XBR rebuild

[JOOLZ]

Well im well into the guts of the engine, its fully stripped down now. The crankcases have been cleaned and some new stainless steel studing put in to hold the oil pipes, the alternator cover has been rubbed down and polished as has the clutch cover, they took some serious work, started on the 800 emery to get the pitting out then on to 1000 then 1200 before I could get on to the liquid polish. The next items on the list are a new gearbox output bearing and seal and a new kick start seal, then I shall think about rebuilding the engine.

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[Dick Scratcher]

Hope you've used plenty of copper-grease on those stainless threads Joolz or they'll likely drag the corresponding threads out of the alloy(?) should you ever need to remove them..................Regards.........Dave.

[JOOLZ]

Dont worry im an experienced engine builder. Im making quite a few changes to the fasteners along the way so some stainless and titanium and a lot of aluminum nuts and bolts. I am aiming to get the bike weight down to 300 lbs or less, and the hp to over 55, that should make for a very exciting power to weight ratio ideal for the very twisty roads that I ride, im also making quite a few changes to the oiling to solve the cooling problems experienced by the rvfc engines including a large oil cooler and 80 / 20 methanol water injection system for a quick power boost but mainly to help cool it and stop any pinking.  picture is my ported and flowed head

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[tommy]

hi joolz good luck with your project i intend to do something similar with a xbr using a dominator motor weight down ..power up.are you planing any running gear mods?  tommy

[Dick Scratcher]

Sounds a pretty potent brew Joolz.............keep us informed !..........good luck with it !.

[JOOLZ]

hi joolz good luck with your project i intend to do something similar with a xbr using a dominator motor weight down ..power up.are you planing any running gear mods?  tommy

Hi Good luck with your xbr, Im mainly concentrating on the engine as the rest of the bike has already been heavily modified, mainly a frame respray and some cleaning, but I have to make a new battery box and I am having the fork legs shortened by 35 mm before they are rechromed  pic of new conrod

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[guest564]

If you are aiming for 55bhp at the rear wheel then thats a big incease over stock (around 32bhp), what tuning parts are you planning on using?

[JOOLZ]

Hi engine tuning parts include flowed head, 601cc high compression piston, special grind cam (will be sorted out in the new year) modified ignition timing, the 40mm amal carb  and the goldstar exhaust that I am already using also there will be some benefit from a tuned intake and exhaust length .. Im not sure of 55hp at the rear wheel I was basing my figures on engine hp, I have already tested my engine on my engine builders dyno software, I have used this before to build several other engines and the accuracy works out to be within 2% of actual dyno readings, the numbers im getting up are 55 hp @ 6900 rpm and 42 ftlbs @ 5700 rpm

[JOOLZ]

The top end is finished. I stripped down the top end and checked all the rocker sub rocker and valve guides specs, and I was pleased with the lack of wear from this 60,000 + mile engine. there was a heavy build up of carbon on the valves but a quick clean with the wire brush sorted that out, I gave the head a respray black this time.. I recut the valve seats fitted new valve oil seals and springs and reassembled. Im now waiting on a bearing for the mainshaft then I shall re assemble the bottom end

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[JOOLZ]

I have finished the engine cases all new bearings and seals, although I cleaned the cases I wasnt happy about the finish, so I am trying out some chrome paint, if I dont like the overall look I will tone it down a bit with an aluminum look paint. ( Word of caution to other xbr and probably xl xr owners there is no stop for the gearbox output shaft oil seal, dont push it in too deep)

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[Ian]

I used to use Zinc-Ox cold galvenizing paint which is very good but I have also used Simoniz Engine paint too. Both are pretty resliant if prepared properly.

HTH

Ian

[JOOLZ]

Thanks for the tip

[guest564]

Im not sure of 55hp at the rear wheel I was basing my figures on engine hp, I have already tested my engine on my engine builders dyno software, I have used this before to build several other engines and the accuracy works out to be within 2% of actual dyno readings, the numbers im getting up are 55 hp @ 6900 rpm and 42 ftlbs @ 5700 rpm

55bhp at the engine is quite feasible. I'll look forward to the results, I haven't seen many dyno runs from other people. How noisy do you like your bike? I found that as soon as you start silencing the bike you start loosing power. Running a Micron pipe I was topping out at 45bhp but compared to 53bhp with the extremely noisy HRC pipe but I gained a huge power boost in the midrange so on the road is was much faster 95% of the time.
I used to run the forks dropped through the yokes about 1", I'd like to hear some details on how you are shortening the forks.
I'm planning to build an extension this year, hopefully when thats finished I'll be able to get  started on rebuilding my XBR, meanwhile I'll look to your build for inspiration 

[JOOLZ]

My xbr has no silencer, I run an original goldstar exhaust which is basically a reverse cone mega, very free flowing, you can hear me for miles, however I have an extra baffle that I put up the tailpipe when I am going to be riding around town that gets it to an acceptable level. Shortening the forks is relatively easy, just lop off what you dont need from the tops and recut the internal threads, then shorten the tubes that fit on top of the fork springs to the corresponding length, or cut them longer for a harder suspension. Good luck with your extension its nice to have room to work. Im lucky Suzanne has allowed me to rebuild the xbr in the dining room ( plastic sheet down and some old carpet on top of that) as my shed has to be taken down to allow for the workmen to put a new sewage system in for a hew house thats being built at the bottom of our garden

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[JOOLZ]

I polished the clutch and alternator covers this week, they were in a right state, pitting and corrosion from the salt on the roads last winter, and some really deep (0.5 mm in some cases) scratches that were there there  from when I bought the bike. I started off with some 180 grit paper and rubbed the cases down all over to remove the deep scratches and pitting, then went on to the 500 grit and got rid of the scratches caused by the 180 paper, then on to the 1000, then the 1200 then finally I could get it on the polisher, I can now see reflections again, I have a little more polishing to do to get it to a full mirror finish but I have broken the back of that particular project thank goodness. I now have very sore fingers and aching arms.

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