Introducing Kit, from Gloucestershire UK

Discussion in 'Introduce Yourself' started by Kit, Dec 15, 2013.

  1. Kit

    Kit New Member

    Hi All

    I built my first Motorised bike back in August this year. It has been the perfect solution to getting me to work for the last few months. I only work a couple of miles from home, and begrudged having to pay out for 2 cars, (one for my wife and kids, and 1 car to drive 4 miles a day, then sit outside work all day costing money).

    I can get to work along a series of farm tracks, so avoid any tricky legal problems. I like my motorised bike as its mainly uphill in the morning, and no fun pedalling, especially in summer. The obvious beauty of these things is that after a couple of hundred quid spent on the motor and a cheap bike, they are almost free to run.

    I used to hammer around on a 1000cc triumph, but my motorised bike is far more use for quick easy short journeys. I also like the simplicity and opportunity for tinkering with your set-up.

    The 300ft hill on the way to work has become somewhat of a nemesis; the stock float bowl carb struggles with being inclined, and the lack of low end torque becomes more evident. I have found that the best way up is to hit the bottom of the mountain at full power, keep it pinned, and hang on. This would be ok if it were not on the most rutted, rough road ever. Its fine for a tractor, but not much else. The sort of road where a digger bucket full of old bricks in a hole is considered a good repair.

    This has lead me to buying an improved mountain bike, with chunky tyres and good suspension. I can't resist tuning my bike up either, hoping for more low end power, (so I can go slowly around obstacles, rather than full speed through them; any less than this at the moment means certain defeat on the hill). I would also like better top speed if possible.

    I have just brought a Walbro Stage 2 Carb and reed valve kit, a Jaguar CDI Kit, and a Voodoo expansion chamber exhaust. I would also like to increase my crank pressure by skimming the head, and upgrading the little end needle bearing...

    I have read a lot around the subject, but will be here for more advice. I'm intending to make the modifications over my Christmas break, so I would genuinely appreciate to hear from anybody who may have any advice or tips from adding similar parts. I'm keen on finding out more about installing my Walbro, (no instructions came with it, unlike the advert said), finding a reasonable priced needle bearing, or just the dimensions of one for the 66/80cc engine, and tips on bending my new exhaust to fit properly.

    Many Thanks, Kit.

  2. bluegoatwoods

    bluegoatwoods Well-Known Member

    Welcome aboard.

    Yup. I ride mine for the same reason, more or less, than you ride yours. It saves me from having to keep an extra car on hand. Plus the bike's a whole lot more fun, of course. Maybe you've already found that there's any number of other reasons, too. But these are two biggies.

    I'm lucky enough to have pretty smooth riding surfaces available and, so, have no need to make the modifications you've talked about. So I'm unable to advise there.

    But others'll be along. And you'll find that there's some good info here.
  3. LR Jerry

    LR Jerry Well-Known Member

    Useful basket on a bike, 200 mpg and 30 mph. Can't help but love them.
  4. Fabian

    Fabian Well-Known Member

    You will need to find a method of delivering a crankcase pulse signal to the Walbro style diaphragm carburettor and you will also need a thermal isolation spacer/block for the diaphragm carburettor, otherwise fuel will vaporise in the small fuel circuits; causing a no-start/no-run condition.
    Kit likes this.
  5. FurryOnTheInside

    FurryOnTheInside Active Member

    Hi Kit,
    Sorry I can't help but I'd be very interested to hear how your upgrades go, as I'm planning a build with some of the same components. £200 sounds a bit optimistic though, lol; I'm budgeting about £1000 for what I feel is a very basic starter setup! I'd love to know what motor you got and what you think of it? Did you get your reed valve and carb from RSE through JNM, and did they send you a thermal isolation spacer for that carb or are they still sending them out without it? :dunce: From what I've read (from what Fabian has written on the subject) the (very expensive) carb is as much use as a chocolate teapot without it; but idk where you can get one as it would be made to fit between the reed valve and carb on specifically a china bicycle motor, so I don't think there's go kart or minibike parts that fit. I've tried to look on the RSE website but I keep getting a message that my country (I'm in the United Kingdom too) is blacklisted! :icon_cry: I'm not even going to part with any cash til I know I can get all of the parts I need, that's why I'm on MBc, homework. I just knew the blurb on the motor kit webshops sounded too good to be true! I'm now finding out just how deep the rabbit hole goes....
    Anyway, I really hope it does work out for you and the parts you've bought all work together. Please let us know how you get on, and have a very merry Christmas. :)
    Last edited by a moderator: Dec 18, 2015
  6. Kit

    Kit New Member

    Hello Furry!
    Thanks for that...!

    To let you know, I brought my motor from Transformer Cycles, (UK). It cost £200 delivered, with a complete bicycle conversion parts kit. I chose to buy from Transformers as they are UK based in case of problems, and offer a 90 day basic warrantee. I felt more comfortable with this than ordering from a distant company, even if it cost a few quid more. Transformers give good customer support, newsletters, etc. The actual engine seems no different from any of the others I have seen online, although apparently it is improved if you believe the spin.

