JBSracing Husaberg 750cc Bore/Stroker kit released.

JBSracing · Jul 8, 2005

As a few of you on this site know JBSracing have been working on a 750cc big-bore and stroker kit for the Husaberg 650 engine. The members of this site have been very helpful answering some of the questions I had at the beginning of the project. I feel it is right that this site be one of the first places to hear of the release of the finished kit.

We completed the kit about 8 weeks ago and have been conducting intensive testing ever since. The kit is designed for Supermoto and Sidecarcross and has been tested in both formats.

A very brief description, the kits contains:

105mm bore forged piston
86mm stroke billet 4340, balancer-less crank
Long connecting rod
New liner
Billet machined head packer
Gasket and all fittings

The kits requires no machining to fit; it is a bolt in conversion.

Please visit my website www.jbsracingpage.co.uk/index

Forgive the naff web address the usual address www.jbsracing.co.uk will be available Monday until then DNS problems prevent its use.

I will answer any questions on this site that you care to put to me. Please look at the site carefully first and read the FAQ, I will not be answering questions that are covered there.

If anyone has a private question please email me [email protected]

Thanks for the help. Look out for JBSracing equipped bikes at races in the very near future, we are testing with teams in Supermoto and Sidecar.

Ben
JBSracing

PowerCell · Jul 8, 2005

Hee-Hee... you said head packer... :lol: :lol: :lol:

But seriously, I'm lookin' for 3 things here:

1) Dale Lineaweaver - whatdayathink???

2) What about the torque curve?

3) Enough with the mystery, what's the cost? Is there a courtesy discount for your fans here at the UHS?

JBSracing · Jul 8, 2005

PowerCell said:
Hee-Hee... you said head packer... :lol: :lol: :lol:

But seriously, I'm lookin' for 3 things here:

1) Dale Lineaweaver - whatdayathink???

2) What about the torque curve?

3) Enough with the mystery, what's the cost? Is there a courtesy discount for your fans here at the UHS?

1) Yes, what do you think Dale?

2) The method I have so far used to measure performance, which relies on data logging does not give me a torque reading that is representative of what you would see on a dyno. Suffice it to say for now it has lots and lots of torque. I will be dyno'ing the engines both in the very free breathing Sidecar set up and in a Supermoto chassis with in the next 3-4 weeks. As soon as I have this data I will publish it, I expect the HP to be higher than the data logger derived readings by some way. The torque figuress are not really comparable directly.

Personally I am more interested in what a bike can do on the track than on the dyno, which is why I didn't rush an engine over there the minute it was done. I knew I'd get asked this though and I will publish a torque curve soon.

3) I am not going to publish prices here, but will send you my latest price list if you email me for it. There might be a discount if I had any fans but I'm sure I don't. If I'm wrong please send your adoring letters, perfume soaked notes and lip stick kissed photos ASAP.

Gix · Jul 8, 2005

Ben,

Can I ask which supermoto meets are you gonna be testing at. I really wouldn't mind seeing the machine in action myself, although I don't relish the thought of coming up against it

are the bigger valves and hi lift cam needed to make it work efficiently?
Any chance I can have a blat

JBSracing · Jul 8, 2005

Hope to test a bike at Anglesea on the 23rd July. I will not personally be there as Supermoto is not my game. If the bike is there I'm sure you wont miss it, it sounds very different than a 650, much less purr much more woof!

In answer to the valves question, this is a quote from the FAQ section of my website.

Do I need to run a different cam-shaft with the JBSracing 750cc kit?

No. We have run our test engines with stock 2003 cam-shafts and have seen excellent results. A performance cam or a low-acceleration cam-train saving cam will have similar effects to installing it in a 650.

Do I have to run bigger valves, can the JBSracing kit breath through the stock head?

No. We have run a stock 2003 head with 37mm inlet and 32mm exhaust valves. We anticipate that the 2005 head which has as stock 35mm and 30mm valves will also be workable, we are testing a 2005 head now.

There are answers there to all the other questions of this type Carb, Elects, Cam, Jetting, does it fit etc in the FAQ section.

http://www.jbsracingpage.co.uk/FAQ.htm

Ben
JBSracing

LINEAWEAVER · Jul 8, 2005

JBSracing said:
[1) Yes, what do you think Dale?

