GT750 SRIS tube placement

GTrida4life · Post by **GTrida4life** » Mon Aug 20, 2018 12:49 pm

Hello GT family, my GT750 was smoking from the right cylinder (right exhaust) so I checked the placement of the SRIS tubes to be sure they were in the correct position. I found that the R and L were in the wrong place so I switched them. Now I'm getting smoke from the middle cylinder (center exhaust). Can someone tell me what is going on

tz375 · Post by **tz375** » Tue Aug 21, 2018 9:20 am

Which crankcase is connected to the center cylinder that was previously connected to the Right cylinder? That's the one with leaking crank seal or weepy oil feed check valves.

Indy650 · Post by **Indy650** » Wed Aug 22, 2018 4:39 pm

here are some pictures of the two different styles of SRIS the 750's had. If its hooked up correctly than it could be the seals between the center and right hand cylinder as that is the only area that is lubricated by crankcase oil.

karl pa · Post by **karl pa** » Wed Aug 22, 2018 5:52 pm

Indy650 wrote: it could be the seals between the center and right hand cylinder as that is the only area that is lubricated by crankcase oil.

Actually, all 3 cylinders on a 750 can pull transmission oil through crank seals, center and right cylinders have the primary gear between them, the starter clutch is on the left side and can pull oil into left cylinder.

When you say it is smoking, is it a heavy cloud, have you gave it a good run, sometimes you just need to wind it up to stir up the 2 stroke oil that is pooling in the bottom of crankcase.
If it is crank seal issue, it will lower your transmission oil level.

GTrida4life · Post by **GTrida4life** » Wed Aug 22, 2018 8:05 pm

Yes l gave it a good 80 mph run on I24 and it was blowing a white smoke screen down the interstate. I’m having to add gear oil on a regular basis. Is there a way to drain the gear oil and replace with fresh oil?

Indy650 · Post by **Indy650** » Wed Aug 22, 2018 11:03 pm

Karl, yes I didn't mention it because if that was the case it would be smoking out the left cylinder from the start. but yes you are right.
GTRida if your going through gear oil and its pouring white smoke than you have no choice but to do a complete engine teardown and rebuild the crank and replace the seals.

karl pa · Post by **karl pa** » Thu Aug 23, 2018 4:23 am

Indy650 wrote:
Post subject: Re: GT750 SRIS tube placement
Karl, yes I didn't mention it because if that was the case it would be smoking out the left cylinder from the start.

Not sure I follow you on that, If the left cylinder is the one pulling gear oil, and the SRIS tubes are transferring the oil to center or right cylinder. He said in his first post that the right cylinder was smoking, he switched the SRIS tubes, now the center cylinder is the one smoking, We dont know witch crankcase SRIS is the one transferring oil , so all 3 cylinders must be questioned.
Does sound like crank rebuild. There are ways to soften seals if they are not cracked.

GTrida4life · Post by **GTrida4life** » Thu Aug 23, 2018 7:53 am

Thanks guys even After switching the SRIS tubes the bike is still smoking from the right cylinder I think it’s time for a crank rebuild

tz375 · Post by **tz375** » Thu Aug 23, 2018 10:41 am

73 has the old style crank and old style oil seal which can get displaced and cause a leak. Best fix is to strip the motor and send teh crank to Bill Bune in MN and have him fit new seals

GTrida4life · Post by **GTrida4life** » Thu Aug 23, 2018 9:54 pm

Thanks

GTrida4life · Post by **GTrida4life** » Sun Aug 26, 2018 4:24 pm

Will a good smokeless 2-stroke oil make the smoking less obvious? What brand or type do you guys suggest?

karl pa · Post by **karl pa** » Sun Aug 26, 2018 5:28 pm

GTrida4life wrote:Will a good smokeless 2-stroke oil make the smoking less obvious?

The smoke is coming from the gear oil burning, 2 stroke oil won't make much of a difference I'm afraid.
On my T250 with leaking crank seals, I put some blue devil pour and go seal repair in the transmission oil, my seals were hard from setting for years. Since doing this I haven't had to add gear oil and smokes much less, might be worth a try, if they are cracked or out of position crank rebuild might be the only answer.

GTrida4life · Post by **GTrida4life** » Sun Aug 26, 2018 8:03 pm

Perhaps I should give blue devil a try before I schedule the crank rebuild

GTrida4life · Post by **GTrida4life** » Fri Aug 31, 2018 7:49 am

Update, I was riding this week and a guy at the gas station said the smoke from my right cylinder was from a primary seal in my transmission that would not require the cases to be split just remove the clutch cover and basket. He said the bike runs too good to be crank seals. Does this sound true? I have not seen anything on this forum that points to a seal other than crank seals that would allow gear oil to be burning. Please advise....... thanks.

karl pa · Post by **karl pa** » Fri Aug 31, 2018 3:04 pm

GTrida4life wrote:a primary seal in my transmission

The primary gear is between the center and right cylinder, it has crank seals preventing gear oil from entering center and right cylinders. There is no way to replace the seals in issue without pulling crank out. There is no seal to change behind clutch.

GTrida4life wrote: He said the bike runs too good to be crank seals.

Bikes with leaking crank seals can run fine but smoke.