a couple questions about problems..

[tribaltalon]

first problem is definitely the front forks, they're extremely soft, front end dives alot under braking.. i'm ordering some 4" over forks this next month so i'm going to be tearing the forks apart anyway. what am i going to need to get other then the forks? should i get some upgraded springs or do they come with it? i'm still not even sure what the forks from frank consist of, if they are just the top part or the entire assembly. if its just the top part, should i get some progressive springs or something, or would just taking it apart and putting new fork oil in it help? thats the first problem.

second, the tach jumps around alot, it seems like its slowly getting worse, is it just the tach, or what? its mainly around 4-5k rpm, it doesnt do it when i rev in neutral. i just want to figure this stuff out before i start really getting into mods.

third, the bike really seems to fall on its face after 6,000 rpm, it'll pull hard until 6 and then just completely falls on its face, i'm thinking this is the carbs needing to be rejetted. it still gets pretty good gas mileage though, light usually comes on around 100-110 miles, and thats averaging 70.

let me know what your thoughts are on this. i need to get my plan of action figured out before i blow all of my money on the chopper stuff and dont have any left for a while for making the bike run better.

[TopCatGr58]

Hey there ?DON?,
Sorry, short term memory not so good, and your PROFILE doesn't list your name, NOR the YEAR MAKE of your machine? I remember it being an 81SH....same as mine!!

The Forks are just the upper tubes, no springs, nada! I'm using my OEM springs with 4" PVC for spacers. Many folks praise the Progressive springs, Just get the set for your OEM model, and then use the 4" spacers! some slightly heavier wt fork oil might also help? These are AIR SHOCKS, and you can increase the preload with a little bit of AIR, which would reduce the dive, but may also make the front a bit harder, stiffer on bumps!?

First, CLEAN all of your electrical connections, the large charging plugs, cables, grounds, as well as the smaller wire bundle plugs! Many gremlins are chased away with this alone! The tach gets its signal from the charging circuit. Bouncing can be just vibration loss of connections, but could also be failing tach?

If your low fuel light is coming on around 100 miles, then you're getting average mileage, but only around 30-35mpg, not sure where you're getting the 70 from?
Just reviewed your photos, and you've got a nice 4-1 pipe, with stock airbox. The 81SH came with very lean jets, ~110s all across. You will probably want to go up at least 2 sizes to 115 with those pipes, IF the PO didn't rejet it already?! But what's funny is that when I put my 4-1 pipes on years before I did my big bore, it still easily pulled past 8.5k! And I didn't rejet for years, due to ignorance!!

Have you checked your air filter?? Also checked to make sure nothing is clogging/blocking the SNORKEL that comes out under the seat?

Have you checked the vacuum advance mechanism? The 81 doesn't have centrifugal advance, it's built into the TCI! You can check the timing, but can't adjust it!!

But yes, you are probably going to want to pull the carbs and give them a good going over.
T.C.

[tribaltalon]

sorry, i meant averaging 70 mph.. i get 100-110 miles to a tank before the light comes on averaging 70 mph. i think it could be alot better. i'll just have to tinker with it. i'm actually wanting to do away with the 4:1 exhaust and go with a custom exhaust with basically drag pipes with baffles in them to get more of a low rumble sound instead of the high pitched wail so should i rejet it even more accordingly?

next, so when i get the 4" over forks, i should go ahead and order some progressive springs and get some 4" inch spacers as well?

i'll probably go ahead and get individual filters as well when i do the exhaust, it'll clean up the bike a little and maybe give it a tad more performance.

i guess when i dissemble the bike to do the forks and the rest of the chopper conversion i'll pull the wiring too and clean the connections.. hopefully that'll clear up the electrical gremlins plaguing the tach.

[TopCatGr58]

Hey Don,

With Indy filters, and a more modified set of pipes, you'll want to get some richer main jets!! As for the mileage,you're getting about the right amount for the 81SH! You'll like the sound it makes when you put the INDY filters on!

Yes, for best performance, new progessive springs, and you can make your own spacers from PVC pipe! The new uppers will retain the Air Shock ability. Your lowers and upper caps will screw right on!

Hope you don't run out of $$ too quickly! Can't wait to see the photos when it's done!
T.C.

[chevy45412001]

jetting

with exhaust alone jetting isn't always needed.Did the bike pull above 6,500 before or is this a new ride?I'm not XSactly sure how the chart in this site came up with the number of jet sizes but stock my xj had112"s in it. Now i run 137.5"s thats 25 numbers up.Mine fell flat as you describe but only when i went to the 4 individual air filters.I just played with mine until i got the best et at the drag strip and left it there. i did make it to 155 mains but that was a no no.

[noeleo]

Originally posted by tribaltalon
i'm actually wanting to do away with the 4:1 exhaust and go with a custom exhaust with basically drag pipes with baffles in them to get more of a low rumble sound instead of the high pitched wail

Please contact me if you want to part with the 4 into 1 exhaust. I'm looking for one for my project...Thanks