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redeem ouzzer |
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redeem ouzzer World Chat Champion
Joined: 06 Oct 2015 Karma :
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Posted: 23:04 - 13 Dec 2017 Post subject: |
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While my YR5 was in bits getting it's dodgy side stand bracket fixed I decided to pull the clutch cover off and investigate the somewhat erratic clutch assembly. Didn't find anything obviously wrong with the clutch
But did discover a primary gear in the process of eating it's way through the clutch side crank seal :o
https://i.imgur.com/5kbFrGX.jpg
https://i.imgur.com/tngyazg.jpg
https://i.imgur.com/Hgb9IIm.jpg
The later RD's use ribbed crank seals so this can't happen, and it's fair to assume Yamaha changed the design for a reason. I've taken the plunge and sourced a set of later cases from an RD250B, which also gives me the bonus of a Euro spec 6 speed box with close ratio 4th / 5th / 6th, certainly a desirable modification!
The bottom end I bought had some damage from a previous chain break so so it's away getting welded, then I can get on with building what is hopefully the definitve engine. I'm also well on with rebuilding the rolling chassis after the stand repair, going for clipons this time, lighter headlight brackets and a new clock setup (couldn't be arsed with Koso / Acewell shit so homebrewing something with various old Yamaha bits that should work well and cost sod all). Pics to follow over xmas. ____________________ Be a REAL MAN! |
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stevo as b4 |
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stevo as b4 World Chat Champion
Joined: 17 Jul 2003 Karma :
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redeem ouzzer |
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redeem ouzzer World Chat Champion
Joined: 06 Oct 2015 Karma :
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Posted: 00:04 - 01 Feb 2018 Post subject: |
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I've been busy but most of it's been waiting for my tuner / fabricator to work his magic.
Crusty 250B euro spec bottom end complete with Smilered top case from broken chain.
https://farm5.staticflickr.com/4675/39301755024_4dc28f4e73_k.jpgIMG_3845
And after blasting and artisan level repair. Looks better than original.
https://farm5.staticflickr.com/4748/39301753534_a7800a9b38_k.jpgIMG_3938
Engine is back together (Vito crank, top end and gearbox bearings from original engine combined with 6 speed CR box and dropped in new casings with later crank seals) and back in the frame.
Major point of consternation has been the clocks. The chinese specials originally fitted looked good but didn't work and the rogue battery issue took out most of the LED's. I toyed with the idea of using a Koso or some shit but it's a lot of money. So I came up with this -
Butchered original clock bracket in unholy matrimony with a 250/400E clock bracket. 250/400E Speedo, TDR250 tacho using LT pulse from coil (seems Yamaha do the calculation for wasted spark in the clock rather than the CDI so it reads fine), i couldn't get any tacho to respond to the pulse from the Zeeltronic unit. Light unit from egay.
https://farm5.staticflickr.com/4750/26138482338_1b2ef070dc_k.jpgIMG_3955
Test fitted ok, wiring harness made. I've stripped it to paint all the metal work and will fit it properly at the weekend. Also in the photo note presence of clip ons and preload adjustable fork caps, because race bike.
While speaking to my tuner about the upper case fail it transpired he had a set of the Indian 350 barrels in his cupboard that never made it onto his 250 special. Price was agreed plus cost of doing the same tune onto them before collection. Once i get them decked and some pistons sorted i'll have a spare top end of the same spec so if i have any issues or it needs a rebore I can just swop barrels.
https://farm5.staticflickr.com/4745/39979516302_7c7b608637_z.jpgIMG_3935 ____________________ Be a REAL MAN! |
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trevor saxe-coburg-gotha |
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trevor saxe-coburg-gotha World Chat Champion
Joined: 22 Nov 2012 Karma :
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redeem ouzzer |
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redeem ouzzer World Chat Champion
Joined: 06 Oct 2015 Karma :
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Posted: 22:19 - 02 Apr 2018 Post subject: |
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trevor saxe-coburg-gotha wrote: | |
Yeah I saw that. Almost identical to mine ____________________ Be a REAL MAN! |
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stevo as b4 |
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stevo as b4 World Chat Champion
Joined: 17 Jul 2003 Karma :
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redeem ouzzer |
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redeem ouzzer World Chat Champion
Joined: 06 Oct 2015 Karma :
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Posted: 21:13 - 08 Apr 2018 Post subject: |
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stevo as b4 wrote: | How much of the gains you saw in performance do you feel can be attributed to the tuned cylinders alone?
