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  1. Today
  2. 4rt repsol. Dropping engine speed

    Crankcase pressure may well have been keeping the butterfly slightly open - since the oiled air-filter will have some resistance to internal-pressure. The idle may have been adjusted down because of this. Removing the breather-pipes from the air-box would then cause the idle to dip - necessitating a CCW adjustment to bring it back up. That idle also may have been adjusted before with physical-pressure from that catch-container on the throttle-cable. All part and parcel of buying a secondhand 4RT. Quite normal!
  3. Side by side bike comparison?

    I could never scratch one! just would not work against the rocks here!
  4. cylinder head needed

    I am pretty sure the 200 head will work, part M387. contact Splatshop!
  5. 4rt repsol. Dropping engine speed

    Given the things you've already checked, and that you already corrected the previous owners breather modification, you may want to: 1) Check the throttle cable to make sure it has enough free play per the manual. 2) Adjust the idle up (CCW) a quarter turn. Start, let warm up until fan comes on, blip throttle a few times. The idle should be adjusted after this much warmup. If, when it drops, it then stalls, try again with another quarter turn. See if you can get it to the point where it idles and doesn't stall after the warmup & blipping. Then adjust to proper idle.
  6. cylinder head needed

    TrialsBikeBreakers have an 80cc top-end complete in stock. 07835 233083. Give them a call and they will give you a straight answer.
  7. Side by side bike comparison?

    Here’s some eye-candy for the ugly-sisters! Tasteful crankcase modification and re-mapping to give smoother low-end torque and first-kick starting. By tomorrow afternoon it will have 2018 plastics and graphics - elevating it from “Angelic” to virtually “God Status”! Enjoy.
  8. Side by side bike comparison?

    There certainly isn’t 10mm between you two
  9. Side by side bike comparison?

    side by side there is probably noy 10mm difference between anything
  10. Yesterday
  11. 4rt repsol. Dropping engine speed

    I appreciate your location isn’t ideal for popping down the shop for a compression test - or borrowing a club-member’s TB for a day. But let’s firstly attribute the cause of that oil in the air-box. Any properly running 4RT should be dry as a bone in the TB. If it isn’t then it needs cleaning thoroughly. The air-box must then be cleaned to ensure it doesn’t re-occur. Then we remove all vents from engine to air-box to prevent any oil ever reaching the TB - sealing-off those vent-ports. Allow the vent-tubes to vent to atmosphere , but keep in view at this point. Stage 1 complete. Next stage is to check the oil level of the engine , to make sure it isn’t overfilled. Clean and gap the spark-plug. Quickly check coolant for level , and contamination - before re-filling oil. (A faulty head-gasket might put coolant in the oil - raising the level and making it overflow into the vents. The final result being a partial-seizure. ) If happy the coolant is correct and unchanged in level - put in the engine oil , then start and run the bike until the fan kicks-in. Now rev it and allow it to come back to idle revs with full-vacuum/no throttle , but don’t allow it to stall. Observe those vent-tubes closely. If oil now begins to exit profusely (or at all) from either tube - then we have a crankcase-pressure problem. Stage 2 complete. Adjust idle-speed to 1,800 if bike comes back to stable idling with no oil-exiting the vent-tubes. ( If there is oil from the vents - go straight to a valve-clearance/compression-test). If the bike isn’t fixed by the above , but not leaking oil either - then we need to know there is a healthy spark at idle , and that idle-fuelling is correct. Tank-vent, Pump , filters , pipes and injector. Since you are happy with the full-throttle operation of the bike , and there has been no reported loss of performance/power - then the injector probably doesn’t need ultrasonic cleaning , but make sure connections and pipes are secure. Do check that injector o-ring. Run the bike as before , but in the dark - and check visually that the HT-lead isn’t arcing to earth at all. The spark-plug electrode needs to be healthy and gapped correctly. The final area is the TB/ECU. Yes , there are ways to trick the unit into doing things in spec , when it has excess-wear on certain components. But to be able to return to a benchmark is essential - and at this point , having a second , reliable TB/ECU is unavoidable. Even if it is only borrowed for a short while. (If there is a little trick with a washer or superglue , then this would be the time to try it). The bike would have to be at a 4RT dealer for comparison tests - or you simply buy a replacement TB ( £242 on ebay). But that is last resort - since the community here may be able to help you - perhaps by lending you a spare temporarily. ..............."................................................. work methodically in the order I outlined - since the oiling is the serious issue here , and I’m almost 99% sure that your TB is probably ok. Very possible that there is still oil-contamination in your TB. But care must be taken when attempting to clean this device - since the sensors are fragile. I’ll take it for granted that you have been liberal with electrical contact-cleaner on any (and all) connections. I’ll repeat - Oil refill is only 410ml after simple draining. (Valve-clearances are actually fun , and rewarding to do on this engine. Once I finally found TDC on the compression stroke (!!!!!!!!) , and realised that you simply undo the adjuster and then bring it back to the feeler-guage blade - rather than trying to slide the guage in first - Then having the valves at the largest range of the spec , was icing on the cake for my 4RT’s idling and smooth-running. )
  12. OSSA fibre glass tanks.

