine some of the cylinder fins off the top end of the Luncheon engine to slide it out the top. Not really ideal !!

vifferman

27th May 2009, 16:30

Sometimes you will be lucky and some engines from the same manufacturer will use common crankcases. For an example (stepping outside of buckets here), Honda used the same bottom end for some of their road and trail bikes. I had a XBR500RS Mutant which was a CB250RS with an XL or XR 500 donk. The lower mounts all lined up, but obviously the barrel was much bigger, so the top mount had to be cut off the engine (better than cutting the upper frame tube!) and the gas tank had to be "cut'n'shut". It meant though that there was precious little room around the engine, so the carb was rather squished and had to run a different intake manifold (shorter) and airfilter.

As for lining the sprockets up: while it's the ideal, sometimes it's better to get the engine sitting in the right place and use spacers to line the sprockets up (if they're only a few mm off being in line).

gav

27th May 2009, 17:02

Oh ok, its an 85 I think. Havnt got it yet, was just wondering how hard it might be.
The rocker cover of the FXR is rather large for a single and was going to be a struggle to fit. In the end I swapped the RG frame for another frame that was a perfect fit. <_<

SHELRACING

27th May 2009, 18:45

Right. I guess I should have mentiond that at first. I'm looking at putting an fxr motor into an rg250 frame, so I'm pretty sure it would fit.
I dont have a welder. has anyone payed to have it done?

Is your RG frame aluminium or steel. Easy to weld brackets and mounts to steel, bit harder if the frame is aluminium.

I fitted a FXR motor into a Yamaha Deltabox frame which worked very nicely. I don't know about anyone else but it takes me quite a while to design, fabricate and fit engine mounts, to pay someone may be rather costly. Got any welder mates who can help ??

Rick 52

27th May 2009, 19:01

Right. I guess I should have mentiond that at first. I'm looking at putting an fxr motor into an rg250 frame, so I'm pretty sure it would fit.
I dont have a welder. has anyone payed to have it done?

Is your fxr frame bent ? The fxr isn,t a bad frame just a little heavy how heavy will the new bike be when its finnished .I got my fxr down to 103kg wet and I think I could get it down well under 100kg .

gav

27th May 2009, 19:12

kevfromcoro

27th May 2009, 19:38

Just make sure you line the front and back sproket up within a knats cock.
otherwise you will be chomping through chains....
as for the rest of it .
just blolt it in

glice

27th May 2009, 21:25

The RG250 frame is aluminium, and being a two stroke twin, the upper area is alot more cramped than a deltabox frame designed for a four cylinder four stroke. Also is it the RG250 rolling chassis you are bidding on, on Trade Me? The 16" front wheel isnt ideal either, may struggle to find some decent rubber.

Yea that was the one, but I've missed out on it. unless the guy who won doesnt come through.
To be honest, it was just an idea to see what was available.

I'm pretty sure the frame is straight. it was in a big front end crash, so I have to put new forks, etc on.

Kendog

27th May 2009, 22:37

The RG250 frame is aluminium, and being a two stroke twin, the upper area is alot more cramped than a deltabox frame designed for a four cylinder four stroke. Also is it the RG250 rolling chassis you are bidding on, on Trade Me? The 16" front wheel isnt ideal either, may struggle to find some decent rubber.

I would agree with this.
We mounted a Loncin into my RG250 frame, had to chop the bottom of the fuel tank out to clear the carb.
I am not a fan of my 16 front wheel either :mellow:

Skunk

27th May 2009, 22:47

I am not a fan of my 16 front wheel either :mellow:
Harden The Fuck Up :lol:

Kendog

28th May 2009, 06:36

Harden The Fuck Up :lol:
Take my bike for a ride :bleh:

Skunk

28th May 2009, 07:34

Take my bike for a ride :bleh:
No. Too many strokes...

koba

28th May 2009, 07:35

I would agree with this.
We mounted a Loncin into my RG250 frame, had to chop the bottom of the fuel tank out to clear the carb.
I am not a fan of my 16 front wheel either :mellow:

Agreed also, I have a 16 incher on the VFR and its not the size of the instument thats the problem its the quality of rubber available to wrap around it :laugh:

Trudes

28th May 2009, 20:57

No. Too many strokes...

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glice

29th May 2009, 15:00

Agreed also, I have a 16 incher on the VFR and its not the size of the instument thats the problem its the quality of rubber available to wrap around it :laugh:

Yea I've just got myself an rg250 race bike, and I'm having trouble finding decent tyres. What do you run on the VFR?.
If missed out on the frame anyways, Cheers for the help everyone. Who knows I might find something else.

koba

30th May 2009, 12:13

Yea I've just got myself an rg250 race bike, and I'm having trouble finding decent tyres. What do you run on the VFR?.
If missed out on the frame anyways, Cheers for the help everyone. Who knows I might find something else.

