dombush

Blimey... sounds like quite an expensive rebuild!! from the detail of the rebuild it sounds like the "seals and bearings" are likely to be the crank seals and bearings. I'm assuming a shop / garage did the rebuild for you? Did the bike run ok when you first got it back? Dom

Zak can you define "full rebuild" for us (some detail of the components replaced) Dom

Zak, your a man of few words. The idle screw (meant to say the idle mixture screw also called the fuel screw) is the brass slotted screw in the side of the carb. Have a look at this video in which most aspects of the carb and faults are explained. See minute 5:00 and minute 20:55 for the pilot and fuel screw http://www.youtube.com/watch?v=1EbXacjIV78. Also see this video (basic tools and uses carb cleaner but you get the idea) .Dom

Zak apologies if slightly patronising. When you removed the pilot jet for cleaning, did you hold it up to the light to check that the jet orifice was clear and was circular (not partialy blocked)? also when you blasted all the various orifices with air, were all of the jets and the idle screw removed? similar to other posts, the work gets more complex / time consuming from here so its worth checking. Let us know your process to save us pointing you in the wrong direction. Dom

Pat The 5EIX plug uses a fine wire electrode (of a higher quality / hard material). This has the following benefits:- smaller diameter core electrode requires less voltage to initiate the spark Smaller diameter improves resistsance to plug fouling. Smaller tip footprint reducing flame masking and other gas flow issues in the combustion chamber. Incorporates a slightly modified earth electrode to give similar benefits to above. Expected life span improved due to the higher quality materials. However... Most of these benefits are aimed at very high performance engines that run richer oil ratios, higher compression, high revs, ignition systems at the edge of their performance. Given that trials engines operate at the other end of the spectrum (weak ratios, low compression, low revs etc) i would say that there is marginal or no benefit other than life span. So, wont do any harm, but not much good either (for increased cost). Dom

Pat splitting the questions up Should you run the BPR5ES?.... Most gas gas bikes in the UK weather, running standard squish / compression do! As you say its all about the heat range. With plugs you want them to get hot enough to burn off any oil / contaminants but not so hot that it causes pre-ignition under heavy load. People far more experienced than me come up with the heat range that suits our bikes. If it isnt detonating with a 5 and the plug colour is good after a plug-chop.. stick with the 5. If its detonating then go colder (6). Would this be the reason for a smokey bike?.....No! if the bike isnt misfiring then the plug isnt negatively affecting the running. If your running a reasonable oil mix (for me ~80:1ish) It'll be smoking because its running rich or is pulling in oil from somewhere else. Dom

Hi some links direct from the Beta website. The manual states an air gap rather than CC's of fork oil. Link to manual:- http://www.betamotor.../0753/rev80.pdf Page 8 seems to have it. Dom

Hi Just to avoid any misunderstandings, the specific bike is?? (your Avatar says Gas Gas and this is in the Beta forum). Dom

Excellent news..

Ben Got to admire your enthusiasm for your bike! But £110 buys most of; a set of tyres; some coaching sessions; correct shock spring for your weight; 50% of a flatslide carb; entries for 7 trials. Any of which will probably have more positive effect on your scores. you too can be this boring... its an age thing. Dom

Apparently its going to be launched on April the 1st, just after Hell freezes over.

Hi i cant answer the TY80 clutch needing removal or not because its been 30 years since i had one. (By the way the answer to this question on most other bikes is yes it does need removing to allow you to remove the crankshaft pinion) However, as you discovered that the Flywheel side seal had been pressed in on the bonk i would let sleeping dogs lie (unless the clutch side is similarly bad). Proof is in the pudding... if you get consistent steady tickover... leave it alone. In case you were considering removing the clutch without some sort of "special tool" , i would think twice as expensive damage is just a moment away (i remember the tears). Dom

Hi Exactly the questions i had 2 years ago when i got started. Totally agree with the poster who said gloves, helmet and boots are the important things. A bit of an intense reply but its what i needed to know. Helmets Formal helmet regs can be found in tha ACU handbook on page 90/91 here http://www.acu.org.uk/uploaded/documents/ACU-HANDBOOK_2012.pdf You will see that trials helmets appear to be exempt from the normal Gold and Silver stamps that you find on road / motocross etc helmets. However... the helmet i use is has an ACU stamp anyway. In trials you rarely achieve "high" speeds and protection is mainly from bumps, falls, branches etc. (road trials excepted). However, tuppeny helmet for a tuppeny head etc. etc. Besides this for a new starter i would say to you that you want something that is comforatable for up to 3 hours use, gives you excellent all round visibitlity, has a peak for those rainy trials and is easy to put on / remove. As you progress and the smaller things become more important you can look for lighter weight, better comfort, venting etc. etc. Boots I rode with motocross boots when i started. Initialy this didnt matter but it VERY quickly became obvious that something more comforatable, grippy, flexible and with a flat sole was needed. The boots you selected look fine. Riding in walking boots is definate no-no and besides the rules you'd be mad to do it (shin protection) Gloves. Trials is all about feel, control and subtlety. Therefore trials specific gloves are quite thin and give you lots of feedback from the various controls. However i use some good quality motocross gloves because they have all this plus a bit more protection. Dom

OK, some good information in your last post. There is no step change, the bike has been like this since you owned it The issue is seen when asking for maximum revs for instance up a climb. That the carb may not be running standard settings. This changes things somewhat. Some other questions will help further diagnosis. What carb is fitted to the bike (to determine the design)?. The model number is normaly stamped onto the side of the carb Dellorto PHBL Dellorto VHST Keihin PWK Regards Dom

