locoboy
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| posted on 22/7/03 at 01:06 PM |
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Yamaha Bike engine choices
Hi all, im new to this site but have been looking at the content and there are some really good ideas/questions and more importantly ..answers
knocking about.
my question is has anyone ever done or known anyone who has installed a Yamaha V-max engine in a kit car. These are about 140 bhp in standard tune and
there is all sorts of tuning gear available for it.
also with its v-twin set up it had a jaw dropping rasp to it, not only that, as it is designed as an engine to be admired there are all manner or
stainless nuts and bolt sets, chrome this and thas for it so it will look good to.
it is shaft drive so it will make hooking up to a prop shaft easier, i think? (put me right if u dissagree!)
It doesnt need canting over to one side either as it sits pretty much upright in its bike frame so no nasty protrusions popping out from the side of
the bonnet on your nice looking car.
If this has not been done before is there any burning reason why not? i am considering an installation but would like any views for or against prior
to me taking the plunge.
thanks
Colin
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StuartA
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| posted on 22/7/03 at 01:18 PM |
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Not aware of anyone using one of these engines in a car so far but I guess someone probably has (might have more luck on the Yahoo BEC list with
that).
Because bike engines are relatively compact there are rarely any problems with unsightly protrusions on the common variants used.
Not sure what a shaft drive will do for you in a car implementation... standard sprocket adaptor to prop-shaft couldn't really be any more
straightforward.
Yes it would probably sound great, and look great and they do have a reputation for being a beast of an engine in their unlimited guise.
Any idea if they use the exup system that I have heard talk of causing problems on Yammy installations? Not saying it is a problem, just something to
be aware of. From what I understand it is some sort of valve installed in the exhaust system that is required on some of the Yams for them to run
correctly. Causes a problem because you don't run a standard exhaust in a BEC.
I am not trying to put you off using one, and would be interested to see what it performs like, but if you are after a straightforward build go for a
proven solution like a Blade or ZX9R. Both give awesome performance and none of the hassles of using something new.
IMHO 
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locoboy
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| posted on 22/7/03 at 02:05 PM |
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Stuart,
That was quick, only about half an hour after my message! thanks for the info, what is an exup system? i know the v-max has a V-boost which opens up
2nd butterflys in the carbs at between 4 and 6k rpm, this is electronicaly controled and am not sure whether it has anything to do with the exhaust
set up or not.what sort of bhp is a zx9 pushing out in standard form?
colin
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StuartA
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| posted on 22/7/03 at 02:23 PM |
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The advantages of having the internet at work!
ZX9 and Blade are pushing out about 120bhp in standard form I believe. Given the gearing and the weight of car and engine the acceleration in a BEC is
very impressive. I have read all about the V boost system and that was what made the V Max such a lairy bike to ride. Exup is something totally
different and it might not be a problem. I am sure there are other people on here using Yam engines that would be able to give you more info. We have
gone for the Blade engine as it is relatively common (i.e. easy to find, cheapish parts etc.)... and we found one locally.
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rojabuck
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| posted on 22/7/03 at 02:26 PM |
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wee read
i've just had a wee read of some tech specs and can't see a single problem with putting a v-max setup into a BEC.. infact, seems like a
bloody good engine!
140hp @ 8500
86.3ft.lb torque @ 7500
1198cc
all making it only slightly less powerful than a yzfr1 (more powerful torque wise!) the only problem i can see is the lack of knowlage about the
engine's application in cars (i.e will it need dry-sumping??) and that shaft drive! There was a disgussion on either this board or on the BEC
group about BMW shaft drive engines and they seemed to agree that the shaft itself wasnt a problem however, what i forsee is that if you want to use
the shaft output on the v-max, the engine will have to be offset quite servearly within the engine bay (could cause a dodgy weight layout?). Sure i
will be proved wrong and would be interesting to see either way!!
just my 2p 
roja
www.ignitedminds.net - build diary
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ChrisGamlin
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| posted on 22/7/03 at 02:28 PM |
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I think the V Max output rotates the wrong way, so the output shaft would spin a conventional diff backwards, and I also have a feeling they dont rev
very highly which makes diff choice a little tricky.
However, these are only little snippets of crap floating around in my head so dont vouch 100% to their validity, but if these arent the reasons, there
must be some other good reasons otherwise it would be an obvious choice.
EDITED TO SAY
From the figures avove, peak power is at 8500, so unless the primary reduction ratio is very high (meaning engine/prop rotational speeds is high
compared to most inline 4 engines which use a reduction ratio of about 1.5:1), then you are going to need something silly like a 2.9:1 diff to give a
reasonable top end. If someone can find me the primary reduction ratio and gear ratios tho, I can whack it into the spreadsheet and see what its
like.
Chris
[Edited on 22/7/03 by ChrisGamlin]
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Jasper
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| posted on 22/7/03 at 02:32 PM |
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Exhaust manifolds would be expensive???
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Simon
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| posted on 22/7/03 at 02:55 PM |
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Chris,
Something to bear in mind with gearing is wheel size.
The Vmax has a 15" rear wheel and great big fat tyre, so putting 13" wheels on car would help a little!
ATB
Simon
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andyd
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| posted on 22/7/03 at 03:11 PM |
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quote:
Originally posted by Jasper
Exhaust manifolds would be expensive???
