Lord Gruntfuttock

Lord Gruntfuttock's 1973 Honda Trail 90 (CT90)

Recommended Posts

So bought another bike last week, just cos it was local and a mate was egging me on with talk of epic cross country rides. This is a 1973 K4 model in Mars orange, 90cc and a precursor to the ubiquitous red 110cc postie bike. I think lots of parts are interchangeable, so should be plenty of sources for the missing bits...

Picked it up yesterday, couple of kicks and she burst into life, I rode it round the house and jemmied it into the overflowing shed...

And even better, picked this up this morning, local and $26. Sweet deal, rough as fuck but has a few bits I need...

So unsure of plans at this stage, too much on to get into it immediately. Will prob keep patina (rust) and replace bearings, brake shoes, cables etc. Loosely planning some overland trips, also the odd scooter run, should be fun once I get some time to play with it...

  • Like 8

Share this post

Link to post
Share on other sites

So picked up the donor CT last night, fair to say the seller was a bit........ odd.

There was a mixup over what bike I'd bought, and he led me through town in the dark then back to his lair in between bouts of abuse - thought I'd have to text my mate the address so's they could find my head. Anyways, survived and got it home, and its up there as the best $26 I've spent on a pile of rust...

Yeah it has some serious rot - looks like it's laid in a hedge for some time so the tinware's pretty much fucked, and the rear wheel is locked so took a bit of shoving to shift it, BUT, it kicks over ok, seems to have compression and the oil looks clean enough...

Plus it has the battery cover (normally missing) and a good plastic downtube cover, and it has the ignition switch, key and helmet lock, and the seat pan may be ok. Best thing is, after I dislodged the battery cover (rusty screw) it had a FULL tool kit in the bag underneath - Woohoo... :cheers:


Really want to rip into it to see if the frame/motor are salvageable for a special, but as I need a new project like another hole in my arse I'll chuck this under a tarp till I have some space and time to deal with it properly.

Doesn't stop me squirelling parts for the orange roughy though (already bought a cable set and brake shoes). I was going to paint the plastics period grey cos it looks cool, but I may just fit them as is to make a fully functional but ratty looking machine, (wife's had me doing house reno stuff so a bit over sanding and painting at the moment). Also nudging my cobber hard to get one himself for rally giggles, shouldn't be too hard, he's got 9 on his watchlist... :)

  • Like 3

Share this post

Link to post
Share on other sites

Grabbed a seat off tardme and new cover from Ebay as both seats are pretty well koozed.

Donor seat has good base but cover is shagged and has section rubbed off the rear of the foam...



Cut rear bit off with electric carving knife and glued on piece from buggered seat...



And trimmed it to suit profile, glued down any loose bits and covered whole seat with thin smoothing foam (cushion foam from Spotlight)...


Gotta stop here as waiting for rubber edge trim to arrive from the net before fitting the cover, but looking promising...

Share this post

Link to post
Share on other sites

Made a start on the mechanicals - pulled carb to inspect, doesn't look too bad apart from a munted air mixture screw that I needed to drill and remove with an ezi-out...




Good clean up and replacement parts from Keyster carb kit, but need some bits for petcock as well so had to stop there...




  • Like 1

Share this post

Link to post
Share on other sites

And while waiting for bits decided to strip the donor bike rusting away in the back yard. The body's more rooted than I hoped, nothing holding the rear suspension points on apart from the carrier, so she's a parts bike...


I'll use the fuel tank on the orange roughy as it's easier than cleaning up a rusty one, but as I was chucking bits on the trailer to go to the tip I had an Aha moment... :-D


My $20 QA50 frame I got at the recycling centre and $26 CT110 should let me make a cheap minibike death machine. :mrgreen:


  • Like 4

Share this post

Link to post
Share on other sites

Pulled forks to inspect. They felt good so I was unpleasantly surprised when what looked like water poured out of the drain plug, then thick, grey poo glooped out...


And the tubes were a bastard to remove, definitely wouldn't slide out, and only when I dropped the tree did I see the rust holding them in. (The bolts are in backwards here pressing against washers to try to spread the clamp).


When I got the tubes out they were rusty over the seal area too, so pulled donor bike forks to see if they were useable. Sliders are in much better shape (top tube)...


I've got a set of taper roller steering head bearings, so will see what bits looks best/what fits and try to make a hybrid fork set from the best of both bikes...