Hi sound like a number of possible causes... First question is.... what has been done to the bike since it last ran correctly? Here's a few ideas that might trigger some further investigation. Cant supply enough air at higher revs. blocked filter Wet filter something blocking the airbox. [*]Supplying too much fuel at higher revs Main jet loose Float bowl flooding at higher revs (difficult to see what might cause this) Needle position incorrect (needle clip come loose or similar) [*]Not rich fueling causing the blubbering, but pulling in oil from the grearbox. Damaged crank seal on the clutch side Damaged crankcase joint gasket (very rare unless reassembling a split engine) Cracked or damaged cases Would be useful to know what has occured since it last ran correctly? Dom

Good news Lewis always nice when some hard work pays off Dom

Hi Swede +1 on Paul W's advice (again) unless they are smashed, a very good fabricator can fix many issues. The job is a specialist one but a hell of a lot easier and cheaper than the alternative you are contemplating. You may need to carefully skim / make good some mating faces but unless it has mashed somewhere unfortunate (across a major bearing housing etc) you may be lucky. There are many tricks to avoid the distortion experienced during welding, but you cant roll back after the distortion has occured. Dont go looking for your average MIG welding fabricator, you need a specialist TIG aluminium/stainless fabricator. Ask to see some examples of his/her work.You can help make the job easier for the fabricator by cleaning / degreasing everything and perfectly masking areas you dont want to dissasemble (lots). As someone else said, come back and ask again if you are unsure. Some photos of the damage will help determine whats possible. Also people tend to know their local fabrication experts so you might want to tell us where you live so that some names can be suggested. Good fabricators are magicians!! Dom

Hi Danny it sounds very like the gearbox breather has pushed out some oil. This is something that many Sherco owners have experienced and may not be a serious issue. There are various causes:- Overfilled gearbox (need only be slightly overfilled). Gearbox being pressurised (usualy clutch side crank seal). Bike tipped over for a period of time. The breather allows the gearbox to vent to atmosphere to ensure no pressure / vacuum buildup. It is expected that at some point during warmup the gearbox will try to push some air out. If the oil level is covering the breather hole it will displace oil rather than air. So the next step is to find out if it is the crank seal or not. have a search on this as many people have written how to check. Dom

Hi a couple of minutes browsing gave me a bit of info, MRS are the importer (same as trials bikes). I think the engine may be shared with other bikes (Aprillia), hence the ability to share tuning parts. This link points you to a spare parts manual. http://www.malcolmra...okandPrices.htm If you can find out which Aprilia the engine is shared with i;m sure this will get you a long way. Regards Dom

Hi Dannyboy Great that you've got into biking and are tuning your bike. I'm 42 and havent stopped tinkering with bikes yet. On the specifics of your post, i'm not sure how many forum members will be ale to help you as most people are involved in trials competition or trials bikes. As well as trials bikes, Sherco make Enduro bikes and clearly some road bikes such as yours, however there are different forums that specialise in those specific bike types. Having said this, i hope someone can help you or point you in the direction of some HRD specialist help. Good luck Dominic

The fuel smell confirms the diagnosis. be aware that crank bearings haven't always failed when crank seals themselves fail. crank bearings are the next degree more complex to replace as this requires the engine out to split the crank-cases. failed crank bearings usually whine and slightly labour free revving. worth checking before you commit to the extra spend.

Hi crank oil seal isnt a big deal, but it needs some experience and tools. The failure you describe could be the clutch side oil seal (is this the LH side?). This fits the air/oil leaks scenario. The parts for this are probably around £10 plus some gaskets if you rip one (likely). There is a TY series Haynes manual that covers the 80 (fairly sure). Do you have someone experienced that can help you? Dom

Hi various thoughts on this one. To acheive the degree of revving that you describe must involve a BIG air leak. Check the obvious things once more, reed valve assembled correctly, carb properly located in the inlet manifold. If its possible, take the subframe and/or airbox off to look down the carb throat and visualy ensure that the slide is coming all of the way down. On some carbs it is possible to fit the slide into the carb the wrong way round. The effect of this is that the slide doesnt go the whole way down but sounds like it's "bottoming" because you hear a clunk. The main clue to this is the fact that there will be a lot more throttle cable play than usual. Are you absolutely sure that the slide is coming all the way down and hitting the tickover adjustment screw. There are at least two places where the "male" throttle outer cable could be "not fully home" in their "female" locations. The ones that come to mind are at the top of the carb and at the throttle tube / pulley location. When your bike originaly started running badly there may have been two faults in play. A bike will run (albeit badly) with damaged reed valve so although unlikely, there may have been an air leak as well. The particular air leak that would fit is a damaged crank seal (flywheel side). like i said... just some thoughts. Dom

They didnt look that good when they were new!! (not that i was born then!!)

Jimmie I'm afraid i dont know which years flywheels it fits. What i do know is the features that affect whether it will fit or not are:- The position of the two holes in the std flywheel. You press the supplied threaded inserts into these holes from the inside of the flywheel. The flywheel weight then bolts to the std flywheel using these fastening points. The outside diameter of the flywheel as the weight very slightly wraps around the chamfered edge. Another point of note was that i slightly modified (shaved) the gear lever to stop it fouling on the engine cover with the spacer fitted. This ensured that the gear lever remained fully on the splined gear change shaft. Dom