GT750 Repair

[GTrida4life]

Hello my name is Ron and I live in Clarksville TN. If you live within 50 miles of me and saw a red streak blowing smoke that was me on my 73 GT750. I need a trustworthy mechanic with the "old school" knowledge that will pull my crank for shipping to BB for seal replacement....my right cylinder is smoking bad and I'm burning gear oil. Willing to travel 100+ miles if needed. Surely someone on this site needs a project Thanks.

[twittemann]

I just pulled my crankshaft and need to get it rebuilt. I'm in Richmond, VA. Does anyone have any advice?

[Dave Robbo]

Im lucky i've a real old school local mechanic who was fixing these when i was 20 and he sorts mine. I'm in England if you get stuck.

[tz375]

There are a few people around the US that can rebuild a crank. I have had several stripped and rebuilt by Bill Bune in Anoka MN and they are excellent.

I have also bought cranks or motors from people who claimed they were just rebuilt by someone local and they were all a disaster in one way or another.

Bill Bune is the go to man.

[Alan H]

I just pulled my crankshaft and need to get it rebuilt. I'm in Richmond, VA. Does anyone have any advice?

Yes. Introduce yourself and ask nicely, otherwise people will ignore your posts.

[GTrida4life]

News update GT family, I just completed a compression test on my GT750 and the reading on all cylinders is 120. Now waiting for leak down kit to check the condition of the bottom end.... fingers crossed please

[GTrida4life]

Hey gang, what is the best way to block the SRIS ports for the leak test? Building my own leak tool using youtube instructions

[GTrida4life]

Hey gang, what is the best way to block the SRIS ports for the leak test? Building my own leak tool using youtube instructions

[dollydog]

hi mate, the ones on the front of the engine are just normal m8 thread, so a m8 bolt with some ptfe round the threads should make a gas tight joint. when you take them out though, just make sure you haven't left any slivers of ptfe tape in the holes. i presume the ones on the back of the engine are the same? gt250 oil lines are only m6
cheers, dd.

[GTandcbr]

Just one word of warning don't pump more than 4 to 6 psi into the cylinder if you do you may tear the seals or displace them

[dorT500]

....... Building my own leak tool using youtube instructions

Cool. Got pics?

Here's an inexpensive intake/engine out of bike version I threw together years ago. Never got around to using it though. Never even taped up the threads or tested the nice low pressure gauge I bought in a small re-sale shop for $3.00 or $4.00 ....it looked brand new though. Just wound up storing the set up away.

Made an extra block off plate. They are 1/8" thick 304 stainless steel plate. Sheared them out of some scrap at a small manufacturing company I worked for at one time, then just trimmed some rubber membrane I got in the plumbing department of a Home Depot.

Schrader valve for a hand air pump.

Anyway, just something thrown together for the fun of it years back but never used.



I agree with member GTandcbr suggestion about not pumping more than 4 - 6 psi

Old rule of thumb is hold 6 psi for six minutes and 6 inches vacuum for six minutes but I could live with testing at 4 - 5 max.






As you probably know, this is the what a lot of people go at it with


MityVac. On this model....pressure or vacuum at the flip of a knob......
https://www.nationaltoolwarehouse.com/S ... Hand-Pump-" onclick="window.open(this.href);return false;"


Here is a great, serious, concise video on leak down testing.... pressure and vacuum. Same basic steps as would be done on our two stroke motorcycle engines.

https://www.youtube.com/watch?v=I5fQ4_jJP5Q" onclick="window.open(this.href);return false;"

[twittemann]

Hello. My name is Todd. Nice looking gauge.

[GTrida4life]

Leak tester looks good, you have given me some design ideas

[GTrida4life]

I need some help posting pics. of my Buffalo

[GTrida4life]

Change of plans, I bought a leak down tester on Amazon. Results of testing soon to be posted. Stay tuned......