sadlotus

Hi all, just rebuilding my Frontera 152 engine, I'm using the Inmotion Italkit piston and crank set, new rod too. There are two piston rings - a chrome one and a black one. Which one is the upper and which is the lower? I've emailed Inmotion but sounds like he's super busy... and can't reply before Tuesday anyway... just trying to get a headstart. Ta.

Thnks Stuart... good idea. Will check

Thanks SS, I’m getting plenty of power. Not sure the split mount is even affecting the running. It’s as if full throttle uses all the fuel in the float bowl, then refills by the time I come to a halt and kickstart. Starts first kick. Carb’s off now getting a blow through, new mount ordered. I do drain all petrol out when I put it away including draining the carb. So may be some dried fuel on the float needle? Hopefully a clean up will fix it.

Evening all. Riding the Frontera round the fields today, all was fine til I opened it up - good for a couple of hundred yards then it cut out. Started immediately. then good for another coupla hundred yards. Then cuts out again. If I pootle along the bike will go on forever. Felt like fuel starvation. Took the carb off and all looked good, felt like a sticky float valve but all looked good. Then... spotted a split in the 'rubber' manifold connector. Question: would this air leak give the symptoms? Would have thought the bike would rev up or cut out at low revs but ticks over smoothly forever. Thoughts?

Mike, the Orlando link paid off. Bit of a wait but got one in the end. Thanks Paul

Ditto condenser, Does it backfire, pop and bang? Hesitate and surge? Condenser. Also, opinion seems to be to relocate it under the tank in the airflow. Good luck.

Hi Graham, thanks for the confirmation. yes it would be easier via an email BUT you're right, it's a lot of pages to scan! Inmotion don't have one, I haven't tried Weavers or any other US suppliers, but will now. If I'm unsuccessful can I come back to you and ask your friend to scan it? I can Paypal a few beer vouchers to ease the strain. Thanks again Paul

213 views and no comments ....does anyone know if they did they do a handbook for the Frontera Mk9?

Does anyone have a Frontera 152 - 1976 250 Frontera - handbook? I've got the parts book and a load of articles, I'm just after the Instruction Manual. I've been through the various download sites and can't seem to find one for the 152 - plenty for other models, not the 143/152 models. A scanned version or borrow to scan would be excellent. many thanks Paul

er yes.. I meant drained out 1.... That was a test.

Hi all Back again. Thanks for all your help and explanations. Took the side cover off and sat looking at the clutch for an hour working out what pushes what etc. Had a chat with the local Bultaco/Greeves/BSA engine builder and racer he suggested just winding the nuts off a couple of turns and see what happens. Yeah - why not!. There are six plates on my clutch. The actuating rod, lever, cable were all good and moved nicely. Took off the clutch arm return spring - the clutch was 'closing' well enough without help from a strong spring as well. Wound the nuts off a couple of turns - from about 6-7 mm threads showing, to about 3-4mm showing. Spun it over with the kickstarter looking for runout (very difficult to see any - if any) Started it with no cover and rode a few yards to see if I could make the clutch slip. Seemed fine. Wiped off the thrown oil! and back together, new ATF and away we went. Much better, nicer action - not light as the 325 but very much improved. I wasn't thinking how heavy the clutch was every time I used it or came to a stop. Had a great time ripping across the stubble. did about 8 miles. No slipping. Great. Ahem. One thing did surprise me. I put three litres in and drained two out. That's 2 litres for 8 miles. That's 1 litre for 4 miles That's 4.5 litres (gallon) for 18 miles mmm... 18MPG! thanks again Paul

Hi all I didn't change my clutch at resto time on my Frontera and it's heavy as a heavy thing, really pumps my forearms. I was also looking at more modern materials. Larry, my Sherpa 325 has a lovely clutch - original clutch - You're suggesting replacing the current (don't know how many) with just four on the Frontera. The 325 had the pin and cup arrangement - the Frontera has the nuts setup. (nuts and bolts... that is). Will the clutch really be up to it with just four plates? Thanks for any info Paul

Yes I've used them. They had something I couldn't find anywhere else..... and still have a few I STILL can't find elsewhere. Wouldn't take paypal or card. Bank transfer was expensive. Good otherwise. ps.... never been there, maybe I will. Paul

