klonheadd

I had the same questions about changing piston/rings. At first wanted to dig in straight into engine after getting the bike, but many suggestions on forums said wait until something goes wrong and enjoy it while its running good. Since trials is so low reving activity engine doesn't take a big abuse. Combined with full synth oil changed on time and clean air filter it's recipe for engine longevity. I think my bike had more than 40 hours on it when i got it. I have put in 90 practice sessions last year and bike is still going strong. Engine doesn't use oil - I don't need to top up and oil level in sight window doesn't change. Thats a good sign if it comes to piston rings - they're not leaking too much oil. It would be good to check compression early in engine life and do periodical tests to see is there any significant change in readings and then inspect. I wonder has anybody had any problem with piston/rings/cam chain/valvetrain or engine bearings on these engines? I hope mine will do another 90 for next season

When I was doing research on carburretor, when setting up Beta 4t evo Mikuni BSR, I have found that website very helpful: Mikuni motorcycle carburetor operation and tuning - Ian Williams Tuning http://www.iwt.com.au/mikunicarb.htm Definitely worth reading and opened my eyes to what I am actualy doing with carb settings.

Hi, you could have used carb cleaner to dissolve the blockage in jet and after that use compressed air. I wouldn't try drill bits to clean as they could change size of jet. You can easily get pilot jets for beta evo 4t from fleabay, just search under name: EBC Mikuni Carburetor Pilot Jets - N224.103 - Pilot Jets Slow Running Jet . And for main jet (has to be small 6mm round jet, not 8mm large round main jet for mikuni) : Brass Main Jet - Round Slot Head Type - Mikuni Carburettors Carb range of sizes When I got my Beta 4t evo 300 with stock exhaust at first I set it up to: 2+3/4 turn on air screw - raised the needle (clip all way down)and it was better than original settings. After getting Arrow exhaust i have changed: Mains jet:130(from120) and air mixture screw to 2+1/2 turns. Works nice and has improved top end dramatically.

If it comes to oil changing color to darker, I reckon it's a normal function of oil mixing with carbon deposits. Not heavy clutch use. I heard many times that when oil turns black it doesn't mean it's used up. I am using also fully synth 10w50 in my ktm 990 and it goes black from fresh very quickly but still i am using it for recommended interval (7500km for 3.8l of oil capacity in 990). I personally would like to keep Beta 4t interval bit shorter than manual is stating but not as often as 2,3 rides since it's a synthethic oil. This is an excerpt from valvoline website: http://www.valvolineeurope.com/english/products/engine_oils?CID=2269&cp=cp1. Myth: You can tell the condition of an oil by its look, smell and color. If it turns dark or goes black quickly, it’s not good. Fact: Nothing could be further from the truth. If an oil is doing its job cleaning the engine, then it will be dirty when it is drained. In the case of diesel engines, the oil may look dirty within a few hours of operation. This indicates that the motor oil is keeping soot, dirt and other combustion contaminants in suspension. These will then be carried to the filter or removed from the crankcase when the oil and filter are changed. Good quality motor oils are formulated to hold these contaminants in suspension until the oil is drained when the oil and filter are changed.

Thanks for all answers guys. Any other beta 4t owners please feel free to share your oil change interval time for statisics .

Hi guys, I was wondering how often do you change synthetic oil on the beta 4t engines? I am using Ipone fully synthetic oil in my bike. Manual states to change after 20hrs. Previous owner of my bike was advising changing oil after just 2 trials which seems to be v. often. I have seen one ad for 4t and owner was stating he was changing oil after 3 rides and filter every 6 rides. What is your experience with this subject? At first I thought maybe 15hrs is good interval but now I more inclined to change that to every 10hrs. Thanks!

Hey, I have Progressive spring in my forks- Evo 4t 2012. Got it from Saunders Xtreme Sports in UK. I think there is one used on Ebay now. I can recommend it. I used to bottom the forks all the time. I really didn't like the forks before, that has changed. It's acceptable now and brought back pleasure in using them. Although the dampening is still on weak side and cant be controlled with adjusters (I think they have finally addressed that in 2017 Evo factory). On big drop offs it still is close to bottoming and not so plush. All in all for the money its's big positive change for me. Hope that helps. ps. Does anybody know which position progressive spring should be mounted ? Tighter wound end should be top or bottom? Thanks

hi italianstallion. Did you get you forks fitted yet? I have the same idea for my beta but haven't bought the parts yet. I could not figure out how exactly the wheel and axle and brake disc would cooperate. After reading your post I see You have some trouble. I have been trying to investigate what the TopTrialTeam did with their bikes but i'm not sure. Some of the bikes have custom wheels but some seem to have stock with tech fork. Could you post some pictures of the setup maybe we could figure that one out. I have not bought the parts for the mod because I was afraid that I would need to get new front wheel like from sherco or montesa, together with it's brake system. Maybe there is a possibility to jus get front wheel axle from latest sherco models, and to fabricate spacers. I really would like to see this problem solved so anyone can do the upgrade if wanted.

Hi all , I have finally invested in Bosi/arrow exhaust for my Beta 4t Evo 300 2012 and have question about jetting. Could I use it without changing any jets or settings on carburretor ? and to get best performance, what jets and settings would I need to change. Can anyone with experience chime in. Thanks!