Looking for Twisted Crank info....

Motor Head wrote:

testarossa wrote: Just my opinion here, you didn't twist your crank. It is said that you need to be running a slick with a wheelie bar in order to do that.

I feel that your lack of compression lies in the head. If you installed new valve guides, then the seats should have been re-cut. The seat needs to be cut concentric to the guide and I don't think that lapping could correct that.

Try running a leak-down test to see where you are loosing the compression. That will tell you all you need to know.

This is what I agree with. You cannot replace valve guides and not cut your valve seats.
If you did your compression test correctly, throttle fully open and warm engine, then the throttle linkage should not be an issue. Do your leak down test, then if you pull the top off do the head correctly.

six862m6 wrote:

Motor Head wrote:

testarossa wrote: Just my opinion here, you didn't twist your crank. It is said that you need to be running a slick with a wheelie bar in order to do that.

I feel that your lack of compression lies in the head. If you installed new valve guides, then the seats should have been re-cut. The seat needs to be cut concentric to the guide and I don't think that lapping could correct that.

Try running a leak-down test to see where you are loosing the compression. That will tell you all you need to know.

This is what I agree with. You cannot replace valve guides and not cut your valve seats.
If you did your compression test correctly, throttle fully open and warm engine, then the throttle linkage should not be an issue. Do your leak down test, then if you pull the top off do the head correctly.

The valve seats were done as well at the time of rebuild. What is sketchy is that when I put the top end back together it was my first time doing this and I used the wrong timing marks on the cams and bent almost every valve in the head. Had another set of valves handy, cleaned them up, did a quick "hand lapping" on them using one of the hand lapping tools and compound, reinstalled them and figured out the correct timing marks before touching the thing again.

Throttle was fully open because I had the carbs removed when I did the compression test.

Love your avatar bike Cavanaughracing. It yours?

cavanaughracing wrote:

six862m6 wrote:

Motor Head wrote:

testarossa wrote: Just my opinion here, you didn't twist your crank. It is said that you need to be running a slick with a wheelie bar in order to do that.

I feel that your lack of compression lies in the head. If you installed new valve guides, then the seats should have been re-cut. The seat needs to be cut concentric to the guide and I don't think that lapping could correct that.

Try running a leak-down test to see where you are loosing the compression. That will tell you all you need to know.

This is what I agree with. You cannot replace valve guides and not cut your valve seats.
If you did your compression test correctly, throttle fully open and warm engine, then the throttle linkage should not be an issue. Do your leak down test, then if you pull the top off do the head correctly.

The valve seats were done as well at the time of rebuild. What is sketchy is that when I put the top end back together it was my first time doing this and I used the wrong timing marks on the cams and bent almost every valve in the head. Had another set of valves handy, cleaned them up, did a quick "hand lapping" on them using one of the hand lapping tools and compound, reinstalled them and figured out the correct timing marks before touching the thing again.

Throttle was fully open because I had the carbs removed when I did the compression test.

Love your avatar bike Cavanaughracing. It yours?

Yep... it's a 79 also

www.cavanaughracing.com/about.html

Did you check the carb synch adjusters?

six862m6 wrote:

cavanaughracing wrote:

six862m6 wrote:

Motor Head wrote:

testarossa wrote: Just my opinion here, you didn't twist your crank. It is said that you need to be running a slick with a wheelie bar in order to do that.

I feel that your lack of compression lies in the head. If you installed new valve guides, then the seats should have been re-cut. The seat needs to be cut concentric to the guide and I don't think that lapping could correct that.

Try running a leak-down test to see where you are loosing the compression. That will tell you all you need to know.

This is what I agree with. You cannot replace valve guides and not cut your valve seats.
If you did your compression test correctly, throttle fully open and warm engine, then the throttle linkage should not be an issue. Do your leak down test, then if you pull the top off do the head correctly.

The valve seats were done as well at the time of rebuild. What is sketchy is that when I put the top end back together it was my first time doing this and I used the wrong timing marks on the cams and bent almost every valve in the head. Had another set of valves handy, cleaned them up, did a quick "hand lapping" on them using one of the hand lapping tools and compound, reinstalled them and figured out the correct timing marks before touching the thing again.

Throttle was fully open because I had the carbs removed when I did the compression test.

Love your avatar bike Cavanaughracing. It yours?

Yep... it's a 79 also

www.cavanaughracing.com/about.html

Did you check the carb synch adjusters?

I thought it might be.

I haven't checked the adjusters yet, in fact I haven't messed with the bike at all yet. Tonight I'm going over to my friends house to help him with his. I'm actually going to be swapping the RSs that are on it for another set that I got that are nicer looking (almost new). Therefore, I will have a good working set of RS34s that will be for sale soon if anyone is interested....