OK. Hope no one out there is bored with this yet. ...not you Larry - I can tell. Funny how you sleep on things and they come to you in your dreams. In all my years of playing with old cars and bikes - all those Minis, Anglias, Corvairs and Lotus’ I’ve never come across a sparkplug that suddenly gave up living - outside the cylinder head. Yesterday was the first time I’d ever experienced it. Then B40Rt mentioned the condenser - and others said to put it under the tank with the coil, Sherpa325 mentioned ‘a faulty one can give a nice healthy looking spark when cranking the engine over yet cause problems when the engine actually runs’ I remember problems in the past with dodgey condensers/capacitors and points, and how they can give a healthy spark out in the open but give up under the pressure of having to fire an engine. And... the fact that it ran well for a while then deteriated. And... as Larry and Lorenzo said - unlikely to be the carb so now is probably not a good time to change things. So... Changed the whole stator for the one off the Sherpa that now has Electronic Ignition. Nice new points and condenser, and nice new felt wad oiler - only three wires instead of four but the red was never used/wired in anyway. Redid points and timing. Bit of a problem getting enough retardation. So turned stator fully anticlockwise and redid the points (after thinking about 2stroke4stroke’s comments) and this (I found) gave me just enough to get the timing right. First kick - MASSIVE BACKFIRE - dammit! Third kick, started and ticked over - once again - a bit late for the children next door, so let it run just for two minutes, sounded so much better. That backfire was probably/hopefully all the petrol I’d been pumping into the exhaust during the ‘no starts’ the last few days - it certainly woke all the dogs up! Over the last couple of days I’ve fettled the tools I use - I now have a nice homemade magneto holder and the dial guage sits nicely in the plughole... Also a picture from sunnier times ...October. Thanks for all your help - if everything is as good as I hope (Idon’t count chickens until.. etc etc) I’ll try and put a vid up. thanks all, lots of good info out there and I'm upping my knowledge... continually.... until it leaks out with age. Paul PS Larry, you mentioned that you can leave the condenser behind the stator and wire in another one up by the coil - so - there'll be two wired into the points... is that what you meant?

Nope - but will tomorrow Also, the plug I'm using is an NGK B8ES which isn't the equivalent for WHAT THE MANUAL SAYS... Should be Champion N57R which equates to NGK B10EG Admittedly the N57R is an old plug.

Evening/morning all. Busy day - must do some Christmas shopping soon! New plug in, tank on, petrol in. Fourth kick and it started. YAY! Choke off and for a few minutes it was responsive and smokey. I don't like to rev too high when engines are cold. As it warmed it began to misfire as I revved up. Standing next to it, it sounded like a backfire/afterfire in the beginning/middle of the exhaust. Ticked over fine. Couldn't get past the bogging and backfire to higher revs. (with or without the air filter) Changed plug - the same. Changed premix from 50:1 to 25:1 as in manual. Predictably worse. Changed plug Back to 50:1 - same as before. Then stopped and no start. Changed coil and cap, rubbed away paint for good earth. Good spark. (bizzarrely one of the spark plugs refused to spark when the other three would) Checked last nights work: Woodruff key good. Points clean, correct and opening Timing spot on. Getting late again, so can’t start it up, so checked the carb out. All clean inside except a bit of greenish verdigris on the main jet and needle jet but not enough to block things, very thin and difficult to remove with a toothbrush. This is what I found compared to what it says in the manual: Needle: Marked 2F1 - 5 grooves - on the top groove. Manual says clip position 4 (which is 4 from top!) Slide: marked 4 - Manual says 2.5 Main jet: 330 - Manual says 360 Needle jet: 107 - Manual says 108 Just researching as to whether it’s been set up lean or rich for altitude - It’s an import from Colorado -which has a quite a few high places doesn’t it? Might just order the standard jets etc Just found this: ....raising the needle richens the "middle" a little bit. At full throttle, the carb should be all main jet... At near-closed throttle, the carb is on the pilot or slow jet... All of which is inferring that it's running rich. If I get a chance tomorrow - I’ll reassemble the carb and see how it runs on the middle groove (down two) and new (different) coil Also going to check the exhaust manifold joint - as I believe airleaks there can possibly cause backfiring. What's baffling is that it ran fine first time out and for about ten miles after that, then started to play up. Annoyingly, a fella two doors down has been showing off by starting his Honda CR500 at will all day!