    My experience of this engine kit is very good. I work daily with chainsaws, and use state of the art kit, and know my way around 2 stroke engines fairly well. This engine is very crude by comparison, and not brilliantly made, in comparison to my husqvanas and sthils, but saying that, it holds together and works well in its basic form. I use my bike every day as a reliable form of transport, and pound it mercilessly over farm tracks. I love it for its economy; a lad who works for me drives a truck up the same track to work, which must cost him at least £1000 per year to run and pay bike hasn't done 10 litres of fuel in 4 months!

    If you buy a decent suspension bike off ebay, for say £100 tops, (my first was £60), then your basic set up is only £260-£300. That will do you fine, until you go down the modification route.

    I have just done about £200 on performance bits, which I justified to myself with the reasoning that, a, it is my work transport, and b, I 'volunteered' to give up my 160 mph Triumph Sprint after recently becoming a father. I have yet to fit the bits, but will keep you posted.

    Initial thoughts are that the voodoo exhaust will need some serious heating and bending to fit a all. The walbro carb needs a pipe drilling and tapping into the crankcase in order to work. It came with no instructions, (which it was advertised with), and no thermal isolation spacer.

    JN motors seem to be the easiest place to get these parts from, but I have been less than impressed by there overall service.

    I would recommend you start with the Transformers GT4 engine, and a cheap mountain bike, and take it from there... I'm fitting my Walbro, Reed Valve, Jaguar CDI, and performance pipe over Xmas, so watch this space!

    Have a great Xmas, and ask Santa for bike bits!

    Take Care, Kit
    Last edited by a moderator: Dec 18, 2015
  7. FurryOnTheInside

    FurryOnTheInside Active Member

    Oh no, thank you, Kit, that's exactly the info I was hoping for!
    Tf.C. is the supplier I was thinking of getting a motor from (I've only found two in UK so far) but you're the first person I've actually heard from who has one of their "GT4" motors, or has ever dealt with the company. I never believe spin; but I had a vague notion/inkling that their motor just might be a bit better if the slant head (being standard on this motor) could be associated with a more modern or evolved motor (internal construction (i.e. the bearings, seals etc)), so may be worth the higher price even if most of the "improvements" that they boast of on the webpage are things I'll be throwing in the parts bin before I ever ride the thing, haha. It is good to hear that this/your motor is still running since August! :)
    I'm a cyclist and experienced with bicycle building rather than motorcycles, so not at all familiar with motors (except being the motor!) so I'm just learning from others' experiences and writings on MBc before I take the plunge. I have been collecting bookmarks and reading up on motor assisted bikes while I save up, so that I'll have a ready supply of tutorials and tips and a basic understanding of what I'm doing for when I finally get a build started. I had decided that the most important "mod" would be the SBP jackshaft so that I can run the motor through my bicycle's gears; then the carb/reed valve and the Jaguar CDI. Being a keen bicycle builder I just couldn't spend less than £300 on the bicycle itself, then I'll be adding a jackshaft too, so that's why my budget is a little higher I think. However if chain tensioners for the jackshaft, and thermal isolation spacer for the carb aren't available by the time I've filled the piggy-bank, I know I'll end up spending it on something else.. yet another bicycle for the collection I expect. :p
    I'm sure by now you've seen Fabian's photo tutorial on fitting the carb, it looks easy enough. :) From what I've read, performance exhausts only help at a specific RPM that you set when you choose header pipe length (IIRC, and I may not!), so perhaps need a jackshaft kit to get the most out of them? Sounds like a good excuse to buy a jackshaft to me, lol! :D
    I certainly will be watching this space and I wish you all the best with it!
    Last edited by a moderator: Dec 18, 2015
  8. Kit

    Kit New Member

    Hello Mate!

    Have you read Michael Forrest's virtual thesis on these engines? There isn't much he doesn't know about them. Google 'Motorised Bicycle Tuning', I think he writes under the name 'DragonFly' He also contributes regularly here as 'Jaguar', and is the designer of he Jaguar CDI. Well worth reading.

    I believe he is wary of the jackshaft kit, and from what I've heard, I think I am too...All those extra chains and linkages sap a lot of power, which with these engines we don't have to spare. They are also quite fiddly to work with a lot to go wrong unnecessarily. I know from blasting my bike to work every day, I wouldn't have enough fingers and thumbs to work gears as well; its not like a motorcycle, where you have foot controls too, everything is jammed on the handlebars.

    Forrest points out that with sensible modifications, you can gain enough overall power to get by on a single gear. I think I'll be sticking with the single speed; if I can find a little more low end torque, I'll be almost happy with mine. Lets see what a bit of festive tinkering achieves!

    Regarding your bike, be prepared for it never to be quite the same after a motor conversion. It is likely to suffer all kinds of bumps and scratches during its career as a motorised bike. On both of my builds I have had to file off the water bottle holder mounts to place the engine properly, and drill various holes in the frame to hold things. On my first build, the chain rubbed a bit over bumps, etc, on part of the frame, and took an inch long swath of paint off. I didn't care, but if you had a really nice bike you might, especially if it was completely devalued. I have also heard that the motor torque can bend lighter frames; it might be best to build a prototype on a cheap strong frame, so you can get your next build just as you want it. That's what I ended up doing anyway.

