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smegballs |
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smegballs World Chat Champion
Joined: 28 Oct 2007 Karma :
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Posted: 00:23 - 28 Apr 2014 Post subject: GN 250 - Touring Project |
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Here it is as I got it. Picked it up for £450 with 3 months T&T.
https://i.imgur.com/TjxKNvs.jpg
I plan to ride it to portugal later this year (the long way thru france) so want to get everything tip-top to have the best chances of surviving the trip.
Done so far:
Oil, filter and plug changed.
MX bars installed.
Rear rack installed.
Voltmeter installed.
Stuff to do:
Install 11mm master cylinder.
Stainless steel brake piston + seals.
Change wheel bearings.
Install gayters.
Change fork oil.
Upgrade lighting.
I'll post up pics for the more unusual stuff as well as the maths involved for stuff like sizing master cylinders, so people have a something to refer to for future projects. |
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TUG |
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TUG World Chat Champion
Joined: 12 May 2007 Karma :
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Posted: 05:26 - 28 Apr 2014 Post subject: |
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I have some fork gators you can have, I probably won't be riding in winter or poor weather conditions so I have no need for them.
If you want some pics let me know or look at my thread. ____________________ Haz ER-5, innit! |
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smegballs |
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smegballs World Chat Champion
Joined: 28 Oct 2007 Karma :
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Posted: 08:36 - 28 Apr 2014 Post subject: |
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I've actually got the giaters already, just need to get them fitted. Thanks for the offer though.
Already coming to the thing of, well if the forks are coming off.... might as well change the oil at the same time. Then if the oil is being changed might as well do the seals too...
Fork cap is a ridiculous contraption, not threaded, rather held in with a circlip.... |
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TUG |
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TUG World Chat Champion
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smegballs |
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smegballs World Chat Champion
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TUG |
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TUG World Chat Champion
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hmmmnz |
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hmmmnz Super Spammer
Joined: 22 Aug 2006 Karma :
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Posted: 09:33 - 28 Apr 2014 Post subject: |
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i think every kiwi biker has had one of those as a learner bike,
they may be slow, ugly, handle like poo and slow but they are reliable, i bet if you just did the valve clearances, and changed the oil and filter, you could head off tomorrow and have no dramas, ____________________ the humans are dead
I kick arse for the lord
Wiring Diagrams BIDNIP it bitches |
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smegballs |
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smegballs World Chat Champion
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STONEY! |
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STONEY! Brolly Dolly
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smegballs |
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smegballs World Chat Champion
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slowlydoesit |
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slowlydoesit Could Be A Chat Bot
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Teflon-Mike |
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Teflon-Mike tl;dr
Joined: 01 Jun 2010 Karma :
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smegballs |
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smegballs World Chat Champion
Joined: 28 Oct 2007 Karma :
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Posted: 15:18 - 28 Apr 2014 Post subject: |
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Well I wanted something cheap to go touring on, so I was looking at C90s and Yamaha Townmate 80s. Both of these seemed to be running around 400-600 quid depending on condition, insurance was 170 for both of these. Fuel economy was the primary consideration here.
So then I widened my search a little to four stroke 125's as well, insurance was 200 for all the ones I looked at, Yam SR, Honda City Fly etc etc.
Then up on the local gumtree sprouted this GN for 450 with three months tax and test. Everything looked in order and insurance was still only 200, I've no doubt it will fly thru the MOT in July. Should still do 70/80 mpg at a 50mph cruise so altho not the 100+ mpg of the stup-thrus still will only cost a shade over 100 quid to ride down to portugal where I'll stay for a few months before coming back.
Consider that last summer I was touring portugal on a bike that derived it's power from my legs the modest progress afforded by the GN will be quite alright. It should be reliable, simple to fix and a not a massive theft magnet.
Moar pichers:
https://i.imgur.com/cpSGsYk.jpg
https://i.imgur.com/jNQ9GAO.jpg
https://i.imgur.com/G5nnUQx.jpg
That weird pink thing on the left bar is my GPS speedo mount. I use an old blackberry as a GPS Speedo. It is a clear pencil case and a pair of zip ties..... Cost less than 2 quid.
Third pic is the voltmeter I installed. I took the tacho off, uncrimped the housing, put a drop of machine oil on the coil spring and installed the voltmeter onto the clock face before sealing it all up again.
So much nicer to ride with the flat bars. I can pretend the cruisery rear end doesn't exist for now. I've been pondering making a new seat from scratch. As I lack the tooling to make a sheet metal one, I reckon some hardwood fly would be sufficiently strong. |
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mattsprattuk |
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mattsprattuk Super Spammer
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hmmmnz |
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hmmmnz Super Spammer
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pepperami |
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STONEY! |
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STONEY! Brolly Dolly
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smegballs |
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smegballs World Chat Champion
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Posted: 15:09 - 02 May 2014 Post subject: |
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Welp, my shiny new stainless brake piston and seals arrived today, new master cylinder came earlier in the week. Even got a new stainless nipple, red rubber grease hasn't arrived tho so I'll have to wait |
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smegballs |
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smegballs World Chat Champion
Joined: 28 Oct 2007 Karma :
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Posted: 22:00 - 03 May 2014 Post subject: |
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RRG arrived today so got the front brake rebuilt.
https://i.imgur.com/Qv8vBLgl.jpg
Parts ready for action, including 11mm R125 master cylinder.
https://i.imgur.com/NU25EsYl.jpg
Manky piston.
https://i.imgur.com/RYX1FUSl.jpg
Treacle type substance.
https://i.imgur.com/940RCvcl.jpg
Nice sludge filled caliper.
https://i.imgur.com/Nbbh0XAl.jpg
Old piston next to shiny stainless one.
https://i.imgur.com/vy67ioHl.jpg
Place caliper on a baking tray and bake at 120 degrees for 15 mins.
https://i.imgur.com/yExEHASl.jpg
https://i.imgur.com/TG5vXG1l.jpghttps://i.imgur.com/aYfaPall.jpg
Quite a lot of pitting on the original piston after I cleaning it up, I'm pretty glad I just manned up and bought the stainless one when I got the new seals.
