collapse

www.dimecitycycles.com


www.restocycle.com

www.CITYLIMITMOTO.com

www.jadusmotorcycleparts.com

www.bisonmotorsports.com

www.speedmotoco.com

www.cognitomoto.com

www.townmoto.com

www.sparckmoto.com

www.Moto-Madness.com

www.pistonsociety.com

GET DTT UPDATES ON FACEBOOK AND TWITTER

Author Topic: XS750 to XS896 big bore  (Read 14141 times)

Offline datadavid

  • Posts: 1038
Re: XS750 to XS896 big bore
« Reply #15 on: Jul 22, 2016, 06:27:30 »
Since i built mine from scrap im not really sure what bike my head came from, but the starter wont turn the engine unless hot so either the starter needs a good cleaning or i got very high comp!

Offline Ryan Stecken

  • DTT SUPPORTER
  • *
  • DTT BOTM WINNER
  • *
  • Posts: 1638
Re: XS750 to XS896 big bore
« Reply #16 on: Jul 22, 2016, 10:44:15 »
Hey guys!

sorry for hijacking your post but I shortly before buying two complete XS750 (stock bikes).
is there any way to check for the famous 2nd gear jumping without riding the bike?
both bikes won´t start cuz they were sitting for years,need carb cleaning et cetera...

if the second gear issue will arise is it hard to fix?i guess it means tearing the motor down to the gears....?

thanks in advance and sorry once again?

Offline datadavid

  • Posts: 1038
Re: XS750 to XS896 big bore
« Reply #17 on: Jul 22, 2016, 13:38:14 »
Hey guys!

sorry for hijacking your post but I shortly before buying two complete XS750 (stock bikes).
is there any way to check for the famous 2nd gear jumping without riding the bike?
both bikes won´t start cuz they were sitting for years,need carb cleaning et cetera...

if the second gear issue will arise is it hard to fix?i guess it means tearing the motor down to the gears....?

thanks in advance and sorry once again?
Its not hard to fix, go to yamaha-triples.org for a few different methods. Only way to see if it slips is under load unfortunately.

Offline Ryan Stecken

  • DTT SUPPORTER
  • *
  • DTT BOTM WINNER
  • *
  • Posts: 1638
Re: XS750 to XS896 big bore
« Reply #18 on: Jul 22, 2016, 13:42:46 »
Thanks datadavid!
Youre xs project is awesome...

I guess I will need to look far better carbs too,got the mikunis 2's on it...but i heard that these suck hard.


Offline XS750AU

  • Posts: 211
Re: XS750 to XS896 big bore
« Reply #20 on: Jul 23, 2016, 08:24:47 »
Hi Dave
Starter are a world of their own!! On my 750 the electric turns it over easily when cold, but when hot not a chance, have to kick it!

Ryan - the 2nd gear on my 750 started popping out so that was the final straw which made me rebuild the engine. Turned out the only problem with second was that the PO had used an old circlip and had put the radius edge facing out. So the gear had pushed the circlip out of its seat and down the shaft so the gear could not engage properly!! So try to get the end cover off and have a look, there are some other fixes you can do once you get the cover off. Check out the triples site.
Mikuni series 2 carbies are not too bad, easy to get jets and parts. Once I got new mounting rubbers and throttle spindle seals they are working beautifully on the 750. Cleaning and seals are much cheaper than any alternative carbies.

Today was in the bush on the Husaberg FE550, that bike really does go. Almost as much Hp(62) as the XS and weighs less than than half @ 105. So no progress on the 896 build this weekend!!
Cheers
Tim

Offline datadavid

  • Posts: 1038
Re: XS750 to XS896 big bore
« Reply #21 on: Jul 23, 2016, 09:59:14 »
Hi Dave
Starter are a world of their own!! On my 750 the electric turns it over easily when cold, but when hot not a chance, have to kick it!

Ryan - the 2nd gear on my 750 started popping out so that was the final straw which made me rebuild the engine. Turned out the only problem with second was that the PO had used an old circlip and had put the radius edge facing out. So the gear had pushed the circlip out of its seat and down the shaft so the gear could not engage properly!! So try to get the end cover off and have a look, there are some other fixes you can do once you get the cover off. Check out the triples site.
Mikuni series 2 carbies are not too bad, easy to get jets and parts. Once I got new mounting rubbers and throttle spindle seals they are working beautifully on the 750. Cleaning and seals are much cheaper than any alternative carbies.

Today was in the bush on the Husaberg FE550, that bike really does go. Almost as much Hp(62) as the XS and weighs less than than half @ 105. So no progress on the 896 build this weekend!!
Cheers
Tim
Mine wont turn when cold, but will start the bike when hot! Had the same thing on the last one, starter just needed a good cleaning..