    Typically, the resin used is Vinylester. Here in Florida, where boats are common, this resin is easily obtained locally and the cost is not expensive. Currently, I am helping my buddy repair two oem MAR tanks. He has been doing the sanding, and I have been doing and teaching him the glass work. When he returns to Florida this Fall we will finish them. No plans to coat them, but one maybe both were coated previously. To find the leaks, I used a bicycle pump on the tanks vent and sealed the cap with a section of flat rubber. Submerged in a bucket of water, I added a couple PSI slowly with the bike tire pump. As for the aluminum tanks, my buddies MAR currently has one of the Spanish aluminum tanks on it. He bought it new, and from day one it had a leak. Not bad, but it was on the upper seam. He rode it this way a while and just recently had it repaired. Our welder guy is a certified aerospace welder. Even when super cleaned, he commented that the aluminum is a bitch to weld as the original welding was kind of dirty. Ultimately, this aluminum tank was welded with the beads left and not sanded. Plan is to mirror polish it and hopefully not dent it.
  13. Gripper timing

    Interesting, but are you certain retarded timing causes backwards running. I was always led to understand if the timing is too advanced, the engine kick back and provided the kickstart is not engaged, this is the initial engine firing that sets in motion the backwards direction. After that, the timing is firing after top center, and look out when you let the clutch out.
  14. 4rt repsol. Dropping engine speed

    I remember reading a post where there was a little play in the PTB and when shutting off the throttle it would go past 0 and stall out, a small drop of super glue under the stop was used to diagnose the issue. I don’t remember 100% what the final fix was , but there was some talk about a washer as a shim and a few other options talked about. not sure if that will help but good luck figuring the true root cause out.
  15. Side by side bike comparison?

    ? Did they finally get them to start in 2019?
  16. Plug fouling

    I would go back to when the carb clean as done. Did you do it yourself? Something happened. Carb in crooked not letting the choke return, bent the tangs on the float, left a jet loose, slide needle installed incorrectly(the needle is floating), choke sticking, gasket on seat has swelled, dropped something into a reed. Lots of little things could cause you all this grief. Running 70 to 1 should not be a problem. And I usually ran a bpr5es, I always seemed to have that heat range filling my parts bin.
  17. cylinder head needed

    I'm trying to track down a serviceable cylinder head for my 2003 Sherco 125 ST. They are no longer available in UK as a new part and the later 2005 onwards head won't fit my engine. The inner o-ring seal groove has collapsed into the water channel above, just below the hose spigot (probably due to corrosion), and leaks compression straight into cooling system I don't think a weld repair is possible due to thin, cast aluminium material in head. It would also need a lot of machining afterwards to restore groove
  18. 4rt repsol. Dropping engine speed

    Ok guys thanks for your reply’s. I will keep trying to see if I can find the fault. Might try another TB, but not keen to pay £300
  19. Plug fouling

    Yes I’ve done it twice was a bit oily
  20. New member

    Hi All, I'm a new member and first time poster from the UK. Not been riding trials long - since Feb 2017. I've currently got a 2003 Sherco ST125 which has a few problems, but I'll post up more info elsewhere.
  21. Dave Cooper torque setting

    PM'd you f1wade
  22. Time Left: 27 days and 14 hours

    • WANTED
    • USED

    Hi I am looking for a 2017 Vertigo Combat Ice Hell 250 and have £4,000 to spend Please contact me if you're willing to sells yours if it meets the following criteria: - You bought it brand new and are the only owner - Little use, at clubman level at the most, no SSDT or well trialled bikes - impeccable maintenance record and in excellent condition I am located in West Yorkshire but willing to travel for the right bike Cheers 07711812856

    4,000.00 GBP

  23. Advice on buying a Vertigo

    @Nebulous Ah, I figured that may be the case. Will take you up on that, thank you
  24. Side by side bike comparison?

    The only negative thing I read on the Beta is Dan Williams complaining of his 2018 bike jumping out of gear. You will need to ride it , since it is like Marmite - people either love them , or hate them. 40% of bikes ridden in the UK are apparently Betas - but that could be for a multitude of reasons - and may well include the prevalence of rev3’s as an ideal starter-bike. Up to you whether you like the balance and clutch-action. The Gas Gas has a woolly clutch , otherwise , it might have been a choice. The 2019 Vertigo is a definite contender.
  25. 4rt repsol. Dropping engine speed

    Another possibility is a dirty fuel pump filter
  26. Side by side bike comparison?

    Ha! There’s a fine line between being a stone’s throw away - and wanting to brick his windows! The Beta is a great bike , but I’ll leave it to others to comment - since my riding-ability is well-below what is required here , to make a reasonable assessment. I have seen the Beta in the flesh - and it is one nice machine though.
  27. Side by side bike comparison?

    You will not find a proper test of a trials bike as the industry is so close knit and chummy that whoever said anything negative about a bike in a test would be soon out of a job that is why they are all great ......the only thing you will find in tests in a shoot out type comparison[usually in a Spanish or French off-road magazine]is that every bike has its own character and that you need to ride one a lot to find out what its like ....Choose the one that you like the best in terms of if it feels good to you when you try it in a carpark or brief test and then when you have had it for six months you will know if like it or not.[If you ride it every week-end that is and do not just polish it]
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