feetupfun

Neo it is quite frustrating to try and help people with bike problems over the internet with such limited imfomation. I will try and answer your questions: Adjusting the idle mixture screw may or may not noticably change the severity of a flat spot caused by too small a pilot jet or a part-blocked pilot jet. I'm sure I already said that it is not just the temperature of the air and the fuel that matters but also the humidity and barometric pressure. A flat spot caused by a carburetion issue is not usually revs, load or gear related. It is usually throttle position related. How about humouring me by either fitting the standard pilot jet or testing it out something like this: Stick some paper masking tape to the inner end of your twistgrip and another piece to the housing. Make a mark on each so that they line up just as the slide starts to lift off the stop. Warm your bike up fully and ride your bike in 4th gear along a flat smooth surface like a road. Hold your ground speed with the rear brake while moving the twistgrip from fully closed throttle to about 1/3 throttle, moving the throttle slowly in both directions. If you do this and still can't feel a flat spot, then there probably isn't a flat spot and we can go back to square one. There are other possibilities for the symptoms you have described but they are very unlikely compared with the possibility of a part-blocked or undersized pilot jet.

Maybe someone else will give an opinion that you can agree with

Neo you have gone too lean on the pilot jet. It was probably marginal until the weather went very cold. Cold air is denser and makes the bike run leaner. The fuel is also probably being affected by low temperatures and is harder to ignite (narrower flammability range). What seems to you to be the motor being more responsive is just that you now have a flat spot where the pilot jet has the most effect (just off closed throttle). You are actually moving the throttle through the flat spot/dead bit and when you go far enough open with the throttle, the mixture becomes strong enough to support combustion, and the motor takes off suddenly. To maintain a perfect state of tune with a carburettor equipped motor requires consideration of the temperature, humidity, barometric pressure and any changes in fuel type, oil type, oil ratio and fuel age.

I'm guessing you don't have Hyundai vans in the UK but the iLoad has taken off here like wildfire with tradies, delivery drivers and private users too. It is a recent and modern-looking design, is good to drive, good value, good on juice and if it is like previous Hyundais (imported since about 1984 here) will be good in the reliability and durability stakes too. iLoad has only been on the market two years so far. Hiace and Vito are the main models losing sales to the iLoad here. http://www.hyundai.com.au/iLoad/default.as...%20iLoad%202010

I'm with the poms on this one (colonial from the other side of the Pacific Ocean)

Issue 1 The airbox prevents water/mud impinging directly on the filter media. If liquid water touches foam filter media, it will wet the foam, increasing the pressure drop across the filter. When the airflow rate through the filter media gets high enough, the liquid water will be drawn through. It may travel harmlessly through the motor, or it may cause problems by bridging the sparkplug gap, getting into the float bowl, or if enough gets into the motor in a short time, it may cause great mechanical damage to the motor by preventing the piston from going past top dead centre. Issue 2 A pod fitted directly to the carby inlet (ie close to where the air goes into the carby) on a two stroke with piston skirt controlled inlet timing will become soaked with petrol, causing problems. This issue is not relevant to TYs as they have reed induction, greatly reducing the reverse pulse through the carby. Issue 3 Some bikes like the TYs have the carby supported by the connectors/hoses. If you don't have the airbox hose holding the carby up, and make the carby even heavier by fitting a pod, the connector between the carby and the cylinder will be overloaded on landings.

That cable is from an Italian aftermarket cable kit. I can't remember the brand - AGV maybe? The rubber concertina boot is from a TY Yamaha cable so no wonder it looks Japanese.

Thankyou. I'll stick with the roll pins

Thankyou Greeves That was fantastic to watch

Our 2007 OSET 16 24V has seen a bit of use now and has had a few electrical component issues along the way, but has been quite sturdy mechanically until the drive pin for the motor sprocket sheared recently. My 21kg son was riding in a manner I consider quite normal at the time, practicing crossing timber railway sleepers on a gentle uphill slope. I know it is quite a simple job to replace the drive pin, but am wondering if it is a common failure or not, to help me decide whether I should use a different type of drive pin or the same again. The drive pin that it came with from new is a 3mm diameter steel roll pin.

