June 8, 201412 yr Hello, I just purchased a model 85 alpina and want to know how hot it should be getting, Im getting about 260 degrees off the plug with a ryobi laser heat gun. Too hot or just right? seems to run alright but i dont want to blow it up. I just would like some piece of mind. Thanks.......Kevin
June 8, 201412 yr Well back with the air cooled bikes we had no such animal. You would get more response with a plug reading, that is true piece of mind.
June 9, 201412 yr Author thanks. the plug could have a little more color in my opinion but is turning brown, i only have a hour or so riding time on it with full synthetic oil i had on hand mixed 40:1 with no ethonal premium. carb is set at one turn and runs best there, i have not checked needle position at this point. it starts right up hot or cold. here is a pic with lights and speedo removed for refurb.
June 9, 201412 yr Nice looking bike, not meant to be reved too hard. Basically a trials motor with a big tank. If you keep that in mind it is a great trail machine. Have fun.
June 9, 201412 yr Nice model Alpina. They have a great look "round barrel" 250 Bultaco motors like yours are prone to getting quite hot if ridden slowly in hot conditions, mainly due to the close fin spacing. 260 degrees F near the sparkplug is nothing unusual, and also quite meaningless unless it is measured while the bike is being ridden. For what you are trying to achieve (checking the jetting), observation of the behaviour of the motor (how it runs at different RPM and throttle position) is the more usual way to check the jetting. If you are going to ride it through long sand washes or at sustained high speed, then I would suggest also doing plug chops using s "safe" heat-range plug (NGK BP7ES or BP8ES). A more sophisticated method for setting the jetting for road riding is to use a cylinder head thermocouple that fits between the head and the body of the sparkplug. I see that the carby looks like the original AMAL concentric. They are prone to rapid wear of the needle jet, needle and slide, so generally run too rich everywhere except full throttle and idle unless they have just been rebuilt. Why do you want to fit a tacho to an Alpina? Does the fork brace hit the front guard on full compression of the forks? It would hit if it was on my Alpina
June 9, 201412 yr how can i wire in a tach? If I need to know how many rpm on an engine that has no tacho, I just clip on a tacho that I bought when the boys were into minimoto's, ( they work from the pulse on the ht coil). The one we have is a pulse pet 2000 or summit like that. It is great whilst the bike is sitting, but not sure how easy it would be to read on the move. Prehaps you may find something suitable if you look for karting tacho's. Edited June 9, 201412 yr by boghopper350
June 9, 201412 yr how can i wire in a tach? If it's not for permanent use the Sthil EDT8 is easy to use, just put the clamp over the spark plug wire. Other tacho's usually connect one wire to the points and a + and - wire for power supply. Make sure the tension is correct for your bike: 6 or 12 volts Edited June 9, 201412 yr by guys
June 9, 201412 yr If it's not for permanent use the Sthil EDT8 is easy to use, just put the clamp over the spark plug wire.That's very similar to the type that I was on about... bit of a job to read on the move. :-) Other tacho's usually connect one wire to the points and a + and - wire for power supply. Make sure the tension is correct for your bike: 6 or 12 volts
June 9, 201412 yr I installed a small tachometer/hour meter on my bike. It has internal battery and one single wire to wrap around the spark plug wire. I connected the wire at the coil end and put some silicone glue to keep the wire secure. Self adhesive velcro on back of case. Simple install. Case is plastic so put it in a safe location. Enter this into eBay search "Digital Hour Meter Tachometer" to see the same unit I use.
June 9, 201412 yr Author thanks for the replys on a tach. the fork brace seems fine, how do i check crankcase oil level ?
June 9, 201412 yr There is no oil level in a two-stroke crankcase The gearbox and the primary drive cases have separate oil systems, and there are no dipsticks, tell-tale screw holes or level glasses in either. To make sure there is the right amount of oil, drain them, and then refill with the recommended quantities. If the motor is working properly, the oils should stay where you put them. If not, oil can transfer from one to the other, or get sucked into the crankcase, or leak out or do any combination of these things. Measuring what comes out when you change the oils is a valuable technique for monitoring what is happening inside. Edited June 9, 201412 yr by feetupfun
June 10, 201412 yr Author sorry, i meant gear case, i thought there may have been a way to check the level. this bike has sat for many years and not done many miles. i just replaced the exhaust coupling this evening and discovered that the exhaust was loose at the cylinder. after the repairs the bike seems much snappier but the petcock is giving me fits (i have one on order). i have played with two strokes for years but mostly all in snowmobiles. this is my first dirt bike ever and there is a small learning curve it seems. but having a blast both learning and riding. thanks for all the help..... kevin
June 11, 201412 yr Author another question. i have 11 42 for sprockets right now and first gear is almost useless, would going to a 12 or even 13 tooth on the front help me out ? i ride in open fields mostly and would also like a little more top end. thanks.....kevin
June 11, 201412 yr sorry, i meant gear case, i thought there may have been a way to check the level. this bike has sat for many years and not done many miles. If its not been changed for many years then its due a oil change anyway Its not worth running old oil when it only costs a few quid to change
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