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Author Topic: 1983 XV500 Cafe Racer  (Read 34232 times)

Offline Karlloss

  • Posts: 193
Re: 1983 XV500 Cafe Racer
« Reply #165 on: May 21, 2017, 14:47:17 »





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Offline focusinprogress

  • Posts: 893
  • City Limit Moto:Parts-Service-Apparel (716)8038606
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Re: 1983 XV500 Cafe Racer
« Reply #166 on: May 22, 2017, 09:51:45 »
top yoke is coming along nicely.
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Offline japstar

  • Posts: 115
Re: 1983 XV500 Cafe Racer
« Reply #167 on: May 22, 2017, 18:23:43 »
Did you simply mount the top yoke on the rotary table with the center line of one of the clamping holes aligned with the rotary table?

Or did you drill them, and then finish with a reamer?
GPZ550 cafe racer http://www.dotheton.com/forum/index.php?topic=69514.0

It ain't about showing up on a bike that the loan officer at your bank, or your parent's inheritance bought for you. It's about skinning your knuckles, straining your back, developing some blisters on your hands, breathing varsol and paint fumes,taking measurements and making mistakes.
It's about standing back, after the dust settles, and being able to say when people ask, "I BUILT it!"

Offline Karlloss

  • Posts: 193
Re: 1983 XV500 Cafe Racer
« Reply #168 on: May 23, 2017, 06:25:44 »
I marked out the centres of the three bores, I used a machined insert for the bores and made a transfer punch. I then drilled the 3 holes and then bored them out using a boring head. I then used an arbor which has an 2MT taper that fits into the centre of the rotary table and is the 50mm of the bore in the yolk. I used the waste area of material to drill holes to secure to the table.


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Offline Karlloss

  • Posts: 193
Re: 1983 XV500 Cafe Racer
« Reply #170 on: May 24, 2017, 15:41:26 »
Thanks guys


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Offline Karlloss

  • Posts: 193
Re: 1983 XV500 Cafe Racer
« Reply #171 on: Jun 03, 2017, 14:26:51 »




Did a bit more machining today, had a couple mishaps, but managed to salvage it. I'm using a manual feed machine, which certainly takes time.


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Offline jagtmans

  • Posts: 7
Re: 1983 XV500 Cafe Racer
« Reply #172 on: Jun 10, 2017, 19:05:10 »
Hi Karlloss, impressive project! I've just purchased an XV500 myself which I'm going to rebuild to be a cafe racer. I've got a complete 2015 KTM Duke 200 front end (USD) which will go on the bike together with an 18" spoked wheel from a XV250. That hub goes right on the 15mm axle from the KTM and even takes the brake disc (got the radial brake system from that KTM too), which only needs a spacer. The wheel is in OK shape but I might have the hub spoked to a wider rim anyway, we'll see.

I was curious about the comment you gave on page 8, where you state that an XV535 spoked rear wheel is a direct fit on an XV500. Do you mean by that, that both the final drive and the drum brake have the same dimensions, and that the width of the rear hub is also the same as that of the standard cast 16" wheel of the XV500? So it's a bolt on solution to get a spoked rear wheel on the XV500?

Offline Karlloss

  • Posts: 193
1983 XV500 Cafe Racer
« Reply #173 on: Jun 11, 2017, 03:53:21 »
[quote author=jagtmans link=topic=44804.msg875503#msg875503 date=

I was curious about the comment you gave on page 8, where you state that an XV535 spoked rear wheel is a direct fit on an XV500. Do you mean by that, that both the final drive and the drum brake have the same dimensions, and that the width of the rear hub is also the same as that of the standard cast 16" wheel of the XV500? So it's a bolt on solution to get a spoked rear wheel on the XV500?
[/quote]


Hi Jagtmans, your KTM front end sounds like it's a better option than I've got. Are the KTM forks longer than the GSXR ones I have. The short forks are the main reason I went for the custom frame. I've seen professional builds which use the short forks on the original frame, but it looks like the front wheel will hit the exhaust as soon as the suspension compresses.

As for the XV535 wheel, the hub is a direct fit for the XV500. The final drive is an exact match, the hub is the same width, however the drum brake on the XV535 is bigger, I haven't measured it but I think it's about an inch bigger in diameter, hence I has to source a brake plate after I bought my wheel. Also the 535 wheel is a 15inch.
« Last Edit: Jun 11, 2017, 06:44:50 by Karlloss »

Offline jagtmans

  • Posts: 7
Re: 1983 XV500 Cafe Racer
« Reply #174 on: Jun 11, 2017, 18:41:21 »
What is the length of the GSXR fork? I've measured the KTM fork and the total length is about 76cm, of which the fork tubes are about 49cm in length. As you can see on the picture I have quite some space left above the wheel (even though the tire is not on yet), and as you can see on the second picture there is also some space left between the steering head and the triple trees, so with some spacers at the bottom of the stem I can lower it another 2cm.

