JUST ME!

Yeah,Pilot power 2cts of sport attacks in compound C if available. Why wait for the warm weather? Could be dead tomorrow! HAVE A BLAST!

Yeah mate, keep your 45 Quid, run your originals for another 10000 miles or so. You may not still have the bike by then.Spend some of the money on PJ1 lube and lube the chain up after every long ride while chain is still warm! For what it,s worth,i get a minimum of 19000 miles out of chain and sprockets and both bikes are flogged! I never wash chain with kero/degreaser as the o-rings don't prevent the kero from entering the rollers. I only ever wipe the chain over with clean rag whist it is warm and relube it! HAVE A BLAST!

Yeah i agree, 170 mph in a straight line really can be quite tedious, however 60-70 mph up and down a nice mountain run is always exhilerating. As far as giving bike riders a bad name, i tend to disagree. Anybody who buys an R1,R6,GSXR and the like and never exceeds the limits has wasted their money! HAVE A BLAST!

Geday, Just a thought, being a 10 year old bike, has the cable ever been cleaned and lubricated properly? I don,t know how often you ride but generally after a while the use of the clutch becomes second nature and even a heavy clutch becomes quite tolerable. As stated, if lever is adjustable, bring the lever in as close to the bar as possible without inhibiting the clutch function, You will find the over extending of the fingers to pull in the lever is the likely cause of your left hand fatiguing. If you are on a long trip and you wish to press on you can upshift without the clutch so long as you ensure you have throttled off fully. However this should not become a habit! HAVE A BLAST!

Have a look at the dramas -WILD FOAMY- just had with his first jetting experience. Can work out expensive trying to teach yourself how to do jetting. Find youself a good 2 stoke wizard and get them to do it. If i could explain how to do it precisely i would. When you know how to do it it is not so hard, but explaining how and all the little tell tale signs and symptoms involved is quite difficult. You won't screw much up by running it too rich.That is why encourage people to start out a little big and work back! You need to witness some mechanical dramas before you can give advise on repairs. Yours sounds like one of those problems.GOOD LUCK!

Sorry to hear that mate, playing with 2 strokes can really test youy patience! Try and get the ring out without splitting the cases. Put her back how she was and treat it like you stole it. Don't get too disheartened , everybody who tinkers has had their share of screw-ups. If you are having difficulty keeping rings compressed while fitting the barrel, You can remove the piston, introduce it part way it to the bore, then hold the whole assembly over the rod whilst you fit the gudgeon pin. Make sure piston is right way about. If your using your original piston, make sure you use new clips! HOPE IT ALL GOES WELL!

Don,t give up until you have dialed in the big bore,you have nothing to lose!

Geday again, I take it this little jigger has a mikuni on it, you don't have to take the carby off to change main jet. Just remove throttle slide, loosen clamps,rotate carby 90 degrees.On some mikunis you have to remove the bowl,some have a large plug that scews out allowing you to remove jet with a socket.From memory it is 8mm. Along time since i have tinkered with a mikuni. From memory some of the main jets on some styles of carbs had an o-ring around them. If it is that style of jet,ensure that o-ring is in good shape. I tend to think this one will be the plain short style. The jet size will be stamped on the bottom or side of jet! If you have a contact at the bike shop, sometimes they will allow you to swap jets. You are doing the right thing getting the top end of the range in tune first and it is essential that you don't allow the bike to run lean,it will pick up the bore and you will be back to square one. Plug checks will be a good indicator, run in or not. As far a messing with a 50cc goes, good on you! Learning about this stuff has got to be better than playing the pokies or doin drugs.Go your hardest! Warning, Jetting can be tedious. Be patient and you will get it just right. oh yeah, is this little jigger pre-mix or auto lube? There is other jets that may have to be played with! The main jet is the one you need to be concerned with first. Get the top end working well and we will go from there! I assume all of the carbon was thoroughly removed from the exhaust port!

Sorry mate, we will have to agree to disagree on both issues.ALL THE BEST FOR 2009!

Geday again mate, I have tried to establish before just what "big bore" size you went for, but am still none the wiser! Without knowing this and exactly what the bike is doing in the various rev ranges, it would be difficult to suggest a starting point. If the bike is running lean, Eg engine overly hot,plug too light,then do not ride it until jetting is commenced. Working on the assumption that the engine is still under 70 cc, as a starting point go up 2sizes on the main jet,lift the needle one notch. Ride bike at say a consistent 30 mph for a couple of miles, pull clutch in and hit the kill switch at the same time,roll to stop. Wip the plug out and have a look at it. Does this make the bike run sweeter or worse? Trial and error until you get it somewhere in the ball park! As i have said before ,in my opinion large capacity increases in relation to the original bore sizes,fitted to the original crankcase,does not produce the same relative power gains. Plus produces new balance problems. Having said that push on with this mod and see how it goes! GOOD LUCK!

Michelin pilot power 2ct for the front and Conti sport attack compound C fot the rear. 2cts are also a very good rear tyre but they don,t do anything better than the Conti's and are more expensive! In my opinion the road attacks are not grippy enough for the back of sports bikes. Sure you will get 1000 mile more wear out of them but it is false economy because the risk of throwing it down the road is higher. I found the Bridgestones quite good grip wise but they go out of shape as they wear. I have no doubt the Pirelli's would also be good but are very expensive. You won't be dissapointed with the first combination! ALL THE BEST FOR 2009!

Just a thought, are there less threads on the new barrel causing the flange nut to bottom out on threads before it compresses the flange gasket?

