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Poor Top speed virago 535


Walrus1#
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OK lads,having rebuilt the bike and fitted all new ignition from CDI,coils,leads, plugs and caps.I bought a set of used carbs as the originals were butchered (at least the mixture screws were stripped by someone using a far too small driver i suspect)and one of the slides had a hairline crack in it.I also bought a used stainless high flow exhaust and fitted that,along with high flow air filter.So after some advice from the internet I fitted an upgrade kit of stage one tuning jets.larger main and larger pilot and raised the needle a notch.Now the bike runs very rich and was very hesitant from standstill until I drilled some holes in the rear plate of the silencers.She now has improved response and is much nicer to ride, but still far too rich. I shall drop the needles back down a notch and see if that makes any real improvement should I need to. But my real gripe is that she struggles to pull over 70 in top gear. I am not a lightweight but even so she should pull more than that I'm sure.I have read that the 535 does not easily pull to its supposed top speed of 100mph but I would think that 90 would be achievable.Anyone any ideas as to what I should try next to get her running better on the top end.All input is appreciated

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The Virago 535 that I had would not do more than 55mph when I bought it - it felt like it was being throttled; pulling the carb tops revealed that the slides were sticking (symptomatic of carbs on their sides). Cleaning off the gunge and a liberal spray with something like WD40 fixed it and it would just about get to a ton.

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My boys does about 75 - 80 however his has been restricted to 40bhp (his restricted licence period is up, but he has never asked me to derestrict it, so I haven't bothered)

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My boys does about 75 - 80 however his has been restricted to 40bhp (his restricted licence period is up, but he has never asked me to derestrict it, so I haven't bothered)

Hi Jimmy they only put out 38BHP when built my friend,so it is not restricted!! I have cleaned and serviced the carbs as they were second hand jobs off E Bay . The exhaust was a problem at first but made some more holes to let it breathe and that was better,maybe needs the holes to be a bit bigger and have the needles dropped by a notch. If you rev it and hold your hand behind the exhaust it gets black .Mind you that is just after start up and running on choke for a few minutes but the rear of the silencers is now black and sooty where they were clean in the picture.It runs great and behaves well around town but try and get it above 70 and it just don't want to know.

Thanks for the suggestions boys I'll just have to keep ferreting away at it until I discover the trouble, or not !!! as the case may be. I'd be happy just to get it running a bit leaner as the consumption is poor at present. It is my second Bike as I also have a Honda VFR750 ,but love the relaxed riding position of the Yamaha around town and on short trips with guys who own smaller Bikes and cruisers themselves. I take the VFR out when I feel the need to scare myself a little.

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Well I was there when the guy put it on the dyno and it was showing either 44 or 47 (cant quite remember it was 3 yr ago) and watched as he fitted a restrictor kit, then continued to watch as the dyno showed 40bhp.....oh and just checked the manual and it states 45.5bhp (33.9kW)@7,500rpm, but hey I bow to you superior knowledge my friend

 

 

Edit// Further reading of the manual states that the maximum torque is 34.7lbf ft @ 6000rpm so maybe that what you're thinking about.....or maybe not

Edited by jimmy
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Well I was there when the guy put it on the dyno and it was showing either 44 or 47 (cant quite remember it was 3 yr ago) and watched as he fitted a restrictor kit, then continued to watch as the dyno showed 40bhp.....oh and just checked the manual and it states 45.5bhp (33.9kW)@7,500rpm, but hey I bow to you superior knowledge my friend

 

 

Edit// Further reading of the manual states that the maximum torque is 34.7lbf ft @ 6000rpm so maybe that what you're thinking about.....or maybe not

Ah could be Jimmy I was going by what I was told off a mechanic,and read it online too in the MCN road test review. They could be upped in power with free flowing and tuning to get over that though. But as you say the dyno does not lie. Just out of curiosity where are the washers placed to restrict it?? are they on the carb side or the exhaust side?? because I never checked for restrictor kit when I replaced standard exhaust nor when I fitted the carbs.This as you may have guessed could be part of the problem with this bike Cheers Dood !!!! On second thoughts the exhaust side was clear of restriction as I dug out the old seals and replaced with new ones.But I failed to check on the carb side as I simply removed the faulty ones and replaced them with the rebuilt items. Leaving the manifold rubbers in place. You know the more I think about It the more it could be that THAT! is the solution. I'll keep you posted many thanks Jimmy bud.

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The mechanic made up his own restrictor kit. It is on the carb at the throttle cable

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Crude but effective Tommy, it got him through his restricted licence. With it being a twin, it has the torque for overtaking. If he asks I'll do it

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Well just checked in My manual and also on line again and have come up with three different supposed bhp values.Manual states as Jimmy says 45.5 bhp @7.500rpm MCN review says 39bhp and Carole Nash site recons 44bhp is the max. Yet everyone sites MCN as the source of the information.Now I'm totally puzzled.How can we have three separate figures supposedly all from the same source????

Me ? I'm going with Jimmy as the only verified Dyno measurement. So I shall have to pull off the carbs again just to have a look behind the rubber inlet manifolds,but if no washer there I'll be just as stumped for an explanation.But It does seem likely that some form of restriction is in place as there is no other reason for the low top end and lack of revs.The over rich mixture can be put down to being set for a non restricted and free flowed system.Done with the ignorance of not knowing about the restriction. Which I would never have dreamed of after being told they only put out 39bhp and were restricted license friendly to begin with DOH!!!

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  • 2 weeks later...

