Cynic

Chassis no/ engine no/ photo's needed.

Sorry WF but this is confusing, the 'proper' way of discribing the needle position is counting the groves from the top for the clip position. Are you saying you have the clip in the top groove or the bottom grove? How can you say she's running fine when at the start of the thread the bike was heat siezing if you run more than 20-30 miles?

Thats why its running a bit off, if you go up on the main jet you can lower the needle position and keep your midrange as well as prevent the high rpm issues.

Shame on you........

The killer question OG, does she run any better now you have got rid of the leak at the manifold. Thats a bit of a critical one.

I suppose logic say's the higher ring will have to cope with higher stresses being closer to the detonation so that would be where i would put it.

Here is an example of what i was on about in the last post: DT175 (2X2/2K4) DT175 (4J4) Manufacturer/ Mikuni Type/ VM24SS IDno/ 2h500, 3U500 Main Jet/ 130, 160 Main air jet/ 0.5 Jet needle/ 4J13, 4J6 Clip position (groves fr top) 3rd Needle jet/ 0-4, 0-8 Throttle slide cutaway/ 2.0, 1.5 Pilot jet/ 25, 20 Pilot air screw (turns out) 1.5 Float valve seat/ 2.5 Starter jet/ 20 Float height/ 21mm+/-1.5mm (0.83+/-0.04 in) Idle speed/ (rpm) 1300-1400 1500+/- 50 Where the gaps are on the 4J4 the earlier model carries over. I know there are differences between the 2 bikes but nothing like your bigbored,race piped,k+n'd rocket ( ) Most importantly as far as the example goes they are the same CC, yet there is a 30 point difference in the main jet with a different needle. Food for thought?

Project.

You may find it slower by a little when the mixture is right. Your engine will use a little of the fuel in the cyl to keep the upper cylinder temperature down. This will prevent you holing pistons/smearing the rings down the barrel. If you run the engine at a leaner mixture you may go quicker but without the cooling effect of the fuel the engine won't last. If the bike wants choke to run at higher speeds ITS TOO LEAN. Seriously Foamy get this right or you will be killing another bore. Every time the power seems to drop of is a heat sieze, fact. The engine may be ok once it cools but every time it happens you are stressing the engine in ways its not designed to tolerate. You are weakening the rings, little end etc. Whats the next post, Oh my rings have broke, why. You have a responsibility to the engine, you cant run a ferrari on the cheap and the work you have put into the engine means you will be a real tit if you let it down for a couple of quidsworth of brass. You need to look at the overall settings and the way the bike is responding, remember: Pilot jet idle/jet needle First 10-15%, Needle jet 20-50%, Needle/ main 50-80% with the main the last 20% It may be the case you need a considerable increace in main size but drop the needle down by most of its travel.

Its probably called radial thickness in proper speak but i know what you mean. The different thicknesses may still be deliberate. Check the depth of the grooves in the piston. The thicker ring will be stronger and at least in theory give a better seal on the bore. The thing is in engineering at least if the mark 1 eyeball can see it its quite a diference.

How about going out with a plug spanner handy run for one or two miles as flat out as you can, kill the motor then have a look at the plug. The following model to yours used a 160 main. What side of the bike is your oil tank?

Back when i were a t'lad i had a dt50m and i fitted one of the better quality big bores and that had a stepped top ring that made it considerably wider than the one below it, the piston was machined to take it as at extended up the side of the piston by about 2-2.5 mm. Supposedly gave much better compression. Dunno bout that but i dont remember anybody else getting 70mph from 60cc (in perfect conditions)so i can't have been all bad. For my money if one of the rings is visibly thicker then there should be a corresponding difference in the groves.

Lucky b#stards, wish they had on the DT...... Had to use the electric spanner on most of mine.

If you have ever worked with the rubbish quality fasteners the japs used on there bikes in the 80's you will quickly see the benefit of the allen jobbies. Are they shiny, if so they are more than likely stainless steel and they have a nasty habbit of coming loose on the outer covers. You really want a spot of low strength threadlock to keep them honest.

I recon they spoilt it when they split the rally and the show, half the fun of the weekend used to be finding ways of getting in to the rally from the exhibitors area.

Ok mate, there is only one spec for the 4J4 modle and the 2K4 and the 2X2 shared the same settings. DT175 (2X2/2K4) DT175 (4J4) Manufacturer Mikuni Type VM24SS IDno 2h500 3U500 Main Jet 130 160 Main air jet 0.5 Jet needle 4J13 4J6 Clip position (groves fr top) 3rd Needle jet 0-4 0-8 Throttle slide cutaway 2.0 1.5 Pilot jet 25 20 Pilot air screw (turns out) 1.5 Float valve seat 2.5 Starter jet 20 Float height 21mm+/-1.5mm (0.83+/-0.04 in) Idle speed (rpm) 1300-1400 1500+/- 50 Where the gaps are on the 4J4 the earlier model carries over. The VM24ss seems to be a carb that Yamaha used extensively through the life of its 125/175 trail bikes so you really need to be sure of which one you have before you get carried away with overhall kits. The manual i'm looking at at the moment has 15 different specs listed for the VM24SS, if you include the VM20 and VM22 which look identical thats over 20 possible variations. You need to be sure of what you have thats why i have listed the 2 most likely combinations. But you cannot discount someone fitting a carb from a different bike as a quick fix. Imagine you have a carb on your bike from a 2X2 for example (which will work fine pretty much) and you then think the jettings all wrong and fit the 160. You see my point. Hope this helps.

Deception

Roland

Yummy

Wasn't it Dianna Rigg in the Avengers, JL was in the 'New Avengers' i think, kind of distracted by the catsuits....

Irony

Wannabe

The best part is they keep on that they haven't broken the rules. Who wrote the rules.......hmmmmm

Lie

Prisoner