860 Big Bore, questions, insight

[SWEETXPBEATCH]

So,
I pulled the triggor, Had a combo of SHR's Cylinders/piston, CPI's head mod, Rave spring mod, CPI's full pipe installed a week ago.
Here's my first weekend ride, insight, numbers, etc. Any experienced insight will be helpful.

Riding at 8000-8500'
490 Mains, .20 shimmed needle, stock air box
441 ramps, 175/355 primary spring, full oem pin (16.5gm's?)
08' (****E) Helix on stock belt, 154" sled, 21/45 gearing.

Pulled real hard mid range and <45 sec hill climbs. Significant improvement over stock sled.
Any pulls longer than 1 minute, I would drop from 8300 RPM's to 7500 RPMS. With letting off the throttle and re-engaging throttle, R's climbed quick. Thinking this is indicative that I am running too Rich on the top?

My immediate changes:
- swap out the 08' helix (fighting those F-ing bolts on the back of the helix)
- drop main jets 1-2 sizes and shim the needle .30 vs the .20 (occas flat spot in mid range during my ride)
- Pick up the Dalton Pin kit, need to add more pin weight (8330-8400 rpms on clicker #3)
- Dyno it, see actual numbers and optimal RPM for HP/Torque. CPI's traditional pipe optimal torque/hp is at 7700/7800 rpm's. Not entirely sure with this application though.
* Will post Dyno results when I get this dialed in.

Any insight from DaveB, FredW, DJ, SHR, appreciated.

 

[teamthunderf**ked]

have u installed the engine tech thermostate if your motor gets to hot in a climb because the stock little plastic therm cant keep up your ecm will retard the timing and u will loose 5or 6 hundred rpm just something to try

 

[Red-eye]

Are sure you never had a flat spot on top too from being too lean? Did you do a plug check? Too many changes make it real hard to tell where the problem is, You could fix one problem and have another and not know where to look. good luck.

 

[tube]

leave everything as-is, put the stock pipe back on then try again.

 

[Cracker]

X2 try the stock pipe, Don't ask just try it

 

[SWEETXPBEATCH]

Going try the stocker

X2 try the stock pipe, Don't ask just try it

I have had this thought as well. I know stock pipe makes good power and has been proven to be "safer". I have swapped out the helix, dropped down to 480 (stock) main jets and will try to get out tomorrow to test.

 

[800HMX]

You have SHR BB Kit. Give Big John a call. He is very knowledgeable and has helped many on here.

 

[SWEETXPBEATCH]

Exactly

You have SHR BB Kit. Give Big John a call. He is very knowledgeable and has helped many on here.

That's where I get the idea to drop 2 main jets. Just needed some convincing. Seemed a bit drastic. I have a lot of confidence in BJ, otherwise i wouldn't have had the BB done

 

[tube]

lots of variables, but when I ran my SHR860 i was running 440-450 mains, so i dont think thats a drastic change, again, try stock pipe, but if possible, do one change at a time.

 

[SWEETXPBEATCH]

WOW! 440's?

lots of variables, but when I ran my SHR860 i was running 440-450 mains, so i dont think thats a drastic change, again, try stock pipe, but if possible, do one change at a time.

What elevation are you running? Again, the majority of the changes I am doing/did were clutching which is fairly well known recipe to start with.
The jetting is what I was more concerned about. The plugs last week were a strong Coffee brown plus the drop in R's with a long hill climb and rapid response of R's with getting off the throttle and then re-engaging.
Thanks for the help

 

[pfi572]

That's where I get the idea to drop 2 main jets. Just needed some convincing. Seemed a bit drastic. I have a lot of confidence in BJ, otherwise i wouldn't have had the BB done

I ran a RKT 860 with boysen reeds,pods,dyno port y and pipe with 14/1 head.
Boysen reeds run alittle richer than stock.
Ran 2 gallons 110 per tank with 2007 needles in middle postion and 480's this time of the year due to colder temps and then dropped to 470's in the spring and not one problem.
Have the top end in a box as sold sled and new one came with 880. The pistons look great and the wash shows that it could have went down to 460's.
Keeping top end until I ride the 880 for abit to see what it makes for power and the difference between the two.

Just my findings.

 

[Idaho Slim]

leave everything as-is, put the stock pipe back on then try again.

Smartest comment on this thread.

 

[SWEETXPBEATCH]

I think FredW is running something similar?

I ran a RKT 860 with boysen reeds,pods,dyno port y and pipe with 14/1 head.
Boysen reeds run alittle richer than stock.
Ran 2 gallons 110 per tank with 2007 needles in middle postion and 480's this time of the year due to colder temps and then dropped to 470's in the spring and not one problem.
Have the top end in a box as sold sled and new one came with 880. The pistons look great and the wash shows that it could have went down to 460's.
Keeping top end until I ride the 880 for abit to see what it makes for power and the difference between the two.

Just my findings.

FredW has also been a good resource with some "practical" experience with BB's. Thanks for the addl input. From what I have read here and another forum, I am close considering I don't have one particular Motor Builders entire Kit. Again, doing something of my own. I am going to bring that stock pipe and drive up to elevation and do some runs once she's warm. I like the 441's from the 09' and that primary spring has worked well with last years motor work. Thinking I will be north of 16.5gms pin weight once I get the fuel ratios maximized. Keep those interested, updated with findings.

 

[pfi572]

FredW has also been a good resource with some "practical" experience with BB's. Thanks for the addl input. From what I have read here and another forum, I am close considering I don't have one particular Motor Builders entire Kit. Again, doing something of my own. I am going to bring that stock pipe and drive up to elevation and do some runs once she's warm. I like the 441's from the 09' and that primary spring has worked well with last years motor work. Thinking I will be north of 16.5gms pin weight once I get the fuel ratios maximized. Keep those interested, updated with findings.

I would like to help with the cluching but i run complete different clutchs and different gearing.
2.52 gearing and race primary with paragon secondary. 9.9 pin weight, 100/260 spring and 55/53helix with very light secondary spring.

 

[Dynamo^Joe]

I would like to help with the cluching but i run complete different clutchs and different gearing.
2.52 gearing and race primary with paragon secondary. 9.9 pin weight, 100/260 spring and 55/53helix with very light secondary spring.

I must say your paragon is one amazing clutch. Cannot believe how a clutch can run so low of temperature and run hard in front of that 174.
Goooooood stuff!!!!

 

[pfi572]

I must say your paragon is one amazing clutch. Cannot believe how a clutch can run so low of temperature and run hard in front of that 174.
Goooooood stuff!!!!

Thanks Joey wish you could come and visit again. You and your better half have a good holiday season.
Say hi to Rocket Rod.

Merry Christmas