OK this is my M49 that has been modified by threading a hole in the cable stopper and using an adjuster on the cable outer. There is also a little hole in the brake arm for a split pin used as a security device to prevent the cable end coming off the arm (required to meet safety specs in our trials competitions)

Ha, I thought you might say that. I actually could get a photo of my M49 front brake real easy because that end of the bike is sticking out, but was taken aback when I went and looked at it - I had forgotten that I had done the mod DabDab talked about on my M49. I didn't want to confuse things with a photo of something non-original so didn't take a photo. Maybe it would be OK though because mr MCman56 might be interested in what a modded one looks like. Yes - in about 6 hours a photo will be up here.

And here is my TY250A motor showing the hole/plug that searay is talking about

I've gotta go and have a look at mine the suspense is killing me Ok here is what a LH case from a TY250D looks like.

Dave the cable on the mcman56 Sherpa T runs down the rear of the fork slider so it is nothing like your later model set-up that runs down the front of the slider. I'm think your M49 cable runs down the back of the slider. David

The TY80 big-wheel fuel tank is too long for a TY175 unless you shorten the seat or move it back. I haven't tried a small-wheel TY80 tank on a TY175. I just re-read your post and because you said "gas" tank I figure you may not know what a big-wheel TY80 is. The TY80s sold in the US are small-wheel models.

As crude as it seems 30 years later, the cable outer simply buts up against the lug on the brake plate. What looks strange in your photo is that the brake arm is on backwards. Next you will be asking how the devil the cable nipple fits through that little hole in the lug. It doesn't. Another standard feature was removable nipples that use a screw to clamp the nipple to the cable. Unless someone has a photo handy, I will put up a photo showing the setup on my M49 Sherpa, which has the same design as your Alpina photo.

Most likely blocked pilot jet

I thought you said you had a TY250A?

The ring it is an interference fit on the flywheel and is also glued. It is not made to be removed and replaced easily. Removing it in one piece - say - in a press may damage the flywheel. Heating it to make it loose will damage the magnets. You could remove it safely by cutting it with a hacksaw, but then getting it to fit properly afterwards would require welding and machining. I suggest you try the lighter A model flywheel first on the C motor. It doesn't take much of a change in the weight of the ring to make a big difference to the motor response.

As well as the different porting between the A and later (B,C,D) models, the A also has a lighter flywheel. If you lighten the flywheel from what is standard on a later model (B,C,D) motor, it ends up similar to the A model in response. You can try the A model flywheel on your C motor before making any permanent changes to the C model flywheel to try it out. I have done quite a bit of experimenting on B and D model model motors and for me the ideal is to reduce the width of the steel band on the flywheel by about 8mm. Some riders like it even quicker response than that and run with the steel band removed completely. We very rarely ride mud here.

If you keep riding it, you risk that the bore, piston and rings will be damaged by the metal particles coming out of the bearing.

The flat slide thing in Twinshock trials has not been much of an issue here yet, but the upcoming 2010 Aussie Titles supp regs makes specific mention of carbys for Twinshock/Classic having to be "pre-86 design" whatever that means. If that requirement was to become part of the MA rule book, it might stuff things up for people who are using something so obviously non-period as an OKO or Keihin flat-slide carby.

199A frame has different ground clearance because of the alloy bashplate instead of the frame tubes. As far as I know the steering geometry and wheelbase are the same for both. sherpa325 if you are sure it is different geometry and have a 199A to measure please help out by providing the details required by Trials09. I had an idea why the wheelbase may be so short. I've seen people fit early Sherpa T swingarms to late model frames to shorten the wheelbase. It requires interesting mods to get the rear engine mounting arrangement to work but it is possible. Again photos will reveal all to people who know what Bultacos should look like.

M198 standard frame, standard forks topped out, standard triple clamps, shockie mount centres 345mm, rear axle in middle of slot, Michelin tyres with riding pressure - fork tube angle 28 degrees from vertical