1229 Gs upper rpm break up when warm or hot under load..

[1229 monster]

Hey guys this is my first gs 1980 1100 that has 1150 motor with the 1229 kit.. Details,I bought this bike used built with a 1229 kit on an 1150 base..Great start up, great response when reving at stand still ..great response when riding with lots of snap..How ever when I get into upper rpm's i get a wicked break up...Now this bike has a 93 GSXR tree and forks along with speedo and tach..My tach says about 7500 to 8 is where I get the problem then the tach goes kinda nuts jumping around..This problem seems more apprent when bike is in the normal temp range (cruising for 10+ min) .. I am a very well rounded auto mechanic and rode bikes my whole life but new to deep Diag. on this type bike.. Plug check looks good with a nice tan color with only #1 plug with a little black around the rim. Still looks to have fact. coils..Is it possible that I am experciecning a coil break up when warm at higher rpm ?.. I am not sure if this is the right secttion for the question I am asking as I am new to fourums and have not had time to read all guides or "stickys"..Thanks for any help or direction to right section for this question.. I have more detail if asked and will be happy to give out..

[blowerbike]

where you at?
many different things could cause your problems.
need more info.

[1229 monster]

......

I am in Mooresville N.C... Let me know what ya need to know and I will gladly spill out.. I just got this bike last Thursday.. Rides and cruises perfect at all temps.. only when wound up into upper R's do I get a Stutter or break up..I powered through the break up till my tach read 11.5 today and seemed to get a split second of smooth power slamming me back into the seat..Does not have points..

[blowerbike]

what carbs.
if vacuum carbs do they have jet kits.
what is the engine number above the clutch cover on the engine case.
factory or after market coils.
factory or after maket ignition.
pay no attention to the tach.........
are you sure it has a piston kit installed?
stock or after market cams?
cams degreed or not?
any information would be helpful.

[1229 monster]

what carbs. --mikuni sliders but not sure how to identify..they do have some exposed vac ports on sides and capped off ports on the insides..
if vacuum carbs do they have jet kits.--that I do not know..but can find out..
what is the engine number above the clutch cover on the engine case.-gs 110x-112195
factory or after market coils. --appear to be factory as they are faided and show lots of age...
factory or after maket ignition. --does not have points
pay no attention to the tach.........
are you sure it has a piston kit installed? --yes have paper work documenting work
stock or after market cams? --my info says no details about cams but bike has a nice lick at idle
cams degreed or not? --again not sure
any information would be helpful.

[blowerbike]

ok for starters...
your engine is an 1100 not an 1150..
this i know from the numbers you posted.
try to find out about the carbs..
a picture could help identify them but you would have to remove a top to see if they have adjustable needles.(if these are vacuum not mechanicals).
i assume your engine is black.
can you post the displacement of your cylinders(cast on the front lower of the cylinder).
this will let me know if you have an 1150 or 1100 cylinder.

[1229 monster]

They do have adjustable needles..
The lower part of motor is aluminum the cylinders and head are black..
1135 cm is cast on bottom of cylinder shifter side..


Have to head to the bed..But will check in the am for replies..will try to answer any qeuston ya have..I want to get my new toy to where I know it should be..Seems to run to well otherwise to be something major..lol I hope!

[blowerbike]

ok 1150 barrels.
80-82 engine cases.
1100 or 1150 head?
is there rectangle covers on each corner of the valve cover(4 total).
on the carbs..is there a rubber cup attached to the slide where the needle goes threw the center?
i'm just wondering if these are vacuum's or mechanicals.

[1229 monster]

Yes rectangle on valve cover.. 4 total
Needle goes through center with only a fiber like small washer under c-clip..but I only worked on the top of sliders adjusting the c-clip..did not pull them completely out..
Just looking at paper work and it says replace cyl w/1260 bigblock ? and replace head with 83 p+p head and replace crank w/1150 crank if this helps

[trippivot]

What octane fuel are you running?
I had the exact thing on a 11.5-1 engine exactly like you decsribed .. good rev - no load and light load. same same as you heavy load and heat. I was running 87 non ethanol unleaded in and the problem instantly went away when 110 sunoco was introduced into engine.

I lowered the compression with thicker head/base gaskets to 10 -1 and ran the 91 available here.

start with the simple things first

[trippivot]

just get some of the highest octane you can. first

If the rpm that you have the problem changes to a higher rpm with better gas ( step in the right direction) then you can also retard the timing 4 ~ 6 degrees and if that makes it better still you may not have to mechanically lower the compression for pump gas--- just tune into it ,( make the problem go so high in the rev range you never rev it that high.) cause how many times are you really going to rev it to 10K ??

if this is the case you have the option to spot weld on the ingition advancer to limit the full advance and still have 13 BTDC at idle and only 28~30 full

no one wants to run 8.00 a gallon gas on the street.

keep us posted on your progress.

[blowerbike]

i was trying to figure out what engine/displacement/head/cams/carbs ect...
its hard to believe people(sellers) on performance upgrades.
whether they straight out lie of whether the information they pass on to the new owner was a BS story from years prior.
his receipt says 1260 which won't happen unless it has new liners.
he was told it was a 1229 kit..
a person needs to know what they have so they can diagnose there problem correctly and make upgrades/tuning changes as per there actual engine combination.

[1229 monster]

My recipt says that a 1229 ring kit was purchased along with the 1260 big block..I need to photo copy the paper work and I alos have a few vids of my gs at the track racing a r1 raptor four wheeler we built..you can really here the break up on the bike in the vids..will tryo to post tonight..I am going to check the voltage all across the board,coils,etc. the carbs are mech. and I have the needle clips set 3 down from the top..I have been told I might be to rich but my plug check really dont support that..Like i said the bike is a monster up till 7 or 8k..just a random thought,since I am using a elctrical tach from a gsxr and it goes bonkers at the time of break up could it be interfering with my spark?..will try to post link to vids and paper work soon.....also I have been running 110 fuel in it since I got it and only back to 93 yesterday,no change in symptoms with fuel change...Thanks guys

[rapidray]

1229, call me at 714-356-7845 if you want to discuss this over the phone instead of going back & forth on the site. Blowerbike & I are friends & both do the same stuff & probably have about the same amount of time working on them. Well, he may have more time working on them as he is a couple of years OLDER than me!!! Ray.

[blowerbike]

1229, call me at 714-356-7845 if you want to discuss this over the phone instead of going back & forth on the site. Blowerbike & I are friends & both do the same stuff & probably have about the same amount of time working on them. Well, he may have more time working on them as he is a couple of years OLDER than me!!! Ray.

WTF MANG