Hi all really pleased with the response to my question. Thank you for all you replies. Here's an update - more to follow tomorrow - not actually started it yet because it's quarter to midnight and a Frontera - even with it's bazooka exhaust - is a loud old thing. Don't want to give children (or the dogs) next door a fright! From the beginning I've been following instructions from the InMotion Bultaco workshop manual and a printed out post from on here: http://www.trialscentral.com/forums/topic/35785-timing-and-points/ I found myself going back and forth between the two so (unwisely) used the printout - No. I don't know why I followed that primarily. I do (now) know that I should have read the post properly and to the end! Anyway. After a bit of logic circuitry in my head I found that if the green and black wires were disconnected at the junction under the tank I can attach my battery, light and crocodile clips between the green wire and earth and make the light go on and off as the points open. LIGHT ON WHEN CLOSED LIGHT OFF WHEN OPEN After setting the points I can turn the magneto CLOCKWISE to set the timing BTDC (as the workshop manual says) and find the points opening moment. NOT COUNTERCLOCKWISE AS THE ARTICLE ABOVE SAYS! This is proven by pushing on the kickstarter (easier to rotate the crank than by hand) which will rotate anticlockwise. ie the way the engine runs. So BTDC is clockwise. After that epiphany, it was all plain sailing. To answer questions above: Larry, thanks, green wire was the clue. Condenser stays where it is at the mo to avoid another possible fault (mine). Greychapel and Feetupfun, I did notice that the light dimmed but didn't realise the significance then - also don't have a strobe where I am at the moment. Larry, Steve and Zerorev3rev4, the plug is new NGK B8ES (non resistor type) JLpar, checked thru the magneto holes to check for touching - all good. Sherpa325, checked cleanliness and tighness - all good. Lorenzo, 1. I have a paper gasket. the exterior joint looks good and the allen bolts all do up snug. Lighting coil was replaced because it was unwinding and someone had made a temporary repair with tape. 2. The InMotion Electronic ignition on my 92 just bolts up - there is no adjustment! Three bolts - done. 3. Don't know why points were wide, wasn't much, I assumed I'd done them 'slack' the first time , What should I lube the little felt pad with? I've been using plain old engine oil. The heel doesn't look any more worn than the others in my box of points (admittedly, we're talking thou here). 4. Good point about the three screws and the stator plate. Not sure I understand how the timing changes when I reset the points, only if I open or close them up or down a bit. Explain please. 5. Yes, I need to get a buzzer. Inmotion Bultaco workshop manual. I also have a Haynes and the WWW (but..."Don’t believe everything you read on the Internet just because there’s a picture with a quote next to it.” – Abraham Lincoln) 6. Stoplight is direct - only on rear brake as per original wiring diagram. 7. The backfiring was happening before it wouldn't start, I'm hoping that by resetting the ignition I can at least eliminate that as a cause. What is strange is that it ran really well for a while then gradually deteriated to a no start. As for an intermittent ignition breakdown, how can I test that?, it ticks over fine and revs high fine, it's the loading on acceleration where it backfires, as tho there's no spark or no fuel. mmm... Ok.... maybe the ignition under load might be breaking down. i have a spare stator to test that - my money's on a carb setting..... I'll let you know. Setting the points and timing these last couple of days has meant taking the magneto off and on lots of times. It has occured to me that the woodruff key is quite shallow in it's 'trench'. The magneto would only have to slip the tiniest bit to stop the bike and give the backfiring and stop scenario. Next time (hopefully not) I'll check the key before I take off the mag. Thanks for all your help and enquiring questions. Update v soon. Paul

Hi all, On my Sherpa 325 I put InMotion electronic ignition - bolt on - could not have been easier. Easy starter no problems. On my Frontera 152 I couldn't afford the electronic ignition so stayed with the points system. Took a while to set up, the bike had been sitting for years and the stator and accociated bits were dusty, rusty and neglected. I cleaned everything, new points, condenser, replaced the lighting coil, all seemed to go together easily. Set the points gap and bought myself a dial guage to set the timing. An evening in the garage had things assembled and timed fine. Ripping across the fields and around the yard the bike went very well, easy to start, hot or cold. on it's third outing it developed a backfire - from/through the exhaust I think - not the carb. I thought it might be muck in the carb and cleaned the tank and carb and checked the flow from the taps. All clean and lovely. Next time out backfire was still there.Still easy to start hot or cold. It was a mid range backfire on acceleration, wide open throttle seemed to be fine. Next time out, won't start. Plug is getting wet and there's a good spark. Air filter is a new oiled Inmotion one. Anyway, decided to check points and timing again. Points gap was a bit wide - reset that. I had marked the timing on the back plate and that hadn't slipped as I thought it might have done. NOW - the question is: no matter which combination of leads from the stator I connect to my timing test light (as well written up elsewhere on here - and in the workshop manual) I can't make it go on/off with the opening of the points - only if I take the stator off the crankcase can I get a make/break circuit. Where am I going wrong? Surely one side of the points should be isolated from earth... I think.Or not. I'm not sure now. I've not dismantled the points from when it was running great. Am I missing a tiny fibre washer that I remember from Mini and Cortina days? Everything else works fine - stoplight, headlight, tailight, horn (haha) - it has a two week old MoT. Where am I going wrong?