Always a difficult question...

The narrow rims limit the tyres to whats available in those sizes.

Mine are 16/100/? oin the front and 18/130/? on the back.

There are quite alot of tyres available for the rear but the front it a real prick.

I use Pirelli Sport Deamons and they seem to work really quite well.

Other Tyres that MAY be available in your sizes are:
Avon Road Rider
Metzeler Lasertec
Michelin Pilot Activ
Bridgestone BT-45 (These are also quite good, I found them to last better than the pirellis but seem a little less grippy)
Dunlop GT501
IRC RX-01 (really good value for $ but not avail for 16 inch front)

The Sport Deamons seem good enough for the bike and do well in magazine write ups. I will keep buying them unless somthing comes along that looks like it may be better.

Now the obvious thing to do would be to change the rims to suit modern rubber sizes but there is a catch!

These odd tyre sizes are crossply tyres, which aren't as stiff as a modern radial, they work better on shitty old 1980's suspension so if you were to change rims to get new rubber it might not work quite as well as one would hope.
I tried a 17inch/120 supercorsa stretched over an NSR 100 wide rim on my VFR and it was sketchy as fuck and no-where near as good as the stock setup.

If you are going racing and gettting serious enough to want really good rubber I think (Havn't got that far yet myself)a full suspension, rim and tyre upgrade is probably worth looking at, it can also be done keeping to pre '89 stuff for posties.

glice

30th May 2009, 14:21

Always a difficult question...

The narrow rims limit the tyres to whats available in those sizes.

Mine are 16/100/? oin the front and 18/130/? on the back.

There are quite alot of tyres available for the rear but the front it a real prick.

I use Pirelli Sport Deamons and they seem to work really quite well.

Other Tyres that MAY be available in your sizes are:
Avon Road Rider
Metzeler Lasertec
Michelin Pilot Activ
Bridgestone BT-45 (These are also quite good, I found them to last better than the pirellis but seem a little less grippy)
Dunlop GT501
IRC RX-01 (really good value for $ but not avail for 16 inch front)

The Sport Deamons seem good enough for the bike and do well in magazine write ups. I will keep buying them unless somthing comes along that looks like it may be better.

Now the obvious thing to do would be to change the rims to suit modern rubber sizes but there is a catch!

These odd tyre sizes are crossply tyres, which aren't as stiff as a modern radial, they work better on shitty old 1980's suspension so if you were to change rims to get new rubber it might not work quite as well as one would hope.
I tried a 17inch/120 supercorsa stretched over an NSR 100 wide rim on my VFR and it was sketchy as fuck and no-where near as good as the stock setup.

If you are going racing and gettting serious enough to want really good rubber I think (Havn't got that far yet myself)a full suspension, rim and tyre upgrade is probably worth looking at, it can also be done keeping to pre '89 stuff for posties.

Sweet, cheers. Its got bt-45s at the moment, but I think I'll go to sports deamons when its time to change them. I had those on another bike and they seemed ok.

Yea I've got an 89 gsxr400 front end with a 120 tyre on it. I'm just not sure how I would go with the rear end.

koba

30th May 2009, 17:52

Sweet, cheers. Its got bt-45s at the moment, but I think I'll go to sports deamons when its time to change them. I had those on another bike and they seemed ok.

Yea I've got an 89 gsxr400 front end with a 120 tyre on it. I'm just not sure how I would go with the rear end.

Bt45 are still really good aye, theres not alot in it but yeah I do preferr the sport deamons.

As for the suspension there is only one way to find out...

quallman1234

31st May 2009, 20:30

Sketchy_Racer

31st May 2009, 20:58

There's actually heaps of 16's out there what are sticky enough for buckets, the problem is usually you have to buy em brand new unless your really lucky and spot some on tardme.
I can't justify buying a new 16 inch tyre when i have a fxr front rim with a 125 slick on it waiting for me.

P.s Kendog, HTFU! Sketchy said your bike was a freaken awesome handler! :D

hmm, I don't quite remember saying those words exactly Kyle, but It it handles ok once you get your head around the weird turning in sensation the 16" front rim gives. So you are going to get that front rim and put it in your bike? You should it would be a good improvement.

quallman1234

1st June 2009, 17:43

hmm, I don't quite remember saying those words exactly Kyle, but It it handles ok once you get your head around the weird turning in sensation the 16" front rim gives. So you are going to get that front rim and put it in your bike? You should it would be a good improvement.

Oh whoops, sorry my bad.

Yeah hopefully if i can budge it. Still more important things to go tho.