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About mcman56

  • Rank
    Advanced Member

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  • Bike
    Evo 300 4t

Profile Information

  • Location
    N California
  • Gender

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9,612 profile views
  1. 4T Carb Tuning

    I had a 130 main so went to 25 and 130. Clip is at 4th position. Spring looks silver. What spring is OEM? What is the blue spring for? It is lighter for quicker opening? I have ridden at sea level and 5500 feet and ti seem sOK
  2. 4T Carb Tuning

    I have been through the carb and tried different jetting plus have the adjuster screw. Initially, I had to run a rich idle to prevent bogging. Once I raised the needle, the bog tendency went away so I leaned out the idle. I'm now running a 22.5 pilot and since the symptom is lean will go up one size to see if improves.
  3. 4T Carb Tuning

    Thanks for the responses, it seems like this means lean.
  4. 4T Carb Tuning

    I have a 2016 300 with the standard pipe and muffler. I have adjusted the jetting and it runs great with one exception. Occasionally, when opening the throttle from idle it will stall. It does not pop through the intake but instead you hear what sounds like fuel burning in the exhaust. It sounds very similar to a gas barbecue being lit. This happens at lower idle settings, below 1200 rpm. At higher settings up above 1400 it does not happen. Is this rich or lean?
  5. Montesa 315r oko carb

    I ran a 26 mm OKO on a 250 REV 3. I bought it from the same place. It worked well and the supplier was helpful.
  6. Poly Fork Guards?

    Does anyone make polypropylene or polyethylene full length fork guards? I think the carbon fiber looking ones are ABS and they break way too easily.
  7. Beta Rev-3 270 rough running? Petrol Info?

    The popping I can get from mine is like adding up 5 or 10 of those pops. It only happens when winding up the engine and chopping the throttle off.
  8. ty80 forks

    I don't know if they would fit but 1992 PW80 forks were very smooth with nice dampening. I assume all PW80 forks are the same. Looking on line, they even sell Chinese copies for very low prices but the OEM Yamaha ones were surprisingly good for such an entry level bike. As I remember the front brake was good also. I found this at http://www.pro50parts.com/buy/pw221-pw80-front-fork-set/PW221 Size Spec: 63.50cm in Length, 26mm in fork leg diameter, 10mm in wheel axle. Leg Diameter -- 26.0mm/34.3mm The same site has dimensions for PW50 forks.
  9. Beta Rev-3 270 rough running? Petrol Info?

    I have a rev 3 that will pop in the exhaust when chopping the throttle off, sort of a Pop...Pop...Pop I chased/ tried everything you can imagine to eliminate the issue but it is still there. I tried all different fuels including race gas by the can. Other bikes I have ridden will do that occasionally but mine does it a lot. Otherwise, it works fine. It was sold as a 200 and I put a 250 top end on it. The top end is from a different year so maybe that has something to do with it. When Beta sold 270 kits, I noticed that there were different kits for different years but I could never find out was was different.
  10. 1994 GasGas JT25 Contact

    If an original carb is not easy to find an OKO from Mid Atlantic Trials would be an option. I assume they could supply a throttle and tube also.
  11. 4t Carb - Vacuum Chamber plug and jetting

    What exactly is a flame out
  12. I have a 2016 300 4t and it runs OK but sometimes spits and dies when opening the throttle. Yesterday, i even got a very serious spit back through the carb, (80 degrees F). I have had bikes spit the carb right off the manifold with spit backs like that. I pulled the carb today to check jetting and noticed that the big vent for the vacuum slide was not capped off like it should be. There was a little dust up there like it had been off for a while. Could missing the cap create issues I have seen? Otherwise the carb looked clean, 27.5 pilot, 120 main, idle mix 2 1/2 turns out, needle 3 positions from top, standard quiet muffler, I don't know how to tell the difference between slide springs but assume it is the original. I have no other 4t to compare it to but the fan does seem to run a lot and sometimes it is finicky to start when hot so I thought it may be lean. The bike does have extremely low hours so maybe that is why the fan runs a lot. I'll install an adjustable idle mix screw. It seems like the only other option is to raise the needle. Are there any recommendations?
  13. X Ring Chain on 4t?

    I have run X ring chains on a number of trials bikes including a Rev3 and Evo 2t. A standard O-ring chain fit on a 2002 Sherco. They need little lubrication, no adjusting and seem to last forever so are very convenient. You can buy wider chain tensioners to accommodate. I did not notice any power loss but none of the bikes were under-powered. Anyway, rider skill limits my riding infinitely more than power. But, there is little clearance between sprocket and engine case on the 4t so I'll give the WD40 method a try.
  14. X Ring Chain on 4t?

    Has anyone run an o ring chain on a 4t? Does it rub on the cases? What front sprocket size do you run? I have a 9 tooth and there is very little clearance between chain and engine case with a non o ring chain. I had a short piece of the skinny RK X ring chain and if I put it on the sprocket and push in on the chain, I can feel it drag on the case when turning the sprocket. The X ring chain is about 0.045" wider than the non o-ring chain (at the link plates not pins)
  15. Is this a slow action throttle? EVO 300 4T

    To clarify, does the Amal 80/200 throttle tube fit into the stock 4T throttle assembly or do you need a complete Amal 80/200 throttle assembly?