I compressed the fork by putting is on the ground and putting my weight on, and managed to compress it about 5-6cm. The total travel is 150mm but that's also the length of the part of the fork legs sticking out, so it will never get that far. An estimated guess would say the fork never compresses more than about 8cm. That should keep the wheel clear of the engine/exhaust in my case I would say. But I still have to get a tire fitted, put the whole thing on the bike correctly, put it on it's wheels and test for real by putting serious weight on it. I'm thinking of using a set of tapered roller bearings instead of the standard ball bearings. The top of the steering head is 48mm so quite standard, but the bottom seems to measure 49mm, a bit odd. But I still have to measure that correctly.

Back to the drum brake. Could you measure it to see what it's size and the difference with the XV500 is? And do you know if it matches the size of another virago? We have a used parts shop around the corner here that has drum brakes of both a XV700/XV750 and an XV1100, as well as a number of drum brakes of an XVS650 Dragstar. If I know the size of the drum brake I can go there and measure. Of course, I still have to get a rear wheel too, but they seem available on ebay. I even found one online here in Holland but that's in as bad shape as the one you got and since I'm not sure yet about putting a new rim on I'm not too happy to buy one with a lot of rust.

Then another thing. I saw on your pictures that you still have the original carbs. Mine are in pretty bad shape. There was fuel in the oil sump and the diaphragms are shot, so they need quite some work (and expenses). Then I found this guy on ebay that get's good credits for delivering a 2 in 1 intake manifold with a new or refurbished 40mm carb tuned on and XV500/XV535 engine which is a bolt on solution. It should give the engine more grunt in the lower rev range, delivering both more torque and more horsepower at lower revs. This would make the bike nicer to ride in daily traffic because you're not forced to rev it all the time. Have you considered such a change to a single carb setup as well?

Offline Karlloss

  • Posts: 193
1983 XV500 Cafe Racer
« Reply #175 on: Jun 12, 2017, 04:31:36 »
I've measured the front fork, from spring cap to wheel spindle it's 73cm with the tube being 45cm. The forks are on the bike but I tried to extend them as best I could.  Here are a couple of pictures from professional builders, which were actually built after I started my project (guess it's quicker when it's your day job), look at the lack of clearance on the front wheel.





I'm not disrespecting others work but it looks dangerous to me.





Your forks are longer than the ones I have, but I'd keep an eye on engine to ground clearance.

As for the head bearings I've replaced mine with tapered bearings, both outer races are 48mm

All you need to do is get the inner race size to match your stem.

The XV535 rear drum is 9inches were I believe the XV500 is 8inches. I am sure the Dragstar650 rear wheel will fit, but you'd need to be sure yourself.







As for the twin carb conversation, this is something I am still considering, the difficulty is finding a quality inlet manifold and I wasn't sure what carb size to use. I'd be interested to see what you've found.




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« Last Edit: Jun 12, 2017, 04:33:30 by Karlloss »

Offline jagtmans

  • Posts: 7
Re: 1983 XV500 Cafe Racer
« Reply #176 on: Jun 12, 2017, 19:10:24 »
Thanks for measuring the drum brake, the XV500's indeed about 8 inch. Will measure the Dragstars at the parts shop.

I agree 100% with you that these projects look dangerous to ride... It doesn't help putting on such fat front tires either I guess. This one look a bit better though: http://www.bikeexif.com/yamaha-tr1-cafe-racer He used a Ducati fork and an 18" front wheel. He looks OK on clearance, even with the exhaust because it seems he hasn't done anything special to it so it 'runs down' right away from the cylinder.

I've lowered the fork by about 2cm as I would when using a spacer on the underside. I then put in the original 19" front wheel because that does have a tire on (see picture). this is a 90/90-19 which is slightly larger than a 100/80-18 that would go on. As you can see there's quite a bit of clearance and I tried compressing the fork as much as I could by putting weight on it (not slowly but really hammering it down) and it didn't hit the engine. I had about an inch left, for what it's worth 'measuring by sight' from the top ;)

An 18" tire would have even a bit more space because of it's smaller diameter, so I think I should be fine there. On engine ground clearance, that could partly be solved by putting in a longer rear shock, partly by riding style... It's not a race bike so the question is how far I will put it down in the corners in real life, then again, you don't want to be caught out by lack of clearance in the middle of a corner. But I think the engine ground clearance is ok for now, and I'm going to replace the rear shock anyway so putting in a longer one is an easy fix.

On the carb conversion. I found this guy (Robert) on ebay: http://www.ebay.ph/itm/virago-manifold-single-carburetor-2-into-1-intake-carb-400-535-500-v-star-650/302336121491 He says in the add that he will sell you a manifold WITH a healthy used carb for $395,-, which is not a bad deal in my opinion. I will send him an email to see what he recommends and what it would cost with a new carb instead of a used one. But he sends the carb and manifold tuned and ready for use on a XV500 and gets good reviews/credits both on ebay and on the viragotech forum where I found out about him. And this saves you the time looking for a suitable carb. He uses 40mm carbs by the way.