OK so it seems that when these things get older the Diaphragms get age/work hardened and no longer work as they should.And I must admit that mine are very hard to the touch and feel like a plastic rather than a rubber. They do seem to be harder to bend and therefor are probably not opening up to the top end of their stroke. So after searching for reasonable priced new ones and having no luck plus the gasket set for the carbs is not cheap either (surprise surprise) I decided on doing a single carb conversion.This was sent for yesterday and will come from the States I shall of course detail the experience of fitting and tuning this set up.

BUT I have developed another problem in that the the battery is no longer getting charged from the motor.So I sent for a new rotor and started the strip down of the side cover.This was an easy task compared to some guys experiences,I must say. Using a selection of flat bladed drivers and help from a rubber mallet using the lugs molded into the cases the cover came away very cleanly I must say. So after time spent scraping away the old gasket and making sure the mating surfaces are flat I now am in a pickle again (yeah I know ) The three wires from the rotor are all the same colour (white) !!!! so my question is does it matter what position these wires end up in the block??? They all do the same job so I presume it does not matter BUT having been shot down and  burned in the past by making up my own connections and getting the sequence wrong I just have to ask if anyone on here knows ?? Please say it matters not one jot and make my life a little easier.

This little bike has now had everything on the ignition side of things  renewed apart from the ignition pick up sensor which is still in spec and works well. I did the coils and the plugs and leads and then the CDI unit ( wallet is still crying over that one ) and everything was working great, after the initial rebuild, the charging circuit was fine. all during the search to find the fault in the ignition circuit it was doing the job but shortly afterwards I started having problems with that too so broke out the multi meter and did the checks and bugger me if the rotor was not reading at all.

So now I have started the replacement of the rotor and find that the gaskets I have are for the wrong side case DOH!!So today I am at a halt

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Mark up the 3 white white wires at one end 1-2-3. Continuity check them at the connector end and then mark them up 1-2-3, just to be on the safe side

I dont actually think it matters, but that way your safe

http://www.electrexworld.co.uk/acatalog/Troubleshooting-3P-PMG-&-RR.pdf

http://www.electrosport.com/technical-resources/library/diagnosis/pdf/fault-finding-diagram.pdf

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You running problems (acceleration) sounds to me that your still running too rich, id say drop a size down on the main jets before forking out for a single carb conversion, if your running a 120 main jet try dropping to a 115, clean the spark plug and go for a ride, if its still running rich, bogging out and giving a black sooty plug drop another size. if how ever the plug turns white your now running lean and need a bigger size 116.5 etc.

It took me 5 attempts to get my 650 draggy to run properly after sticking straight through pipes on so in the end she had 120.5 main jets and adjustable pilots, ran a tad rich, spat flame on over run but still managed just over 105mph on a good thrashing day.

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Already sent for the kit ,but was considering going single carb anyhow as the low and mid range torque improves vastly , making the ride  a real pleasure. We have have some real nice minor roads up here and pootling around those makes life a joy to live.  Plus of course the mpg figure also improves along with it.

Thanks for the info though as it is good to know these things for future projects.

Just to say that the only problem I now have is that the top end is still poor and it IS running rich  but she responds well enough from standstill now that the silencers are a bit more free flowing, acceleration is good up to 70mph then she starts to struggle. So maybe yes drop back down the jets size and fiddle with needle position.

Soon as I get the rotor done and all checked I'll give it a try before the kit comes.

Cheers.

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  • 3 months later...

Not updated this for a while . weather too cold and wet and windy to be outside holding spanners lol.So not done the carb conversion yet.Did manage to drop the needles back down and fit the original main jets back in.Now not running as rich as it was but still not got any better regards top speed.So conclusion is that it IS restricted from inlet side. Have since been informed that correct restriction was with washers in front of inlets.Some guys have even still got owners packs with washers in as they were taken out by dealers who did the conversions back again as the need arose. I have not been able to contact the Lady who owned the bike previous to me as they have moved house.But it looks as if the bike was her ride during her restricted period and then sold on with the washers still in place.

I now have another query for you experts out there please. How do I go about fitting LED indicators  as the relay on these has about 9 pins and is very much larger than any I have seen for sale on the Bay etc. ??? I intend to do the conversion while I have the carbs off and the tank out of the way and have all work completed before getting back on the road.I have got LED bulbs for everything  but the indicators are the main problem now.Thanks in advance .

 

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You just need to get some in line resistors to slow down the blink rate if you can't find a LED resistor for the viggy. on my Draggy i got some 0.9ohm (i think it was that) resistors from work, soldered wire on each end and added a bullet connector, heat shrinked it all and put them on then plugged the LED indicator onto that and it worked fine untill i pulled them off again and just rode with no indicators at all.

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Magic!!!! I had wondered about those things after seeing them advertised for sale in the led lighting section. It is entirely possible I shall get a lot more riding done this year if we don't have a sudden change in weather again.Been lucky not to have had any snow and ice to contend with,so far this year. I can manage rain no bother that don't put me off too much ,but the ice and snow riding, I left that behind years ago when I was a young stud and a hard as nails hairy arsed biker.But now I only ride for pleasure and have no need to face arctic conditions anymore (thank feck).

By the way do I need one resistor per bulb ? I take it that I do :wacko:

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Yer one respistor per bulb, where the LED draw way less current than a normal bulb does if you just fit one resistor yout have three really fast indicators and one normal one haha.

Thankfully we haven't had any snow darn sarf for ages, don't really want it either haha.

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