Also cleaned up brake hubs, they were pretty much seized, and the speedo drive tabs were flattened on the front wheel so bent them back into position and greased speedo drive/fitted new seal...



New sealed bearings in too, and wire brushed and etch primed rims before fitting new tubes and tyres...



Waiting on some seals and new cush rubbers to arrive before I can continue. In two minds now about painting it while it's in bits. Can't really be arsed so think I'll use that as an excuse to keep the patina (rust) and just have it mechanically sorted. Gonna be a bit of a Frankenbike anyway.... :)


  • Like 3

Share this post

Link to post
Share on other sites



got any spare gear stick/pedal/things? need a double rocker as my cub has a 'normal' style one fitted

Share this post

Link to post
Share on other sites

chur! would love to see ya do a dual tank ride from brimmed to empty in one hit haha

Share this post

Link to post
Share on other sites

oooh tapers...


oooh other new bits...


And a new front sprocket to match.

CT90 front sprocket = $$$$$

ATC 90/110 front sprocket = $

(zact same thing)...




Appears the old oil screen needed a clean too ...


  • Like 5

Share this post

Link to post
Share on other sites

got any spare gear stick/pedal/things? need a double rocker as my cub has a 'normal' style one fitted

Seems I have 3 (orange roughy, donor bike and a pattern new one). All slightly different and you're welcome to one. Only prob is I'm not sure which one I'll be using till it's running and can see what works best...

Share this post

Link to post
Share on other sites

all good mate I found one the other day actually. 

I think i'm in the same boat though, haven't ridden with it fitted yet so may be pretty yuck (was off a different model) so will see that the go is and modify from there. 

Share this post

Link to post
Share on other sites

Been away but got 30 mins in the shed yesterday. Wasn't going to take covers off but what looked like gobs of bathroom sealant changed my mind, so I pulled cyl head and rocker arm covers and cleaned up gasket surfaces...


Also wire brushed and spray bombed cylinder with engine paint, came out looking ok considering I masked it with a piece of cardboard...



Gotta grab a 23mm socket to get stuck inspection caps off, seems someone has gorilla torqued them on. Looking at Aliexpress exhaust options too, pretty sure I can rig up a cheap system...

Share this post

Link to post
Share on other sites

Since I paid $400 for the bike I didn't want to spend $200 on an exhaust system, so considered a thumpstar header pipe from tardme worth a punt ($27 delivered)...

It had a different flange mounting system so I scribed around  it 10mm from the welded end...

Cut around it with a teeny dremel cutoff disc, and levered it off...


And (after redrilling the wonky flange clamp holes) it fits. :)

Fitted some stainless studs with brass nuts while I was at it...

And spun a couple of brass plumbing fittings into an adapter to the 38mm Aliexpress muffler ($36 delivered). Left some thread grooves  on just for effect...


And looks like it'll work. Just need to mount muffler clamp on a standoff... ykugtujv.ytc.jpg


Less than $70 all up, great success...


  • Like 4

Share this post

Link to post
Share on other sites

Progress, not far off kicking it over...


Looks like a shitta but has good bits like new bearings, tyres, brakes, cables, stainless bolts...


And cheap zorst looks like it'll work, have to check clearances of plastic bits...


And seat cover finished, plus new grips, levers, blinkers etc, pretty much hard work is done...


Sort electrics, set carb, clutch etc and fill with fluids should be good for a ride...  :)

  • Like 5

Share this post

Link to post
Share on other sites

Looked at pipe clearances before bolting things up properly and header is touching the bash plate bar...


Surprisingly a 4lb club adjuster didn't fix it, so trimmed a little off the end, angling it for better clearance of side cover. Got a few mm clearance now...


And I was trying not to paint anything, but the donor battery box was a bit scody so decided to clean the rust off and chuck some epoxy on it.


And since I was doing that thought I'd try painting the spare red plastics, mainly cos 70's orange & grey looks sweet. Just reshaped the melted airbox with a heat gun and scuffed them up...


Really rough colour match as just mixed grey and black durepox to an approximate shade. Hopefully the pox will stick to the different plastics ok...


and... probably the worst paint job in the world. :)


I'm a shit painter anyway, but (excuses) the gun blocked, a gasket blew on compressor half way thru, I ran out of reducer, was pressed for time and it was raining. I'm telling myself it won't matter as this is a cheap shitta, but I'm thinking of rubbing it down and redoing it properly, cos embarrassing...

Hope the first coat sticks.

  • Like 2

Share this post

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.