Hi Ben,
Based on our numerous correspondnece I have the utmost confidence in your 750 kit.

I would like to know what you finally decided upon regarding liner sealing.

Hope all is well otherwise.

Sincerely,
Dale

JBSracing · Jul 9, 2005

Hi Dale

Here is what I did with the sealing - You will notice from the photos that the liner reduces in diameter at the base. This is the diameter of the original liner, the un-supported wall of the JBSracing liner encroaches 2mm into the original water jacket space. The larger diameter is 2mm shorter in length than the machining in the cases so when installed it forms a circular box/square section doughnut fully closed on 3 sides and mostly closed on the front side 2mm x 2mm. I run a bead of RTV around the bottom of the larger diameter in the liner then push an OEM o-ring into the RTV. Then 4 more thin beads of RTV and sit the liner in. All this effects a very good seal that we have had no problems with at all. If you use the RTV that we recommend which has adhesive properties as well as sealing it has the advantage of preventing the liner ringing and giving strength to its thinnest part (2.5mm).

Hope that makes sense.

Best regards

Ben
JBSracing

Before anyone asks, encroaching 2mm into the water jacket has no adverse effects on the cooling. If you have a very large water jacket you have a lot of slow moving water in it so the cylinder has to heat up a large volume of water but has more time to do it. If you have a thinner water jacket you have less water in it at any one time but the water moves much faster so the cylinder has to heat up less water but has far less time to do it. We run a temperature probe on our engines the 650 was running at about 88-90 degrees C the 750 is running 2-3 degrees cooler on average.

LINEAWEAVER · Jul 9, 2005

Hi Ben,
Thank you for the reply.

As our sanctioning body limits single cylinder displacement to that of 500 (down from 600 in the late nineties) my personal experience regarding "large Displacement" singles is limited to that of the 680 Rotax.

As you stated, taking the left side crankshaft from the outer circumference to the main bearing edge via a 45 degree certainly will reduce crankshaft flex. I am however curious as to if you increased the big end pin diameter and / or interference fit to further reduce said flex? I do not recall seeing such mentioned under FAQ. Please excuse the oversight if indeed it was.

Kind Regards,
Dale

JBSracing · Jul 9, 2005

Hi Dale

I did not increase the pin diameter, I would have liked to but as this would have pushed the big-end OD up I couldn't. We have gone up 4mm on the stroke already so we are getting close to the cases. The pin is 32mm same as stock.

I did increase the interference, and increased the thickness of the drive side crank web by 4mm. I.e. left the inner face where it was and push the outer face 4mm closer to the case. This enabled the use of a longer pin with the obvious advantages that gives for stiffness coupled with a higher interference fit.

I did consider tacking with weld like Falicon and a number for others seem to do but I have never really liked the idea I always wonder if the heat will distort the hole and possibly stretch it and lessen the fit? I don't know if it does or could I have never had the time to investigate. And of course it is a bit of a pain in a race bike where the crank comes apart rather more often than usual. Suffice it say that with the 750 kit I have found methods mentioned so far very satisfactory without welding.

Regards

Ben

PowerCell · Jul 9, 2005

Hey Ben -

When fitting the kit onto a 2004-2005 650, how do you handle the carb clearance problem? Being that the intake manifold is cast into the head...

Have you tried scalloping the underside of the radiator for exhaust clearance, as opposed to relocating it?

Can the kit be applied to smaller bergs, like the 550 or 470?

Thanks ~ Ken

LINEAWEAVER · Jul 9, 2005

Hi Ben,
Once again thank you for a prompt and insightful response.

Given all the discussion of late regarding a Husaberg SM section:
If Brett Saunders and / or BMG are truly interested in making a SM showing stateside perhaps I will get the opportunity to build and tune a 750 Husaberg single.

Perhaps a three way venture?

Please keep me posted as to your progress.

Best Regards,
Dale

PowerCell · Jul 9, 2005

What's all this talk about an SM section???

I thought any discussion that Taffy was part of was a Sado-Masochistic section... :lol: :lol: :lol:

JBSracing · Jul 9, 2005

PowerCell said:
Hey Ben -

When fitting the kit onto a 2004-2005 650, how do you handle the carb clearance problem? Being that the intake manifold is cast into the head...

Have you tried scalloping the underside of the radiator for exhaust clearance, as opposed to relocating it?

