tobster

thanks x 2 for the info.

what year yz125 brake plate do i need to find? Presumably end of the 70s early 80S?

3/8"!! Yikes that's nearly 1cm. Re the reedblock, I was thinking of using one from a later RD350, of the YPVS variety that have a cross over tube. Presumably an earlier version, say air cool RD350 did not have one??? Did you need to rejet?

hi, I've only just seen this thread, but what thickness of spacer do you use? Also, how do you seal off the crossover pipe hole in the RD350 reed block?? Do these changes require jetting changes?

Hi, I've just acquired a 1979 Ty175 majesty and whilst I intend to trial it, the tank needs painting. So, I thought I might just as well try and use the correct white. Can anyone please tell me the paint code for the tank, same for the frame. Thanks

I have a barrel like that that was apparently modified by John Shirt. It is also a 270. It rattles like hell when cold, but quietens up a bit when warmed up. I probably need to whip the top off and measure things to make sure all is well. I too would be interested to know what piston/rings to use if/when I need to replace them.

Hi Jon I was hoping you would offer some advice. I shall look at the master cyclinder as suggested. I'll also bleed the system to make sure no air has got in which might reduce the travel of the clutch. The bike runs on ATF and getting it into neutral once stationary is nigh on impossible. All part of the clutch 'issues' I guess. What volume of ATF should it be using in the gearbox? Thanks

hi guys as the title says, the clutch on my sons TXT200pro drags badly, so bad that the bike will move forward even with the clutch pulled fully in. Is this 'normal'? If not, how can I adjust the hydraulic clutch? All advice appreciated. Apart from that it is a beautiful bike and a mega step up from his previous bike (TXT70) he had last year - makes my Pinky seem very old and heavy (like me). thanks

RIRCrider - surely if your bike had been running OK, but is not running rich, then this implies something is not right (sounds so much better than wrong). To change your jetting or adjust the needle height won't solve the problem but merely mask it. So I would investigate the usual reasons that can make a bike start running rich eg blocked/dirty air filter, poor plug/ignition, then move on to exhausts BEFORE you start replacing jets etc

if you're not into a project bike, then your decision sounds correct, even though most of the issues are quite minor, there are too many of them - also,

or you try this club, which as you can see by its cunning name, is something to do with north berks http://www.northberksmcc.com/ indeed strike whilst the iron is hot as they have a closed-to-club trial this Sunday at Seymour's arena, Aston Tirrold (just South of Didcot) in Oxfordshire!!

Dougie I think this is their web site http://www.outlawtrials.com/index.htm

hi tim did you manage to get any info on the Shirt modified TY 250 barrel?

oops, thousand apologies Tony - I took no toil as typo (so many in forums nowadays) for no oil. I use air filter oil from an aerosol, so i can control the wetness of the filter. I've always found the dunking/soaking/squeezing method gives a very well oiled which has been too oiled for our Ty250, TY80 and now gg rookie 80. Steve _ I hadn't realised/thought that the needle had so much (indeed anything) to do with starting which I though would be controlled by the pilot & starter jets & the slide (ignoring the air box/filter issues). Ah well, if it works for you. Did you get around to doing the stop/start experiment and have you done plugs chops at the various throttle settings? The later should prove to you (and us) whether the beast is indeed running rich at low revs. Have a nice play this weekend

you should ride it!!!!

Tony - do you really run your bike with a dry air filter??? How do you stop dust getting into the engine? Obviously if you run the bike without a properly installed & unoiled air filter it will run leaner, therefore 'curing' the rich problem, but surely this is not a very good fix, more a bodge? You've just moved the problem to another area??? Also, have you got a link for that GG airbox modification as that does sound interesting?

