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I have seen 2 stroke mix used, shake it well all over the inside of the tyre and throw lighted paper at it from a distance, be ready to pump the tyre fully up immediately without dislodging it from the rim.
If you have a few days the best way is to put a tube in your tyre a few days before fitting it. Inflate the tube and it bulges the tyre beads out.
Nomally I do it with a compressor after removing valve core to get a good air flow
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Make up a blanking plate for the barrel to replace the exhaust, block the inlet to the reed block (where carb fits) with a bung and hose clip. Either the bung or exhaust blanking plate needs a hole for a tyre valve. Pressurise to between 5 an 7 PSI to see if you have a leak.
If it is a dellorto carb check the fine wire clip that holds the float arm to float valve plunger ifs fitted correctly and not distorted.
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$1500 is about £1000 and that would be in the ballpark for the bike.. I would expect a bit more off if there was anything major that needed attention, replate and piston for example.
You say a bit beat. Tyres, Chain and sprockets, a few bearings, seals and brake pads can soon add up to a fair bit.
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I have known Nigel for near on 40 years and bought bikes and bits off him but until Ossa supply EFI diagnostics gear at the price of a cheap auto code reader and a £10 CD for mapping I would not even consider buying one. Call me tight if you like buts that's the way me and quite a few others think.
Quite a few of my friends have had expensive enough trouble with electronic ignition failure and a move to a bike containing the "black art" of EFI is just a step too far.
I am fairly competent with auto EFI diagnostics but I have little inclination for anything that is effectively "sealed off"
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Its some years since I rode a 4Rt and wondered if someone can answer following questions about the new ones.
Firstly due to the high tick over speed can they be ridden in tight circles without clutching?
Can tickover speed be turned down?
How hard are they to kick over compared to a 280 / 300 2T?
One thing I would like to see on them is a formed wrap round sump guard rather than that protruding flat thing.
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I am near certain 7075 T6 has a yield strength approximately 25% higher than Avional 2024 but it depends on the exact grade (heat treatment) of 2024
I think the Avional is a Spanish designation aimed at the aero industry.
Ergal is a trade name for aluminium alloys that have a similar composition and characteristics to Duraluminium which is similar to 2024
The above are age hardened which can be modified by heat treatment. I once bought a piece of 1/4 inch thick Duraluminium to make a Bulto sump Guard and it had to be shaped within a week and would gain full strength in 14 days.
All the above have yield strengths of 325 to 450 MPa whereas "ordinary" steel is about 270 MPa.
7068 is the strongest grade (I have heard of) with a yield of 700 MPa
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Contact DVLA and get it registered - Free if for offroad use only. Registration is a useful anti theft measure
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Since the plug is black and oily it looks as if its not lean mixture that is causing pinking. It could be carbon deposits in combustion chamber, either because they are glowing causing "pre ignition" pinking or because they are raising the compression causing "detonation" pinking.
PS before anyone picks me up on, pre ignition and detonation I have put them in "".
Unless the squish clearance is within spec you are wasting your time messing with the carb. Also you need to know what your insert is doing to combustion chamber pressure, If it is a high pressure insert yo may need to run on Avgas or premium fuel with an octane booster.
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Scorpa would be my choice
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Track suit bottoms, but wear knee guards as well
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I would be very reluctant to use heat on a cast, precision machined component to the extent needed to release a seized thread, you could distort it.
Drilling the head off removes tension from the threads, potentially loosening them.
If you cant undo the remains with mole grips, heat the bolt (not calliper) red hot then try to undo it when fully cooled.
When trying to undo the bolt make sure you apply torque evenly to both sides at say 3 and 9 oclock. This is very important. Pulling on one side only (as with allen key) pulls the bolt over and greatly increases friction. T handle keys are far better.
If all else fails phone Phoeton Aptec, the solution they use to clean barrels dissolves steel and aluminium oxide without harming aluminium. If you were to drill the core of the bolt out they may (I have never asked them to do this) be prepared to dissolve the threads and corrosion out whilst they are treating barrels. If the will, get both half's of the calliper cleaned as the probable cause of you pistons binding was corrosion in the seal grooves.
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Do internet search for David Silver honda spares = they do mx bits as far back as 1980s
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Oh for the good old days when forks came with gaiters, not stylish or cool but cheap and effective
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Thoroughly wire brush and wash the rim - power wire brush best
Get a valve from an innertube or nut fixed car type and fasten it securely into the rim with sealant, Smear the groove where the rim tape should be with a good layer of sealant instead of using a rim tape.
For sealant use sikaflex windscreen fitting sealant or some other neutral (non acidic) sealant like leadmate gutter seal.
