Project X

Post here if you are doing anything different
Post Reply
madforitkev
Posts: 292
Joined: Tue Dec 13, 2016 7:21 pm
Location: Poole

Re: Project X

Post by madforitkev »

Burg, I've got fan and water pump speed control in the in the final electronics so its all about keeping the ideal temp and that should sort it.

Tonight I thought I would attack the throttle bodies.

Basically they dont fit but not by much.
tb3.jpg
using the centre as the reference, cylinder/body 3 needs to shift 12.1mm and cylinder/body 1 by 8.1mm.

Any ways a bit of head scratching later (they are not supposed to come apart you know!), I have a bag of bits!!
tb1.jpg
All fairly logical and basically I have a few spacers to make and one new extended butterfly rod and a couple of linkages. Not too bad really.

There is a tricky gearbox with the motor but i've managed to leave that alone. (Phew!)
tb2.jpg
I also need to make an adapter plate for the reed valve bodies to fit the Triumph rubbers then its a go!
Honest baby....this is probably the cheapest bike I have ever bought!!
teazer
Posts: 1035
Joined: Mon Mar 07, 2011 8:10 pm
Location: Chicago

Re: Project X

Post by teazer »

How much has the cranking compression risen from the first set of low compression inserts?
madforitkev
Posts: 292
Joined: Tue Dec 13, 2016 7:21 pm
Location: Poole

Re: Project X

Post by madforitkev »

I havent put a PSI gauge on it yet but going from 37cc to 27cc has to help.

My stock head measured at 30cc. So I am running about 10% compression up on stock.

Dyno next wednesday, so time will tell. Its definitely running lean again now so could do with bigger mains which is going in the right direction. :D
Honest baby....this is probably the cheapest bike I have ever bought!!
madforitkev
Posts: 292
Joined: Tue Dec 13, 2016 7:21 pm
Location: Poole

Re: Project X

Post by madforitkev »

Dyno disaster!!!

Well it was all going swimmingly well then one of the water jacket walls fractured near the barrel top face, head O ring lost tolerance and the water jacket pressurized from the cylinders running, it dumped a lot of water and over heated badly.

This pic show where one of the waterway walls just snapped off near the top
jacket 2.jpg
It was made weaker by the head O ring system. I copied it from a BDK TR750 100+bhp design so was hoping it would be OK.

The secondary issue caused by the overheating is head O rings blew on one other cylinder because chunks of metal seemed to come off of the outside of the barrel liner which changed the O ring groove tolerances.
jacket 1.jpg
Initially I though the liner was delaminating but a magnet told me it was Ali that was coming off!

Bottom line is the liners have a bevel on the outside edge at the top and I can only assume were cast in the cylinders. Having cut O ring grooves near to the liner outside diameters, it left a small triangle of aluminium which was stuck to the liner wall covering the bevel. With the extra heat this just delaminated.

Still the good news is I have found a week point and my liners are not delaminating :D

So now I am making stainless bevel rings as O ring backing rings to reset the groove dimensions. This should make it a lot more reliable. Also a bit of waterway welding where the walls are thin ....one step forwards.....

Teazer, I am now running about 160 psi compression
Honest baby....this is probably the cheapest bike I have ever bought!!
teazer
Posts: 1035
Joined: Mon Mar 07, 2011 8:10 pm
Location: Chicago

Re: Project X

Post by teazer »

Compression: Perfect

Water jacket O ring groove: not so much.
burgs
Posts: 70
Joined: Mon Feb 06, 2012 9:07 pm
Location: Hunter Valley NSW Australia

Re: Project X

Post by burgs »

Ouch, one step forward one back.
Looks like there is not much room there for an O-ring, a mm or so inboard may have just been OK, easy to say when looking at a photo, has any materiel been cut off the top face of the cylinder block?
Can you put O-ring grooves for the O-rings in the head inserts, instead of the cylinder block face?

I am sure you will sort it.

Regards
Burgs
madforitkev
Posts: 292
Joined: Tue Dec 13, 2016 7:21 pm
Location: Poole

Re: Project X

Post by madforitkev »

Burgs

Its so tight in there. I can't go any smaller on the O rings or they get a bit fragile. The backing ring will work and I can't believe the TR didnt have the same problem unless it did and they did a mod for the factory bike :o

Anyways she's at the welders now and i've started machining the rings. I'm kinda glad it happened. That's what testing/development is all about right?

I will get it back together and do some temperature controlling runs to get that stable first. Its a function of the water pump speed which at the moment is tunable via a potentiometer. The main computer (when fitted) does it in software.
Honest baby....this is probably the cheapest bike I have ever bought!!
User avatar
Alan H
Posts: 12104
Joined: Fri Aug 05, 2011 6:38 am
Location: Wombwell, Republic of South Yorkshire

Re: Project X

Post by Alan H »

I love these straightforward 5 minute jobs. I'm pleased I retired so I can't be sent to any more of 'em.....
Proof that four strokes are over complicated
teazer
Posts: 1035
Joined: Mon Mar 07, 2011 8:10 pm
Location: Chicago

Re: Project X

Post by teazer »

BDK have been machining blocks for O rings for a while now and should have the answers.

TR750 didn't use O rings did it? They used a head gasket and the same crappy head design as the street bikes. I have a head here with inserts and the O rings are in the inserts and not in the block.

TZ Yamahas had the cylinder bore O ring in the block and the outer O ring in the head but they were one piece alloy and didn't have a liner.

Polaris, ROtax and other snowmobiles also have the O rings in the block but again they don't have a liner. They all have plated bores. Maybe it's time to have the liners bored out and new alloy liners pressed in and have them plated. And go with larger transfer ports and reed cages at the same time. And if you go there, why not machine up some billet cases to take a GSXR1000 six speed transmission and change the crank spacing between #1 and #2 to allow for straight transfer ports instead on the twisted design.

Just sayin.......

Some years ago I had this crazy idea to do all of the above but fortunately I didn't have enough cash to start down that road. I have seen pictures of a H2 top end on a set of GT crankcases and had the idea that maybe a complete Polaris XCR800 or Arctic cat top end might be persuaded to rest on top of a set of GT crankcases, but there's just not enough space between 1 and 2. The crank would need to be spaced out and the cases would need to be widened. It's an easy path to 150-180 HP though.

It's not unusual to have detonation damage on a TZ and people used to press in a brass inserts to replace the mouse nibbling with solid metal, so that would work. For O rings, try and get some from a small bore watercraft or sled or large bore Banshee/CPI motor. They are very small cross section and do seal well.
Kettletimes3
Posts: 1620
Joined: Thu May 03, 2012 12:58 am
Location: Sunny Wales

Re: Project X

Post by Kettletimes3 »

The factory used steel head gaskets.
Post Reply