Just picked up on behalf of a friend, a 1993 TYZ bargain in very useable nick - and it has had its fuel capacity increased by utilising the void inside the large frame spar!! - just wondered if any of you yammy boys have ever heard of this conversion? apparently it was for the SSDT?? Very professional looking job complete with a neat looking little breather stub protruding from the frame just in front of the coolant filler cap! Any idea who may have carried this work out and for who??
Thanks for your comprehensive reply - plenty to digest there thanks. Looking at the original carb as compared to the VHST - the inlet bellmouths are considerably different in size ie the VHST being much bigger so fitting the airbox rubber correctly whereas the original setup need a plastic spacer doughnut to make airboot fit down to carb size - this would surely restrict airflow a lot?? So I reckon the bigger bellmouth is simply supplying a largley increased amount of air and so will need re jetting more richly than first thought. I actually leaned off the pilot and main jets to original spec. When the VHST was first fitted it had the larher jets in but still bogged on full throttle openings - am sure lifting the needle would have cured this. Think I will revert to the original VHST jets 38 & 108 with needle lifted. Will let you know.
Me and my feinds go to Harwood Dale every week if we can, usually Thursdays - when its nice and quiet. They also hold a superb Pre 65/Twinshock sporting weekend soon - camping allowed - see 1st link
The 2nd link link is a pic of me on one of my Jumbos practising last year at Harwood Dale just up the hill on the right hand side as you go in - its all changed now with piles of rocks setup and some fine clearing out work in new gulleys, steps and warm up areas.
You dont mention your main jet?- tho I have just fitted a 300 fuel valve to my Jumbo along with a longer headed pilot jet and its definitely improved things on that bike - so was considering the 250/300 fuel valve for the Gasser - tho wouldnt expect a little 125 to want to gulp so much fuel that a 2mm fuel valve wouldnt cope. I cant believe how lean the bike was running with such a similar carb setup - do you think that slide cutaway has more effect on the flatslides?? smaller cutaway = more suction = leaner running??? Not sure either way. The plug was seriously dry with a hint of pink from ipone 2 stroke oil it uses - far beyond self cleaning. Also raising the needle to max to helped alleviate the bogging but suggests not enough fuel somewhere along the line - main jet as I mentioned is 105....
Just fitted a Delorto VHST 26 Flatslide to my sons gasser. The original carb was jetted: 105 main, 36 pilot, 268 emulsion, D36 needle, 200 fuel valve. The new carb I have rejetted to the same spec other than emulsion 270 - but the motor is now running very lean and have had to raise needle to max (clip @ lowest) so it doesnt bog out on big handfuls of throttle. Could anyone please post their standard specs or any that are known to run better??
Recently traded my Berlingo and got a Transporter T4 due to an increase in family size - both vans however are superb. The Berlingo holds one full bike when boarded and with bulkhead and is as cheap to run and manouverable as a car. The T4 holds 3 bikes comfortably and even with the rear seats clipped in it carries 2. My T4 is ex AA and very powerful 2.5 tdi 5 cyl - yet economical on mpg and insurance. It will tow my caravan and all the family camping gear tools etc easily in excess of motorway limit all day long.
I had the same prob last week on my 03 Scorpa - had just cleaned out its carb and on first outing flooded real bad. Tapped float bowl with handy branch and hey presto no more flooding!!! must have slightly disturbed the float pin when re instaling....
What main jet are you running? and is your air filter really clean or contaminated with too much filter oil?? Check out the Scorpa Hell Team site for altering your timing and other tips.
Have a pic of my SWM shirts if they of any interest - bought them with my son in mind as my frame doesnt quite match that of the early 80s Trials riders
Had a similar problem with my sons 05 125 gasser recently - its new (04) retro fit thermostat came with no conector plug. I improvised by using 2 fully insulated plastic coated yellow spade connectors and sealed their ends with clear silicon - job sorted.
My Ex Bernie Jumbo is all fettled and ready to go after its appearance at the Malvern Classic show - rides as well as my Scorpa!! Big climb down when riding my boggy 240 or revvy 200 or even the good old 280!! Call it spoilt for choice but you just got to love em all . ..(Italian trash a bit strong mate!) Got a few Twinshock trials coming up April May and June - so the Jumbo will get its legs stretched. Getting Bernies earlier Jumbo ready this year so Scrumpyjack can make up a Works Jumbo double at one of the later twinshock trials :-)
You got any pics of your bike you can post? - would appreciate a viewing . . .
You can bust on me anytime mate - all good clean fun :-)
Bought a Plastic tanked 200 SWM from a lad in Keighley a couple of years ago - will have to have a closer look at it. I also bought a "200" from a Paul Waugh back in 1982/3 tho at the time was told it was 175cc. Had a sound all of its own - pretty much like the one I have now. Any idea what size the upgraded carbs were??
rolls royce suspension - whippy but grippy - ultra reliable - light as is sensibly possible - not bad looking too. Maybe this is why they havent changed too much over the last 4 years???
I have a factory released document somewhwere which shows this reed removal modification being carried out - suposed to make em go better - will have a look thru my old suitcase over the weekend and see if I can send you a scan..
jumbostu 
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Tyz Fuel In Frame
in Yamaha
Posted
Cheers Martin - it is a real neat mod - very interesting . . .
Stu