If you get leakage where the tyre fits the rim spray it with contact adhesive just before inflating the tyre. Toolstation do good adhesive cheap
I know the above may sound a bit like a codge but it generally works better than new rim tapes or tubes on old or corroded rims.
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What is spark plug colour - is is wet? or black?
When you say its struggling do you mean its will hardly pick up revs and misses a lot? - that can be a sign of excess fuel
Sounds like your float valve is sticking or has dirt on valve seat or float height could be wrong.
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Incorrect ignition timing may give those symptoms. Do you know for certain stator was faulty before it was rewound - how was it checked?
Faulty coil can give these symptoms.
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The difficult starting of some Ossas when others start more readily is difficult to explain.
The fundamental issue is that EFI (Electronic Fuel Injection) components (transistors, MAP sensors, TPS sensors etc) typically need a constant 5 volts to function correctly. A fuel pump could be made to operate on AC or 5 V DC but more typically they need 12V DC.
I have not been into the generating system on an Ossa butt it is probably 4 to 6 coils which produce AC peaking at over 80 volts. This will be rectified to convert it to pulsed DC then capacitors and other electrical components will be used to try to give a near steady voltage and current suitable to drive the EFI components. Capacitors and voltage regulating components store and consume energy and this has to be built up before there is sufficient power available to drive the EFI, this is why the addition of a battery helps - it pre energises these components.
The variability between bikes may be due to varying quality of diodes (which always leak electric to some extent) or other minute causes of electric power loss such as resistance in joints or surface conductivity electron leakage.
To build an EFI system without a traditional battery and charging system is quite a feat, Honda managed it but it is likely such systems will always be quirky.
Edit - Migel Birkett importer at near Barrow in furness for battery kit 01229 716806
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I think may be a threaded hole in the swinging arm but they are prone to stripping, helicoiling is the usual repair. Certainly this was the case on Some Betas but I can't be sure of the exact models or dates
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Try Sandifords (they moved not long ago but I think they are still in Bury) for info.
The carb was an Amal Mk2 but I an't remember if it was 26 or 27mm I can't remember the jet sizes either but stock jetting was pretty well spot on, Maybe a tweak on the air screw and a notch on the needle clip between summer and winter and that was about it.
Engine is good but check for damage in upper rear of ignition side of crankcase caused by miss fitting of kickstart
I think shock length is 13.4 inch
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Is the make of bike / model a secret?
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The Beta feels soft because it lacks a few cc compared to a 250. The Scorpa feels soft because the power builds slowly, more like the 250 beta with a flywheel weight.
Though both 200 Beta and Yam engined Scorpa are soft they are different, you need t tryo the Scorpa before deciding. I did not like the very slow power build up of the Rotax engined Armstrongs and Aprillas, The Yam engined Scorpa is quicker than those and although it finds grip easily on slippery rocks the power delivery may not be to your liking.
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Did'nt watch the test but what a brilliant opener from Qatar
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GG article clearly says "any obstacle". I guess something has gone off message in the translation from spanish - A bit like the GG USA info about magnesium's susceptibility to damp and salt.
Price is not yet on GG Uk website.
It would be interesting if GG put a decent rider on one in the championship or experts class just to show what they could do especially if bike was kept standard spec.
Edit - In UK I think the 125cc limit up to 19 years of age will damage the market for this type of bike. I think there may be quite a few who otherwise would like a trail / commuter bike that was decent enough for trials. 125s generally just do not have enough power or have to be thrashed at the expense of reliability.
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Just finished servicing the hydraulic brake (shimano) on a mountain bike. Seized slave cylinder piston was the problem due to corrosion. The bike is 2 years old.
What this has in common with trials bikes is the lack of dust boots to protect the seal / piston / calliper bore from corrosion and it is very common to see trials bike with brake corrosion problems at 2 to 5 years old, sometimes much sooner
Contrast this with some road bikes and cars I work on that have dust boots, in the past year I have worked on cars and motorcycles from 1980 to 1998 and all were on their first calliper strip and rebuild.
To give this increase in reliability would mean having the callipers a few mm wider, the pistons a few mm longer. The cost would be a few pence for the dust boot and machining its mounting grooves in the calliper and piston. The weight penalty ? maybe 300 gammes on a bike.
Whilst i agree with the FIM increasing minimum weights, they need to go further and regulate materials used and component designs or they weight rules may primarily result in added lead solutions, not cost reductions or reliability improvements.
The new Jitsie sprocket because of the sharp machined edges on its faces will still make a right mess of any flesh unfortunate enough to go between the side of the sprocket and the swinging arm.
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Pour a whole can of petrol fuel system cleaner into the tank with about 2 litres of clean petrol. Start the bike morning and evening for a few days and it might cure itself.
Mechanics in this area charge about £30 per hour and may charge about £40 for a 4 stroke carb service including ultrasonic cleaning.
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