Offline Karlloss

  • Posts: 193
Re: 1983 XV500 Cafe Racer
« Reply #177 on: Jun 13, 2017, 06:30:53 »
Other XV models don't appear to have the frame/engine to wheel issues to the same extent as the 500 from what I can see.

As for the single carb manifold, I've looked at this supplier before, on another thread on Virago Tech or the Facebook Virago pages these manifolds were being criticised, and rightly so the weld on them is absolutely shit. I'd be embarrassed to sell a product of that poor quality and especially charging what he is. Look at the finish of the flange, it looks like a blind monkey with two left hands has been let lose with a hacksaw. Your choice, but I'd rather save my money or spend it on having someone weld up my own.

You can get brand new carbs of eBay at a reasonable price, yes they are Chinese but they are exact copies of Japanese products and they manage to run the Chinese bikes just fine. As for the manifold to have a couple of flanges made can be cheap then all you need is some aluminium 90 degree tube bends and have someone tig weld them.

Sorry to have a downer on the eBay manifold but I really think it would be a waste of hard earned money.



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Offline jagtmans

  • Posts: 7
Re: 1983 XV500 Cafe Racer
« Reply #178 on: Jun 19, 2017, 18:39:35 »
I thought about it and have come to the conclusion that I agree with your opinion on the welds on the manifold. So that's a no-go!

So now I will either make it myself or have someone weld two 90 degree aluminium tubes together. The tubes cost around € 30,- and welding shouldn't cost much more if I deliver them cut to size I suppose. Another thought I have is to make them myself by gluing the aluminium tubes together. Glue is supposed to be as strong as a weld and much easier to do yourself. Another thing I found that might be interesting is alutite (http://www.alutite.nl/). This stuff works like soldering but is almost as tough as a weld. It's something that supposedly comes from Sweden and is specially made to bond aluminium parts together. The youtube movie looks interesting anyway.

As for what carb to choose. I talked to a mechanic I know this weekend. He said that in principle any carb would work (they all mix fuel with air). Because the single carb needs to feed two cylinders you need more air than with stock. That can be accomplished by an aftermarket air filter, but using a bigger carb than stock besides that won't hurt either. That's probably why they all offer 40mm carbs with the conversion kits, as supposed to the stock 34mm carbs. That said, the guy from OneUp uses a 32mm Mikuni VM round slide carb and got his bike running by the looks of it. The only thing I know is that a smaller carb will produce a faster airflow which gives you "more" power at low revs and less at high revs. A 40mm carb is better at delivering more power at high revs but won't hurt the low rev performance either I guess.

Mikuni has VM carbs that are really simple. No things like accelerator pumps so less that can go wrong. But with those you have to be gentle on the throttle to prevent the engine from going lean on you. The TM (pumper) carbs have an accelerator pump that fixes this problem, as have the FCR from Keihin. The third option is of course a CV carb, but I wouldn't prefer one of those because they have a slight delay in throttle response and maintenance on them is more expensive if the diaphragm fails.

A shop in Germany sells new Mikuni VM36 (slightly larger than stock) for € 184,- and TM36 for € 255,-, both new. A Chinese carb for € 50,- or € 60,- would probably work too, but getting parts seems hard so you'll probably looking at buying a new one if a part fails. I've also seen reports of them being very hard to set up properly.

I myself am tempted now to buy a used Keihin FCR40. That's a pumper flat slide carb that has everything going for it, and it would cost me € 130,- including throttle cables and handle. Sound's like a bargain to me and parts are available. What do you think?

Offline Karlloss

  • Posts: 193
Re: 1983 XV500 Cafe Racer
« Reply #179 on: Jun 21, 2017, 11:42:39 »
Regarding the carb. This is something I've pondered over for a while. You are right in what you say about any carb working, as for size, remember it is only feeding one cylinder at a time on the 4stroke cycle, therefore I am thinking a 34mm might suffice. The only issue being that the intake strokes on the v-twin might be too close together to allow for a 34mm carb to supply enough mixture. I have noticed that a lot of Harley Davidsons run a single 40mm carb, and they have twice the engine size.

I have thought about a standard round or flat slide carb, but I agree the lack of a acceleration pump might be an issues. As for a CV carb, the standard ones (and on most 4 strokes) are CV, therefore I don't think a delay in throttle response would be an issue, especially on the XV engine.

My understanding was that the Chinese carbs are copies of the Japanese carbs, and the parts are interchangeable, but I don't know.

As for the glueing of the inlet manifold, I'm not sure if this is going to work, as it will have to be absolutely air tight and also the glue will need to be fuel resistant. I still think having two aluminium bends welded is the best option, for a few small tig welding runs it cannot be too expensive?

The second hand carb sounds ok, but how worn is it? Would a new Chinese carb be better? I don't know.


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