Bonneville America Forums Forums Technical Forums Performance Mods Another big bore complete! With Video!

I finished up my big bore install this past weekend, but still haven't really been able to ride it more than a couple of blocks since it's been raining like hell here, I mean cats and dogs and the streets are flooded...I was worried about the garage flooding. Seriously.

I should be able to ride today though.

Here's a vid I shot last night with my Digital camera, it's a 904 Bonnie with ported/polished heads, bigger intake and exhaust valves, and Bub pipes:

Sweatmachine's 904 Bub video

good stuff, cant wait to hear the review after you get some good riding in

Frank

great to hear its done i have those same pipes on my 904 thruxton

Most friggin excellent!

You ought to get some pipes and open that thing up a bit.....<g> Sounds awesome!

now I think the head gasket is blown...going to inspect later...I was going 80 down the freeway and it just died and wouldn't start....there was a little oil on the cylinders near the head gasket...suck

That would suck. Check the obvious stuff first though. It just might be something else and I hope so!

Compression test should tell on that gasket.

Hope it isn't major. The thing sounded great in the vid.

thanks for the video, and hope all goes well. would love to see another vid later if you don't mind and also more of how she goes compared to etc thanks for sharing

sounds soooo sweet!

sweat,
So, what's the scoop? I thought I read on another forum that something bad happened? Fill us in.

Ouch!

Thanks Fill. I missed that.

yeah, it hurts bad.

I'm going to split the cases by this weekend. Hopefully there isn't any (fingers crossed!) internal damage.

Have you pulled the cam cover or head off yet to see if anything up top is damaged?

I'll keep my fingers crossed too!

I have pulled the cam cover, the cams are ok, and the idler/cam chain gear is ok. I pulled the shims/buckets and the tops of the valves are still there...In the position the cams were in the valves would have all been closed. Hopefully there was no piston to valve contact and all will be good. I can't see me getting off that easy, so I'm expecting a bent valve or 2, but you never know. I'll pull the head this week and find out.

Excellent and nice to see you took the pics and videos, just come back with report on how she handles and runs

Good luck on it Sweat. When we split jaymos I was expecting bad things, there were bad things, not as bad as anticipated though. The bottom end is not that big a deal either, just be sure you remove then replace all 8 of the head studs too. It is a lot easier to work upside down with the long studs removed. Be sure to realign the counter balancers as well, they have similar marks as the cam gears so it is nothing to worry about, and if you remove the crank, you should replace all the stupid little bearing shells too. And there are a boatload of different ones - white/blue/red. You need to look VERY close at the sides of the bearing washers to see this color - really hard to see, but they are all the same once you determine what color they are. You will also have to completely remove the counter balancers to get them aligned too, they can stay in when you remove the crank, but once the crank is out, you need to remove them so you can realign the since there is no way you will be able to prevent them from turning at that point. You should also be good with the transmission and not have to remove that either, just be sure everything is in neutral when you break it apart. Oh, and you will need to pull the bigazzed rotor on the electrical side which requires a special tool and to reinstall it you need a special tool. We used a big belt clamp to re-tighten the rotor when we reassembled it.
If you get in a puzzle, give em a shout, I've been in there and can splain most of it to ya if you have questions.
Cheers, I'll have a cold two or three for ya.

thanks Pat. I'm sure I'll have some questions. I'd rather be riding for sure, but this shizz is interesting and entertaining too.

Yea, entertaining, yea, that's what I thought as I was totally disassmebling Jaymo's motor on the floor all covered in oil with cold beer too far out of reach.
Also, you may need to get a REALLY big torx bit for the large motor cases, maybe. The manual says they are supposed to be 10mm heads, but Mike's were all huge torx. T-50 mine were.
And this is also where you will discover what all the little green and grey colors on the case bolts are for too. They are for the varied torque settings.

Do I have to remove the alternator/rotor to slip a new cam chain over the crank? I've heard it's a beotch to remove and the Triumph tool sucks. Here's a pic from Jojje's website, looks like I won't have to remove the big rotor, no?



What happenend with Jaymo's motor?

Unfortunately, yes, you must remove the alternator/rotor to get the friggin cases to come apart. And it is a real PITA. We took the motor down to the Triumph dealer to borrow their tools, but I actually broke the tool for removing the alt. Oops. It seems you can then just use a really big bolt that fits the threads, get it so it snugs up to the crank, then put a big wrench.handle on it and whack the handle really really hard with a big hammer to get it to break free initially. once it breaks free, it needs some oomph, but it will spin off then. Getting it back on is even harder since youy need to hold the motor down and apply about 6 zillion tons of torque. We waited until we had the motor back in the frame to attempt this part. That is when Ed (biker) came up with the band strap tool idea. Worked like a charm! And be sure to use a feeler gauge to gap the little magnetic sensor so you don't have to drain your new oil and do it. (Oops again)
Jaymo's bike? On the way to georgia last year his bike literally grenaded a piston inside when he ran out of oil. This was just after his big bore and we deduced that it wasn't broken in enough before hitting the slab at 90mph all day long. The rings didn't seat properly and oil then blew by the rings, eventually it ran out of oil, BANG! Dead on the side of the interstate at 9pm at Wytheville, Virginia. But on the bright side, Whytheville is a very nice little city with very friendly and helpful folk.
Lesson learned: ALWAYS check your oil level when you gas up. Had we done that, Jaymos would have just needed a new ring job and a gallof oil.

I've heard that Triumph rotor tool is no good, Bill Gately says to use the big bolt method.

Glad you got Jaymo's bike back together, makes mine seem like a cake walk.

any pictures of the process?

Frank

picture

A: are the counterbalancers
B: the crank gear that drives the counterbalancers
C: alternator rotor
D: Cam chain drive gear

The trick Jojje told me was that you can remove the crank without removing the alternator rotor by marking both the crank and the counterbalancer gears, then lifting the crank out the top. When you reassemble, you need about 10 hands to line it all back up, but it's still easier than pulling the rotor. The pain of it is that the crank has to go in straight, into the 2 counterbalaner gears and also the primary/clutch side. It took some doing, sweating, and swearing. My friend helped me, and we got it back in after about 15 tries and 10 minutes.