Can the kit be applied to smaller bergs, like the 550 or 470?

Thanks ~ Ken

Ken

For fitting to a 2004-2005 you use a 470 inlet which has a slight curve in it. It is normally fitted with the curve up to raise the carb to align with the air boot. You just fit it up-side-down and it lowers the carb with the same effect.

This kit will not fit in a 550 or 470 engine due to their differing case heights. It would of course be possible to make a kit that fitted any of these. In fact with a few relatively simple modifications to the JBSracing liner you could fit the 105mm piston and liner in and either rebalance the crank or billet machine one. However..........

I am not a fashion follower so I would always advise some one to simply buy a bigger stock engine if one is available rather than spend money on modifying one.

Take for example the Honda TRX 250 quad I have seen barrel kits up to 510cc for it. Why not just fit one of the readily available 500cc 2-stroke engines from an open class solo, a CR 500 for instance. Chopping frame lugs etc is always much cheaper than working the internals of the engine which are precision engineered components.

The only benefit I can see to one of the smaller cc Husaberg engines that I could offer is a billet machined balancer-less crank. You may perhaps even consider stroking an engine 2 or 3mm at that stage because it is no more work if you have gone to the trouble of billet machining the crank.

Regards

Ben
JBSracing

JBSracing · Jul 9, 2005

LINEAWEAVER said:
Given all the discussion of late regarding a Husaberg SM section:
If Brett Saunders and / or BMG are truly interested in making a SM showing stateside perhaps I will get the opportunity to build and tune a 750 Husaberg single.

Perhaps a three way venture?

If Brett Saunders and / or BMG want to put on a show and draw some attention to SM in the US the 750 would I think be quite the crowd puller.

As I mentioned before its sound is very unusual. As I am sure you have experienced, some times when you tune an engine you have no idea what it will sound like, and some engines have a unique sweet sound. The 750 has such a sound, the closest I have every heard to it is a well tuned Ducati twin strangly enough. Perhaps I put an extra piston in there when I built it by mistake.

I would like to see some dyno results for a 750 tuned by yourself, I sure you could persuade a few extra BHP out it.

Best regards

Ben
JBSracing

LINEAWEAVER · Jul 9, 2005

JBSracing said:
I would like to see some dyno results for a 750 tuned by yourself, I sure you could persuade a few extra BHP out it.

Best regards

Ben
JBSracing

Thank you for the vote of confidence. Perhaps someday we will have an opportunity to share a project.

As I believe both Brett and Jedi to be selective regarding which posts they decide to read I shall foreword Brett a link to this thread.

Sincerely,
Dale

JBSracing · Jul 9, 2005

Dale - Perhaps one day when the 750 has gained some footing we could try your FI system. If the FI throttle body offers better clearance (?) that would be an advantage is Sidecarcross, and we have plenty of room else were for ancillaries to be located unlike a solo.

As you know from previous communiques my aspirations capacity wise are not limited to what cam be squeezed into a set of Husaberg cases so there is scope for development there.

Best Regards

Ben
JBSracing

Gix · Jul 9, 2005

Bugger, can't make anglesey as I go on my hols the day before.... keep us updated about your outings..cheers

JBSracing · Jul 10, 2005

Well that serves you right for going on Holiday!

More seriously enjoy your hols, and I will indeed keep you posted as to future dates when the beast will be roaming.

Incidentally www.jbsracing.co.uk is now working, the naffness has subsided.

Ben
JBSracing

Jocke_D · Jul 10, 2005

Just wanted to send you my congratulations for pulling this one through :hello2: :notworthy:

I'm looking forward to hear more from the testing and also of course your success on the track.

PowerCell · Aug 10, 2005

Hey Ben! How are things going with your 750 kit? Have you seen any weeknesses, any success stories? Have you made any changes to the kit since your last post?

~ Ken

JBSracing Husaberg 750cc Bore/Stroker kit released.

Help Support Husaberg:

JBSracing

PowerCell

JBSracing

Gix

JBSracing

LINEAWEAVER

JBSracing

LINEAWEAVER

JBSracing

PowerCell

LINEAWEAVER

PowerCell

JBSracing

JBSracing

LINEAWEAVER

JBSracing

Gix

JBSracing

Jocke_D

PowerCell

Similar threads

Register CTA

Recent Discussions

Recent Discussions