JUST done this today, I couldn't fit a 6mm, but a 5mm went in ok. In the parts book it says 5.5mm. Paul

Running. Used the Sherpa stator, set the points (just about) Set the timing (just about) Big backfire and kickback. Second kick started. The Frontera stator is a bit dilapidated. Broken coil. Anyone know what the red wire from stator is for? Seems to be the only difference.

Hi all, REVIVE! Found this post coz I've had the same problem with a 'rod in a death end'. WOW! thats a tough clutch pull - my 92/325 is easy and can pull in with one finger. This 80/250 broke the nipple! Actuating arm nice and smooth - ball bearing present and correct. The rod slides in nice and easy, yes the mushroom end ball bearing was missing (must have dropped out duing dismantle) but replacing it made no difference. (no small homemade extension piece either like above, but contemplated making and using one) Had all the clutch apart - all looks good. Maybe a bit at the end of it's wear. The adjuster was quite screwed out. All back together and no difference. Bugger! have I got to take the clutch apart and start again. Start with the adjuster cover and see if I can see what's going on. EUREKA! The inside of my new ally adjuster cover is scored by the adjuster nut! Soon as I took it off, everything worked fine - still heavy - but working. So. Have to screw the adjuster cover in just so far. Just enough to let the clutch push out, but not touch. But. I have a feeling the gear lever will rub my shiny adjuster cover! I was so excited to share my news I haven't tested that yet. Hope nnyerges found his answer.

No. The seller said he'd had it running on brake cleaner... Not fully sure I believe that coz I've not had a spark yet. P

Hi all, Just aquired a Frontera 250cc/152, can't get a spark at all. Eventually after various tests I swapped over the stator from the Sherpa 92 and it sparked straight away. The frontera stator is gummy, dusty and covered in rust and sand. my question is: can I leave the Sherpa stator on? - they both look the same, both have lighting coils. Is there a performance difference between the two - between a revver and a slogger? Thanks Paul

Blimey! I first posted in Sept 2011! I thought I'd be back before this! Well, finished bar the carb fettling - but seems good to me when I ride it. Enjoyed my time in the shed, all went fairly well - a few problems putting the engine back together, but goes lovely now. What have I done? strip everything down, frame off to I Cleenz Macheenz in South London, £50 and ready for spraying, used Hammerite spray over powdercoating - after a lot of thinking. Frame's not quite right and if I want to weld/change/alter it that'll ruin the powder, paint's easier. Small fortune (it's relative) at InMotion and Ebay, including: new crank, tank cap, electronic ignition, brakes, cables, new rubbers throughout, new bearings and starter spring etc, new clutch casing, levers and Bultaco front wheel (instead of the Yamaha one)and rear (later) silencer (instead of the SWM one), paint and glass. Reglassed the tank under the seat to lose the rounded shape - but not deep enough as original - I like the 'shorter' shape. Repainted the tank myself but got a mate to laquer it. Had the logos made up by another mate before lacquering - they're cutout instead of on an oblong clear base. New tyres instead of the perished things on there before. Engine was rebuilt by a friend - a retired Finair Jet Engine engineer now restoring planes at Duxford - knows his stuff and found he had to return the crank a couple of times until it was correct, he fixed other unexpected stripped threads etc, was quite apologetic that it took so long, he said he can usually do a two stroke in a few weeks at home in Helsinki. Cracked the front shock at the wheel bolt - then told it needs a shim - Doh! (ring..ring.. Hello? Is that BultacoUK? I need a fork leg) Seat redone in Poundland neoprene Laptop cover - ahem, looks nice but not sure how robust it'll be. Later clubfoot silencer, cheaper and easier to find/fund than the triangle one. Litre of 50:1 mix in, and third kick it started - YAY! putted round the yard and up over the fields, brakes are nfg but chuggs from nothing and feels so much better than before. Two days later took the bike cover off in the shed and WHOAH!! what's that? The tank's bubbling in places from the petrol, from the Ethanol I reckon - E's.. Grr I used to be only wary of them in Smarties! Used KBS Gold standard tank sealer and seems to have worked - so far - looks and feels like Hammerite. I’ll redo the tank when I can… be bothered….let’s use it first. Loving it. Thanks for the help and advice on here, often found myself scrolling through the old posts looking for colour codes, positionings, etc.