Got the whole lot back together with lots of nice red rubber grease. It's the first time I've used RRG and it is awesome stuff! The piston slid right into the caliper with just a little thumb pressure.
Brakes are awesome now, easy 2-finger stopper with barely any effort. The lever does come all the way back to the bar though, when static and squeezing with my whole hand. In practice though the wheel would look at (I'm guessing) 1/2 and 2/3's of the lever travel, it doesn't take much to haul the bike right up! Is this an MOT failure? Even tho the lever can touch the bar with excessive force, in riding use the braking power is very much improved! Now just to address the fork dive! |
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i.p.phrealy |
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i.p.phrealy World Chat Champion
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slowlydoesit |
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smegballs |
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smegballs World Chat Champion
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BenR |
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BenR World Chat Champion
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pepperami |
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pepperami Super Spammer
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Posted: 10:03 - 04 May 2014 Post subject: |
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Well Mr Smegballs!
I am enjoying this thread
MOAR NOW!.
If you make this bike road-worthy and don't tour on it, we will come round your house ____________________ I am the sum total of my own existence, what went before makes me who I am now! |
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Teflon-Mike |
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Teflon-Mike tl;dr
Joined: 01 Jun 2010 Karma :
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Posted: 11:36 - 04 May 2014 Post subject: |
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smegballs wrote: | The lever does come all the way back to the bar though, when static and squeezing with my whole hand. |
BenR wrote: | An old trick you could try is to cable tie the brake lever & leave it overnight. |
That's if it still has any air in the lines; yes, good trick.
This ere' brake be a bit of a hybrid though, with Yamaha R125 master cylinder and Suzuki GN250 caliper.
Smegs;
1/ Whats the new master cyl sizing compared to original?
2/ Is the new Master cyl, gen Yamaha Spares?
3/ Whats the lever on it?
Thoughts occuring to me, after eliminating air in the pipes;
1/ New master may be slightly under-sized compared to original, hence takes more travel to get same piston pressure; in which case may be a mis-match you cant solve other than by a different substitution.
2/ If copy cyl or lever... then it MIGHT be possible to shim the actuation cam on the heel of the lever so that it moves lever at 'rest' further from the bar.
I have done this a few times as I have big hands; using M6 washers on the end of the master-cyl piston; on one cyl I had to file a little metal off the back of the lever so that it would return fully, but with a little jiggling with file and washers you can get quite a significant difference in lever angle vs take up point.
But do it fucking carefully, if you try! If you have no clerance on the end of the master cyl piston you can end up 'jacking up' never fully relieving pressure on the caliper, so every time you brake it tightens up.
Could be worth a mess, though.
As for MOT Fail for touching bars; they test brake efficiency, Rollers put force on wheel, tester pulls in brake, and it has to stop the rollers. Provided it does that before lever touches bar, should pass... but dont rely on a static lock test as your guide, rollers are putting a lot more force on the brake than you pushing against it.
Snowie's 'Pup' brake lever is similar; she has tiny hands, so her brake lever heel-cam has been filed to bring the 'take up' point closer to the bar, so she can get her fingers around it at 'rest'.. was also re-shaped a tad to increase the take up rate to compensate a bit, but even with stanless braided line, I can get the lever to touch the grip if I pull it hard enough... though wheel's well locked well before, and MOT efficieny test'passed' long before.
smegballs wrote: | Now just to address the fork dive! |
Have you got round to replacing fork seals yet?
smegballs wrote: | well if the forks are coming off.... might as well change the oil at the same time. Then if the oil is being changed might as well do the seals too... |
Did you measure the fork-spring free-length? Cos they could have gone soft with age; new ones would stiffen it up a bit, if you can get them, and old trick is to use 2p pieces on the top under the fork cap to shim them up to add pre-load, again, stiffening up the initial rate a bit.( & one chap I knew, used to use Diesel Truck engine valve springs to 'extend' dirt-bike fork springs.)
New oil, often makes a workd of difference and makes damping 'smooth' again; but if oil fork oil REALLY shitty, then can have gone 'thick' or previouse owner could have stuck anything in there, really, like engine oil! And new fork oil of correct grade have much lower effective weight. Found a few people find overhauled forks rather 'soft' when rebuilt to book, for this sort of reason. However, one weight 'up' from book, is usually quite helpful.
But a bit of 'dive' is just a feature of old bikes and lightweights I think... you just have to be a bit more 'predictive' and easy on the anchors and not load them up too quick... technique over technology. ____________________ My Webby'Tef's-tQ, loads of stuff about my bikes, my Land-Rovers, and the stuff I do with them!
Current Bikes:'Honda VF1000F' ;'CB750F2N' ;'CB125TD ( 6 3 of em!)'; 'Montesa Cota 248'. Learner FAQ's:= 'U want to Ride a Motorbike! Where Do U start?' |
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Old Thread Alert!
The last post was made 9 years, 362 days ago. Instead of replying here, would creating a new thread be more useful? |
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