Offline XS750AU

  • Posts: 211
Re: XS750 to XS896 big bore
« Reply #22 on: Jul 31, 2016, 02:26:26 »
Productive day. Brought the engine back to my shed and stripped it down. As I said earlier the PO had started and thankfully lost interest, but he had left it open. The reason it would not turn over was due to the cam timing being completely out, causing a valve & piston clash  :o. No damage done  ;D. The crowns of the pistons had a layer of crud on them, but it had not gone beyond the compression ring. What is clear is that this engine has not done much work, if you look on the cylinder you can still see the original hone marks ;D ;D ;D.
It took about an hour to pull it down and four hours cleaning. The original owner had bought it for speedway and there was plenty of dirt built up on the outside to get off. I used a wire brush by hand so as no to ruin the silver engine paint. Not all perfect though as there was a thin layer of gunk in the bottom of the sump, and the carbies had some dusty build up in them. I guess the original owner did not have a great air cleaner for his speedway racing. The carbies must have blocked up before he did any internal damage to the engine.
The head on this engine is definitely the high compression version. Have a look at the photo and you can see the complicated machining to create 2 dome areas. I could not save the base gasket off the 750 cylinders so I need to get another one before reassembly the 896 so I can lower the compression a little from the 11.4 calculated.
Quick video of Saturdays work

Photos of bits - the gudgeon  pins in the pistons look like they have been hot especially the centre one.

Offline datadavid

  • Posts: 1038
Re: XS750 to XS896 big bore
« Reply #23 on: Aug 01, 2016, 03:58:52 »
Mine runs just fine with big bore and hi comp 😊 glad me and the machinist decided not to skim the cylinders at all! It will run like hell even on standard pump gas, only problem is starter engine cant turn it anymore 😆 not too hard to kick though.

Offline datadavid

  • Posts: 1038
Re: XS750 to XS896 big bore
« Reply #24 on: Aug 01, 2016, 04:09:31 »


Thanks datadavid!
Youre xs project is awesome...

I guess I will need to look far better carbs too,got the mikunis 2's on it...but i heard that these suck hard.

Thank You! :) The mikunis dont suck at all, they are just old. And if they have been sitting chances are all seals have been dry rotted. If they are low mileage carbs with no mechanical damage or wear they are well worth repairing. Mine were not! Triumph carbs were just the cheapest option + its nice when you calibrate them and they Stay calibrated! :D

Offline Ryan Stecken

  • DTT SUPPORTER
  • *
  • DTT BOTM WINNER
  • *
  • Posts: 1638
Re: XS750 to XS896 big bore
« Reply #25 on: Aug 01, 2016, 07:22:42 »

Thank You! :) The mikunis dont suck at all, they are just old. And if they have been sitting chances are all seals have been dry rotted. If they are low mileage carbs with no mechanical damage or wear they are well worth repairing. Mine were not! Triumph carbs were just the cheapest option + its nice when you calibrate them and they Stay calibrated! :D

Lets see what they do when I mount them on the old bastard :-) may i ask you what type of triumph carbs you installed (searched for t900 carbs but they are all 4 cylinder banks...)

thanks!

Offline datadavid

  • Posts: 1038
Re: XS750 to XS896 big bore
« Reply #26 on: Aug 01, 2016, 07:23:35 »
Yes first gen new triumphs were all fours. Look for trident, legend or thunderbird carbs.
Preferrably not the first mikuni carbs as they wore out needles and needle jets. Keihins are superior. You can achieve stoichiometric mix across the range, they burn so clean you can run catalytic converters on these bikes..
« Last Edit: Aug 01, 2016, 07:25:21 by datadavid »

Offline Ryan Stecken

  • DTT SUPPORTER
  • *
  • DTT BOTM WINNER
  • *
  • Posts: 1638
Re: XS750 to XS896 big bore
« Reply #27 on: Aug 01, 2016, 07:25:23 »
Yes first gen new triumphs were all fours. Look for trident, legend or thunderbird carbs.

thank you!are there any 3 cylinder flatslides models :-)?

Offline datadavid

  • Posts: 1038
Re: XS750 to XS896 big bore
« Reply #28 on: Aug 01, 2016, 07:29:09 »
thank you!are there any 3 cylinder flatslides models :-)?
My slides are flat! But I guess you mean proper mechanical flatslides? Nope, dont think so. It would probably cost you as much to get three of those as if you would install a daytona Fuel injection, not to mention installing and tuning ☺

Offline XS750AU

  • Posts: 211
Re: XS750 to XS896 big bore
« Reply #29 on: Aug 05, 2016, 09:01:47 »
Beautiful morning today, so I took the XS750 to work. Great start to the day, I love that exhaust note, jetting seems pretty close, no coughs, flat spots or backfires!



It is pushing a bit of oil out of the case breather - any ideas anyone?

Was planning to valve stem seals and lap the valves this weekend on the 896 but I might have to look at the breather issue on the 750. Going in the "Distinguished Gentlemen's ride" in September so better off fixing it now.
Cheers Tim