Yeah that could be an issue. On a V-twin one pipe comes out at the front and one at the rear. If you did mount it in a BEC then you'd have to
route the one from the offside (rear on the bike) to exit on the nearside (or vice versa come to that). May be a bit tricky, not impossible and
I'm sure that someone could make up a custom fit system but maybe not what the engine requires in terms of breathing performance.
Andy
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locoboy
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| posted on 22/7/03 at 03:46 PM |
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some differing advice i see, as far as i know the engine is pretty bullet proof and they do a v-max trike which i believe is not drysumped, so should
not prove problematic in a car. i have seen custom trikes (just a rear axle grafted on to a frame) that use kwaka engines with shaft drive and they
just have a small prop shaft coming off at an angle, meeting up with the main shaft running down the centre line encapsulated with a bearing at the
front of the long shaft. so dont think the engine will need to be off set by much if at all.
if the output spins the wrong way am i right in thinking that this cant be overcome?
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ChrisGamlin
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| posted on 22/7/03 at 04:48 PM |
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quote:
Originally posted by Simon
Chris,
Something to bear in mind with gearing is wheel size.
The Vmax has a 15" rear wheel and great big fat tyre, so putting 13" wheels on car would help a little!
ATB
Simon
I think I may not have explained it properly but the bike's wheel size hasnt got anything to do with it, its all to do with the rotational speed
of the output shaft against the rpm of the engine.
Discount engine type, engine revs and gears for a mo. To propel a car equipped with 13" wheels and a 3.54 rear diff at 120mph, you need to turn
the prop at X revs per minute to give you that 120mph. This is true no matter what engine you have, or even if you are using an elastic band 
If for arguments sake the VMax has the same gearing and reduction ratio as the blade, then you would go the same speed at the same revs in both BECs,
which means (assuming a 9000rpm timit on the VMax) a top speed of around 90mph. This is what needs checking, to ensure that the VMax is sufficiently
geared so that at 9000rpm in top, it would give a reasonable top speed using readily available diffs and common wheel sizes.
Chris
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andyd
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| posted on 22/7/03 at 08:25 PM |
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And to put Chris's wise words into real (theorectical) figures have a look at this thread ->
http://forum.locostbuilders.co.uk/xmb/viewthread.php?tid=4662
My post on there has an excel spreadsheet you could use to try a few variations out. Basically you'll need the gearbox and final drive ratios
for the v-max box. Then you can decide what wheels/tyres and axle ratio to use to get the top speed in each gear. A bit of trial and error and
you'll be able to tell if it'll be a worthwhile engine to use.
And about my other post about the exhaust routes. My esteemed colleague StuartD pointed out on the way home today that you could just run one pipe
out each side of the chassis a la V8! What a smart a*** eh? 
Andy
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j999sjw
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| posted on 22/7/03 at 10:46 PM |
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I will vouch for the fact the V Max motor does turn the WRONG way. Having helped a friend build a trike c/w jag axle that had 5 reverse gears before
we turned the diff over........
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Rorty
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| posted on 23/7/03 at 07:15 AM |
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Not v familliar with the V-Max, but if it does have an ex-up valve in the exhaust, which I doubt, then you would need it in the car. I know of several
other Ex-up Yam powered cars that were pigs until the ex-up was re-fitted. It's tiny though, and just sits inobtrusively in the system.
I wouldn't recommend using the V-Max shaft. It probably wont stand up to the tortures of driving a car.
I would turn the engine 90 degrees, dump the Yam bevel gear housing, make an adaptor flange for the output shaft, and drive a conventional prop shaft.
One pipe down each side, would be logical with this orientation.
Cheers, Rorty.
"Faster than a speeding Pullet".
PLEASE DON'T U2U ME IF YOU WANT A QUICK RESPONSE. TRY EMAILING ME INSTEAD!
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Macca
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| posted on 23/7/03 at 12:26 PM |
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also with its v-twin set up it had a jaw dropping rasp
Isn't that only half an engine!
Thought the V-Max was a V4?
Col
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locoboy
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| posted on 23/7/03 at 02:21 PM |
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correct, you spotted my deliberate mistake! everyone else seemed fooled though.
colin
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mr loo
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| posted on 23/7/03 at 11:00 PM |
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hi col ,
Don't know anything about the v-max motor .It's just nice to see your still alive after eating the dodgy bbq food on sunday.
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locoboy
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| posted on 24/7/03 at 10:59 AM |
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Dodgy food no kidding! Who is this? I dont recognise the car but you obviously over heard my polite comments reference to food on Sunday!
Nice car by the way, looks nicely finished and bet she goes a bit too!
Col
PS anyone know how i turn off the "recieve E-mails to notify you of replys t your message" feature, its doing me head in now!
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andyd
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| posted on 24/7/03 at 11:11 AM |
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quote:
Originally posted by colmaccoll
anyone know how i turn off...
Go to the top of any page and click the "Control Panel / Options" link? Not sure if this will solve it but if not email ChrisW and ask
him how to get rid of it.
Andy
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Bob C
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| posted on 24/7/03 at 12:16 PM |
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Vmax engine
My brother had a Vmax. If I recall right one of the standard mods to get morehorses was to ditch the bevel gears on the engine & back wheel and
use a chain drive - this liberated several tens of horsepower which was previously used to stir oil & scrape gears past each other. They made
bold claims for aftermarket exhausts too, but then - who doesn't....
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mr loo
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| posted on 24/7/03 at 04:40 PM |
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Hi , Col
Ian here ,steve's (dug's )mate.
I was at the food from hell bbq.
car's nearly finished,sva next
v-max sounds like a good bit of kit.
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