    Again, I'd recommend transformers. I don't think that the engine is that different from the others, but your dealing with a bloke in Birmingham, rather than China, should anything go wrong. My kit arrived in a few days, and you get lots of support and emails from them, and spares if you need them. My engine is well maintained, but there for a job. Its always covered in mud, and has pounded miles up rough tracks without missing a beat, so I can't fault it or transformers. Also, my mate has clocked me in his truck doing anywhere between 20 -30mph, even uphill!
  9. FurryOnTheInside

    FurryOnTheInside Active Member

    I haven't the engineering knowledge to understand Jaguar's more technical writing, once he's into graphs and stuff I'm pretty lost, lol! I have read most of the modification tips on the dragonfly site though, and plan to do a couple of the more simple ones. :)

    I'm sure that is the case, turning three chains rather than one WILL sap some power. However I view that against being in the correct gear to be almost always running at the correct RPM for longevity and RPM that any power mods are set for. I DO recognise that I'm only a student/reader of these things atm though; but while experts disagree I can only pick one route to take, for now.
    I quite enjoy fiddling, and from working on full-suspension mountainbikes I am confident I can take care of the chain handling.. I guess I'll just have to see about that and about managing the gears changing and throttle and clutch.. maybe I'll need to upgrade to a centrifugal clutch and see if that helps, I think that's a bridge I can burn when I get to it, though. :)

    Yes, back to YOUR bike! :D I'm sure it'll be a lot of fun and will work well in it's own way however if differs from the ideas and plans I have. Power mods may well trump (idk what to call these..) rev-moderation/longevity mods. One day we'll have to race each other, eh? :D I have to say, from my cycling knowledge I know the best mod for getting better acceleration and hillclimbing is.. go on a diet! :p Hopefully the festive mince pies won't counteract your bike mods too much though.
    Indeed I am going to build, or at least mock up, on my winter salty bike (my old 26" tourer) while keeping an eye out for a bargain 2nd hand in Cash Converters, eBay, etc. I still need to keep my other five bikes working as human powered.. for some reason, lol. :p I'd love to get a Thorn chromoly touring frame to build on, but they're expensive and rarely ever found 2nd hand.

    I think it's hard to tell which engine is better, as even comparing anecdotal evidence of performance/longevity is impossible when each rider uses his bike for different types of riding, has different maintenance (or lack of) schedule, rider weight, etc etc. The other company I know of is also in the midlands, but to look at, the TfC motor seems more modern, and I'm just going to cross my fingers that the £70 more they charge will be worth it. I think if yours has lasted as long as it already has then one of those will do the job for me, too; so you've sorted motor choice for me anyway. :) Just out of interest.. I don't suppose there are any markings in roman alphabet that might give a clue to it's origins? You make a good point about spares, though.. the other site doesn't offer any, just a kit in a box. It sounds like you're having a lot of fun with your bike, that you "just bought for work" hehe ;) I hope you have lots of fun tinkering over the holidays too. :) and thanks for taking the time to reply, your posts are very helpful to me and all the forum lurkers reading this! :grin5:
    Last edited by a moderator: Dec 18, 2015
    Kit likes this.
  10. Kit

    Kit New Member

    Hi Fabian

    I have been advised by 'Furryontheinside', that you have posted a photo tutorial on fitting the walbro type carburettor? Would you mind directing me on how to find this; I have been hunting around on this site, but there is s much stuff! Also, what is this thermal isolation block? I doesn't come with the carb / reed I need to buy or make one? Do you think I'll need one for shortish journeys in cold Britain, where the carb may not get hot enough to cause problems?

    Many Thanks,

  11. FurryOnTheInside

    FurryOnTheInside Active Member

    Fabian posted the link to it on your other thread "Walbro Pulse Pipe Installation", Kit. :)
    Also check your first thread "Piston Wrist Pin Dimensions" as you have a new reply there too. ;)
  12. Fabian

    Fabian Well-Known Member

    Questions in reverse.

    All chainsaws use Walbro style diaphragm carburettors and they "all" use thermal isolation spacers. That said, you "will" need to install a thermal isolation spacer with a diaphragm carburettor.
    Because this type of design carries a very small amount of fuel inside the fuel passageways, it is very susceptible to "heat soak" and fuel vaporisation, which makes the carburettor untunable and virtually inoperable under such conditions, hence the reason why a thermal barrier is needed for this type of design.
    There is no reason why you can't make up a thermal isolation block, but you will need to use a machine grade plastic, designed to be thermally stable under high temperature. The most commonly used plastics with this specification are "Meldin or Vespel" - Meldin 7001 being the lower cost variant of thermally stable and mechanically durable engineering grade thermoplastic.

    Yes, you can order a thermal isolation spacer from Rock Solid Engines, as described in my threads here and here.
    Read both of the threads carefully and you won't have any problems getting the reed valve intake and diaphragm carburettor installed and working correctly.

    It might take a while for the pages to load the photos if you have a slow internet connection as they contain a lot of photos.
    Last edited: Dec 23, 2013