I'm stopping at 125 tuning at std port maps, as I just want to see what everything else can do for my engine and see the best numbers I can, before fitting a ported 191cc top end and starting again.
Silly way to waste money, but I'd only go buying new or more bikes if I didn't mess with it until my curiosity has been satisfied.
Would you go to a YPVS lump in yours if you wanted to develop it further, or do you have a line to draw under it too? |
I think the tuned cylinders make a hell of a difference, as well as the JL pipes. You can’t make power without revs and the JL pipes extend the rev range which also fits in with the easier breathing from the bigger ports. The ignition makes it a) more reliable and b) gives the ability to ease some of the peakiness which will always be an issue with a massive fixed exhaust port and huge expansion chambers. It’s still fucking useless below 7k in higher gears but before fiddling with the curves it had a huge hole at 5.5k where it would buck and stutter. I can also back it off near the redline to help cooling and reliability. The squish is a bit big at the moment, it wants to be 0.9mm but it’s about 1.2mm, so that’s a job to do. Other than a dyno session once the squish is done that’s about it, possibly a switch to YPVS reed blocks. Once you cross the 60bhp rubicon on an aircooled you start poking the unreliability god with a big stick as well as making it even more horrible to ride.
Funnily enough I was considering the YPVS route in the bath earlier, but narp, I want it to maintain its aircooled routes and then you’d be looking at R1 front ends and monoshock rear, which defeats the point as you’d be better off buying a 3MA or 3XV. ____________________ Be a REAL MAN! |
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Hahadumball |
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Hahadumball World Chat Champion
Joined: 07 Oct 2015 Karma :
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Posted: 10:34 - 28 Apr 2018 Post subject: |
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we know youre getting on a bit dan but can we have more pics and updates ____________________ Fin: no matter how much I look at It I can't understand what was going through my head, all I remember is going about 80 and redlining it to stop it seizing.
360 Deg... Five 1/4 turns. :- Teflon-Mike 18 Jan 2015 |
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redeem ouzzer |
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redeem ouzzer World Chat Champion
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Posted: 18:04 - 08 May 2018 Post subject: |
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redeem ouzzer |
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redeem ouzzer World Chat Champion
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Posted: 08:51 - 23 Jun 2018 Post subject: |
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I took it to Cadwell for the Classic Bike Trackdays weekend (along with my now fixed GSXR400).
It worked pretty well, I split the sessions equally with my 400, ended up doing 170 miles / 78 laps over the weekend, and i basically thrashed it till the shift light came on in every gear without an issue.
https://farm2.staticflickr.com/1836/42913632152_da3838befa_b.jpg
https://farm1.staticflickr.com/899/29090717288_88611ed4be_b.jpg
However my ground clearance issues are not solved...
https://farm2.staticflickr.com/1814/42061571905_a58d502d34_b.jpg
To be honest i'm pretty dissapointed in the JL pipes. They are pretty to look at but they still deck out, i can't stop them leaking from the headers for more than a few hundred miles and they need a sympathetic noise tester. My plan is to get Mick Abbey to make me a set of bespoke pipes over winter with the focus on ground clearance and also increasing midrange. ____________________ Be a REAL MAN! |
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Suntan Sid |
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Suntan Sid World Chat Champion
Joined: 07 May 2009 Karma :
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Posted: 08:33 - 26 Jun 2018 Post subject: |
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That's a real bummer with the clearance and fitting problems on the pipes, the bike does look exceptional though!
You have a PM. ____________________ "Everybody needs money, that's why they call it money!" |
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Old Thread Alert!
The last post was made 5 years, 321 days ago. Instead of replying here, would creating a new thread be more useful? |
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