Steve Would I be right in saying that adjusting your fuel screw has no effect? Have you tried proving to yourself that the engine is indeed running rich at low revs - I did this by doing plug chops at the various throttle settings. I found all of my middle to upper throttle settings to be spot on, but those at low revs were v rich. Try Mathew Cooper at Eurocarb (Dellorto dealer) for some good advice and excellent parts availability. To try and lean it out I only very very lightly oil the air filter (and would certainly never recommend running the filter dry) & also spray the inside of the air box with filter oil to catch any dust that gets through. I haven't tried the world of the exotic spark plug, but it does sound to work and is certainly a very cheap try, BUT it clearly won't solve the rich running, just mask the symptom. So I would and have tried to solve the problem and not effect a 'bodge'.

out of interest do you have to use choke when you start it from cold or can you get away with nothing & does it start easily (i.e. only a couple of prods) when cold? our rookie 80 behaves like yours when dropped/stalled - I think it's because it runs chronically rich at low revs. You could always do an experiment - something along the lines of: ride it around 'normally' for a trials bike i.e. slowly. Take the plug out (probably v sooty). Put another plug in, ride around again, but this time 'fall over' or just lay it on its side until it stops. Now try this 1) try a couple of prods. If no start, change the plug for the old sooty plug 2) try a couple of kicks . 3)If no start put in a new or clean plug & try again. My guess is this will happen 1) hopefully it won't start i.e you've replicated your problem 2) still no start 3) it will start immediately. I reckon they run soo ruch at low revs that if stalled the plug is nearly fouled i.e. v sooty, hence is difficult to start. Only a clean/new plug will produce an instant start. I hope this is of some help, but I would suggest you either get more air into the engine (i.e only very lightly oil the air filter) or/and less fuel in. Phew that's it. Good luck, and beware, this is only my opinion and I have been wrong before....

I've had a closer look at the air box and it does indeed look a fairly straight forward job of moving it forward afew mm - it might even end up not looking like a bodge!!! Re the piccy of the airbox top mod that would indeed be v useful. I'm not expecting to have to replace jets etc as the original bike tends to run on the rich side anyway. I'm not sure if it is essential/recommended for this type of modified engine (John Shirt actually), but I think I shall probably use superunleaded fuel to try and reduce any pinking. We shall see.

Scott as you didn't increase engine size but 'only' ported and modded the inlet length, what differences did this make to the way the engine performed? I find my standard bike runs a little rich, so perhaps all these mods may lean it out a bit and I may not have to do much replacement tuning in the carb, just adjustments (probably wishfull thinking). re your airbox mod - would this also apply to a mono airbox, as I can't think/see what I'm supposed or even able to cut off without letting in unfiltered air. Perhaps it's only for twinshock airboxes 2fargone yers it is a mono (aren't all pinky's mono's??)

thanks for the replies - looks like a little bit of bodging, sorry tweaking, is called for. presumably your engines were also bored out as well (270cc) or did you only do the inlet mod? If you did both, what kind of carb setting changes (eg jets) did you find works best or was it just fine tuning (eg needle position). when you've answered those questions I'll move onto the need for high octane fuel etc later

Major, just out of interest, what carb settings have you got or more precisely, what has been changed? atf is fine in gas gas transmittions and mineral oil is fine for trials brakes - it's not like you're repeatadly braking from 150mph is it??

hi when/if you fit a barrel with a shortened inlet (eg J Shirt) to a pinky engine, the carb will therefore be mounted a cm or so nearer the engine - so, how do connect the air box rubber to the inlet side of the carb as surely it won't be long enough? that's it - I'll sit back and await the flood of suggestions

I believe the disc should be slightly loose i.e. floating (At least the disc on my Pinky is loose). That's probably why you have 2 sheared bolts, because someone has tried to tighten them up too far to try and immobolise the disc. Re the spares angle try Birketts or John Cane.

my son, now 11, went from a year on a ty80 - enjoyed it enormously, did v well in trials etc, to a gasgas rookie this winter. he has found the jump in size quite intimidating. My elder boy looked huge when he rode the ty80 when he was 12. Soo, I would not recommend the ty80 for an 11 year old - clearly the only other option is a full-size junior bike. If he hasn't ridden the small ty80 then he won't find the modern junior bike large. Perhaps a Whitehawk would be a good alternative - nope on reflection, go for a 'modern' 70/80cc bike. that's it, my final answer.