Finally got back to working on my Buffalo after a 10 month delay. Last night I reinstalled the pistons and block. Not an easy task without help. I was proud of myself for devising a plan that involved suspending the block using tie down straps hooked to an overhead beam. :) Next up is to determine which of the 3 heads I have available to use and bolt it in place. My goal is to have it running by the end of the month. We'll see.
Very cool! I want one lol.
Hi Willie- so this job can be done without taking motor off frame? I've got to do the same thing and Allen Wood is going to help me as he has a homemade cylinder puller. It seized on me last May at Deal's Gap by sludge in oil tank causing a major restriction in the oil line leading to left cylinder.
I may email you offline with a few questions on the repair.
looks great :olaf:
Willie,
That (early 72) barrel is absolutely the best looking of the lot and quite rare now. Looking good so far.
Evans,
Barrels can be removed and replaced in situ in a stock frame. I usually do that when I rebuild a motor because they are so heavy. You have to take your time lowering the block over the rings, but it's not too hard to do.
If you have to use a puller to remove the barrels, it's easier with the motor out of the frame. You can still strip off the clutch and alternator and side covers to reduce weight a little. A complete motor weighs around 180 pounds IIRC.
Thanks for the responses, especially the compliments. lol Kudos on spotting that it's a '72 block. ;) I consider myself extremely lucky to have been able to remove the block without a puller. Not easy by any means, but it did come apart.
Normally, I would have done this job with the engine out of the frame but I figured I'd make the most of having the forks off for rebuilding and installation of emulators and Progressive Suspension springs. I also wanted to lube the roller bearings in the steering head. Doing it solo was definitely a pita, and required me to use some positions normally associated with Yoga. I knew that supporting the block while making sure the rings were properly located was the hard part. The tie downs made it all possible.
Fwiw, the reason I had to pull the top end was that it had rusted together from setting too long without being turned over. This was the 1st time I'd ever had this happen and came as a real surprise since the bike was in a normally closed garage. Also, it happened in less than 2 months time. I figure condensation from warm and cold cycles was to blame. Still, 2 months?! Wtf!
Also, to make the most of this post and for anyone interested, since I had to clean up the bores anyway, I decided to get the block Nicasil plated, my 1st experience with having this done.
Finally, and excuse me if I've posted a pic of my bike before but I thought I'd attach one for anyone who hasn't seen it. Amazing that I've owned it since '78.
Quote from: Striker1423 on January 06, 2022, 09:19:23 AM
Very cool! I want one lol.
Have had one under a bench for years now.
Originally was planning a cafe racer...but I have enough 2T troubles already.
Was going to turn it into an end table, but too lazy to strip it down.
Could be available if you want to travel to get it... probably crazy expensive to ship, weighs almost as much as some of my 250's.
Busa, I'd love to come and poke around under your work benches! :dawg:
Quote from: dgorms on January 06, 2022, 09:38:48 PM
Busa, I'd love to come and poke around under your work benches! :dawg:
If I'm home, the garage is always open to 2T addicts :thumbs:
Thought I'd post a pic of the head now that I've spent some time polishing the combustion chamber. I'm hoping to install it tomorrow.
That must be an aftermarket gasket. See how much larger the bore is compared to the combustion chamber and to the bore. The best head gaskets come form Cometic. Order one with 71mm bore.
The large bore gaskets tend to cause detonation.
http://pinkpossum.com/GT750/GT750head.htm for more info.
Quote from: teazer on January 09, 2022, 01:12:24 PM
That must be an aftermarket gasket. See how much larger the bore is compared to the combustion chamber and to the bore. The best head gaskets come form Cometic. Order one with 71mm bore.
The large bore gaskets tend to cause detonation.
http://pinkpossum.com/GT750/GT750head.htm for more info.
Richard,
Would the 71mm still be recommended for 1st overbore (0.5mm)? Thanks in advance!
Evans,
That is what I use for a 70.5mm bore. It leaves a little wriggle room to get it to fit all 3 bores.
Thanks for the heads up (pun intended), Richard. I was of the belief that the gasket I've got is OEM. I'll definitely look into one from Cometic.
A new issue has presented itself since I posted earlier today. It involves making a decision between which of 2 heads to use. Here's the deal.
The thermostat housing (cavity?) of the head shown above has been machined down to the point where the thermostat, if used, fits down into the bore and presses against the opening of the fitting directly below it. There is no recess to locate the thermostat and, as such, would essentially float in the bore, being pressed down by the thermostat cover/cap/housing. The other head has the OEM setup with regard to the thermostat. However, the combustion chambers have apparently been filled in (with weld) and reshaped to provide a traditional squish band.
I've attached 2 pics. One shows the underside of both heads for comparison. Please excuse the presence of the thermostat cover.
I would appreciate opinions regarding which head to go with.
The squish band head is certainly the better head as far as combustion chamber shape is concerned. You might want to measure the volume to figure out what exactly is going on there unless you already have that information from whoever did the work.
That's what I was thinking. As for measuring the volume of each head to see what's going on is concerned, I could do that too and report back with my findings. How close should they be?
What about the issue with the thermostat? Would you run without one?
The thermostat only serves to allow the engine to come to temp before opening and letting the radiator do its job.
I ran my old sled without one. But on those really crispy single digit mornings I'd have to let the sled warm up for almost 20 minutes before I could get on the throttle hard. Cold seizing being the biggest worry.
Same issue here. You would be heating the entire radiator contents before the motor would actually warm up. Can be done, but if the stat works, why bother?
It's not a matter of the thermostat working, its a matter of it being against the opening directly below it IF I went with that head. And, I'm aware that it'd take longer to warm up, at 1st. On a similar note, it's possible that the motor wouldn't really come up to the proper operating temp without the 'stat. Both valid concerns and, in a sense, an answer to the question I asked of savOr.
a restrictor is a good way to go as well.
The GT has an interesting cooling system design and the thermostat is specifically designed to close off the bypass hose when it opens the path to the radiator. You need that bypass hose and you need the thermostat.
Please measure the the combustion chambers in that squish head and let us know what you find. You could also measure the stock head for comparison.
Stock should be around 30cc +/-1cc and squish heads ought to be around 26cc IIRC.
I took another look at the relationship between the head gasket bores and the combustion chamber bores and have ruled out the milled head because of the vast difference between the 2 IDs. I appreciate Teazer's and Savor's comments which lead me to take a closer look. This leads me to choose the welded head with the squish bands. I've attached a pic showing the relationship between the gasket and combustion chamber OD on that one. Also, with regard to the head gasket. Its a Suzuki NOS item with an ID of 71.5.
Willie,
Thermostat and head volume pictures.