If I have this right, you say it screws onto the original barrel OK. If it does, the nut must still be usable. Look at the male thread closely and prepare the start of the thread with a thread file. Leave the rest of the chamber mounted very loose whilst trying to get the nut started. This will give you more range of movement. When you get it aligned properly run the nut up and down the thread a few times without putting weight on the flange gasket, just to clean the thread. Out of interest let us know what capacity you have gone to and how it panned out. Don,t forget,you will most likely have to change the jetting! Keep an eye on the plug colour. ALL THE BEST WITH IT AND ALLTHE BEST FOR 2009.

Thanks for the link! Best wishes for 2009.

Yeah you are right mate, but you mostly have to worry about the larger particles damaging seals. Any really fine particles of piston alloy will be spat into the atmosphere faster than the space shuttle crew. As you know these jiggers are pretty tolerant machines! ALL THE BEST!

Geday again, MY OPINIONS ONLY,Definately don,t ride it until you fix it. The point of lever release is not a good indication of proper clutch engagement, definately check,or have someone check the clutch freeplay at the clutch itself.Just because you could smell the clutch plates burning does not mean the clutch is stuffed as these thing can take an incredible amount of torture. Synthetic motorcycle oil will not cause a clutch to slip. If there is any chance of someone putting non specific bike oil in the machine, change the oil and filter just to be sure. Many car oils, synthetic or not, contain friction modifiers and these can cause clutch slippage. The proper way to clean and inspect the plates is to disassemble the clutch and wash the plates in white spirits, carby cleaner or brake cleaner. Because you are only new to sports bikes you probably are not going to ride it like you stole it. As such i would only run mineral oil in it until your next service. Definately have the primary clutch adjustment checked, as this really sounds like the problem. ALL THE BEST!

Leave her as a 250, For all the rooting about it just isn't worth changing,let alone the balance problems you end up with. Simply wash the bottom end out with petrol, blow it out with compressed air, lube the bottom end bearings with 2 stroke oil, fit the new slug and rings. Fit the bored and honed barrell and your almost done. In my opinion,considering the much greater cubic capacity, the 400s did not go that much better than the 250s. Going by the pics, the piston has grabbed the bore through lack of,or no oil. ALL THE BEST!

As far as crotch rockets go, The RZ 500 in it's time and the first of the R1s. Simply for the benchmarks that they set. Both machines were way ahead of their time.

Good stuff isn't it? Wish i had been shown properly how to do it years and years ago. Never too old to learn! HAVE A BLAST AND ALL THE BEST FOR 2009!

Geday Mate, If the clutch is in fact slipping, Don't automatically assume the clutch is rooted, The clutch on my brand new K6 1000 was adjusted all wrong from the factory. Firstly, working on the assumption that the 2000 R6 has a cable clutch, there may be a secondary adjustment under the clutch cover. If there is, loosen the adjustment at the lever end of cable.Then check that the mechanism in the centre of the clutch assembly has a small amount of end float. If it has not, adjust it until it has. Then re adjust cable at lever end. With these miles I doubt that the clutch is worn out, more likely that it is not fully re-engaging and not applying full pressure on the plates. Another slight possibility is that the previous owner was running the wrong engine oil. Keep us posted. I will try and bring the R6 clutch up elsewhere just to view the exact arrangement.ALL THE BEST

Geday mate. All of the above is fair enough but anyway you look at it, short of leaving the DT engine how it is, it is still going to cost you money. The 250 DTs never revved well and an unbalanced 400 modded version will be worse! The 82 model aircooled IT 465 engines were a great motor, but i don't know if they were in the UK and these only had a 5 speed box.The 250s out of the 82 onwards were also good and had a 6 speeder. Lengthening the consistent diameter pipe at the start of the exhaust increase the midrange at the expense of the top end. Some of the old timers use to speak about reducing the volume of the crankcases by lacquering the inside surfaces. You would have to contact someone more knowledgable on this technique to advise on the power gains. All good fun, just be careful that the money you spend on a pig of a donk doesn't end up equating to the cost of a good one. In my opinion even the early air cooled YZ 125 engines are better than the DT engines. If your a light weight they will scoot along quite well. HAVE A BLAST!

Hi, I take it you are constructing some sort of hybrid road racer. You probably will get the 400 top end to work, if you decide to go ahead with it, get the whole show rebalanced. I don't know if you intend on road registering it, but i think a water cooled YZ250 engine would be a better thing. More power straight up with no rooting about and very reliable.Even with the radiator this engine would be a fair bit lighter. FOOD FOR THOUGHT!

Geday mate, Trust me i am the last person that should suggest that you take care on a bike, so i wont. Just a liitle tip,if you insist on riding this little jigger like you stole it, keep one finger very close to the clutch lever so when the piston grabs, you may have a chance of saving yourself! In my experience, increasing bore size by anymore than the normal factoy oversizes is not very succesful simply because it is too difficult, so nobody bothers, to dismantle the entire engine and rebalance it! But it is refreshing to see some young bloke so keen about his hobby.Try never let anyone dampen your enthusiasm. SOUNDS LIKE ANOTHER BERT MUNROE IN THE MAKING.

If you have the old bearings you can usually read the number on the bearing seal that is pressed into bearing. For example NSK 6004. IF not, take the wheel and axle to your local bearing centre or Yamaha dealer and they will measure the axle and bore size in the hub. Very important that the bearings are also the correct width. ALL THE BEST! Sorry oldgitonabike, I did not see your 2nd reply!